MDZ28

I recently swapped the old 95 350 lt1 motor I had with a revamped 96 (just over stock) 350 lt1 (see signature for upgrades).

Anyways we transferred a lot of the old equipment from the previous motor to the new motor as it did run fine and it was a budget job .

The car ran fine for about a week and then the dtc 26 code popped up (which I was already familiar with because the previous motor had the same code). I checked the EGR and actually blocked it off (to eliminate that as the cause).

I also unplugged the AIR pump as I heard that was the correct way to test if the AIR pump worked.

I checked the fuse like everyone suggests and all my fuses have continuity and are fine.

The only thing I have not checked is the Evap canister. I wasn't sure if that would cause my issues though?


My problem is my car runs fine at idle when the codes are cleared. I start to drive and within 30 seconds the SES light comes on and the car runs terrible. No power, sputtering acceleration and just sounds bad.

I can clear the codes when the car is running and the car doesn't feel like it will stall but it still doesn't have the power it should/any power.

That doesn't do any good really anyways because it comes right back on in 10seconds and runs terribly again.

I will say the car smells like its running very rich and the left side o2 sensor is reading higher than the right side o2 sensor at idle left is like 500-850 and my right side fluctuates between 45-150. I replaced the right side 2 weeks ago because I originally thought that was the problem.

Anyways I threw a lot of information out there in this post so I hope you were able to follow it. Any information would help greatly.

Any ideas? Thought? something to add?

shoebox

Code 26 is for EVAP on your car. The quad driver thing only applies to 1993s. The code is for the EVAP solenoid and circuit.

MDZ28

I will check that, apparently I assumed the codes were the same for the obd1 and 2 cars.

I learned a valuable lesson today

I will post if the evap solenoid/circuit fixes the issue.

Skedaddle

Neither of those O2 sensor reading ranges is correct, if the PCM is in closed loop. Both sides should be rapidly cycling over a range of 0xx - 9xx millivolts, with a long term average of 450 millivolts. And each bank is controlled independently, so you will not necessarily see the readings in synch on both banks.

MDZ28

They do cycle higher/lower when I drive but at idle I have noticed them cycling through the aforementioned above.

Thank for the info, I'm testing the evap canister and I'm looking into a new PCM as well.

Injuneer

The PCM rarely fails.

DTC 26 is for the ELECTRICAL circuit on the EVAP purge solenoid, mounted on a bracket on the passenger side of the intake manifold. The code has nothing to do with the canister itself. Check the resistance of the solenoid (harness off the solenoid). Should be 15 - 30 ohms.

MDZ28

Thank you, the reason why we thought it was the pcm failure was because someone wired an extra green wire to my pcm that went through my fire wall into home made switch under the dash. This wire was also wired to another ground wire which made no sense.

When we fixed this the power doors, oxygen sensors, AC, and (ignition problems) all started working again. The evap solenoid was the only thing it did Not fix however.

I will check the solenoid's ohms tomorrow evening and get back to you guys with my findings.

Thanks,

Ryan

Injuneer

You should also have 12 V on the brown wire at the solenoid connector with the key in "run". The PCM provides a pulse width modulated ground on the other wire to open the solenoid. That is harder to check since there is typically no EVAP purge at idle.