Injector electrical gremlin (everyones favorite!)

[silviaguy240]

Ok let me start off saying that im not necessarily looking for a solution or fix because this stuff is a pain, but more for ideas on what to look at/for so i dont spend hours looking at the wrong things...

So this happened about 6 months ago but kinda fixed itself and i parked the car for the winter. i kinda just let it go and was going to see what happened once it was back on the road, and sure enough last night i had my car out for a cruise and after about 20 min of smooth sailing the car began to break up and proceeded to just shut off on me..not all the power, just the engine... so i pull over and sit for a sec and then start it up again and it does, no problem... i let it sit for a min and ends up shutting off again...like its not getting fuel.... so i check a few things: pump works, have fuel pressure, powers good blah blah, so i get back in and try again.... it turns over and over and over..no good... try again it fires, runs for about 5-7 seconds and then dies.... rinse repeat until it no longer will start... so i checked the actual injector wiring and somehow one of the injectors had melted its wire kind of to the intake manifold... so juussstt enough wire on both wires was exposed and i assume it grounded it out... so i check the fuse..its good.. and try the car again since the wire is off the manifold and no good (mind you the temp of the car is at opperating temp) so i get it towed..... today i go out and start it cold...and it fired right up..ran fine for about 5 min so i shut it off...

so that brings me to this conclusion..it has to be something to do with heat? making a relay stay open? the injectors are fine, the ecu is fine, pump and relay are fine so im stuck.. i looked at some wiring diagrams and it looks like the injectors are wired right into the ecu and theres no relay in between? maybe i just cant read diagrams well but thats what it looks like so im wondering what may have been damaged if anything with those wires touching the manifold so i can check it.... otherwise im just going to just start tracing wires and seeing if something else melted maybe from the grounding out and only touch when the car heats up?

it is a KA-T and its an ams fuel rail with aftermarket 65lbs injectors and im running nistune but idk if any of that info really matters..and the car has had the same tune for 2 years now and never had a problem

any insight would be helpful i know this stuff is tough to begin with and not being able to see it is worse... i can explain more if needed

Thanks!

[ultimateirving]

Loose ground is what it sounds like, but the wire melting to manifold is cause for concern.

The manifold is not likely hot enough to melt a wire to it, so that means the wire itself is super heating.

[OnTheChip]

I've had an ignition coil exhibit this same behavior.

[Aurimas]

I had same exact problem.

Car was down for 2 months and shop was not able to figure out what was wrong with it.

30 mins and a buddy with multimeter - car is running.

Now, the injectors share one 12V wire. My injectors were getting 9V.
All ground perfect.
That wire might be broken for you (that's how it is on mine).

What we did was just run a hot wire from a battery to the injector to rule it out, and sure it started. Now if this is your case too, run a hot wire from the fuse box to one of the injectors and just splice it in. This is half assing, but it works until you get a new harness.

If you got any questions, just shoot me a PM.

Edit: This is my thread. http://zilvia.net/f/tech-talk/501701-sr-redtop-cranks-doesnt-start.html

[ShadowMan]

When I had a problem with a dead cylinder, it just ended up being one of the signal wires backed out of the injector clip just enough to lose contact with the prong but not enough that it looked like it came out. Found it by meticulously going through every wire related to the problem.