A friend of mine bought a 91 GTA. When we picked it up, it worked ok, as it had stood unused for 1 1/2 yr.

But after a couple of days, it started acting weird. When running in higher rpmīs, thereīs no problems, but when on idle and cruising, it jumps up and down and stutters.

On idle, it smells gasoline, and we get wet spots under the exhaust.

We have set the IAC and TPS. Checked the timing. But we canīt find this thing out. I ran a scan with my TurboLink, but donīt know how to read it, as it differs to my TTA.

Could anybody please help me take a look at the log, it would be VERY appreciated. I donīt know what to do to help him.

LOG-file

Thanks in advance
/Andreas

 

I downloaded the log file but all I get is a handful of strange characters.

AS for the '91 GTA it sounds like the injectors may be bad. It is common for the injectors of that year to have the windings break down and short out. Check them with a DVM (ohm-meter) they need to be between 12 and 16 ohms (each injector).

Another possibility is that the fuel pressure regulator has a pin hole in the diaphragm. Pull the vaccum line off of it and check it for gas (petrol).

Can also run the fuel pump with the hose off and see if any leaks from the vacuum fitting on the regulator.

RBob.

 

Thanks for the info. Gonna check that when in the week.

The log-file is from TurboLink. Itīs the raw data. I have converted it now to a .csv, but everything is compressed into one cell http://www.turbolunkan.com/temp/uffe_040502.csv

/Andreas

 

Took a look at the log file. Most definately a fuel problem, either a leaking/bad fuel pressure regulator or leaking/shorted injector(s).

Look at the BLM & CLCCOR terms, they are used in closed loop to control the AFR via the O2 sensor reading.

Notice that they are dropping to low values, 108 & 109. That is the ECM removing fuel by lowering the injector pulse width. The PW is also in the log and can be seen dropping in value.

The ECM is doing this as the O2 sensor is reporting a rich condition.

RBob.

 

Ok. Weīll take a look at it during the week. I had a thought it could be something with the O2 sensor, but likely not then? Thank You for the info!

/Andreas

 

Ok, the injectors are checked. Five of them where 17ohm and the rest where 4, 7 and 8 ohm. Iīll guess this would be the problem then.

Thanks RBob