Cutting Back, Stalling, Cel, Ect........

Discussion in '1994 - 1995 Specific Tech' started by from6to8, May 19, 2014.


  1. from6to8

    from6to8 There's suction so I used that end O_O

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    Ok guy's I had a broken spring and slightly bent valve on the no. 2 cylinder that and replaced all the springs as well as that exhaust valve. Also changed the cam ( well had it regrind) and the specs are 275/283 with a 330 lobe lift. Guy from Texas quote was that cam will whip any FMS cam. He tested and compared on the dyno and at the track and his is wayy more drivable as well. I talked to this guy extensively and he has helped me with a lot of things I never did before as far as installation and such, all thru texting and phone calls.

    Got the car back together and it is running well, nice and strong but I am having an issue with surging when come to a stop it will surge up to 2k and stay there for a little while. CEL comes on and stays on for awhile while driving. Checked the code and it was 121 for Closed Throttle voltage too high or too low. I checked the TPS voltage and it was .99. Also checked the other 2 wires and they were 4.96 and the other didn't have much on it so they are all fine as I've read over the years about checking the tps wires/voltage to determine if they were in range. I had previously when having issues before Jan when I last drove the car, I probed the appropriate wire while doing a throttle sweep and the numbers on the voltmeter swept fine with no erratic jumping or anything

    I also reset the idle and basically set the stop to 0.10 on the feeler gauge then went a half to one turn clockwise on the screw. I started the car with the IAC unplugged and played with the throttle to keep it running. I did have to turn the screw in some to keep it running. What I did eventually was just creep down some on the screw counterclockwise little by little till it would idle without cutting off. It went as low as about 650-700 but it didn't just stay there. As it wanted to die, it would go down to 650 then would idle back up to about 800. It sounded as if it wanted to cut off but didn't. It stayed at 650 for a little then would go up to 800, fluctuating.

    I opened up the IAB screw about half a turn after I rechecked the tps volts. Took car for a drive and it did fine but eventually starte with the CEL again and the bucking, sort of like the car would as I'm driving, it would seem to break it's speed and then catch back up but not really break speed. I guess it would be a cutback. It would cutback sometimes from time to time. I stopped and tried what I belive it was Irwinner who has had success with what he said on page 1 where he stopped the car and cut it off, turned the stop screw counterclockwise some and started the car back up. I repeated that a few times and then didnt do it anymore. Basically now I am lost as to what the heck is going on if the test show the TPS to be fine. I even unplugged the tps while car was running and it didnt cut off. The car seemed to get a little richer by smell with the tps unplugged for a few minutes. Showing the guy who regrind my cam the plugs the other day, he said it's rich at startup definitely. Right now I just don't know what to do. I would think to just try a new tps just to see. Also checked the IAC and with car running when I unplugged it the car wanted to cut off and would have. Last time I drove it this evening when I pulled up to a stop it cut off a few times actually when I threw it in neutral

    Car still has the 05 tune with the autologic 2000 tune
  2. toyman

    toyman SN Certified Technician

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    Not certain the autologic tune wasn't much more than a timing adjustment that you can do by rotating the distributor. You make no reference to cleaning the MAF sensor. If that hasn't been done and especially so if you are using a K&N oiled filter cleaning the MAF sensor is a "must do".
  3. from6to8

    from6to8 There's suction so I used that end O_O

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    Yes cleaned the MAF
    I do indeed know how to set the timing. the guy back in 05 actually burnt a chip and dyno tuned the car
  4. toyman

    toyman SN Certified Technician

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    That's not my recollection of the autologic chip. I only recall them as an off the shelf item, a one size fits all chip. An on and off CEL is from a sensor that falls out of spec and then back into spec. Perhaps the O2 sensors reacting to a rich condition than back into an expected value. The IAC valve only has functionality at idle. It in no ways affect anything while driving other than returning to an idle position based on the TPS signal. I'm puzzled by the statement, "I checked the TPS voltage and it was .99. Also checked the other 2 wires and they were 4.96". The three wires are: Ground, VREF (voltage reference) and signal. The VREF voltage and the TPS signal voltage need to be read only when using the TPS ground. Do not use any other ground source. So KOEO you should only see VREF = 5v and TPS = .99v (in your example) there isn't a third reading.
  5. from6to8

