04 Volvo XC90 6 Cylinder Stalls [ blue streak aftermarket junk MAF ] Topic is solved

diydad · Post by **diydad** » 29 Jan 2020, 07:10

A Hi Everyone,

We have an 04 XC90 which runs amazingly besides the stalling issue. When running it seems that she generally stalls after accelerating to between 2000 to 2500 rpms.. This is usually noticed after acceleration and while coasting I notice that she is beginning to sputter as the rpms will dive below 500. Now, if I peg the accelerator she will pull herself out of the slump and rocket to about 3000/3500 rpms. As long as I am giving some throttle consistently, she will maintain and run pretty well. This typically happens within first 15 minutes of running. As a matter of fact, if started cold and left she will almost always die after idling in park for 12-15 minutes. I got this car for a pretty good deal and have tried some things that needed to be done regardless in order to get her up to speed. They are as follows: New Maf, New ECM, New Alternator, New Pipes for Intercooler-Turbo-Intake, Injectors pulled and cleaned, intake manifold pulled cleaned and replaced with new gasket, vac lines new and POV system cleaned, new coils and plugs. Have done fog test and she is tight as drum.
After all this She is still throwing a MAF code which will go away for about a week if I put a brand new one in. I have replaced the MAF twice, cleared codes and she will run perfectly for a week. That being said, cleaning the MAF doesn’t seem to help the issue as I have been doing this on a weekly basis.

After writing the above, the following happened:

So, when idling in park I decided to watch the MAF reading and graphed it from idle to about 2500 rpm.. The MAF reading stayed at .25 gr/sec. and did not fluctuate after giving throttle. Thinking that it could be symptomatic of a short, I went out and checked the MAF wires and wiggled them to see if I could disrupt the signal. The only way I could change the reading was to unplug the MAF which sent the reading to 0 gr/sec. so I then decided to clean with MAF cleaner once again. After cleaning the MAF, I plugged the tuner back in and started getting readings on the MAF. The reading at idle was 3.25 gr/sec and moving up accordingly with throttle which gave me the idea that the MAF was getting dirty fast (Although visibly looked clean). I also sealed up the airbox as I thought some cold air/dust could be seeping in around the seal. So after doing this, I took her for a short 5min spin and the MAF worked perfectly until I returned and left her idling in the driveway. After idling appr. 5 min. the engine stalled. When I cranked the car again, I checked the MAF reading at idle and now it has gone down to 0 gr/sec.. At this point the MAF doesn’t appear to function or could the computer have turned it off? Could the MAF have gotten that dirty in 10 min of runtime?

Thanks in advance!

Post by **RickHaleParker** » 29 Jan 2020, 07:34

Are you using MAF cleaner to clean the MAF sensor? Anything else can leave a residue behind that will effect the sensor performance.

The Thermal mechanics of the MAF sensor is real touchy.

A residue from a Non-MAF cleaner can bond to and hold particles too small for the air filter to trap.

Clean and inspect the electrical connector to the MAF.
MAF Cleaner works good on the electrical connector.

Is the bottom of the Air filter box clean?

diydad · Post by **diydad** » 29 Jan 2020, 07:48

Have never used anything other than MAF sensor cleaner to clean the MAF. Have also cleaned the pins and the inside of the connector. Bottom of the air box did have some light dust when I opened it and I cleaned it upon seeing it. Could I have stirred up enough dust to dirty the sensor again?

Post by **RickHaleParker** » 29 Jan 2020, 08:02

diydad wrote: ↑29 Jan 2020, 07:48 Bottom of the air box did have some light dust when I opened it and I cleaned it upon seeing it. Could I have stirred up enough dust to dirty the sensor again?

You may of loosen up some dirt when you cleaned the bottom of the air box. Might be better to remove the Air Box, wash it with soap and water, let it dry then reinstall. .

Check for Air leaks after the MAF. You can use starter fluid to find Air leaks. Spray around the joints if there is a leak it will suck in the starter fluid and you will hear the engine surge. Take the bellowed section out, stretch it, look for cracks in the valleys.

Post by **RickHaleParker** » 29 Jan 2020, 08:17

Does your Fresh air hose to the turbos have the boxy baffles on the sides of the pipes? The rubber seals on the baffles can leak.

diydad · Post by **diydad** » 29 Jan 2020, 08:45

RickHaleParker,

No baffles on this one. They are straight and we’re pretty easy to clean. I am getting ready to reinstall the air box now and see if the reading changes. Thanks for the advice I knew these maf sensors were finicky, just did not know how much.

diydad · Post by **diydad** » 29 Jan 2020, 08:57

Ok so cleaning done and everything reinstalled. Started cold and surged just a little hunting but I have readings on the MAF from 3.5 gr/sec and responding well to throttle. Going to drive it around for the day and see if the issue resurfaces.

diydad · Post by **diydad** » 29 Jan 2020, 09:16

Did not make it out of the driveway before the engine stalled. Cranked right back up but MAF shows no reading once again.

Post by **RickHaleParker** » 29 Jan 2020, 23:56

Any DTCs ?

diydad · Post by **diydad** » 30 Jan 2020, 10:38

No DTC’s but the P0102 did pop back up. Drove all day yesterday and the P0102 actually cleared by itself while driving. Maybe that indicates it was functional to some extent. Driving with the sealed up air box and the fresh clean definitely helped. Cranked up this morning and the MAF was working again according to the tuner. Have cleared the code and MAF still showed normal readings as the vehicle idled for exactly 20 minutes this morning and stalled. Upon cranking back up 1 minute later there is a check engine light and the P0102 has come back. On checking the tuner, the MAF is showing a 0.00 gr/sec reading again.