Electrical New member needing help..codes 42,92, 12, cyl8

[89Stanger]

Hello, I’m Ruben..I have a 1989 5.0 that sat for 13 years, here is what I have replaced:
New fuel tank, fuel pump, 19lb injectors, FPR set to 39lbs at idle, EGR, TPS set to .98v, new 65mm TB, IAC, BAP sensor, replaced all vacuum lines and smoked system, had ECM reprogrammed…car runs but has black smoot out the exhaust and after about 30 minutes driving it will surge while in gear but settle in Park and neutral.
OBD codes 42, 92 voltage reading at ECM pin 43 is .999v and pin 29 is .990v steady and does not fluctuate.
I have checked ground on orange wire for O2 sensors and it’s good, and checked the fuse link also good.
Vacuum reads low at idle between 15-18hg
Fluctuating.
Any help is appreciated, Thank a you

 

[General karthief]

I think the fuel pressure at idle should be 32-4 psi and what do you mean by 'had the ECM reprogrammed?

 

[89Stanger]

Sent the ECM to get fixed…had a few blown resistors and wasn’t reading the o2 sensors

 

[90sickfox]

You need to check the o2 sensor harness. The 5 speed and auto harnesses are different but can be made to work for either by moving the jumper wire.

Electrical - O2 harness repin

This thread is a HOW-TO for the process of repining the o2 sensor harness to match ECU/Trans, in the event the car is swapped. See post 15 as to what the jumper should be repinned to. Step one. Remove the o2 sensor harness from vehicle. I find it easier to do on a bench plus it allowed me to...

stangnet.com

Now, those readings would indicate pegged rich. Check the FPR vacuum line. It shouldn't smell like fuel or be wet.

What color are your fuel injectors ? Didn't notice mention of the MAF. Is it the correct one for the injectors ? Bigger injectors than the MAF is calibrated for will cause this issue.

Is your manifold vacuum line hooked up to your MAP sensor ? 89 doesn't have a BAP.

( The next paragraph leaves out timing, load sensing, idle control, and several other systems that the computer uses to control the car. )

These cars are pretty simple. Maf reads air volume, computer reads it, uses reading to control injectors, computer reads o2 sensors to verify fueling conditions. Computer compensates fuel injection by the 02 sensors readings. The o2 sensors don't talk to the computer right away. Once engine is warm car goes into " open loop " and everything starts talking.

To test the o2 sensor you can take it out of the pipe, plug it back in, and run the car to operating temperature. The reading should be below .5v ( really more like .2v ).
The best way to test an o2 sensor is with an oscilloscope but ya gotta do what ya gotta do.

 

[89Stanger]

You need to check the o2 sensor harness. The 5 speed and auto harnesses are different but can be made to work for either by moving the jumper wire.

Electrical - O2 harness repin

This thread is a HOW-TO for the process of repining the o2 sensor harness to match ECU/Trans, in the event the car is swapped. See post 15 as to what the jumper should be repinned to. Step one. Remove the o2 sensor harness from vehicle. I find it easier to do on a bench plus it allowed me to...

stangnet.com

Now, those readings would indicate pegged rich. Check the FPR vacuum line. It shouldn't smell like fuel or be wet.

What color are your fuel injectors ? Didn't notice mention of the MAF. Is it the correct one for the injectors ? Bigger injectors than the MAF is calibrated for will cause this issue.

Is your manifold vacuum line hooked up to your MAP sensor ? 89 doesn't have a BAP.

( The next paragraph leaves out timing, load sensing, idle control, and several other systems that the computer uses to control the car. )

These cars are pretty simple. Maf reads air volume, computer reads it, uses reading to control injectors, computer reads o2 sensors to verify fueling conditions. Computer compensates fuel injection by the 02 sensors readings. The o2 sensors don't talk to the computer right away. Once engine is warm car goes into " open loop " and everything starts talking.

To test the o2 sensor you can take it out of the pipe, plug it back in, and run the car to operating temperature. The reading should be below .5v ( really more like .2v ).
The best way to test an o2 sensor is with an oscilloscope but ya gotta do what ya gotta do.

Thank you for this I will check it all as soon as I get a chance.. got other cars to get out of the way but I will try all this within the next few days and get back to you with results..