Peake code 90 and 91

taninbim · 16th June 2012, 06:23

While driving today, I noticed that my throttle was acting very strange. My car was suddenly very jerky and almost stalled on me a few times. After reaching my destination, I let the car idle for a bit and all seemed OK. I parked and went on with my business. When I tried to start the car again, the engine would turn over and fire up, but wouldn't stay stable and the rpms would eventually drop to a point where the car would stall even with some throttle applied.

After getting home with the help of a tow, I looked up what he problem might be and found JoeFromPA's recent post, which was very handy.

Suddenly stranded? Testing your fuel tank levels, fuel pump relay, and fuel pump in 10 minutes with a piece of copper wire

Unfortunately, I don't have a copper wire handy so I cannot test the last step. My question is this: if the relay still makes a click when the ignition is in position #2, could it still be faulty? I had a friend help me with that test and I can feel the initial click when the key is moved to position #2.

Given that the car will start up, I think that the fuel pump might be OK, but I certainly could be wrong. After a bit of searching, it could be my fuel trim levels or even the MAFS from some of the posts that I read.

I'm trying to see if I can get a bit more diagnosis done before spending money on parts that I might not actually need. In the meantime, I'll see if I can find some copper wire.

Thanks.

Sailor24 · 16th June 2012, 06:44

Need more info. What are your running symptoms if any. Have you tried unplugging the MAFs, what changes do you note?

taninbim · 16th June 2012, 07:10

Quote:

Originally Posted by Sailor24

Need more info. What are your running symptoms if any. Have you tried unplugging the MAFs, what changes do you note?

No, but I should have looking in hindsight. It looks like bad MAFS.

When the MAFS are plugged in, the car will now run for a few secs before stalling out (no throttle applied). If I unplug the MAFS, the car will remain stable and settle in around 600-700 rpms with some minor idle hunting.

I was so focused on the fuel pump and relay that I didn't think to check the MAFS by unplugging them. Greatly appreciate the help.

Sailor24 · 16th June 2012, 07:25

Your description looks like Mafs so keep them unplugged, you will get codes and your IAT will not be plugged in but.... If you feel the car overall performs better then invest in MAFS. The new MAFs will knock you socks off.

taninbim · 16th June 2012, 21:04

Might be more than the MAFS.

If I keep the MAFS unplugged, the car will continue to run on idle. However, with any throttle and engaging the clutch, the rpms will suddenly drop possibly stalling the car. Letting up on the throttle might recover the situation.

I can read the following Peake codes.

29 = MAF 1
39 = MAF 2
90 = fuel control, bank 1
91 = fuel control, bank 2
01 = fuel relay

The last entry, 01, is actually new. It only showed up today when the CEL came on.

Sailor24 · 16th June 2012, 21:33

Often it takes more than one thing to be wrong before they act up. They adapt so well. With the Mafs unplugged the will have some hiccups.
The real story is hidden in the 90 and 91 but you likely have no way of reading the long term fuel trim. Do you know anyone with an OBDII code reader those codes will tell you rich or lean.

taninbim · 16th June 2012, 22:00

Unfortunately, I don't know of anyone with a reader.

I plan to replace the relay and MAFS for now. Hopefully that will get the car back into a usable state and I can take it in for further diagnostics to check the fuel trim levels.

taninbim · 20th June 2012, 01:21

Replaced the relay today and unfortunately no change in the symptoms. The car is still not drivable. Also the car is now stalling after idling for a few mins even with the new relay and the MAFS unplugged.

Sailor24 · 20th June 2012, 01:32

Have you tried jumping the relay?
Suddenly stranded? Testing your fuel tank levels, fuel pump relay, and fuel pump in 10 minutes with a piece of copper wire
After that you need to get a fuel pressure gauge and or someway to read fuel trim and calc load +g/s air going thru the MAF.
Short of that plug the Mafs back in and drive it see how it drives. I suspect it will do well for a bit then act like this again. Then you will be able to unplug the MAFs and it will be fine for a bit then go back to bad.
If you plug the MAFs back in and the car runs wellish do a MAF test(know what I mean) before the car changes.

taninbim · 21st June 2012, 03:41

Installed the new MAFS today. So now new MAFS and new fuel pump relay. Unfortunately, no change in the symptoms. Since I don't have a more detailed reader, I brought it into a local shop for further diagnosis.