Jackrabbit501

iTrader: (3)

im sorry for this post but ive been searching and couldnt find a solution to my problem yet, hopefully someone can point me to a helpful thread..

ok im consulting the experts after trial and error and still no luck. so recently i was having fuel pressure "problems" (i was stupid and put the fuel lines backwards for my hsr), now thats fixed and i have the fuel pressure i need at my injectors, but now i dont seem to be getting injector pulse. I hooked up the noid testing lights and they arent lighting up for either side, both fuses are fine.

So i started checking my harness for bad grounds and found i never plugged in my distributor to computer connector. (i had already plugged in the coil)
So i started searching around and couldnt find the damn little connector! went to the junkyard and clipped one off of the camaros they had there, came back and found the same color wires to a connector i wasnt using. i realized the wire colors were the same, so i spliced them in and connected it to the distributor. tested them again and no pulse. started searching around for bad grounds, couldnt find any (that i know of), although my maf blue wire is clipped and i cant find where it could have gone.

Also i read somewhere that the prom could be bad, so i hooked up my other prom and still no luck... i seem to be having a bunch of wiring problems, my fuel pump also doesnt kick on in the on or start position, but hooking the pink wire on the oil pressure sensor to hot gives me the pump, so im not really sure what to do there yet, ill have to figure that one out after i can figure out the injectors..

sorry for the long post, i hope u guys have some advice for me..

camarotucker

iTrader: (2)

http://austinthirdgen.org/mkportal/m...ine_wiring.gif


Assuming battery tests good. Check for 12v (key on) on PNK/BLK at injectors. Check for 12v (always hot) on orange at fuel pump relay.

Jackrabbit501

iTrader: (3)

ok i have 12 volts at my injectors on both connectors, but i am getting no power to the fuel pump relay. well to any relay on that little bracket with an orange wire..

Jackrabbit501

iTrader: (3)

So im thinking it might be a bad ground causing this problem. What is the pin-out on the computer for the ground that the injectors use? The computer is from an '88, harness is i believe an '87 from the diagrams ive looked up.

Also next to the mass airflow sensor there is a relay with a clipped black/red wire. Where is this going? Been looking for anither clipped wire in the harness but there is none. Ground?
Along that side of the harness there is also a clipped light blue wire.

On te pinout diagrams on the ecm, below each pin it shows c1, c2, or c3, is that the following circuit that gets continued?

Jackrabbit501

iTrader: (3)

Bump for some help...

Still havnt resolved my problem, injectors have power at connector. Does anyone know what ground the computer uses for the injectors? I was thinking of clipping it and making a solid ground somewhere by the computer to make sure its contacting ground.

I pulled a fuse and cranked over the engine with a voltmeter in the fuse place and it shows voltage. Im just stumped as to what it could be. I read about injector drivers? How could i test to see if the drivers are bad? I have an aftermarket computer, the delco, 16198259.

Im thinking it could be a bad ground, but some wires are clipped, want to be able to rule them out as a possibility.

camarotucker

iTrader: (2)

The car is an 86, the computer is an 88, the harness in the dash is a ?, the c100 (engine side, drivers side) harness is a ?, the engine harness (pass fender) is a ?


My initial thought was that the 88 computer may (or not) vats/pass key, but I have not had time to research it.


In the mean time you could work on getting fuel pump to power on.
https://www.thirdgen.org/forums/elec...-gets-not.html - post #9

Jackrabbit501

iTrader: (3)

Car is 86, engine harness 87, computer 88, interior dash is 86. Vats is disabled from the prom i bought. I was going to try and swap the ICM, as per deadbirds post in this article.. :https://www.thirdgen.org/forums/elec...or-signal.html

I will work on getting the fuel pump going, but from the above link, could the two be related? Possibly ignition control module is bad (even though its a new dizzy), which doesnt allow the fuel pump to prime, i dont know if the fuel pump kicks on after turning over though, i cant hear it as my car is running open headers right now. But ill check again tomorrow to see if i can hear it come on.

any idea what the thick, black with red stripe wire coming from the relay coming off the maf? I dont know if its a ground and i havnt seen it in the wiring diagram so far...

camarotucker

iTrader: (2)

87 350 TPI http://austinthirdgen.org/mkportal/m...ine_wiring.gif

Fuel pump (relay) should have 12v on orange always (constant). DK GRN/WHT will be a reference signal 5v-8v (key on) give or take, this will show that the ecm is commanding fuel pump on. Applying 12v to RED will turn pump on, just shows that pump is physically is working.

