Hi There,

Im having a couple really minor issues and im wondering if its pointing at a maff (that i hear so much about).

And i would like to know if there is any way to check if the Maf is a-OK.




My issues: for one week (and one tank) only, when just started the idle fluctuated. Like it almost stalled then pulled the revs up then back down. After a min or so idle was fine.

After last track day, on the way home, im 4th and 5th gear, if i put tiny amount of throttle after no throttle it hesitated/didnt pick up. If i put more throttle on it was fine.

Now, i dont know if its in my head, but the engine doesnt feel 100%. Flat out its still perfect, but when driving slowly it just doesnt seem as responsive.

Now im talking REALLY small things here. Nothing obviously wrong, so this could all be in my head. Either way, if there are any checks i can do, i.e. the maf, then the better.

Cheers
Chris

 

one of the normal ways of checking if the maf works is to unplug it while the car is on. if its working it will cut the car out. but this is only a guide and no real identification. with the idle it could be due to the idle control valve.

 

Ive read somewhere th unplug it thing to be a bit of a myth.

Is there no definitive test for the MAF or just a combination of symptoms.

 

Exactly the same as mine, Not as smooth at low revs as should be, tiny hesitations on small throttle openings but still quick when floored. Also have black exhaust, always was black but now soooty. Sometimes have the fluctuating idle. No fault codes.

Have swapped out the MAF from my other MY97 car, and also the Lambda, but still the same. Checked both Lambda, heaters ok and voltage swings between 0.1v and 0.9v nicely.

Havn't done voltage check on the MAF tho. Apparently other things to check are idle control valve (fluctuating idle usually means it is working, but you never know) and the emisions (PCV) valve is another suspect for messing things up.

Havn't had a chance to have a good look as have had "man flu". Man flu in my house means the wife takes the week off work and I struggle on working 12 hour shifts and get the takeaway on the way home as she is "too poorly" to cook, but that's another row brewing....

 

Had exactly the same problem with lots of back firing under easy driving but my car was also running lean up the rev range. Fitted a SimTek and its A OK!

 

What's a SimTek?

 

Pete thats exactly why i want to investiagte. Im worried mine is leaning off up top too. Dont wanna blow anything.

Looksl ike im in on the groub buy mapping for JGM in december. so untill then ill just be checking/changing things.

All the symptoms only seemt o happen once, cant make them again.

My exhaust too was a bit sooty! However i aint cleaned it in about 3 months. I do get some pops and back fires, nothing consistent, but usually when driven hard, then really slowly between slow gear changes i might get a pop. Only the odd one every now and then tho.

we shall see.

 

I found out mine was running lean when I had it on a rolling road and the operator lifted off quickly when he heard all the det through his det cans and the AFR confirmed it!

I am lucky that I dont drive the car hard as I always have my kids in it or who knows what could've happened!

 

Yeah perhaps ill take it easy till december then when i can get it mapped/rr'ed.

 

Mine behaves the same with the original ecu and the Prodrive one so I don't think mine is a mapping issue, something is causing it.

Oh yes, am also getting the odd pop on overrun.