General Spark plug reading fiat stilo 1.6

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General Spark plug reading fiat stilo 1.6

Your 1.6 has a compression ratio of 10.5:1 so I’d expect it to make around 150PSI. Was the engine hot and did you have all the spark plugs out, or just the cylinder you were testing?
You also need to hold the throttle fully open when you crank it.

The main thing though is that the readings were more or less identical and within 10% of each other. It’s not indicating any serious issue with the piston rings or valve seats, anyway.

The wet test was only a marginal improvement.. which normally suggests that the rings are okay and the lost psi are down to the valve seats or guides.. but the reading is so close to the dry test that even a tiny rings issue would read higher on a wet test.

If your valve guide seals are leaking then that doesn’t show up on the compression test, since that just measures how gas tight the cylinder is when the valves are closed. Not a bad result though.

Ralf S.

Yes the car was warm. Not right up at operating temp but warm.just came back from a drive.

How does it look? Seems to be a sensor issue?

I read that carbon build up can make compression high.

Also we don't know maybe the additive sealed off now is showing us we have good compression?Should have test before though. But if it is so, then problem would go away if compression is the problem.

The lower than the rest cylinder was number 3 and number 3 once or twice kicked out a misfire detected code.

If it's not compression then I'm going to have a look at good quality o2 sensor.

She will have a low idle on start up in the morning and I noticed when she does that, my scan tool says, o2 sensor heater:incomplete. Not as a code. Just as info it gives you etc. Then she will after 30 seconds she will bump up her idle and smoothen off. When she does that, tool says,o2 sensor heater:complete.

Maybe o2 sensor is lazy? This is the old o2. The new one is reading steady-ish voltage downstream but ecu don't like it in upstream???
 
Number 3 sounds a bit suspicious. Have you tried swapping the plug (into number 2) and the coil (into number 4) to see whether the plug, coil or cylinder itself is the moody article?

I'd guess it could be misfiring because of what we think is an oil seal leak .. but it doesn't hurt to try moving the other items, to see whether the problem persists, or moves to another cylinder.

The old O2 sensor sounds like it's not operating at 100%. It sounds like the heater circuit is knackered, so don't waste any more time on it. I would replace it with a new, quality sensor.

The new sensor also seems to be not that great, since it upsets the ECU. Again, it's been useful to show where the problem is but it's not good enough. The ECU decides what to do with even a 0.1v variance, so if the sensor has too much internal resistance, it'll be giving the ECU no chance.

Until you swap the sensors for decent ones, anything else could be a red herring.. so start there and then see what else is still playing up. Sounds not tooooo far off now.


Ralf S.
 
Number 3 sounds a bit suspicious. Have you tried swapping the plug (into number 2) and the coil (into number 4) to see whether the plug, coil or cylinder itself is the moody article?

I'd guess it could be misfiring because of what we think is an oil seal leak .. but it doesn't hurt to try moving the other items, to see whether the problem persists, or moves to another cylinder.

The old O2 sensor sounds like it's not operating at 100%. It sounds like the heater circuit is knackered, so don't waste any more time on it. I would replace it with a new, quality sensor.

The new sensor also seems to be not that great, since it upsets the ECU. Again, it's been useful to show where the problem is but it's not good enough. The ECU decides what to do with even a 0.1v variance, so if the sensor has too much internal resistance, it'll be giving the ECU no chance.

Until you swap the sensors for decent ones, anything else could be a red herring.. so start there and then see what else is still playing up. Sounds not tooooo far off now.


Ralf S.

Hi

I havent got a misfire code for a while now. It only came once or twice and that was it. So I wouldn't be able to tell. I will still swop it however.

I'm also putting my money on the o2 sensor giving issues. The heater is supposed to do the exact opposite. Come on immediately to compensate for a cold engine and heat itself up.
Slow responding sensor could be issue. When I give her some rpm the sensor takes some time to respond. Never responds immediately ,at times doesn't even respond how it should.

Think a new sensor is what ill buy next.