I don't have a test method for ICM as I only have access to 90 and newer.

*edit* MAF BLK/RED, I don't see it for 87. I'm seeing a BLK/RED on coolant fan relay.

With Passkey ruled out I would be curious to know what the voltages are on fuel pump relay.

Jackrabbit501

iTrader: (3)

Ok so i applied voltage to the red wire, anddd nothing happened. I applied voltage to the tan/white and it kicked the fuel pump on. I didnt get any voltage reading on my orange, or my dk green/ white with key on.

Ok the fan relay makes sense. so is ther a problem in the system getting power to my orange connectors? If i hardwire 12 v hot to the orange, im wondering if my relays will work correctly and get my fuel pump to prime im the on position and run the pump correctly.
Thanks for all the help with the diagnosing

camarotucker

iTrader: (2)

Get 12v on the orange wire to fuel pump relay and report back.

Tuned Performance

iTrader: (92)

Do you have spark ?
The only think the ECM needs to see is a distributor reference pulse to pulse the injectors. Shorted injectors can cause the injector driver to shut off, or if there is a memcal issue where it's expecting vats signal. The pink/white stripe wire from the icm to the ECM pin B5. Check the continuity on this wire.
The ECM injector grounds are d1,d3,d6

Tuned Performance

iTrader: (92)

The green/white will only do a 2second power out to the do relay. Can you blink codes to verify the ECM is powered up .

Jackrabbit501

iTrader: (3)

I do have spark, i can run the car on starter fluid just fine. I had to wire in the correct connector to the icm, but all the wire colors Matched eachother, just assumed they were for the same circuits. They are new injectors, but i suppose that might not make a difference.

Ill check continuity of that rigt now and get back to you on the results. Would it be possible to ground the d1, d3, and d6 circuits straight out of the computer to somewhere in the cabin to ensure there is no breaks in the circuit somewhere along the line without tearing it all apart? Also tuned performance, i know i said i would get a tune from you, but i havnt successfully ran it yet.. But i still plan to have you tune my prom to adjust for 24lb injectors.

Camarotucker, i supplied hot to the orange on the harness and got fuel pressure on prime which is great! But since this circuit isnt getting a hot signal, im wondering why. Also on the fuel pump relay, i have 2 orange wires, the diagram shows that the second smaller orange wire is suppose to be red, but its not.... So maybe this harness isnt an 87 since it is a different color? Instill dont hear the pump hum, before i could clearly hear the little buzz from the prime. Dont know why its so quiet now

Jackrabbit501

iTrader: (3)

Also how do i blink the codes to check if the ecm is powering up?

Jackrabbit501

iTrader: (3)

I checked and couldnt find any continuity through the pink/white to icm. So what is the next step i need to take? Trace it for a break in the connection? so this could mean the computer is recieving no signal from the icm?

Jackrabbit501

iTrader: (3)

Also by adding power to the oil pressure switch, i can hear the fuel pump kick on, does the prime not use the fuel pump? Do i actually need an oil pressure switch to have the fuel pump on?

camarotucker

iTrader: (2)

I didn't complete my thought on my last post. The orange wire that powers fuel pump also powers some of the ECM. There is no diagram that I know of that shows the internal workings of the ECM so I don't know where the injector driver receives power. That's why I suggest you fix the orange wire to fuel pump relay first, because its plausible that may be why the injectors are not firing.


There is only one red wire and one orange wire to fuel pump relay, all years should be like this. The wires have probably faded and working with poor light (home garage) only exaggerates the fading problem. The red wire is only three feet or so long. I would suspect that the wire you feed 12v to and got pump to prime is the red. You can simply pull the red wire out, and verify its red by finding a spot its not faded in, or by its length, or feeding it 12v and pump priming. The figure out and repair the orange wire.


