sszq803

Ok i just finished putting a 03 5.3 engine out of a avalanche into my 85 c-10,i did the wiring thanks to lt1swap.cam.The problem is that when you crank the engine it will only rev once, it does run good except this.Now if you kill the engine and crank it back up it will rev again and so on with the killing and cranking.One thang i will note is that the engine is not completly finished it is running on two open manifolds with the two front oxygen sensor are not hooked up,and the mas air flow sensor im not 100% for sure came off this engine because i had one for a 06 4.3 liter engine laying around and they got mixed up,but the one on the engine pluged up to the harness and it does run good.Other than that im lost.Would the neutral saftey switch have anything to do with this?Now i have done some reading on here about the tac module and pedal asy. have to match and i did pull the tac from a silverado and the pedal from a tahoe before i know this,but its weird because it will rev once so i would think they had to be communicating.Any help would be appeciated.

gofastwclass

iTrader: (2)

Sounds obvious but I would check for codes and see what comes up. Anything else is just a guess.

ls1nova71

iTrader: (4)

With the engine off, and the key in the run position (on), when you move the pedal does the throttle move more than once? It should move as many times as you move the pedal, if it doesn't then check for codes like gofastwclass said, or check your parts compatibility.

fptransport

actually on mine,, once the throttle moves once it doesnt move again..with key on the on position, but it works fine once its running.. could be like he said,, pedal from once car, tac from other

sszq803

Im going to the junk yard tommorrow and getting a new pedal and tac from the same truck and a dianostic port to wire in to check the codes,and im going to pray that one of the other will fix the problem.

72truckman

gonna sound kinda funny but i had the same problem and... charged the battery. the trouble codes which were putting the motor into "Limp Home Mode" went away and with a full charge has worked flawlessly

sszq803

Well just to follow up, i called current performance and gm and found out that the tac module has a part number and it has to match the computor and from my understanding the pedal makes no differance ,so im good as far as the tac module part number goes i usume,but i did get another tac module and pedal from the junk yard both out of the same truck,still the same thing.I cleaned all my grounds (2 on the back and 1 on the front of the motor,1 from the battery to frame and 1 from the battery to body)i did put a new battery in and when i changed them i left it out for about 10 mins. still the same.I did find that if i ground the light blue wire going to the tac module for the cruise it will throttle up slowly but maybe only to about 2000 rpms though? I hav'nt had time to wire in a dianostic port yet due to work but sone as i can ill see what kind of codes i have.

fptransport

the tac only needs the pink wire to have power and I think there is a black wire with ground going to it also... check the ground wire to see if there is good ground in it.... good luck

sszq803

Well i finaily got the diagnostic port wired in,It has about 4 codes but the only one i see for a throttle issue is p2135. I was told it maybe had something to do with the wiring from the pedal to the tac, so i have checked the pin outs on all the wiring to the tac from the pedal and to the throttle body and ohm them out(all are less then .3 differance). Ive also double checked the the power and ground to the tac (all good)But I have found out that if i don't throttle it more than 1/4% on the pedal it will continue to work throttling up ever time? I think my next step is to find another throttle body and switch them out,i don't know though im just guessing at it now. Just to let everyone know i appreciate all the advice from everyone

sszq803

Oh yea she all fixed,I replaced the whole throttle body, no more issues.Thanks for everyones help.