Thank you
 
Number 3 sounds a bit suspicious. Have you tried swapping the plug (into number 2) and the coil (into number 4) to see whether the plug, coil or cylinder itself is the moody article?

I'd guess it could be misfiring because of what we think is an oil seal leak .. but it doesn't hurt to try moving the other items, to see whether the problem persists, or moves to another cylinder.

The old O2 sensor sounds like it's not operating at 100%. It sounds like the heater circuit is knackered, so don't waste any more time on it. I would replace it with a new, quality sensor.

The new sensor also seems to be not that great, since it upsets the ECU. Again, it's been useful to show where the problem is but it's not good enough. The ECU decides what to do with even a 0.1v variance, so if the sensor has too much internal resistance, it'll be giving the ECU no chance.

Until you swap the sensors for decent ones, anything else could be a red herring.. so start there and then see what else is still playing up. Sounds not tooooo far off now.


Ralf S.

Hi

So I done another compression test and got results of 220 , 220, 200, 220.cylinder 1 to 4.
Cylinder 3 I put some oil into it and it jumped to around 240 or higher.

Then when putting the plugs back in,I literally basically hand tightened plug on cylinder 4 and it snapped in the head??managed to get it out and had a spare plug luckily.
Went to fetch my partner after that and she drove pretty good actually.lets see if it gets fouled out by some oil??
 

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Number 3 sounds a bit suspicious. Have you tried swapping the plug (into number 2) and the coil (into number 4) to see whether the plug, coil or cylinder itself is the moody article?

I'd guess it could be misfiring because of what we think is an oil seal leak .. but it doesn't hurt to try moving the other items, to see whether the problem persists, or moves to another cylinder.

The old O2 sensor sounds like it's not operating at 100%. It sounds like the heater circuit is knackered, so don't waste any more time on it. I would replace it with a new, quality sensor.

The new sensor also seems to be not that great, since it upsets the ECU. Again, it's been useful to show where the problem is but it's not good enough. The ECU decides what to do with even a 0.1v variance, so if the sensor has too much internal resistance, it'll be giving the ECU no chance.

Until you swap the sensors for decent ones, anything else could be a red herring.. so start there and then see what else is still playing up. Sounds not tooooo far off now.


Ralf S.

Hi

Also after enquiring by NGK as to why my plug broke when it wasn't tightened tight,after giving my car make and model etc they said the plug I've got is the incorrect plug for the car!!!!

Every parts store in Cape Town has this plug listed for the 1.6 stilo!!

Wow!
 
Hi

Also after enquiring by NGK as to why my plug broke when it wasn't tightened tight,after giving my car make and model etc they said the plug I've got is the incorrect plug for the car!!!!

Every parts store in Cape Town has this plug listed for the 1.6 stilo!!

Wow!

NGK is probably quoting the OE standard fit, which is a BKR5EZ, in the UK at least. South Africa could well have listed a BKR6EZ instead.

The 5 and 6 reflect the plug heat rating. The 5 is a hotter plug, since the UK has a temperate or just cold and miserable climate. A hot plug warms up quicker and fires better when cold.. it also burns off soot, since in cold climates cars use more “choke”.

The 6 plug can foul more when it’s cold... which gives less fuel economy/more emissions rather than a misfire... but it can run at a higher temperature before it starts to degrade through heat (the 5 would melt first). So it sounds sensible if you’re in South Africa in summer.. you want a plug that keeps cool, not a plug that keeps hot.

In real life, the difference between a 5 and a 6 is negligible. The heat ranges overlap by miles.. and your plugs don’t look like they’re out of their heat range (sooty or melted respectively).

A too cold plug is also better than a too hot plug.. since a sooty plug is less serious than one that drops molten metal into your cylinders after melting..


Your new plugs are BKR6EK.

BKR6EK are identical to BKR6EZ in all dimensions except that they are twin electrode. Twin electrode gives you more chance of a spark .. the plug fires on whichever electrode gives the least resistance (not both of them at the same time, like the promo photos always show). But it’s still a BKR6.. so it’s fine.