Thanks Tuned for chiming in, internal ECM is not my forte.

Jackrabbit501

iTrader: (3)

Well I traced the wire that's suppose to be red and it's orange the entire way back... not that it matters because I know what the wire is for. But anyways, I'm wondering why I don't have power to this always hot orange wire on fuel pump relay. Does this mean I'm not getting the correct power to the computer for this circuit? I'm interested to hear what you say about this, I'm just afraid its going to be extremely simple and I'll feel real stupid

Jackrabbit501

iTrader: (3)

So question for you, is the fuel pump "red wire" bigger or smaller I'm gauge compared to the always hot "orange wire" ??

Tuned Performance

iTrader: (92)

Iirc the red wire is a large diameter like the orange wire. To see if the ECM has power just turn the key to the on position the check engine light is commanded on. To verify the ECM is powered just jumper the aldl connecter. That's the connecter under the dash drivers side knee bolster. Jumping a to b will cause the check engine light to come on. If the check engine light blinks you know the ECM is powering up. Back to the red wire it will be hot at all time if I recall it's ran off the starter power lug and protected bye a fusable link. I didn't read back to see if disconnecting the ECM and if you tried to apply 12v to the green/white wire at the ECM connecter and or relay to see if it controls the relay. Don't forget the ground of the relay is just as important as the power side. It maybe hooked to the drivers side cylinder head back bye your master cylinder.

Tuned Performance

iTrader: (92)

On the orange wire it starts at the battery then goes to the fuse on the fender then splits power to the ECM and oil pressure switch. It will only send power past the oil pressure switch when cranking the engine produces 4psi. Hth

Jackrabbit501

iTrader: (3)

I see no fuse on the fender. I originally had one on the v6 harness, but now I don't see a connector for the v8 harness. Do all of them have fuses?

Also I checked the aldl a to b jump and no engine light came on.. so I'm guessing I'm not getting power to the computer. Where should I start looking next?

Jackrabbit501

iTrader: (3)

This should be fuel pump relay, but the wire is orange even far under the harness wrap. So which ones prime and which ones always hot?

Tuned Performance

iTrader: (92)

http://www.hotrodlane.cc/newtech/tun...elcircuit.html
You might want to start at the eco and follow the harness back. The Eco will have constant 12v fuse power to pins B1 and C16 if this is tpi mad 1227165 ecm.

Jackrabbit501

iTrader: (3)

Ok tuned performance, heres the update:
Tore my harness apart looking for the inline fuse to power the ecm and fuel pump and cant find it anywhere! Im thinking about creating a fuel pump/ relay/ burnoff/ mass/ pump swith harness. Basically run a hot with my own inline fuse to my relays, grounding what needs to be grounded very close to the connectors, and whatnot and seeing if that helps with my ecu powering up. I check my B1 and c16 connectors at the ecu where hot was suppose to be and got nothing.
My mechanic buddy was telling me about wires underneath insulation breaking contact or kinda dieing? Losing a solid connection throughout the wire.

So i think im going to try my idea so i atleast know all my connections/ wires/ and grounds are all solid before moving onto something else. Ill keep you updated when i can. Appreciate te help

Jackrabbit501

iTrader: (3)

OK so before I start cutting stuffew I decided to check power to the ecu. So the computer has both injector banks 12 but in the key on, it also receives voltage from B5, the distributor reference. Nothing from fuel relay or mass.

So according to the diagram, the ecu receives 12 volts constantly for the fuel pump relay circuit. So I wired in a 20A fuse along with just a regular hit wire to both pins that receive power from these circuits. Ecu still didn't power up, even jumping the a to b on aldl showed no code.

So I went to O'Reilly and decided I would just buy a computer and see if it would change anything, and if not just return the computer. The results were nothing has changed. So ecu goes back to oreilly. How can I forcefully power up the ecu? Is it within the fuel pump relay circuit? I have a feeling its not and I should be looking for a bad ground somewhere..