    from6to8 There's suction so I used that end O_O

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    isn't the third wire supposed to be pretty much nothing, at 0 or so? Unless that's what you mean not a third reading because it doesnt matter since it's zero or better yet i guess since its a ground. It is funny though today I checked the tps using the battery ground and also using the ground on the tps. With the batt ground the tps was pretty much horizontally straight and as you are leaning over pass side to adjust it, knocking it down just a tad would adjust it to .95 where it's set at now. Using the tps ground I had to turn the tps all the way down, pass where it was using the batt ground. Well not all the way down but significantly. When I tested it at the same spot that I got .95 using the battery ground, I got only about .35 with the tps ground. I played with the safety pins and moved them around a good bit making sure I had a solid connection.

    i do know this though after unplugging the chip, the surging and stuff went away and the car drove real strong, maybe a tad bit stronger than with the chip plugged in. I didnt get the code 121 for TPS but did get during koeo test a 327,552,553,558, and 565. During Koer test I got a 311, 327 and 314. I'm about to see what those are. I guess I probably will just get another tune. The guy who did mine back in 05 has since passed away. He did put the car on the dyno and plugged the laptop up and made several changes to the chip. I think it was a Diablo chip that he actually used but the autologic 2000 was the software or something of that nature. I wish there were someone who could use that chip and just make some minor changes i guess to the A/F and whatever else because it seems to be running fine as of unplugging the chip. I hate to have to spend 500 more bucks on another tune and if can find someone to use what I have and pay no more than 300 that would be much better. I am going to do some digging and see what I can come up with
  6. from6to8

    from6to8 There's suction so I used that end O_O

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    only thing i seem to have to check and see what that means is the code 327 which is EVP or DPFE circuit below minimum voltage and that's code 327.

    also the 311 and 314 thermacator air system inoperative right and left so have to see bout those as well. The rest seem to be EGR and smog related which I don't have on car
  7. toyman

    toyman SN Certified Technician

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    Then why are you wanting a tune?

    That would explain the 121 code as that's the signal voltage the ECU sees.

    I would remove and clean the battery to engine and engine to chassis grounds to ensure there isn't a problem with these connections.
  8. from6to8

    from6to8 There's suction so I used that end O_O

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    Actually the guy who told me to unplug the chip and try that asked me that this morning or told me rather to not worry about getting it tuned. I do know I wana get rid of the Engine light though and have the Air fuel checked so if they have to tune it if it is off or if it is bad then I may need a tune but won't know till i ask those questions.

    As far as the .35 with the TPS ground, I didnt run the car and got the 121 code with that setting. I got the code 121 with a .99 or 1 volt tps setting but that is when the chip was plugged in. I was just saying that I wanted to check the tps volts via the tps ground and the battery ground. The car ran fine with chip unplugged and the tps volts set using the battery ground at .95 So right now I guess using the ground on the tps it would be about .31 but the car is running fine so not sure why the ( forgot the word for a wide gap in numbers) wide gap in numbers using the different grounds

    And yes I am going to just replace the grounds and the Hot as well going to the battery and probably the starter ones
  9. toyman

    toyman SN Certified Technician

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    The only ground that matters when testing the sensors is the sensor ground. If that's lower than expected there is likely a bad ground source to the ECU. When I get home tonight I'll give you the ECU ground pin # so you can confirm that source and the sensor ground pin as well. The TPS closed voltage of .31 will be an idle issue for the ECU but not necessarily at an open throttle condition. When you did the TPS sweep from idle to WOT what was the range and was it a smooth progression from .31 to 4.7?
  10. from6to8

    from6to8 There's suction so I used that end O_O

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    before my car went down in Jan I performed all of those tests and checked the tps, did the sweep from idle to WOT and yes it was smooth. Putting the car back together I can't see how there would be an issue with the TPS now.
  11. toyman

    toyman SN Certified Technician

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    TPS ground is pin #46 (signal return). The ECU case ground is pin #20 and power ground pins are #40 & 60.

    Given the numbers stated there is a TPS issue.
  12. from6to8

    from6to8 There's suction so I used that end O_O

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    I'm not sure I understand you correctly from what you just said.
  13. toyman

    toyman SN Certified Technician

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    Those are the ECU ground pin-out numbers. If you want to verify the TPS signal you could back probe pin 46 to see what the voltage at the ECU is. The other ground references were just for information purposes.

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