You probably broke the plug yourself when you were unscrewing it, I’m sorry to say.. if the plug socket isn’t on dead square and touching the metal face of the rocker cover, then as you unscrew it, especially if it’s tight, you can inadvertently put sideways bend on the plug body... particularly if the plug is tight and then suddenly let’s go.

The ceramic won’t bend at all, it will crack exactly like your picture shows. It might have been faulty or dropped on the ground before you fitted it.. but statistically... i’ve Only seen a broken plug once, and that was a slip of the wrench when I went to unscrew it, as above.

Any road up.. a plug is a few quid.. fit a new one (same as the others) and why one of them broke doesn’t really matter.

Did NGK recommend some completely different type of plug? Anything with “V” in the name after the 5 or 6 (e.g. BKR6EGV) would be a platinum or iridium jobbie.. they last longer and supposedly work under sooty conditions better, but they cost 5 times as much.

Ralf S
 
NGK is probably quoting the OE standard fit, which is a BKR5EZ, in the UK at least. South Africa could well have listed a BKR6EZ instead.

The 5 and 6 reflect the plug heat rating. The 5 is a hotter plug, since the UK has a temperate or just cold and miserable climate. A hot plug warms up quicker and fires better when cold.. it also burns off soot, since in cold climates cars use more “choke”.

The 6 plug can foul more when it’s cold... which gives less fuel economy/more emissions rather than a misfire... but it can run at a higher temperature before it starts to degrade through heat (the 5 would melt first). So it sounds sensible if you’re in South Africa in summer.. you want a plug that keeps cool, not a plug that keeps hot.

In real life, the difference between a 5 and a 6 is negligible. The heat ranges overlap by miles.. and your plugs don’t look like they’re out of their heat range (sooty or melted respectively).

A too cold plug is also better than a too hot plug.. since a sooty plug is less serious than one that drops molten metal into your cylinders after melting..


Your new plugs are BKR6EK.

BKR6EK are identical to BKR6EZ in all dimensions except that they are twin electrode. Twin electrode gives you more chance of a spark .. the plug fires on whichever electrode gives the least resistance (not both of them at the same time, like the promo photos always show). But it’s still a BKR6.. so it’s fine.

You probably broke the plug yourself when you were unscrewing it, I’m sorry to say.. if the plug socket isn’t on dead square and touching the metal face of the rocker cover, then as you unscrew it, especially if it’s tight, you can inadvertently put sideways bend on the plug body... particularly if the plug is tight and then suddenly let’s go.

The ceramic won’t bend at all, it will crack exactly like your picture shows. It might have been faulty or dropped on the ground before you fitted it.. but statistically... i’ve Only seen a broken plug once, and that was a slip of the wrench when I went to unscrew it, as above.

Any road up.. a plug is a few quid.. fit a new one (same as the others) and why one of them broke doesn’t really matter.

Did NGK recommend some completely different type of plug? Anything with “V” in the name after the 5 or 6 (e.g. BKR6EGV) would be a platinum or iridium jobbie.. they last longer and supposedly work under sooty conditions better, but they cost 5 times as much.

Ralf S

Hi

They showed me on the picture that it was previously over torqued.
They only mentioned the BKR5EZ. I enquired now about the platinum plugs if they have for the stilo.

I currently have a previously installed plug in that cylinder. Same type. Looks good still. I remember the set that plug came off I took off prematurely to it failing. So it was still a good plug.

Yesterday for some reason i got a whole range of codes appear and then I cleared and they never returned. Fiat electronic glitches???or what you say?
 

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I had a better look at the photo of your broken plug.. I hadn't spotted that the damage was under the hex, not above it.

I've never seen anything like that before... usually the threads would strip (or strip the threads in your rocker cover) rather than shear off the entire plug... so I don't think over-torqueing it is all that likely.. but as I wrote, it's out of the engine and no harm done, so it's not worth worrying too much about.

