my friend just put an 85 TPI 305 in his 98 S-10 and we cant get it to run right!!! it idles fine, but it dies as soon as you get it past a high idle. it acts like its running out of fuel. we used a painless harness and double checked every single plug and wire on the thing yesterday, things that are odd: the filiment in the MAF glows orange like a light bulb.....the fuel pump runs constantly, and you can hear fuel constantly running through the rails with the engine off and key on, shouldnt they pressurize? my thinking is something is messed up with that and we are not getting enough pressure in the rails. i havent checked pressure yet, we are getting codes for tps, maf, fuel pump something, coolant temp sensor, basically every sensor on the engine is throwing a code. is the computer supposed to be externally grounded? its kinda just sitting on the fender right now.....i really hope somebody is able to help me lol. thanks guys

steve

 

Those ECU's themselves arent supposed to be grounded. They are VERY sensative to static shock. Its possible you'lve shocked the ECU some how causing it to run in Limp Home mode..

just taking a quick guess... We put a 87 TPI together on a 69 ss with a painless harness,- works fine. now we are just dealing with tuning.

Another thing could be that your fuel/ignition wires may be wired wrong. our fuel pump just comes on- then stops when its pressurized. but when you start the car it pumps like it should. A tpi fuel system ( stock) should have about 35-40 psi at startup and 43-47 while running.

hope this may help some. just double check everything. also- make sure your pump is as close to the tank as possible..

 

the ECU's aren't sensative at all, mine rolls around on the passenger floor most of the time,

I've even been not thinking and pulled the chip with the car running




if you are getting codes for every circuit sounds like a ground issue,

unplug your MAF and see if that solves the problem,

the wire on the MAF shouldn't be glowing

 

we are running the stock in tank 98 s10 fuel pump, which is supposed to create 41-47 lbs of pressure, dont know if it flows enough volume or not, but with the engine off it should in theory create enough pressure....i tried unplugging the MAF and it starts and runs exactly the same. we have a ground strap from the block to the frame. im pretty sure the fuel and ign. are wired correctly, the wires came labeled very clearly and like i said, the engine starts and idles just fine, it just wont go past a high idle. i'm going to check the fuel pressure next time i am over there and see what i can find out. the motor came out of a totaled out T/A so who knows what could have got bounced around or broken off in the accident. also, would not having exhaust mess with anything? we dont have the exhaust on yet, just open manifolds. my buddy said one time he started it trying to figure it out and it ran great, he reved it to 5k a couple times and shut it off. then it wouldnt run right again after that.... thanks guys

steve

 

What computer are you using? The TPI computer or the s10 computer?

 

Ever check the TPS voltage? Should be .45V closed throttle.

 

we are using the computer out of the 85 t/a, i will definitely check the tps voltage. nobody knows why the MAF filament was glowing? it doesnt anymore so thats probably in need of replacement now lol.

 

85 ECM (870?) is a totally different animal and I am pretty sure Painless doesnt even offer a 85 harness so I would guess You need a 86-90 ecm (165) for it to work correctly. You will also need a chip from those yrs. The 85 chip wont work in an 86-90 ecm

 

didn't even notice it was an 85,

get rid of that, get a 165 ECM and go from there,

 

arent the 86+ cars MAP cars? does that even matter? thanks guys

steve

 

no 91-92 are map.

 

90-92 are map and they run a 730 ecm
86-89 165 ecm is MAF

 

yeah- the 85 computer is a WHOLE nother animal..

As far as an 86-88.. i can get you one probably around $45 shipped....

PM me if you are interested..

 

first check your TPS should be at .45-.50 V .45V is optimal, i think that should fix it, probably is not pressure as it most likely would not idle if that was the issue. let me know what you find after the TPS check

 

tps voltage at idle should be .54v +/- .075v