88 trooper, fuel problems

Put new motor in last week. Ran fine except for lots of smoke. Replaced valve seals Thursday. Smoke stopped. Friday, it won't run without human help.
Have replaced the fuel pump and strainer, new fuel filter, removed and cleaned injectors and fuel rail. Injectors were tested out of vehicle. They do work. Properly or not, I do not know, I have no way to check that. And it has plenty of pressure when you ease off the fuel rail bleeder screw. BUT !!! It will not run without feeding it some gas manually. I don't know what else to check. Any ideas? :banghead:

You need to check to make sure you are getting a signal to the injectors. It should run even if one is bad. It sounds like a possible electrical problem. There is a fuel injector resistor pack, a little silver box mounted on your fender well that works with the injector system. It could have gone bad. Do all the injectors spray the same or do some spray less/more than others? The first thing I would do is test for the proper signal at each injector.

I just ordered an electrical trouble shooting manual from Helms I should have it in a week. Ill check the proccedure on testing them if you haven't already by then. I have a resistor pack for you if that is it.

I don't know if all of them are spraying the same or not. We did not pay alot of attention to that. Just cleaned them real good and checked to see if they worked. They did spray when we had them out of the truck cleaning them and powered them up individually. We did check for voltage in certain areas around them. But had no idea which box worked them. We have 12 volts to the harness but they do not seem to be firing since it is getting no fuel to run. Like I said before, it has pressure in the fuel rail, so it must be the injectors. And since they fired when we had them out, it would make sense if it were the resistor pack you mentioned. Yes, please keep in touch. We need to get this thing going. And we are at wits end. Had to just turn and walk away from it. Sometimes that helps. When you get your book, let me know if it tells you how to check the pack. That may be where the problem is.

Will do.

thought I would give my two cents on this one, you need to check to see if injectors are getting pulse signal from ecm when cranking or they will not work. I would check resistor before going to that trouble since it seems fairly easy to check. They make a special electrical tool for the injector, but I have used a simple digital volt meter with a peak hold function so you don't miss the action.



to check resistor:


Disconnect dropping resistor electrical connector.

Measure resistance across center terminal of dropping resistor side connector and remaining terminals. Resistance should be 5-7 ohms.
If resistance is not as specified, replace dropping resistor.