Thought it was the MAF but it was a cracked Intercooler!

Post by **MadeInJapan** » 16 May 2008, 18:50

Ok, so I'm asking for help and that's pretty rare. Don't ask me why but out of necessity, I let one of my son's friends drive my S70... he ran the car off the road. This was Wed. night. No damage to the body but I was happy that I had a skid plate on my car...it saved my oil pan. The skid plate is bent up and scratched pretty good... Nothing else appears out of the ordinary. However, after going off the road, the car wouldn't start. I got a phone call late Wed night that this happened and drove over an hour to go pick my son (who was with him) and his friend up. I read the codes but nothing...the car would try to start then sputter. It was also blowing black smoke. Last time this happened was about 2 years ago and it was the MAF so I remembered that and unplugged the MAF sensor and the car started right up. I let my son (only has a learner's permit) drive the car home with me following close behind just in case. No problem going highway speeds to get home. So the car has sat until this evening when I thought I would try to figure out what's going on. I have the old MAF setting around so I cleaned it with electrical connector fluid...something I didn't do when it went 2 years ago. I put it in and the car came to life for a few minutes and then it died again. NO CODES. I unplug it and the car starts...Code P0102...what you would expect with the MAF unplugged. Tried cleaning and using the other MAF...same thing. Just seems strange because I know when the MAF went 2 years ago, there was a MAF code that came up- this is what sent me in the direction of buying a new one. This time no MAF code at all when it's plugged in- just the symptoms of a bad MAF.

So, my question is, would going over a bit of rough terrain off the road really cause a MAF to suddenly die? It's very strange. No problem right before the "little incident" and out of nowhere this. I'm thinking that it could be something else electrical that doesn't necessarily set a code that depends on information from the MAF....for all I know I've restored both MAFs now to working order but since something depends on it's signal, the car is a no-go...just blows some black smoke and then goes Kaput. I would buy a new MAF to see if things are restored but would rather not if someone can guide me here. I'm thinking that maybe there is a reason the car would run if there is no signal from the MAF at all but if there was a signal from even a good MAF the car won't run.

Any takers on this one? There's a few used MAF's that are suppose to be in working order I'm tempted to bid on tonight anyway...otherwise, I guess I'm in for a new one from Grotton.

drsugg · Post by **drsugg** » 16 May 2008, 19:15

I would think that a fuel return line or the pressure reg may be the problem. I think it located low on the passanger side near frame.Perhaps?

Post by **MadeInJapan** » 16 May 2008, 20:20

Thanks for your suggestions but with the MAF unplugged my son drove the car home without any issue (over 60 miles) so fuel related issues are not the problem I don't think. I just don't want to keep driving it like this...it will foul the plugs and it's just generally not a good idea.

Post by **MadeInJapan** » 16 May 2008, 20:54

Anyone?

Post by **tailor** » 16 May 2008, 23:25

Here goes out in left field suggestions!

Yeah I know no codes!!!!

1) front o2 sensor(maybe got knocked about by stones)
2)computer relearning procedure(60 miles with no maf)
3)obstruction of air flow through the intake vent
4)torn or damaged intercooler pipe/s

a little farther out....

5)Thermostat and or temp sensor gone/going out.

I am sure that all of these have crossed your mind.

somebody

Post by **MadeInJapan** » 16 May 2008, 23:39

I'm going to get up under her tomorrow (well, today) and see what all is wrong....it still could be just the MAF. We'll see.

instarx · Post by **instarx** » 17 May 2008, 00:19

Out of the blue thought - it may be that ambient air temperature sensor data is used in conjuction with the MAF sensor data to determine engine settings. The temperature sensor is down there at the skid plate and may have been damaged. That isn't such a strange idea since the MAF sensor uses a heated-wire resistor bridge that measures how much the hot wire is cooled by the intake air moving across it. That can't be used directly to calculate mass - the Engine Management Computer would also need to know ambient air temperature to do its calculations correctly. Maybe it gets that information from the skid plate sensor.

That would explain why there are no MAF error codes - technically there isn't anything wrong with it; and would also explain the engine running when you disconnect the MAF entirely - the EMC may default to an average value. This is a completely wild guess.

Post by **MadeInJapan** » 17 May 2008, 05:42

Thanks for your guess and your time to respond. Initially I disconnected the plastic skid plate or what is often called the air dam in order to get a look under the front section of the car (turbo hose, etc.) and when I did this I unplugged the ambient temp. sensor. With it unplugged, sure enough I got a code for it. I thought it was the IAC (idle air control) at first from the code (which made sense for the no-start). However, when I discovered that the code was for the sensor I unplugged, I plugged it back in. The information I posted above is AFTER I put plugged the ambient sensor back in and cleared the codes. With it unplugged I got P0112....with it plugged back, I get no codes at all. Of course, when the MAF sensor is unplugged I immediately get P0102 as a code but the car runs. I'm thinking it is the MAF after all. Any other comments are much appreciated.

Post by **MadeInJapan** » 17 May 2008, 11:28

Ok, been under the car now and took the damaged skid plate off. I've found the problem: CRACKED INTERCOOLER!

So that's why the MAF sensor was giving me fits and until I took it and the turbo piping out of the equation, the car wouldn't run. It looks like I also have damage to the front subframe mount. As good as the IPD skidplate is (Yes! it protected my oil pan and engine, it doesn't extend forward enough to keep the front section of the subframe nor the intercooler protected.

Thanks everyone for your help...if anyone knows of a decent used intercooler let me know. It might be time to change to the front IC but I really don't want to put a lot of time or money into this...my car has no mods to the exhaust so I don't see how the mods on the front end are really going to make too much difference to my IPD upgraded ECU/turbo combo.

Post by **tailor** » 17 May 2008, 14:42

4)torn or damaged intercooler pipe/s

Ok! So no cigar ?

Glad you found the problem.
Never loan you car, wife or gun to anybody!!