Technical Jerkiness on light throttle, esp when cold.

[Pugglt Auld Jock]

Oh deary me. I started typing when noone had replied and so many have beaten me too it. Hope there was something in there to help though! I'll be reading them all because I bet there'll be something I didn't know!

 

[koalar]

OK, first things I've checked:

Battery/alternator - battery shows 12.6v with engine off, 14.02 with engine running but no lights or AC and 13.9 with lights and AC. On switching off, battery shows 13.1V dropping slowly down over time, so I think this shows alternator and battery are good.

Pulled the MAP sensor and it's oily.

Will try car with breather pipe detached next, and pull the plugs and take pics.

Edit - clock not resetting. But stalling at junctions was back yesterday.

The main symptoms for me with an oily MAP has been on acceleration, it start to then stops then accelerates again, often not too bad after prolonged use at higher revs and worse around town

Also a little longer to start not much maybe 1-2 seconds

Its always difficult as the same symptoms can have different causes and the same faulty part can have different symptoms

 

[Pugglt Auld Jock]

The main symptoms for me with an oily MAP has been on acceleration, it start to then stops then accelerates again, often not too bad after prolonged use at higher revs and worse around town

Also a little longer to start not much maybe 1-2 seconds

Its always difficult as the same symptoms can have different causes and the same faulty part can have different symptoms

I think you're spot on with the MAP symptoms here. Pretty much exactly what I've found, especially on the sluggish and jerky acceleration. Clean it every service and it pretty much stops it.

 

[irc]

As you say, there is a known loom fault with the 1.1 but not, as far as I know, with the 1.2 But I like your idea to reseat the plugs.

If this a non-aircon Panda, it's possible it is the same loom (55203115). Although I only remember seeing problems on 1.1s, it is definitely possible that at least one of the same things could happen on a 1.2.

Definitely follow advice from @koalar and @Pugglt Auld Jock first, but if all seems well, you could try GENTLY manipulating the engine loom section that runs between the injectors and the coil area. There are a couple of earthing junctions in this section which have been known to break up, leading to injectors and coils stopping briefly.
Moving the cable slightly may be enough to provoke a stutter.

On 1.1s the ECU plug can also become loose, and occasionally a fatigue break on a wire near the ECU plug causes problems. I think these are probably specific to the 1.1 though.

As I said before though, only recall seeing it on 1.1s, even though the loom is the same - I have swapped a few looms from scrapped 1.2s onto 1.1s to fix.

 

[PacoJones]

If you raise the revs at this point the voltage should go back to 14V if it does the alternator is almost certainly fine

With lights on main, rear screen, fan on full, etc, the reading at the battery drops to 13.3 and when I rev the car to approx 3000rpm, it goes up to 13.85 - a little shy of 14 but it's consistent, if the I let the revs drop and then press the accelerator, it jumps straight back to 13.85. So I think that's good enough.

 

[koalar]

With lights on main, rear screen, fan on full, etc, the reading at the battery drops to 13.3 and when I rev the car to approx 3000rpm, it goes up to 13.85 - a little shy of 14 but it's consistent, if the I let the revs drop and then press the accelerator, it jumps straight back to 13.85. So I think that's good enough.

Correct

The results are exactly as expected

 

[PacoJones]

What are the plugs like, wet with fuel, wet with oil, black with carbon, fine,

Post a picture in the order they come out

See pic below, I notice that plug 1 is oily.

 

[PacoJones]

I also see oil where the breather attaches to the airbox, and also inside where the air box attaches to the throttle:

 

[koalar]

See pic below, I notice that plug 1 is oily.

View attachment 461697

Electrodes are dry

I suspect that just a bit of oil or water that's run down as the plug was then out, the threads are oiled as well

 

[PacoJones]

You've tried so many things already but I'll try to help.

The Launch is a very big and trusted name but there have been many posts on our forum about how our cars don't really "like" generic code readers and how they often lead you down a "rabbit hole" by throwing up erroneous results. I find Multiecuscan works well but there are one or two others which also get recommendations on the forum - Alfaobd being one? - Maybe others could make recommendations?

A simple way to check if the alternator is charging the battery would be with a voltmeter. Let the car stand for about an hour so the battery can stabilize then apply the meter to the battery terminals. You should see around 12.5 volts. A good battery may show a little more, ie 12.8, a poor one a little less, ie 12 .3. However if it's in this range it's likely Ok. now start the engine and run it at a fast idle - 1500 to 2000 rpm. Actually most alternators will charge strongly even at idling but running the engine just a little faster will ensure a good output. The Voltmeter should now be showing somewhere between 13.5 to 14.5 volts. If it does then it's probably charging just fine.

As you say, there is a known loom fault with the 1.1 but not, as far as I know, with the 1.2 But I like your idea to reseat the plugs. I apply a light coat of Contralube to any electrical connector before I reassemble it https://www.autoelectricsupplies.co.uk/p/contralube-770-the-terminal-connector It waterproofs, protects and improves electrical pathways.

