V70 died. installed new MAF. idle insanity ensues.

pablotar · Post by **pablotar** » 03 Jul 2010, 22:06

Hi, I was driving my trusty 1998 v70 (non turbo with 138k miles on it) home when the tach went bonkers and basically died on me. I was able to restart the engine and since I was headed downhill, i was able to coast home. I called my regular volvo guy and he was away for the week so I took it to one of those chain places(I know, I know). They tell me it's the MAF. charge me $450 to replace it.
Car drives ok for about 10 minutes as soon as it heats up, the idle goes bonkers again.
I take it back. they said there was a vacuum leak. It drives ok for a day and a half, then the idle starts going bonkers again.
I decide I'm going to investigate.

Before this happened the car had always performed flawlessly, so I couldn't figure out what the hell was going on(It's about time for me to change the timing belt and water pump, so I really don't want to throw money at the idle issue, plus, I want to make sure it's resolved before any other work is done).

For the following two weeks, I've combed these forums looking for info on what it could be; I spent time tightening all my hoses, changing out all the vacuum elbows. I cleaned out my idle valve. I did a complete pvc change, which sucked.
I changed the coolant temperature sensor 'cause I heard that could cause a rough idle. I tried a new(used) fuel pump relay. I changed out the coil. I would have swapped out the camshaft position sensor if I would have found one at the junkyard.

I finally came upon a post that said to disconnect the MAF and see how that runs and the bastid idles perfectly!
I wish I'd tried that first! Although I must admit that I feel like I have a much greater understanding of the workings of the car and I'm confident I can do the timing belt and water pump and mostly anything else on the car myself now! Thanks to you guys!

Anyway, if the MAF going bad is what caused the car to stall originally, how is it that I can drive with it unplugged, with no issues?

Post by **j_cd** » 03 Jul 2010, 23:02

If a new MAF was just installed, it shouldn't do that. Other components I would check are the Idle Air Control Valve and Throttle Position Sensor. Both are fairly simple to replace yourself... so is the MAF. I did the same thing though, paid a mechanic $400 to replace it. That was before I started working on the car myself. In my case it did cure the stalling problem.

Post by **egads** » 04 Jul 2010, 04:05

Was the MAF OEM? Volvos are not keen on non OEM MAFs. Also might be worth disconnecting the battery and draining the residual charge by pressing the brakes until the brake lights go out then reconnecting the battery. Make sure you have your radio code before doing this. This will force your ECU to relearn what fuel to use when and should let it use the MAF signal correctly.
Hope that helps

Post by **Pauloil** » 04 Jul 2010, 06:21

I think the mech put a bad MAF in.

pablotar · Post by **pablotar** » 04 Jul 2010, 10:27

HI, thanks for the replies.

I'm sure it's the MAF, as it says rebuilt and it looks like a cheapie. Like I said earlier, car idles perfectly when the sensor is disconnected.
I'm going to take it back to the mechanics and do a simple demonstration of the car running with and without the sensor in place. After this I'm going to demand that they get me a new quality one.
While I understand that mechanics have to make a living, I'm actually kind of pissed that they charged me so much for the labor, when it's such an easy part to swap out.

Back to my original question; if the car was un-drivable when the sensor went; why am I able to drive it with the sensor off now?

Post by **Volvo_240_Atari_2600** » 04 Jul 2010, 11:25

pablotar.

I feel your pain with the mechanics.
One: They should know better but at these chain places, 99.9% of the techs know nothing about Volvos and think that ever car is the same. Not the case.

Two: With that said, they sold you a cheap (rebuild) MAF for $400 when our cars DO NOT accept the cheap aftermarkets or rebuilds. They want Original BOSCH and as you now know how to change one out, look at what a new BOSCH MAF will cost from FCP

http://www.fcpgroton.com/product-exec/p ... gory_id/10

Now I do not want to add insult to injury, but allways try to read up on your car's problem first before going to the mechanics. This will always help you sound asertive and knowledgeable about your car before they lay a finger on it.

Below is a thread I started when my 98 v70 had the same issue of choking, stalling, bucking and acting erratic. I read and read till I was able to go ahead and move forward on my own saving a ton of money from the thieves.

https://www.matthewsvolvosite.com/forums ... =1&t=26103

Now to answer yur last question... For me it is hard to say but from what I understand, our cars will start and run w/ the MAF disconnected and will run better than if connected to a faulty MAF, however, it will not run like it should. You should notice the slight hesitation upon acceleration with it disconnected, but that test is the ultimate to diagnose if your MAF is at fault or not

Tell the shop that you want BOSCH original and not a rebuild and that they should have been able to know this. Print this thread as well as mine and the FCP listing and explain to them that you really want a replacement at no additinal cost. I am sure they will get a credit on their cheap rebuild and they can easily buy the one from FCP and they are still making money.

Goog Luck.

bobice · Post by **bobice** » 04 Jul 2010, 20:28

pablotar wrote:HI, thanks for the replies.

Back to my original question; if the car was un-drivable when the sensor went; why am I able to drive it with the sensor off now?

The car runs at "limp mode" when the engine runs at a preset setting, if the MAF is disconnected; you should see the radiator fan is on constantly.

pablotar · Post by **pablotar** » 15 Jul 2010, 17:29

Thanks again for the replies, everybody. I went back to the place and told them that the sensor was bad. The guy looks at me and says ok, we'll check it out.
6 hours later, he calls and says "yeah, the mechanic says that your sensor is probably bad".
I told them I wanted an oem one and not a cheap rebuild and he told me they didn't use rebuilds. He was surprised when I pointed out the sticker on it that said remanufactured.
Car runs perfect now.
I was a little worried because I tackled the timing belt and water pump before the issue was resolved( I have no patience) but it all worked out in the end.
Now I just have to tackle that loud noise when opening the door. . .

kahf2008 · Post by **kahf2008** » 15 Jul 2010, 17:31

you go online to ebay.com and you ll find plenty, 40 bucks, I had the same issue with my 850, I still have a new standard one that it made me stuck in the middle of the road just 1 mile away from home.