Technical Rough running

[afroking]

I currently have a problem whereby the engine coughs and splutters when I jab the accelerator or when accelerating at low revs. For example less than 2000rpm in second gear in traffic. When idling you can hear every now and again a misfire. I have checked and cleaned the Idle control valve and still have the same issue.
Could it be;

A faulty injector?
A faulty coil pack?
A faulty variator solenoid?
My back box seriously needs changing?

Thanks,

Ad.

 

[topher]

Ad,

I guess it could be a faulty injector or coil pack. At work I have written down the resistance measurements for both so can check for you tomorrow. I may not tell you for sure but it may just indicate something wrong somewhere!

As for the variator solenoid, I guess if it was stuck and the inlet valve timing was advanced all the time then yes that may cause it but I cant see it happening. Having had the solenoid in and out of mine about 30 times yesterday it only takes 30 seconds to take it out and check it. It doesnt do anything below 3000rpm so if it isnt stuck then it wont be that.

Chris

 

[HP]

Daft question, but is it due a service? Has it recently had plugs and filters etc.?

 

[afroking]

@ Tropher, thank you for your input, if you could get those resistant values I would really appreciate it. With regards to the variator solenoid I was just shooting off ideas trying to cover ever posibility.

@ HP its not a daft question, before I put it into the garage about 6 months ago I had changed all filters, plugs and oil. It is due an oil change now which I will do this week. The problem is it had these symptoms before the previous service so I doubt its related.

Any other input is welcome, I really appreciate it guys thank you.

Ad.

 

[topher]

Ad,

OK data is from the Auto data CD so it should be correct but is for my car (1996-1998), I have written down anything that may help

Coil - primary resistance 0.54 - 0.66 ohms
Spark plug gap 0.9mm
Engine coolant temperature - 320 ohms at 80degC
Injectors 10.8 - 13.2 ohms
Lambda Sensor 4 - 5 ohms

Hope it helps.....

Chris

 

[Mad Matt]

Quick check list, but I imagine you've already covered it:

1. Clean throttle body.
2. Clean idle valve.
3. Check plugs are not damp.
4. Take plugs out and check colouring.
5. Clean mass air sensor.
6. Check for leaks in air intake system, especially after the mass air sensor.
7. Check battery condition.

I doubt it's any of the above, but number 4 may show if one of the injectors is faulty.

Good luck!

 

[afroking]

Just drove my girlfriend back to University (130 miles each way) and the misfire seemed to be more noticeable than before especially when I accelerate full throttle at 2500RPM.

I cleaned my throttle body and idle valve yesterday and although they needed it, there was no change. I need to check the plugs. Where is the air mass sensor? My car is 2000 'X' reg and it is not part of the intake pipes. I also need to check the battery condition.

Thanks Mad Matt, at least that will give me something to think about until I get home.

 

[Mad Matt]

I had an older one, I think on the newer ones it's built into the throttle body, but exactly where I do not know!.

LRB?

 

[Robot]

LRB seems to have gone missing. Probably something to do with a combination of wife, hatchet, and unfinished hall :shrug:

 

[Richpea]

LRB seems to have gone missing. Probably something to do with a combination of wife, hatchet, and unfinished hall :shrug:

LRB is working 200 miles away from his home.

Is the attached a picture of what you call the air mass sensor? Had a new one fitted to my '97 B 2 years ago when it kept cutting out but it only made a little difference and after a lot of testing, and massive labour costs, it turned out to be the timing that needed adjustment.

 

[afroking]

Thanks Richpea but that is the idle control valve.

 

[Richpea]

Thanks Richpea but that is the idle control valve.

Most grateful for you putting me right - I am not that good with things mechanical.

 

[afroking]

That's ok, thank you for your input.

 

[topher]

Have you got any further forward Ad?

 

[afroking]

Yes, yes I have. Got back late last night so couldn't do anything, however this morning I set about checking the plugs, took the top cover off and would you believe it I have left my allen keys round a mates! Pretty annoyed to say the least.
So anyway, I had a look around the engine bay and got out my trusty extension bar (to use as a stethoscope) and listened to different components.
In the end, I don't know why but I pulled out a connection in the throttle body (the one marked in the picture). At first the rev's died but quickly picked up again, I kept it unplugged until I heard a misfire. I didn't hear any misfires within 5 minutes of it being unplugged so I turned off the engine, plugged it back in, turned it back on and what do you know? Misfiring again! When the sensor was unplugged the engine ran a lot smoother and the injector light came up on the dashboard. It didn't rev as freely as before but it certainly cured the misfire.
Obviously I can't run it without the sensor plugged in without knowing what it does. So what does it do?

Thanks,

Ad.

 

[Robot]

It makes your engine misfire

 

[afroking]

Nice one Robot!

Shouldn't you be at work?

 

[Robot]

Nah, I'm done for today

 

[HP]

I'd say that's your throttle position sensor:

 

[afroking]

Do you think it is likely to be the culprit or just a red herring?