Cam or crank sensors should leave a trouble code you can look for but sometimes they don't. "Misbehaving" when they get hot but working normally when started from cold is not unknown. Sometimes you can make them "misbehave" by lightly tapping them with the engine running. But do be very careful you don't get anything tied up in rotating parts!

Here's a pretty good video about checking MAP sensors:



One of the advantages of buying into Multiecuscan is it lets you watch stuff like this live on the screen but the video also shows you how to do it using just a voltmeter (multimeter)

Poor ground? The earth lead under the battery tray is always worth checking as they are known to corrode and fail. The exposed woven type is easy to check but the type with an insulating outer covering can, I'm told, corrode internally where you can't see it. I imagine a good "wiggle" will find it? I've only ever had the woven one on any of our Pandas.

Thanks very much, that's all really helpful. I'd go with Multiscan but I figured a simple code reader would be a quick way to get some codes.

Will check the ground under the battery.

 

[PacoJones]

I'm thinking this is coming back to the MAP getting oiled up. When it happens again, I will pull the breather pipe and try driving without it.

But I'm wondering what causes the oiling. Is there a fix? Should I add a cheap catch can?

 

[koalar]

When your scanner arrives, you can check how much vacuum the inlet is pulling

 

[PacoJones]

If this a non-aircon Panda, it's possible it is the same loom (55203115). Although I only remember seeing problems on 1.1s, it is definitely possible that at least one of the same things could happen on a 1.2.

Definitely follow advice from @koalar and @Pugglt Auld Jock first, but if all seems well, you could try GENTLY manipulating the engine loom section that runs between the injectors and the coil area. There are a couple of earthing junctions in this section which have been known to break up, leading to injectors and coils stopping briefly.
Moving the cable slightly may be enough to provoke a stutter.

On 1.1s the ECU plug can also become loose, and occasionally a fatigue break on a wire near the ECU plug causes problems. I think these are probably specific to the 1.1 though.

As I said before though, only recall seeing it on 1.1s, even though the loom is the same - I have swapped a few looms from scrapped 1.2s onto 1.1s to fix.

It's an AC Panda, so less likely to be the same loom, I expect.

 

[koalar]

Thanks very much, that's all really helpful. I'd go with Multiscan but I figured a simple code reader would be a quick way to get some codes.

Will check the ground under the battery.

Just measure

Voltmeter on volts one lead battery negative and the other on engine block

Crank the engine

Should stay below 0.2V, under load, there's a bit of leeway

If it does we can move on, if it doesn't we can address the problem

 

[Pugglt Auld Jock]

Electrodes are dry

I suspect that just a bit of oil or water that's run down as the plug was then out, the threads are oiled as well

Exactly my thoughts. You beat me to the punch with your reply. There's oil on the threads which couldn't get there from inside the cylinder and an "oily plug" where excess oil is being burnt in the cylinder, will result in a heavy deposit of black slightly "stodgy" carbon around the "business end". I think there's probably oil leaking into the plug recess from either the breather pipe or cam cover gasket?

 

[PacoJones]

Exactly my thoughts. You beat me to the punch with your reply. There's oil on the threads which couldn't get there from inside the cylinder and an "oily plug" where excess oil is being burnt in the cylinder, will result in a heavy deposit of black slightly "stodgy" carbon around the "business end". I think there's probably oil leaking into the plug recess from either the breather pipe or cam cover gasket?

Could well be from the oil that was present around the throttle when I first started experiencing this, which was coming from the breather pipe. As the electrodes look good, I'll put the plugs back into the car.

 

[Pugglt Auld Jock]

Could well be from the oil that was present around the throttle when I first started experiencing this, which was coming from the breather pipe. As the electrodes look good, I'll put the plugs back into the car.

They certainly don't show anything much by way of electrode wear so probably fine. Is there oil up the side of the plug or it's HT lead? If so clean and see if things improve. Genuine plugs give very little problem these days but I'm always careful about where I buy as there seems to be quite a problem with counterfeit plugs over the last few years.

 

[koalar]

. Genuine plugs give very little problem these days but I'm always careful about where I buy as there seems to be quite a problem with counterfeit plugs over the last few years.

Correct

 

[PacoJones]

Is there oil up the side of the plug or it's HT lead? If so clean and see if things improve. Genuine plugs give very little problem these days but I'm always careful about where I buy as there seems to be quite a problem with counterfeit plugs over the last few years.

No, pretty clean except for the oil on the thread - I've cleaned that. Plugs were from Euro Car Parts in May last year, so quite new and (hopefully!) genuine.

 

[PacoJones]

Voltmeter on volts one lead battery negative and the other on engine block

Crank the engine

Should stay below 0.2V, under load, there's a bit of leeway

If it does we can move on, if it doesn't we can address the problem

It measures .019V so I guess we can move on!

I will post some updates when the code reader arrives in a day or two and I can check for codes and live data, or if the problem reappears and I can detach the breather pipe and see what effect that has.

Thanks everyone for your fantastic input so far!