If they list BKR5EZ for South Africa too, then no worries. The difference between a 5 or a 6 rated plug isn't going to change things so that you would notice, except at extremes of engine temperature. You could put some BKR5EZ in there just out of curiosity.. but you won't spot any difference at all.

The codes I dunno.. if you had a cold night out of the blue then the battery (if it's old) could have had a moment...

Otherwise, next time you have the spanners out, just take off the earth lead where it attaches to the car body/inner wing and clean the contact faces of the inner wing and the cable end.. then refit the lead with a spot of grease over the top of it.

And check the battery leads at the battery terminals for being clean and tight. Mine are quite easy to false-tighten.. the terminal clamp is a stamped metal frame thing, rather than being a solid lump of lead with a hole in it like the old days... so if it's not lined up right, when you tighten it, it works slightly loose.

And check your battery is clamped to the tray tightly. If the battery can slide around in the tray, it could pull on the battery terminal clamps, which might cause a random spike to confuse the ECU. If it doesn't do it again... best let it go. :D


Ralf S.
 
I had a better look at the photo of your broken plug.. I hadn't spotted that the damage was under the hex, not above it.

I've never seen anything like that before... usually the threads would strip (or strip the threads in your rocker cover) rather than shear off the entire plug... so I don't think over-torqueing it is all that likely.. but as I wrote, it's out of the engine and no harm done, so it's not worth worrying too much about.

If they list BKR5EZ for South Africa too, then no worries. The difference between a 5 or a 6 rated plug isn't going to change things so that you would notice, except at extremes of engine temperature. You could put some BKR5EZ in there just out of curiosity.. but you won't spot any difference at all.

The codes I dunno.. if you had a cold night out of the blue then the battery (if it's old) could have had a moment...

Otherwise, next time you have the spanners out, just take off the earth lead where it attaches to the car body/inner wing and clean the contact faces of the inner wing and the cable end.. then refit the lead with a spot of grease over the top of it.

And check the battery leads at the battery terminals for being clean and tight. Mine are quite easy to false-tighten.. the terminal clamp is a stamped metal frame thing, rather than being a solid lump of lead with a hole in it like the old days... so if it's not lined up right, when you tighten it, it works slightly loose.

And check your battery is clamped to the tray tightly. If the battery can slide around in the tray, it could pull on the battery terminal clamps, which might cause a random spike to confuse the ECU. If it doesn't do it again... best let it go. :D


Ralf S.


Hi so ive been sick in bed and partners father took him to work this morning with the car.

He mentioned that the car just switched off(in traffic) and wouldn't start after the first try.
Partner also mentioned the car did not want to drive.

I was like what the hey! Anyway take out the scanner and plug him in to see if codes were set. P0638 was set again. In my pic i sent before you can see it's the 2nd time this code is set. I am going to clear it and drive again as normal and see what happens. If it keeps on coming back could our problem lay with the throttle body itself or is a ECU upgrade needed?

Thank you
 
The P0638 fault is related to the throttle body.. no surprise there I suppose.

I remember that you've cleaned your TB to death, so I doubt that the spindle/potentiometer or the valve are sticking... but it's worth a double check while you have it in pieces.

It's more likely to be a wiring issue though, since you had the ECU brownout a day or two ago. Check the wiring to the TB looking for any damage, especially anything that could cause a short circuit or loss of earth. Trace it back to the fusebox and the relays.

It could you have something loose, dirty or corroded around the fuse box on top of the battery. Anything showing fresh air around the wheel arch liner allows spray from the road wheels up into the bottom of the battery and fuse box area, so even if you have the battery and the separate fuse-box covers, usually the worst area is the under-side.

Before you pull all the fuses and relays out, mark them all up (the relays at least) and take a photo of where they fit, so you have a chance to get them back in the right place. You need to clean the female pins in the fuse tray (easier said than done) and also as far as you can, check the condition of the wiring where the spaghetti emerges from out under the tray.


Ralf S.
 
The P0638 fault is related to the throttle body.. no surprise there I suppose.

