installed an 87gnx engine and underhood engine harness in 88 monte carlo ss and have no pulse at injectors.i have power and no ground.if i follow the gm manual it says to check for juice at terminal b at the crank and cam sensors using terminal c as ground.these tests show i have a refernce signal and ground at the sensors.if i jump them as per gm they dont fire (ground ) injectors.remeber i do have 12 volts at injector harness with key on ,a check engine light that functions and spark.i have a new ecm,chip,coil pack and module as well.also i have no fuel pump relay voltage from fusible link or with key on as the harness mating to the firewall probably doesnt have these connections.i know this as i have done the conversions before but used the dsh harness from the gn and didnt use it this time as it was not removable from the wrecked car..need to know how the relay is juiced up,not like key on power and fusible linked juice all the time.want to know where the wires go and if they in any way can stop the ecm from grounding the injectors.according to the factory manual the drivers are bad but this is not true.please offer assistance with schematics please.
some minor hair pulling need help
- Thread starter chris718
- Start date
Welcome!
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I'll try to help as best I can here.
The pnk/blk wire going to ECM at connector C437 (or where C437 should be. C437 is not the Big fire wall connector) should be connected to +12V hot while cranking.
This wire (pink/blk) goes to A6 at the ECM (A6 located on the smaller black connector).
After coming out the ECM at connector A1 (dark Green/white), this wire goes to the Fuel pump relay (A) coil.
The other side of the relay coil (blk/wht) goes to ground.
As far as the feed for the relay (pink/blk) this goes in to relay pin D.
Out pin B to Fuel Pump (Grey) wire.
Now lets talk about the injectors. Here's what the injector plug looks like.
_________
|E|F|G|H|
_________
|D|C|B|A|
_________
If you unplug the injector harness, this is what you'll be looking at on the injector side.
Pin E = +12V (Brown Wire)
Pin A,B,C,F,G,H = switch GND (ECM's job) (Black/X) X=either solid or w/stripe
What you can do is put +12V on pin E using an insulated connector (very carefully, maybe insulated connector), then tap Pin A,B,C,F,G,H to ground. Do you hear injectors clicking?
No reason you shouldn't besides having 6 bad injectors.
Point is, on the engine harness side, is the +12V present on the pink/blk wire? (this needs to be hot while cranking)
Here's another big help. ALL Pink/Black wires in the engine harness need to be used. If you find any that aren't hooked up, it should be. If you do find one thats not hooked up, let me know.
The pnk/blk wire going to ECM at connector C437 (or where C437 should be. C437 is not the Big fire wall connector) should be connected to +12V hot while cranking.
This wire (pink/blk) goes to A6 at the ECM (A6 located on the smaller black connector).
After coming out the ECM at connector A1 (dark Green/white), this wire goes to the Fuel pump relay (A) coil.
The other side of the relay coil (blk/wht) goes to ground.
As far as the feed for the relay (pink/blk) this goes in to relay pin D.
Out pin B to Fuel Pump (Grey) wire.
Now lets talk about the injectors. Here's what the injector plug looks like.
_________
|E|F|G|H|
_________
|D|C|B|A|
_________
If you unplug the injector harness, this is what you'll be looking at on the injector side.
Pin E = +12V (Brown Wire)
Pin A,B,C,F,G,H = switch GND (ECM's job) (Black/X) X=either solid or w/stripe
What you can do is put +12V on pin E using an insulated connector (very carefully, maybe insulated connector), then tap Pin A,B,C,F,G,H to ground. Do you hear injectors clicking?
No reason you shouldn't besides having 6 bad injectors.
Point is, on the engine harness side, is the +12V present on the pink/blk wire? (this needs to be hot while cranking)
Here's another big help. ALL Pink/Black wires in the engine harness need to be used. If you find any that aren't hooked up, it should be. If you do find one thats not hooked up, let me know.
