Still having dtc 33. Heres today data log.

 

Since me last post I found 3 leaky injectors and got those replaced. Now when I try to start car I have to pump gas pedal to get it to start. Definitely having vacuum issues, replaced map sensor, map sensor pigtail and checked all vacuum hoses.

 

Nothing has changed with the latest log file. The vacuum is too low and so the pcm sets a code. I think the sensor is fine since it correctly reads the atmospheric pressure at startup. This is a consequence of having the s/c setup. Get the code programmed out.

 

Ok, now finding someone who tunes, lol.

 

Ok so I downloaded TunerPro RT and read my pcm. How do I program DTC 33 out? Do I set the flag on the map sensor?

 

Are you sure that supports OBD2? Their support page only lists OBD1. At least that was all I say. To the best of my knowledge HPtune is on the software you can get for this type of work on a OBD2 setup. You should find a skilled tuner for your setup, You could gain an amazing amount of HP from a good Dyno tune.

I know you said the car was tuned but the fact you still have the stock MAP sensor and you still have codes active that should not be tells me your tune is less then optimal.

 

I have a 94, it's obd 1. I've already read my pcm. Just need to know how to turn off the map sensor code.

 

My bad, I realized after I walked away from my computer. It had to be OBD1 or it would not have been Code 33. I don't know Gary but I think you will find the less then 5% of the mechanics that work on fuel injection actuality reprogram it. I am sure the software will vary also. This might be a better question at the forum for the software.

Do you know who did the original tune? I would think they would fix it for free.

 

Ok, so I got my map sensor code taken care of. I am still having problems when I put car into gear. Idle's around 900 but when in gear drops to 300-500. I know a lot of that is related to my cam. Looking at my data log I noticed that my spark advance at idle is in the lower 20's but when I shift into gear it drops to 9-12. IAC count is maxed out at 160, shouldn't that be at WOT, not when rpms are low? TPS voltage is at .57, I read in another forum that at idle it should be closer to .67, is this correct? Finally, car battery voltage sits at 13.3v at idle but when in gear drops into the upper 11's like 11.5-11.9

 

IAC motor should close off as the system hands over the RPM control to the throttle plate. You should see the IAC count drop off as the RPMs goes up. At least that is the way the older system I worked on in the 80's worked.

The voltage drop is a symptom of the low RPMs. Once you drop below 600 RPM the alternator is not turning fast enough to make power anymore.

Timing advance table will drop timing advance very quickly at low RPMs in an attempt to keep it from stalling.


It will be tuff to get a good idle with a stock one Bar MAP sensor. Even a stock 2 bar sensor from a super charged GM car would be a lot more accurate but I don't know if you PCM would support and it would need programmed for it.

Is there any chance the IAC is bad/slow or dirty? If an IAC start moving slow you get the up and down surge in RPMs. It is also known as a lazy IAC.