Eureka! 2 MAF Sensors, 3 Computers, 1 throttle body, and several sensors later!!!!

[jameskjeldsen]

2002 Saturn L 300
112K miles

I wanted to share my eureka moment with anyone who comes across the same issues that I have had. I have read several posts on here describing similar issues to mine - but never really saw one that came to complete resolution. The story starts over 4 years ago...

Problem started when my wife (trying to be helpful) took our 2002 Saturn L300 to a Fastie Lube to get the oil changed. After the oil was changed - car would not start back up. Took the car to the Saturn dealer we had bought it used from just a year or two previously. They replaced the computer on the car and returned it to us. There were some minor bugs when we got the car back (headlights bright/dim switch seemed to be reversed from what it should have been). So we took it back and the replaced the computer again - didn't seem to have any problems after that for a couple months.

Then the car began to stall out at high speeds, had a rougher idle, and began to throw codes. All seemed to correspond with needing new Cats. Took it in to a non-Saturn exhaust shop and got the new cats put on. Car drove ok for a few months. Then the rough stalling out idle came back. At the same time I began to see some antifreeze leaking down the front of the motor (from the water pump). Car was parked for a few months until I had time to replace the water pump and timing belt (fun process - but used the binder clip method outlined on another post from this site which worked great). Then the car needed to be smogged and had started throwing codes about the MAF sensor and throttle position sensor (yeah - the one that is part of the $350 throttle body). I replaced the MAF sensor a with an after market replacement from one of the national parts stores. It was ok for a day or two then started acting up again and threw a MAF sensor code again...back to the parts store since several posts on here said it was common to get a bum one from time to time. Put MAF sensor number two on car - lasted maybe a week. Car still had rough idle when warmed up and was slow at first to pick up speed when engine was cold. Started getting codes about the throttle position sensor again. I went to a junkyard and found a throttle body that was a little rugged - but after putting it on the vehicle did not seem to make anything better or worse. Got ticked off and with the upcoming smog needing to be done - took it to another non-Saturn mechanic. When I got to the mechanic's shop the computer started wigging out and crashed n fried -- had to push the car into a spot on the mechanic's property to wait the month it took him to get the backordered computer and have it programmed and returned (or at least that was the story I got - although I do trust this guy). He put the computer on and the car was running again but was still sluggish and didn't seem to have the great idle it used to.

Was at a parts store a few days ago (like I said this is now four years from the start of our problems - with the car having gone several periods of sitting for months at a time because it was just not reliable). Out of curiosity I asked if they had a new throttle body in stock (thinking that maybe with the new computer - if I just put a new throttle body on - that might do the trick. They actually did and had a pretty reasonable price for it. So I got it and put it on (with a new gasket which I had to buy separate). Same hesitation - same idle problems. Started throwing another MAF sensor error. GGGGRRRRRRRRRRRRRAAAAAAAAAA!!!!!!!!!!

Got mad - wanted to rip out every sensor in the (*)&(^*&^%&^* car and replace. Cooled down and took out the MAF sensor again, MAP sensor, and EGR (it was in my view also). Back to the parts house. Lucky for me they didn't have the MAF or MAP in stock but they did have the EGR.....OK Whats another $150 at this point??? Replaced the EGR, put the maf and map back - and TADA!!! Car runs like a champ again!!!

Made me think back to some of the other symptoms. The lack of power when starting off and when running (or stalling more like it) at idle - egr was probably pegged wide open and it was recirculating that crap (the stuff it picks up from the exhaust to recirculate and complete burning) - it was snuffing out the combustion. The higher than normal temperature - not by much - car normally runs between the 1/4 and 1/2 mark on gauge - it had been sitting at the 1/2 mark during all of this = caused by recirculating the hot exhaust constantly with the stuck open egr valve. This was also causing the intake manifold (or whatever that's called on these new engines) to get hotter than it should have. (Possibly frying the computers repeatedly). This also was probably the cause of the CAT failures - and thinking back I had seen the primary cats get visibly hot one time when I only had driven around the block.

Long story short. If you have similar issues - even if there is no indication from the computer codes that there is anything wrong with the EGR - keep that in mind. And if you have CAT failure - consider replacing the EGR - what is another $150 - $300 bucks when you are already paying $1000+ for the cats to be replaced?

I worry that the additional heat and improper burning may have done additional unforeseen damage which will come up in the future - but thanks to everyone who posts on here I will be able to address those when I get there! Thanks and hope this helps someone out there.

[jameskjeldsen]

PS... I was about ready to junk this car and get something else - but at 112k miles and paid off - the though of a payment on a new car hurt almost as much as the migraines I was faced with from fixing this car.

[born again]

Well, I don't know whether to commiserate on your troubles or congratulate you on finding the problem. Perhaps both are in order.