2001 V70 mechanic is stumped -- stalling at idle, no codes

eric v70 · Post by **eric v70** » 08 Jan 2015, 00:53

stalls at idle (upon deceleration...), seems to be ok when the engine is cold but after a few minutes it dies at every stop. other than that runs very smooth and starts right back up -- and then will idle -- but start to drive and as soon as the foot comes back off that pedal it's done... Took it to a volvo mechanic and he says he has never seen something like this, been working on volvos for 30 years... No engine codes (with the volvo software, not just an OBD scan...), passes the ETM test... fuel pressure is good...

regarding the deceleration part -- if it you start it up and let it idle, you can put it in gear and idle forward or reverse and it won't die, but if you give it any gas as soon as you let up it dies...

if anyone has experienced anything like this and has any suggestions it would be greatly appreciated -- I think the mechanic is going to tell me to part it out and get a bicycle...

thanks

Post by **abscate** » 08 Jan 2015, 01:12

Sounds like a large vacuum leak somewhere. Brake booster perhaps? Do the brakes feel normal?

eric v70 · Post by **eric v70** » 08 Jan 2015, 09:33

Yes, brakes are good... wouldn't vacuum leak of that severity cause some codes to come up?

Post by **jimmy57** » 08 Jan 2015, 09:46

Passing ETM test doesn't mean it is not the ETM.
Has the ETM been removed and checked for any binding?
Is the throttle bore clean.
Another possibility is bad battery. If the battery is weak then cranking the engine will drop the voltage enough that the ECM/ETM can lose its idle control memory. IF it is this then the problem would be better after it is driven without having to be restarted for a time. Te idle control is relearned by going off idle, back to idle, and in gear and out of gear several times once engine is fully warmed up.

donis222 · Post by **donis222** » 08 Jan 2015, 09:57

I had a pull out your hair problem with my 99 v70, no codes and drive cycle tests would not clear.
Finally, I started just replacing or checking parts. Started with MAF, then ETM. Bingo!
The original ETM had a problem with no indications. Look ETM up here on this site and you will find some like your problem.
ETM's are expensive. I found a clean one from the same year, model and part number the same, in a junk yard.Pick and Pull --$45.00.
If you aren't careful these can require a software upate.

draser · Post by **draser** » 08 Jan 2015, 11:49

My cheapo Torque app shows throttle position, so if you have a similar scanner may want to check that parameter. I have 12.2% on fully warm engine at 670 rpm idle.

eric v70 · Post by **eric v70** » 08 Jan 2015, 13:03

I had originally suspected the ETM so I pulled and cleaned it -- it wasn't really dirty but I did it anyway and no change. Throttle moved freely. I cleaned the MAF sensor too and tested it with a multimeter and it rose steadily with rpm. I was expecting the ETM to be the problem since it is the "white sticker" but it ran so smoothly and even idles smoothly (when it idles) so I didnt want to start buying parts until I knew it was the problem.... and it is a brand new bosch battery. Is there any physical way to test the ETM simce it seems to be working within the computer's specs?

eric v70 · Post by **eric v70** » 08 Jan 2015, 13:07

donis222 wrote:I had a pull out your hair problem with my 99 v70, no codes and drive cycle tests would not clear.
Finally, I started just replacing or checking parts. Started with MAF, then ETM. Bingo!
The original ETM had a problem with no indications. Look ETM up here on this site and you will find some like your problem.
ETM's are expensive. I found a clean one from the same year, model and part number the same, in a junk yard.Pick and Pull --$45.00.
If you aren't careful these can require a software upate.

I thought I would necessarily have to update software -- if there is a way to put in a used one without the update please advise, that's $160 I'd rather keep for tacos : )
mechanic said I already had the newest software installed...

eric v70 · Post by **eric v70** » 08 Jan 2015, 15:57

Update:
Mechanic says manifold pressure sensor is either not working ($100 fix) or the CEM isn't reading it (not worth fixing)

We are replacing the manifold pressure sensor and keeping fingers crossed...

eric v70 · Post by **eric v70** » 21 Jan 2015, 00:16

UPDATE:
map sensor wasn't the problem, so mechanic just unplugged it and it quit stalling -- the assumption nownis that the ECM is faulty... but now a new problem :
The third time it was driven the engine was accelerating as if the pedal was about 20%... just idled up to about 20 mph or redlined when put into nuetral or park.... so the wife parked it and took a cab home.
can't say I blame her....
next day it drove fine, but no way convincing the wife to ever get in that car again, especially without a firm diagnosis of the problem...
so -- does this sound like an ECM and can a salvaged one be reprogrammed? They are really cheap on ebay so worth a shot...

Any input? Am I on the right track here or is it time for a new car?