[foresthump]

Hi everyone. Newbie here. I posted on Matthews volvo forum also, but only got 1 response. This problem is becoming unsolvable.
2001 c70 2.3l hi pressure coupe with additions of short ram air intake, HD boost controller, silicone turbo hoses, mitsubishi 18t turbo, "R" exhaust manifold, 3" downpipe and TME catback exhaust, stage II IPD ECU flash and suspension modifications.
Over the past month or 2 I`ve noticed a gradual decrease in cold start ease. That is to say, normally, I turn the key, no gas pedal needed, it cranks right up and idles smoothly at 900rpm. But now it idles roughly, stumbles and will cut off if I don`t apply gas. If I keep the revs up above 1500rpm for a minute or two, the problem goes away and the car settles down and idles smoothly. This is only a cold start issue. And it only lasts for up to the first 5 minutes. Otherwise the car runs perfectly. Its very strong. No problems at any other rpm range or at cruise control.
The dealership always blames any problem on the fact that it is a tuner car. So I go to an independent volvo repair shop. This is what we`ve done...after checking the codes....and checking for electrical faults and air leaks, used B&G product to clean the intake system and trottle body, changed the coils, plugs and MAF, found a broken brake booster bleed valve and replaced it...but the cold start problem persists.
The repair shop says the last remaining code (381: DIM-000D Communication engine control module(ECM) Faulty signal. Permanent fault.) would require them to reboot/reload the ECM, which may not help anyway but would wipe out IPD`s stage II flash. How could it possibly be the ECM when the car runs fine other than the first 5 minutes?? I think the mechanics are just following the codes instead of using their brains. I would think it must be related to the air/fuel ratio at startup, or this is the very first hints that the throttle body is going bad.
Please help if you can. Thanks, Richmond Va.

 

[PM]

Perhaps the Idle Air Control Pump or a loose or crack hose around the MAF??

 

[mune237]

Which ETM are you on? The original?

 

[LloydDobler]

If you run an oiled air filter, sometimes the MAF can get oiled and start giving faulty readings, maybe swap that or just unplug it and see if it starts better. Also they can do a sweep test on the ETM which will show if it's worn or still okay, it can at least give you a general indication of condition.

 

[foresthump]

If you run an oiled air filter, sometimes the MAF can get oiled and start giving faulty readings, maybe swap that or just unplug it and see if it starts better. Also they can do a sweep test on the ETM which will show if it's worn or still okay, it can at least give you a general indication of condition.

Ok. You`ve all given me 3 good suggestions. I`ll try them out and get back to you. BTW, 90,000 miles and the original ETM. Thanks.

 

[Toronto1]

Before you start the car, unplug the MAF. Right on the MAf there is a connector that plugs into the MAF. Start the car. If the car starts right away, but is a bit rough, then it's the MAF. If you continue to have the same issue, then it's not the MAF. Just a suggestion.

(I know you've mentioned it above, but it doesn't hurt trying this). I had something similar and although Volvo didn't think it was the MAF, it turned out that once we replaced that unit, ($200), the car returned to normal.

 

[foresthump]

I have already replaced the MAF a week or so ago. didn`t help. Also replaced the plugs and coils. Also cleaned the intake system with that BG product.
Still doing the same thing. Have been through my independent repairshop`s attempts to find the problem, (they say I need to reboot/reflash my ECM).I am beginning to believe the car`s ETM is in the early stages of failure, EXCEPT, the problem goes away after just a few minutes and doesn`t reappear until another cold start cycle. If it was suffering a vacuum leak or a bad MAF, or some other chronic failure of some small part, then wouldn`t the symptoms occur at all low idle times? Or, maybe the better question is, what part, or system of the engine, would, after @ 3minutes of warm up, begin to function properly? Thanks again for your thoughts/help. Right now I`m just driving it like normal (after it warms up a bit).

 

[LloydDobler]

Temperature sensors are a good place to start, either intake air or ambient, or coolant. Also when a problem gets that confusing it's a really good idea to shell out the dollars for a shop to pull the volvo specific codes. A lot of my problems have been made very obvious once I see the code for it.

 

[foresthump]

we`d already done the codes; they were for misfiring, maf, and faulty signal ECM....cleared them all except the ECM. checked all the vacuum lines and turbo hoses; and repeating myself, replaced the plugs, coils and maf.
THIS IS IMPORTANT...
Yesterday, while sorting thru the problems, changing the oil...I decided that my 5 year old battery ought to be replaced. Did that. NO More Cold Start Problem. YES. So far at least. cranks fine first time everytime, so far. Its quite possible, that the car, having sat overnight, or for several hours during the day, had enough power to start the engine, but not enough power to fire all the plugs evenly until the alternator ran for a minute or two and gave enough charge to smooth it out. Or so that is what my less than technical brain surmises. An easy fix. Had I only known.