Jeep TJ 5.3 problem
Thread Starter
Registered User
Joined: Mar 2012
Posts: 5
Likes: 0
Jeep TJ 5.3 problem I have '97 Jeep TJ that I have put a 5.3L in out of a 2005 GMC Sierra. It's the L33 aluminum block. It also has the 4L60E behind it. I had Novak do all the wiring as well as wire into the Jeep PCM so all my gauges work. I'm in Alaska so they did the wiring and I installed it all. Anyways the Jeep has no exhaust on it just the sanderson block huggers. Well it starts and runs and all the gauges work but, the driver side header dumps raw fuel out of it. So bad I can't let it idle. So I started unplugging injectors and found that the #5 injector when it was unplugged the fuel dumping out stopped. So of course I pulled the rail and bought a new injector and replaced it..well it still does it?!?!? Any ideas, thoughts or comments would be greatly appreciated.
Thread Starter
Registered User
Joined: Mar 2012
Posts: 5
Likes: 0
I tried swapping coils around and that didn't make a difference. I think like you say #5 plug in has a short in it somewhere. When it's plugged in and you hook the battery up it arcs towards the post. When you unplug #5 and then hook the hot lead up on the battery it does nothing...wonder what could be happening? It's a scary thought but, the only way to find it is to trace back injector wires? Yikes.....
TECH Apprentice
Joined: Aug 2010
Posts: 381
Likes: 0
From: Melbourne, FL.
Keep in mind that when the key is on the injectors will get a constant positive signal (pink wire) and the PCM switches to ground to fire the injector.
So what this means is you need to chase the (-) side of that injector wire back to the PCM. If the injector is staying open you'll find that wire is grounded along the way somehow.
So what this means is you need to chase the (-) side of that injector wire back to the PCM. If the injector is staying open you'll find that wire is grounded along the way somehow.
Thread Starter
Registered User
Joined: Mar 2012
Posts: 5
Likes: 0
So I did find the - side of the injector coil and cut it before it plugs into the computer and also cut it before it plugs into the injector eliminating the wire from the harness. Then I ran a wire outside of the harness straight from the computer to the injector and its still doing it? Odd thing is the injector when plugged in from the - side shows 12 volts? Is that normal? The other ones are showing 0.00 And as soon as I touch the wire from the computer to the injector it sprays....Also if you let it sit there with the key on it periodically sprays into the cylinder. Is it an ECM problem?
Trending Topics
TECH Apprentice
Joined: Aug 2010
Posts: 381
Likes: 0
From: Melbourne, FL.
Bypass the other wire (the pink one) from the injector and run it straight to a 12V (+ Key on and cranking) source.
Note that all of the pink wires going to the injectors should be 12 V (+) when the key is on or in the crank position. The ECM provides the ground path and causes the injector to open.
If there is still a problem even with both sides (+ and -) of that injector bypassed from the harness, I'd say there's an issue with the ECM.
Note that all of the pink wires going to the injectors should be 12 V (+) when the key is on or in the crank position. The ECM provides the ground path and causes the injector to open.
If there is still a problem even with both sides (+ and -) of that injector bypassed from the harness, I'd say there's an issue with the ECM.
Last edited by Docked Wage; Mar 26, 2012 at 07:45 PM.
LS1 Tech Stories
The Best V8 Stories One Small Block at Time
6 Common C5 Corvette Failures and What's Involved In Repairing Them
Pouria Savadkouei
Retro Modern Bandit Pontiac Trans AM Comes With Burt Reynolds' Autograph
Verdad Gallardo
Top 10 Greatest Cadillac V Series Performance Models Ever, Ranked
Pouria Savadkouei
Top 10 Most Powerful Chevy Trucks Ever Made!
Hennessey's New Supercharged Silverado ZR2 Has 700 HP
Verdad Gallardo
Coachbuilt N2A Anteros Is an LS2-Powered C6 Corvette In Italian Clothes
Verdad Gallardo
Awesome K5 Blazer Restomod Comes With C7 Corvette Power
Verdad Gallardo
10 Camaros You Should Never Buy
10 LS Engine Myths That Refuse to Die
Verdad Gallardo
TECH Fanatic
Joined: Oct 2011
Posts: 1,356
Likes: 2
From: Felton Pa
Put a test light on the - side of the injector connector and the clip side to the battery + and start it and see if the test light blinks. Or you can put a noid light on the connector and start it and see if it blinks. If either stays lit all the time and you say you have run an overlay wire then there is a PCM problem.
