Lost

[Crystalvictoriamail]

​My name is crystal and I love love Camaros can I say lol I live in ms and a friend referred me to this site because I'm at a stand still I recently got a 91 Camaro rs v8 tbi for Christmas only under the impression that it was a fuel pump and I replaced fuel assembly fuel pump fuel tank also n now the thing is is its a PROJECT having an issue w no power to gray fuel pump wire could anyone help please!

[buddrow]

Verify that is the correct color for 12v to the pump as there is a ground, a 12v feed for the pump, and a 5v feed for the level sensor. I dont recall off hand if purple or grey is the correct feed for the pump. Possibly a fuse, ground, relay... Start by checking the fuse box, every fuse visually and with a dvom if u have one. Then check the pump ground and all engine and body grounds. Check the fuel pump relay for power coming in and leaving the relay. Does your ignition key have a little black chip in it? Could also be a passlock issue. Usually the signal wires to the computer.fairly easyfix if u have a meter and the correct keywith the correct chip. This give you something to start with. Lemme know how it goes.

Buddrow

[Crystalvictoriamail]

Yes the purple is for the float it's good the gray is for the 2sec prime to the pump all fuses and grounds are good too checked all relays inside under dash good and on firewall outside good and heard the oil pressure ties in its good too yes the key is chipped but vats has been bypassed by carbine after market security the car was wrecked on pass front checked all crash sensors that's not it and security works how it's supposed to when vats is bypassed you name it I've tried it what I'm not getting is power to that gray wire it goes from pump area to under dash to steering colum then to the lil black box under center consol think it's called SMd I have the name wrote down but I'm sure your fimiliar w it

[buddrow]

Ok i can offer a bypass which is approved many oem's. Just bypass the bad section. Run a new wire from the relay to the pump. Sounds hokey but it could save you hours of digging through a wire loom or testing black boxes. Have you check to see if the grey wire is grounded out? It may not have positive voltage. Check continuity to ground on the grey wire. Either way as long as you keep the wire safe from harm and is the same gauge as the grey wire running a bypass wire is the easiest way. And if you want to track it down later when u have the desire to u can. When in doubt, cut it out.

Buddrow

[Crystalvictoriamail]

oGonna try it I guess I've had someone suggest it but I don't like shortcuts on a car I don't know much about is the big thing I know. I have t hook it up so that it turns on n off w the switch though but how do YOU suggest I check to see if the gray wire is grounded

[buddrow]

Using either a digital or analog ohm meter, place one lead on the terminal (grey wire) and place the other on a known good ground. Usually a spot on the body whee there is are metal. If the is any reading on the meter other than O.L or "infinity" then the wire is shorted to ground. The bypass method will ensure you have power to the pump and allow you to see if the engine will actually run. Once you verify it will run on the pump the you can make proper repairs to the circuit. Ive seen peoe chase their tails for weeks trying to figure out whats wrong with a wire when there was a mechanical issue with the car. Start there and lemme know if u have any questions.

[beestoys]

I would also recommend finding a factory manual it will come in handy older project vehicles can be fun and tormenting as well at times. The manual will be a good investment if for nothing else but your sanity. And when your ready to put a match to it walk away and regroup and you'll get it figured out.

[Crystalvictoriamail]

Haha I'm not setting anything in fire it will be done by the way it analog ohms is 053.5

[Crystalvictoriamail]

And I have the manual that came w the car from the dealer new but no help

[buddrow]

Ok so u have continuity between the power wire and ground. Im assuming you have also checked for voltage on this wire? ;) someone has probably inadvertently used this wire for something its not intended for or the alarm has it grounded. Either way just bypass it with a similar gauge wire and see if it fires up. Shotgun diagnosis I know but since you dont really know the state of the engine other than what you were told Id get it running then go back and spend time tracing the affected wiring.

[Crystalvictoriamail]

[QUOTE=buddrow;36346]Ok so u have continuity between the power wire and ground. Im assuming you have also checked for voltage on this wire? ;) someone has probably inadvertently used this wire for something its not intended for or the alarm has it grounded. Either way just bypass it with a similar gauge wire and see if it fires up. Shotgun diagnosis I know but since you dont really know the state of the engine other than what you were told Id get it running then go back and spend time tracing the affected wiring

yes had voltage I'm gonna try it I'll get bk to you

[Crystalvictoriamail]

What if there's no 2 sec prime from gray wire

[EagleMark]

Then you don't have power to fuel pump from fuel pump relay.

But if your turning key on and off? Sometimes it will not prime until off for awhile, all ECM/PCM have different timers but 30 seconds should cover them all.

Does your fuel pump relay have an extra Red wire hanging from it with a plug on the end? If so you can run 12 volt Batt power to it to keep fuel pump on while testing.

[Crystalvictoriamail]

No extra wire but can how can I run a 12v from batt to relay will give 2sec prime if so what wire do I attach 12 v to

[Crystalvictoriamail]

[QUOTE=EagleMark;36357]Then you don't have power to fuel pump from fuel pump relay.

But if your turning key on and off? Sometimes it will not prime until off for awhile, all ECM/PCM have different timers but 30 seconds should cover them all.