I remember that you've cleaned your TB to death, so I doubt that the spindle/potentiometer or the valve are sticking... but it's worth a double check while you have it in pieces.

It's more likely to be a wiring issue though, since you had the ECU brownout a day or two ago. Check the wiring to the TB looking for any damage, especially anything that could cause a short circuit or loss of earth. Trace it back to the fusebox and the relays.

It could you have something loose, dirty or corroded around the fuse box on top of the battery. Anything showing fresh air around the wheel arch liner allows spray from the road wheels up into the bottom of the battery and fuse box area, so even if you have the battery and the separate fuse-box covers, usually the worst area is the under-side.

Before you pull all the fuses and relays out, mark them all up (the relays at least) and take a photo of where they fit, so you have a chance to get them back in the right place. You need to clean the female pins in the fuse tray (easier said than done) and also as far as you can, check the condition of the wiring where the spaghetti emerges from out under the tray.


Ralf S.

Hi

So I went to fetch my partner and when I left the work the car struggled to start. Then when starting,she wouldn't rev. Just had a high idle so I put in gear and parked one side of the parking. Again p0638 returned I unplugged the connector and plugged it back in and reset. She then had a very jumping idle. Like she would drop down to almost 0 then back up. I switched off and on and kept at steady RPM with the pedal until I drove off. She was more sluggish and had that surge more prominent. But I could get home
 
The P0638 fault is related to the throttle body.. no surprise there I suppose.

I remember that you've cleaned your TB to death, so I doubt that the spindle/potentiometer or the valve are sticking... but it's worth a double check while you have it in pieces.

It's more likely to be a wiring issue though, since you had the ECU brownout a day or two ago. Check the wiring to the TB looking for any damage, especially anything that could cause a short circuit or loss of earth. Trace it back to the fusebox and the relays.

It could you have something loose, dirty or corroded around the fuse box on top of the battery. Anything showing fresh air around the wheel arch liner allows spray from the road wheels up into the bottom of the battery and fuse box area, so even if you have the battery and the separate fuse-box covers, usually the worst area is the under-side.

Before you pull all the fuses and relays out, mark them all up (the relays at least) and take a photo of where they fit, so you have a chance to get them back in the right place. You need to clean the female pins in the fuse tray (easier said than done) and also as far as you can, check the condition of the wiring where the spaghetti emerges from out under the tray.


Ralf S.

Hi CEL on again

Code set p0606

I have a old battery I never yet replaced. Could the battery be causing this and symptoms I have?
 
The P0638 fault is related to the throttle body.. no surprise there I suppose.

I remember that you've cleaned your TB to death, so I doubt that the spindle/potentiometer or the valve are sticking... but it's worth a double check while you have it in pieces.

It's more likely to be a wiring issue though, since you had the ECU brownout a day or two ago. Check the wiring to the TB looking for any damage, especially anything that could cause a short circuit or loss of earth. Trace it back to the fusebox and the relays.

It could you have something loose, dirty or corroded around the fuse box on top of the battery. Anything showing fresh air around the wheel arch liner allows spray from the road wheels up into the bottom of the battery and fuse box area, so even if you have the battery and the separate fuse-box covers, usually the worst area is the under-side.

Before you pull all the fuses and relays out, mark them all up (the relays at least) and take a photo of where they fit, so you have a chance to get them back in the right place. You need to clean the female pins in the fuse tray (easier said than done) and also as far as you can, check the condition of the wiring where the spaghetti emerges from out under the tray.


Ralf S.

Hi so while driving on high way and I want to accelerate to overtake,it feels like clutch engaged halfway,like the car revs up but does not accelerate. Like the clutch is halfway engaged. But the pedal is fully up. I didn't press the clutch on accident.
Then dropped someone at home and then car didn't want to rev. Check engine light. P0638 again. Reset and it was fine.

I had fault regarding clutch switch. Could my performance(surge and poor acceleration)symptoms be because of this switch? Does the stilo have electronic or cable clutch? That the switch telling the ecu the clutch is being pressed when its not.
This only happened when i want to overtake or speed up. When at constant it doesn't do that.

