1990 injector issues

[2stix]

did you happen to install a new fuel filter? common mistake many people overlook when buying a vehicle that may have sat for a while. a clogged fuel filter will cause similar symptoms.

 

[feral badger]

Filter is new also.

 

[cruiser54]

But Cruiser, if its off a tooth either way it will run but not run "right". I was once told you could drop the dizzy in a 4.0 anywhere and it will run but I soon found out that was not true as the injectors will not be timed properly. Its waaay more touchy than I would have imagined.

That's true but you can't "adjust" the ignition timing with the dizzy. You're changing the timing of the injector firing and making the spark have to jump a mile to the terminal it's trying to fire to. Timing is controlled by the ECU.

 

[xjtrailrider]

That's true but you can't "adjust" the ignition timing with the dizzy. You're changing the timing of the injector firing and making the spark have to jump a mile to the terminal it's trying to fire to. Timing is controlled by the ECU.

I agree. I found out the hard way that the NAPA harmonic balancer that I bought had its TDC mark about one tooth off once i pulled number one to TDC compression stroke. I about pulled what hair I had left out over that one!

 

[feral badger]

Re: 1990 injector issues (Fixed)

Found a smoked diode in the ecu. Replaced the ecu and it runs great. I was told the motor was swapped but not with a 91. When I got under the intake to check the CTS I found out there wasn't one. And since they had an extra connector hanging around they plugged it into whatever connector it fit. And that was the power supply for electric fan. So, I added a CTS and ECU and not it runs like a top.
Thanks to everyone for your help.

 

[cruiser54]

Re: 1990 injector issues (Fixed)

Found a smoked diode in the ecu. Replaced the ecu and it runs great. I was told the motor was swapped but not with a 91. When I got under the intake to check the CTS I found out there wasn't one. And since they had an extra connector hanging around they plugged it into whatever connector it fit. And that was the power supply for electric fan. So, I added a CTS and ECU and not it runs like a top.
Thanks to everyone for your help.

No CTS because they got the motor in and wished they had removed the coolant galley plug first!!

 

[feral badger]

Re: 1990 injector issues (Fixed)

No CTS because they got the motor in and wished they had removed the coolant galley plug first!!

LOL That was a bear to get that front plug out. And had to sacrifice a torx socket to grind down to fit the square hole.

 

[cruiser54]

That's why I always advise people to do that before installing the block into the chassis. 5/16 square socket. I don't have one. I ground down an old faucet seat wrench til it fit kinda tight. Then struck a coupla tack welds with my wire feed welder.