Does your fuel pump relay have an extra Red wire hanging from it with a plug on the end? If so you can run 12 volt Batt power to it to keep fuel pump on while testing.[/Q
k so trying to figure out if I had a short somewhere I check the wires. Under dash while doing this the black brain security box light flashed on then off then stayed on then just did this often so I continue feeling There is a short found a. Nic by accident touched w knife n it turns the car over like the starter over k so disconnect batt taped the red ignition wire I'm assuming n hook up batt n n ow no turn I over I even tested starter solenoid w jumper it's good I'm just lost. Now

[steveo]

a 1991 camaro rs didn't come from the factory with a black security box with a light.

you likely have an aftermarket alarm system.

maybe some idiot wired up a fuel pump disable with it.

i'd get that aftermarket alarm out of there, every single car i've ever owned that has one has been a huge source of problems.

[Crystalvictoriamail]

​My name is crystal and I love love Camaros can I say lol I live in ms and a friend referred me to this site because I'm at a stand still I recently got a 91 Camaro rs v8 tbi for Christmas only under the impression that it was a fuel pump and I replaced fuel assembly fuel pump fuel tank also n now the thing is is its a PROJECT having an issue w no power to gray fuel pump wire could anyone help please!



How how many volts r supposed to be going to the injectors

[steveo]

on your injectors, there's a power wire, and a switch wire.

the power wire is constant ignition voltage, fed by the ignition switch. you check the power wire against GROUND.with key on and engine not running. it should be within a volt of battery voltage, but more importantly, it should be fairly close to whatever the ignition +12v @ the ecm is so the injector offsets work correctly.

the switch wire simply connects and disconnects the ground, and is fed by the ecm. you can't really measure that signal in a meaningful way without an oscilloscope

[Crystalvictoriamail]

​My name is crystal and I love love Camaros can I say lol I live in ms and a friend referred me to this site because I'm at a stand still I recently got a 91 Camaro rs v8 tbi for Christmas only under the impression that it was a fuel pump and I replaced fuel assembly fuel pump fuel tank also n now the thing is is its a PROJECT having an issue w no power to gray fuel pump wire could anyone help please!



K so got the right voltage new tank fuel pump n regulator assembly the whole nine yards and defiantly know there's fuel coming to the top plate but it's not coming outa the injectors

[EagleMark]

You may have a VATS issue? If key does not have correct resistor to match VATS module then no pulse to fuel injector.

The injectors also need a DRP Distributor Reference Pulse to fire injectors. Sometimes you can tell when there is no spark at plugs. But other times the EST module in distributor will still produce spark at plug, but no fuel pulse at injector. The EST is a very finicky part when it comes to failing or being faulty and it's very rare for them to go bad, but they do.

Some auto parts stores are set to test this EST module. If you find one and take it out to test ask them to run the test three times. The module will get hotter with each test. If it fails any part of any test? Replace it with a AC/Delco brand. Aftermarket EST modules are just not as good!

Also check your grounds! Should be two from EFI system to engine, one on intake and one on back of head IIRC on Camaro. Clean, rust free, no loose wire, no paint underneath. As stated earlier the injector has power to it, the ECM grounds it to pulse/fire. Grounds are always an issue with EFI. They have to be perfect.

[Crystalvictoriamail]

K so got the right voltage new tank fuel pump n regulator assembly the whole nine yards and defiantly know there's fuel coming to the top plate but it's not coming outa the injectors




Alright might might sound crazy but nope no vats issue I know this n I have a pulse n also I have good grounds throw em at me any ideas cause I'm telling ya I did it all idk anymore! Oh and any one got directions how to take the actual injector apart let me know

[jim_in_dorris]

Crystal, go to an Autoparts store and rent a NOID light. Plug it into one of your injector connectors. Crank the engine. Does the light blink Yes/No

[Crystalvictoriamail]

K I have no pulse to the injectors what could I do?

[Crystalvictoriamail]

Crystal, go to an Autoparts store and rent a NOID light. Plug it into one of your injector connectors. Crank the engine. Does the light blink Yes/No





When keys keys turns over light comes on but when u crank no pulse also when I manually ground it it shoots fuel

[EagleMark]

Alright might might sound crazy but nope no vats issue I know this n I have a pulse n also I have good grounds


Crystal, go to an Autoparts store and rent a NOID light. Plug it into one of your injector connectors. Crank the engine. Does the light blink Yes/No


K I have no pulse to the injectors what could I do?

Just looked up a 91 F car and it does have VATS enabled... so earlier you said it's not a VATS issue and you have pulse? Now no pulse with Noid light...

Is your key in good shape? Does it have the resistors in it? Did you recently get new keys? Is the key switch worn/loose?

Do you have spark at spark plugs? Even if you do it could still be a faulty EST module or wiring issue at EST in distrbutor.

I'm open to other ideas as well, but these are top 2 for no pulse injectors... could also be a faulty ECM. Are there any error codes set?

[jim_in_dorris]

Okay, you injectors are fine. Your ECM is not commanding the injectors to fire. That can be a lot of different things. If the ECM is not seeing a reference pulse, I don't think it knows that you are trying to start the engine. Because you can ground your injectors and get fuel, I will assume that the fuel pump is coming at at Key On. The reference pulse comes from the distributor and goes to the ECM. Seeing the reference pulse tells the software that the engine is turning over. Do you have any SES codes set? there is one for no DRP's

[Dewayne_S]

For those following this, the problem has been found.
Friday evening I burned a new chip disabling the vats, security light went off but still wouldn't run. After a little research I found that the pinout for the 8746 was the same as a 7747 ecm so yesterday morning I drove over and swapped out the ECM's. The engine now runs. The problem was the ECM.

Crystal is now a very happy girl!