kruqnut

when testing the MAF with a DVOM what exactly am i checking for? there are 3 wires to my MAF, a yellow one on the left, a black one witha white strip in the middle, and a red one on the right. Which one do I want to check? I tried myself and one of the wires read 4.53V at idle, and dropped down steadily to 4.0V when i increased teh throttle to about 2500 RPM. I didn't test the black wire witha white line in it, the other wire read 14V so im guessing that was the power feed.

kruqnut

ok so I just figured out my s-10 has the same MAF sensor, So I took the sensor off my s-10, cleaned it, and put it on my monte carlo. I started it up, the injectors were pretty loud, but they usually are when I first crank it. Then I ran a bit, it misfired alittle but then it started making it to 4k rpm, and the rev limiter, So I took it on the road and punched it, it worked fine, I drove down the road with the occasional hiccup but it climbed to 6k RPM then cruised at 8- mph fine. I turned around to come back, and punched it again, and then it started missing again and I'm right back where I started. I don't know if it was working good because the engine was really cold or what, It threw no dcodes and now I'm back to where I started, I'm so confused and disapointed with the false hope I was given.

any ideas?

Mike Sigmond

Well its hard to diagnose things over the net sometimes, were just trying to help you out.

kruqnut

Ok I ran it a bit more and got the original symtoms again, except worse. I went about 4 miles to the gas station, when I pulled in, it died. I put 5 bucks in the tank then I was gonna ride softly to autozone since at lower rpms it seems to be fine, well not now. I pulled out of the gas station and it started bucking at around 1500 rpm, the tach would drop and jump all over the place. So I turned around and drove home. Even with my foot off the gas and cruising it would want to die, the tach would drop 500-600 rpm and I still couldn't get it to go over 2500 rpm, also when I pressed the gas sometimes it would seem to do nothing, Obviously this problem gets worse the more warmed up the car is, and first thing in the morning with dew on the car it managed to get to 6k rpm. I read somecodes and got a new freeze frame data from when i unplugged the MAF I think tho I may be wrong, heres the info it put out tho.

MAybe its an electrical wiring problem? I don't know.

p0102

Load 1.1%

2610 RPM

MAP sensor 37 KPA

Air Flow Rate 1.90 GR/sec

Throttle position 16.4%

Coolant temp 197 degrees.

Fuel trim same as above

Fuel system open.

If I goto I/M monitor it says OK or N/A or INC, no fails.

It threw p1676 again as well I guess I need to check that wiring as well.

Hope some of this helps, and someoen can figure out what -96.7% short term 3 fuel trim is.

kruqnut

nothing towards you guys, just it ran good for 5 minutes when really cold, I had my hopes up.

Mike Sigmond

Id wait and see if one of the shop techs here have any input on the 96.7% fuel trim. It could be many different things.

kruqnut

will do, seems to be my biggest lead as to the cause of this problem. My fuel trims are teh same in every code, whetehr the code was set while the engine was running, idling or whatever, i always see teh same numbers. I just want to find out what is wrong with it so i can start fixing it, this trial and error **** is why i never went into repairing things, I work on computers too and it's the same crap.

kruqnut

I got another p1676 code so I'm really starting to think this has something to do with fuel tank vapors constantly flowing into the vehicle maybe?

I noticed my fuel trim hasn't changed in this code, I read that the PCM doesn't adjust anything untill the engine goes into closed loop? So why would my engine not meet closed loop requirements?

Mike Sigmond

Closed loop is in the o2 system, its used to bypass the o2 senors until the sensors reach operating tempature. It shold be open loop at cold start and they should close and begin sending the o2 data once the motor basically warms up.

kruqnut

I think I may be stuck in open loop for some reason because my fuel trim isn't adjusting and everything is running messed up, so what would cause the system not to go into closed loop?