Thanks
 
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Hi CEL on again

Code set p0606

I have a old battery I never yet replaced. Could the battery be causing this and symptoms I have?

It could... but it would be more consistent. If the battery was failing it would cause a problem that didn't go away until the battery was replaced - they don't usually come in and out, although there may be some problem with the plates that's affecting the current. Usually battery plate problems are terminal (no pun intended) since the damaged cell won't work at all, then the battery only has 2 cells (10.x volts) to play with.

But check the earthing of the battery negative terminal and the fuses/relays/wiring to the Throttle Body. It's doing "something strange", which is usually an earthing problem.


Ralf S.
 
Hi so while driving on high way and I want to accelerate to overtake,it feels like clutch engaged halfway,like the car revs up but does not accelerate. Like the clutch is halfway engaged. But the pedal is fully up. I didn't press the clutch on accident.
Then dropped someone at home and then car didn't want to rev. Check engine light. P0638 again. Reset and it was fine.

I had fault regarding clutch switch. Could my performance(surge and poor acceleration)symptoms be because of this switch? Does the stilo have electronic or cable clutch? That the switch telling the ecu the clutch is being pressed when its not.
This only happened when i want to overtake or speed up. When at constant it doesn't do that.

Thanks

The clutch sounds like it's slipping.. either because the plates are wearing out, or the release mechanism is sticking.

The 1.6 has a hydraulic clutch with an external slave cylinder, so check that circuit for leaks and make sure that the gearbox actuator lever isn't sticking when you press the pedal in and out.

I can't think how the clutch switch could cause surge or poor acceleration. It usually interrupts power in the starter circuit, so that the starter doesn't crank the engine when you turn the key to "MAR", if the clutch pedal is out.

A faulty switch could also fail so that you can turn the engine over without the clutch being "in".. which is only a problem if you leave the car in gear.

So if the car doesn't turn over, or it turns over when the clutch pedal is out, then the switch could be faulty.. but once the engine has started, the switch plays no further part.

The 0638 is related to the throttle body.. it doesn't sound like it's linked to the clutch slip or the switch error.


Edit: Does your car have cruise control? A faulty clutch switch can cause the engine to race if the cruise control is set and you press the pedal in... since the car's brains thinks the clutch is engaged when it isn't. If you have cruise, and a message that the clutch switch is dicky, then the "slip" is more likely to be the switch than a knackered clutch.


Ralf S.
 
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The clutch sounds like it's slipping.. either because the plates are wearing out, or the release mechanism is sticking.

The 1.6 has a hydraulic clutch with an external slave cylinder, so check that circuit for leaks and make sure that the gearbox actuator lever isn't sticking when you press the pedal in and out.

I can't think how the clutch switch could cause surge or poor acceleration. It usually interrupts power in the starter circuit, so that the starter doesn't crank the engine when you turn the key to "MAR", if the clutch pedal is out.

A faulty switch could also fail so that you can turn the engine over without the clutch being "in".. which is only a problem if you leave the car in gear.

So if the car doesn't turn over, or it turns over when the clutch pedal is out, then the switch could be faulty.. but once the engine has started, the switch plays no further part.

The 0638 is related to the throttle body.. it doesn't sound like it's linked to the clutch slip or the switch error.


Edit: Does your car have cruise control? A faulty clutch switch can cause the engine to race if the cruise control is set and you press the pedal in... since the car's brains thinks the clutch is engaged when it isn't. If you have cruise, and a message that the clutch switch is dicky, then the "slip" is more likely to be the switch than a knackered clutch.


Ralf S.
Hi,

How do I test clutch actuator?
And where is the hydraulic clutch slave cylinder and how do I test that too?

I've got a better software to log data(using a elm327 obd2),decided to see what the throttle is doing because its becoming more and more clear that something is going on there and almost everyday she goes into limp mode especially after starting with no acceleration and only revs up until 2000rpm. Then I must clear codes and switch off then on then i can go. Sometimes she runs in open loop because of a system failure then I reset codes that may be lingering then im back to closed loop.

