Replacing Fuel injectors myself
 

So, my '89 auto will not start and the crankcase oil has fuel in it. I tested the ignition system and it is working perfectly, all spark plugs are firing. I tested the fuel pressure and it holds 39ish' psi when powering the fuel pump at the test connector under the dash. I also checked the fuel flow at the fuel rail and it is ok. The car normally does not even fire or try to, i replaced the plugs and it runs very roughly for a breif second (only with me fethering the throttle, will it even try to run) and then quits and will not start agian. So sounds like leaking fuel injectors right? The car was not drove much this winter so im guessing there is some kind of build up in the injectors from the fuel sitting there.
So, anyways, I was looking at the intake plenum and wondering if you can remove the fuel rail(s) assembly (regulator/injectors/rails) buy just removing the upper part of the intake plenum and leaving the lower "runners". It looks like when you pull up on the fuel assembly the lower runners might trap the assembly ????? anybody done this before??? Im trying to avoid removing the lower runners and the valve covers. ADVICE PLEASE!!!
Thanks in advance
noobe Cameron

RE: Replacing Fuel injectors myself
 

Are the plugs wet and smell of fuel?

RE: Replacing Fuel injectors myself
 

yep! theres so much fuel leaking into the cylinder that gas is ending up in my oil after it sits a couple days( after attempting to start it).

RE: Replacing Fuel injectors myself
 

I ran into the same problem with a jeep last month. The injectors turned out to be fine. The problem was the coolent sensor bad and made the computer think it was sub zero and dumped to much fuel in the motor. You may want to do some more checking. Did you check the codes? Local auto parts stores here loan out code readers so you may want to check that out.

RE: Replacing Fuel injectors myself
 

See if you can get a noid light from your auto parts. If you can, unplug a fuel injector and plug the light in and spin the engine over. The light should pulse, if it doesn't pulse, but stays on all the time, you may hace ECM (Computer) issues, because the ECM is grounding the injectors all the time. Also check your vacuum line to the fuel pressure regulator to see if there is fuel in it, shouldn't be. If it does, then regulator diaphram has a hole in it causing engine to suck in raw, unmetered fuel into the vacuum system. Also, when you cut the key off after measuring fuel pressure, does it maitain pressure for a couple of minutes. A sign of leaking injectors is that the fuel system doesn't maintain fuel pressure and usually drops off rapidly. Good Luck!! [8D]

P.S. If you do have to replace any injectors, be sure and replace the upper and lower orings on the injeotor, upper will leak fuel and lower will leak vacuum, both causing problems.

RE: Replacing Fuel injectors myself
 

Well its not throwing any codes currently, but i was begining to suspect the ecu myself. The fuel pressure does hold after i stop energizing the pump.......i see what you mean, the injectors probably are not the issue because of how long it will hold fuel pressure after the pump is shut off. I will test the injector harness/plug tonight and pull the pressure regulators vaccume line to see if its dry. So assuming the injectors are gettting a incorrect signal, where can i go fron there? Simply replace the ecu, or is it possible to further pin-point the prolbem?

RE: Replacing Fuel injectors myself
 

Word of caution, you probably have a ton of fuel in the crankcase. Try to avoid turning it over any more for you could risk an explosion.

RE: Replacing Fuel injectors myself
 

If I had the car at my shop, I would check to see if I was getting any scan tool data. Since that is not possible, wait to see if your injector pulse is present. If not and it lights the noid light constantly, most likely ECM is bad. Most reputable auto parts stores (Carquest, Bumper to Bumper, etc.) sell a remaned unit fairly cheap, $150 - $200 range.

RE: Replacing Fuel injectors myself
 

Well the noid light stayed on when i tested two of the injectors. Actually it lit-up the second i turned the key(the "click" before the click that turns the engine over) and stayed on the while trying to start. I pulled the ecu and it was already replaced with a rebuilt unit from gm....recently?..... the board was very crean and new looking and all the connections appeared perfect. Im getting another ecu today, i'll keep everyone posted!

RE: Replacing Fuel injectors myself
 

Good move, the noid light shouldn't come on until the ECU sees an ignition pulse, so if it comes on immediately with out spinning engine, the ECU has grounded the injector driver transistors in the ECU, which means it's bad. GM had a lot of trouble with ECU's in the middle 80's, particularly 86-89. Gave up on building them and turned it over to AC/Delco. Those were the first years of the high data rate and they just couldn't get there act together. Rebuilt from GM could have same probs, although you need to check all of your solenoids (EGR, Diverter valve, cannister purge, etc) to make sure they are not shorted out since the ECU controls the solenoids. A solenoid that is shorted to ground could confuse computer and make it do weird things. Also, take an ohm meter and check each injector across the two pins and each pin to body of injector to make sure they are not shorted to ground. Should be around 15 - 17 ohms across the pins and no continuity to the body, as a defect injector shorted to ground will mess with ECU also. Do this before you plug in you new ECU.