Fuel injectors will not fire...sorry long post

[Donniejr81]

Ok here's what I've done. I swapped the drivetrain from an 85GN into an 85 NA Regal. I swapped the engine harness, dash harness, ECM, instrument panel, as well as engine, tranny, etc.

Now the problem. The injectors will not fire. The car will fire right up and run smooth for a few seconds if you pour a little gas in the TB though.

I have checked cam and crank position sensor voltage, all of the grounds underhood as well as at the ECM (visually and voltmeter), even getting voltage at the injectors, and that all jived.

The two problems I found are the TPS voltage is WAY low (.004-.008) the wires to it have voltage but lose it as soon as you plug the TPS in. Next the injectors have 12.5V and drop to 9 or so when cranking. I can manually ground the injector and it will fire. Can the TPS be causing my injectors to not fire or am I dealing with two separate problems?

 

[S10xGN]

Ok here's what I've done. I swapped the drivetrain from an 85GN into an 85 NA Regal. I swapped the engine harness, dash harness, ECM, instrument panel, as well as engine, tranny, etc.

Now the problem. The injectors will not fire. The car will fire right up and run smooth for a few seconds if you pour a little gas in the TB though.

I have checked cam and crank position sensor voltage, all of the grounds underhood as well as at the ECM (visually and voltmeter), even getting voltage at the injectors, and that all jived.

The two problems I found are the TPS voltage is WAY low (.004-.008) the wires to it have voltage but lose it as soon as you plug the TPS in. Next the injectors have 12.5V and drop to 9 or so when cranking. I can manually ground the injector and it will fire. Can the TPS be causing my injectors to not fire or am I dealing with two separate problems?

Have you actually checked the injector(s) with a 'noid light? Try that first to be sure they are not pulsing, as pulsing at the wrong point in the engine's rotation will make it seem as they aren't working at all. The ECM grounds each injector to fire it, so if they are pulsing, it would seem that your ECM, crank sensor or cam sensor is at fault...

 

[Donniejr81]

Thats the next thing to do on my list. Im going to use my power probe to test each injector and to check to see if its pulsing or just not doing anything. Also I just checked the cam and crank position sensor voltage via the ECM plugs and while cranking one of them varied 1-7.2V and the other 1-9.5V which I think is within spec or really close.

 

[Donniejr81]

It runs!! Its alive and sounds beautiful...except for an exhaust leak lol. Im such a menso too...my problem all along was the little orange ECM power wire by the battery was not hooked up duhhhhh:redface:

 

[85begalttype]

good job man! im currently doing the same swap into an 86 cutlass. Did u have any troubles with the speed sensor? lock solenoid? and other things related to the ecm?

 

[Donniejr81]

I havent had a chance to road test it yet to check out everything, but so far all is hooked up and working beautiful. Still running just a tad rich, but other than that its all been good.

Hows things coming with your swap?

 

[85begalttype]

thanks for the reply. I dont have much money so things are slow lol. almost finished putting the motor back together. frame is all painted with new suspension. body is ready for paint. dash is removed. got my turbo wiring harness are cleaned up. Sounds pretty easy to just plug into the ecm and connect the other part of the harness into the regular v8 harness for lights and ignition. im excited to get it all done in a few months.

 

[Donniejr81]

I hear you on not having much money to spend. Im taking summer classes so I can graduate respiratory therapy school in december...broke college student.

All in all most of my swap was foolproof. The dash wiring harness was a PITA though. Next time Im definitely pulling the dash out lol. Im wishing I couldve detailed my frame and engine bay a little better, but it would've taken quite a bit more disassembling that I didnt really have the room for.

Im just glad I got that fuel injector prob straightened out, I was pulling out what hair I have left.

 

[GNVenom]

The low TPS is the give-away. It could be that your engine is in "clear flood" mode, which means, if your TPS is at or near 100%, the injectors won't fire.

Check your TPS wiring and make sure cavity A is a black wire (TPS return). Also, make sure the TPS voltage is just short of half a volt. The 85's had a reverse-operating TPS and the connector was wired differently than the 86's.

 

[Donniejr81]

Once I got the ECM hooked up to voltage my TPS miraculously started working too...hmmm imagine that one lol. Im getting ready to start tuning on this thing now, it starts and idles great but hesitates when I rev it. Thats my next gremlin.

 

[85begalttype]

well good luck man, ill be working out my gremlins in the next few months once i get the body back on the frame. hesitation is usually maf or tps