Anyway,logged some data while driving and wasn't happy with what I saw. Forgot to video or record the data. Found a pic though of what mine looked like. It would go kind of smooth and then would spike either negative or positive and then smooth then at idle the graph wouldn't lay flat, it had drops here and there. Sometimes when driving it would drop down to 'closed throttle' and back up.
Also past a certain point on my pedal,the throttle body is dead as if that was WOT. I could push her to the floor after that point and no change. Like a complete dead spot. Hence remember when I mentioned in other threads that she does not rev to her limit.
Putting motor straight onto positive and negative terminal,she goes completely open and completely closed when I let go off terminals but the problem i think is lying with what is telling the ECU what the angle is of the throttle,the TPS. Not the motor in the throttle body.

Could this have been our problem all along and wasn't setting a code until now?

Here's the pic,however mine read in percentage but a bad waveform like that is what she showed. Maybe but more spikes

Thanks for the help
 

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The clutch sounds like it's slipping.. either because the plates are wearing out, or the release mechanism is sticking.

The 1.6 has a hydraulic clutch with an external slave cylinder, so check that circuit for leaks and make sure that the gearbox actuator lever isn't sticking when you press the pedal in and out.

I can't think how the clutch switch could cause surge or poor acceleration. It usually interrupts power in the starter circuit, so that the starter doesn't crank the engine when you turn the key to "MAR", if the clutch pedal is out.

A faulty switch could also fail so that you can turn the engine over without the clutch being "in".. which is only a problem if you leave the car in gear.

So if the car doesn't turn over, or it turns over when the clutch pedal is out, then the switch could be faulty.. but once the engine has started, the switch plays no further part.

The 0638 is related to the throttle body.. it doesn't sound like it's linked to the clutch slip or the switch error.


Edit: Does your car have cruise control? A faulty clutch switch can cause the engine to race if the cruise control is set and you press the pedal in... since the car's brains thinks the clutch is engaged when it isn't. If you have cruise, and a message that the clutch switch is dicky, then the "slip" is more likely to be the switch than a knackered clutch.


Ralf S.

Btw I have got a code for clutch switch once or twice.
No I don't have cruise control and yes it starts without clutch pressed in.

Anyway screengrabbed some live data. Will post on you tube so you can see in video form what's happening.
 

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The clutch sounds like it's slipping.. either because the plates are wearing out, or the release mechanism is sticking.

The 1.6 has a hydraulic clutch with an external slave cylinder, so check that circuit for leaks and make sure that the gearbox actuator lever isn't sticking when you press the pedal in and out.

I can't think how the clutch switch could cause surge or poor acceleration. It usually interrupts power in the starter circuit, so that the starter doesn't crank the engine when you turn the key to "MAR", if the clutch pedal is out.

A faulty switch could also fail so that you can turn the engine over without the clutch being "in".. which is only a problem if you leave the car in gear.

So if the car doesn't turn over, or it turns over when the clutch pedal is out, then the switch could be faulty.. but once the engine has started, the switch plays no further part.

The 0638 is related to the throttle body.. it doesn't sound like it's linked to the clutch slip or the switch error.


Edit: Does your car have cruise control? A faulty clutch switch can cause the engine to race if the cruise control is set and you press the pedal in... since the car's brains thinks the clutch is engaged when it isn't. If you have cruise, and a message that the clutch switch is dicky, then the "slip" is more likely to be the switch than a knackered clutch.


Ralf S.

Hi Ralf

So another coil pack just failed on me.

Start her up this morning to go to work and she misfired bad. Checked each cylinder and one pack wasn't firing AT ALL. Put one of old packs in that Seems to have life because after swopping it the car didn't misfire.

Heres more pics of my throttle body readings.

At 9% is the car at around 2000 rpm.
At 4% she was idling.
Just posting these pics so you can see and tell me if my TB is bad or not

Thanks
 

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