Jeep09

Background is Jeep with old school SBC, after market First fuel injection TPI setup, Affordable FI harness and bits. Bought it as a trail ready Jeep. had fits to get it to run, that was a couple years ago.
Was out rock crawling, Jeep started slowly having problems running. It stopped and wont run, thought a few things might be a problem.

I currently have good spark when cranking, sounds like wants to start.

I have 44 psi fuel pressure on my gauge when cranking, separate return line is flowing good.

Checked TPS- its 5 volts in any position

Got a new one and checked it. Its a ACD 213-905...its weird, the voltage when the throttle is wide open is about .5 and 4.5 volts when idle/closed...like its opposite?? Took it off and manually checked it. Same. Is it a bad TPS?

Assuming my TPS problem was NOT the issue. What is the chances my ECM failed?

Jeep09

trying to source this out, I replaced my::
- distributor, coil, cap/rotor
-spark
-AIC
-CTS
-MAP
Cranks and tries to start but will not "catch" and run

bigal55

iTrader: (1)

Here's something to try, with the TPS un-mounted to the throttle body but connected to the harness, run the wiper to WOT so the ECM sees the 0.45 volts. Will it start and idle now?
Are you sure your checking the wiper to ground and not the positive reference of 5 volts?

Jeep09

I tried that its so seems so close to running. When starting it will spin trying to fire/firing then kick back/hard to spin it. I hard played with the distributor static timing by just turning it. Trying to dial out the kick back

I know there are two modes as I understand it. Starting, runs off distributor till 400 rpm - ish then the ECM kicks in. Is it possible the ECM is doing something funky when the transition happens?

Just been guessing, now really unsure??

Jeep09

should I get another ecm?

bigal55

iTrader: (1)

Disconnect the Set Timing connector so the ECM no longer has control of the timing. Will it start now or does it still "kick back"?
One thing should be noted here, any harness swap can be difficult to diagnose problems, especially when it was done by a previous owner. You should go over all the wiring connections including the ground points to the engine and chassis. This being a rock crawler, I imagine it has seen it's share of bumps and rattling around. Did the ECM connectors jar loose or possibly some ground or power distribution block connections come loose? Did you check the ECM for any codes? It's good you changed those parts but just jumping around and throwing parts at it is going to take a lot of time and money, you need to do a systematic diagnosis of the system to find out exactly what is wrong. Have you followed any diagnostic flow charts for a no start condition? ChevyThunder.com has a complete set of diagnostic charts and all sorts of info on TPI systems, take a look, maybe it will help. GL!

Jeep09

thanks, no I have not disconnected it. I have no flow chart I have followed. I will look for the ChevyThunder Flow chart, is there a link?