If you remember we were discussing the IAC and TPS problem about a week ago. I did the vent trick to the IAC and now I have it idling. THank you. I have exactly 1 week to get this thing running good enough to make a 250 mile trip. If you have a chance to look these over I would appreicate it. I have a bin file for those of you who want a look and have something to offer. And a TTS file for those who want to see the log. I changed the injector scaler per my tuners instructions, so I dont wash the rings. I believe I have it leaned out a bit since the first time. But if someone would confirm that for me I would appreicate it. ALso if any of you see anything else that would cause a problem on a 250 mile trip, please speak up. This is the last chance I have to fix it before I drive it to the dyno and my tuner. I dont need it perfect, just limpable to get it to the shop. Thanks to all, for the advice and views.

Tunercat Bin File

TTS Datamaster log


Q

 

Q,

I looked at your Datamaster log and the problem I see is that you are still having an issue with the TPS voltage. It pretty much stayed at 0.16 volts, a couple times it got up to 0.39V at 20%. You also have a DTC 22 TPS Circuit signal voltage low error. Which according to my '95 service manuals is as follows:

Circuit Description:

The Throttle Position (TP) sensor provides a voltage signal to the PCM that increases as the throttle blade angle increases. This signal voltage will vary from approximately .5V at idle to 4.8V at WOT. The TP sensor is one of the most important inputs to the PCM for governing fuel control of the engine.

DTC 22 Will Set When:
TP sensor signal is less than .2V with engine running, and RPM greater than 400. Condition must be met for 3 seconds.

Action Taken (PCM will default to):
The PCM will determine fuel and air calculations using calibrated values from a default table. The transmission will have maximum line pressure, no TCC and no 4th gear in hot mode. The MIL will become illuminated.

DTC 22 Will Clear When:
A current DTC 22 will clear when a low signal voltage below the calibrated DTC 22 threshold is no longer detected. A history DTC 22 will clear after 50 consecutive ignition key cycles without a current DTC 22 being stored.

Since we know that you are under .2V, disconnect the TP sensor and check the voltage between the gray and black wire, it should display over 4.0V. If it doesn't probe the black wire with a test light connected to battery +. If the light comes on (or have over 4.0V with meter) then the gray wire is either open or shorted to ground. If not then the black wire is either open or shorted to ground.

The gray wire is a 5 volts buffered reference signal. If it's shorted to ground, DTC 22 will set.

The dark blue wire is the signal wire back to the PCM.

I would get a DMM and start checking voltage and ground at the TP sensor to see if those are okay, if they are then check continuity of the dark blue wire from the sensor back to the PCM.

Get in touch with me if you need some help. I could come up there Sunday morning if you need more help.

 

Yeah, thought we had been through this before. The TPS is all whacked out. Apparently not enough voltage at key ON for the pcm to initialize the reading. The TPS percentages are messed up because of that. The voltages/percentages jump all over and don't relate linearly to each other as the log plays.
Get that fixed an then move on to the next problem.

 

The PCM does have an auto zero feature built in, but the TPS voltage needs to be between .3 and .9 volts at startup. The PCM will then use that value as closed throttle.

 

Thanks guys, I will try it again. I thought I had it ovaled right. Man I hate the electronic part. I'm so much better with the engine part.

Q

 

If you wanna try another TPS, i've got some laying around. Just send me a couple bucks to cover shipping

-Shannon

 

Turn the key ON (not start) and fire up your Datatmaster. Loosen your TPS screws and move the TPS you slotted until you get at least .3v with the throttle closed. Tighten the screws. Turn key OFF for 5-10 seconds. Turn key back ON and see if the voltage is still .3v or so. If it is, fire it up and see how it does. If not, readjust.

 

And my optimum setting would be? Just curious.

Thanks for the offer Shannon, I will keep it in mind if need be.

Q

 

Ideally you want to be around .5V but anywhere between .3 and .9 will work.

 

I got it to .35 and set it tonight. I could have gotten as much as .41 but I didnt get you response till after I did it. Runs much better, idles where it is suspose to. But now the IAC is running around 108. I will post the logs tomorrow, and you can see what a difference it made. Thanks to both of you!!! I will have another post tomorrow after the exhaust is put on and let you guys have a look.

Q