You can see if the pump is getting voltage at the switch in the trunk. And you can force the pump on at the data link connector. Ground the terminal called fuel pump with the key in run. Then check the fuel pressure.
No start. Has fuel and spark, cranks.
- Thread starter luckyGAT
- Start date
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OhioGuy82
New Member
I had the pump replaced and still nothing. I'm just about to give up and just part ways with the car. I do have a few alternatives in mind. 1, there are scads and scads of street rodders that live around me. I've told them the problem. A lot of them suggested to buy a stand alone fuel pump relay harness and put a switch on the pump. So this way I'll cut out the middle man and the pump will have it's own relay and wiring. Would this effect anything? ECM..ect..
Good idea? Bad idea? I'm kinda getting desperate here.
Good idea? Bad idea? I'm kinda getting desperate here.
Storm-Chaser
New Member
First, how are you validating that you have fuel and spark?
Second, a dimming [ CHECK ENGINE ] Light indicates an electrical problem/short.
Third, have you pulled the codes?
Simply pulling one plug-wire to check for spark or checking the shradder valve for fuel does not mean the car is getting sufficient spark or fuel pressure. The easiest way to check for a bad coil is to swap-in a known working coil. In order the check fuel pressure, you should either borrow or rent a fuel pressure testing kit.
If during prove-out the CEL dims, but the other cluster lights do not, the CCRM is most likely bad. If all the cluster lights dim, then you have an eletrical problem - bad battery cables and/or connectors, bad battery, bad starter, harness short, (ICM in vehicles that have them), and/or bad ECM .
What codes did you get? What codes you get (or cannot get) will give you a starting-point for trouble-shooting the problem. Otherwise you're likely to get ass-***** by a dealer or shop that has little experience with the SHO engine/electronics.
Second, a dimming [ CHECK ENGINE ] Light indicates an electrical problem/short.
Third, have you pulled the codes?
Simply pulling one plug-wire to check for spark or checking the shradder valve for fuel does not mean the car is getting sufficient spark or fuel pressure. The easiest way to check for a bad coil is to swap-in a known working coil. In order the check fuel pressure, you should either borrow or rent a fuel pressure testing kit.
If during prove-out the CEL dims, but the other cluster lights do not, the CCRM is most likely bad. If all the cluster lights dim, then you have an eletrical problem - bad battery cables and/or connectors, bad battery, bad starter, harness short, (ICM in vehicles that have them), and/or bad ECM .
What codes did you get? What codes you get (or cannot get) will give you a starting-point for trouble-shooting the problem. Otherwise you're likely to get ass-***** by a dealer or shop that has little experience with the SHO engine/electronics.
OhioGuy82
New Member
I called the shop today. They said they could not communicate with the ECM at all.
Time to hit the JY or the forum and get a $30 ECM. That $650 is just horrible.
If I had a spare I'd send it to you but my X2J went sideways and I'm back to using the normal one.
If I had a spare I'd send it to you but my X2J went sideways and I'm back to using the normal one.
OhioGuy82
New Member
I'm having it towed home ASAP. I'm gonna try to take a stab at it. My friend happens to have a '91 that runs perfect. I'm hoping to swap out a few parts and see if I can get this thing going again!
Storm-Chaser
New Member
Sorry, but this is probably the worst "method" for validating whether the fuel pump has "failed", given the multiple possible causes for the pump to not energize.
I've owned several SHOs and non-SHOs in which you could never hear the fuel pump - engine running or not. My current SHO, I could not hear the fuel pump until changing to a used pump from another SHO (the sending unit began acting-up). That pump I could hear, and that pump failed four months later. I took the "silent" pump and mounted it with the good sending unit and continue driving on it to this day.
If you have one of the "noisy" pumps that you hear everytime you start your car, then you can use the lack of pump-noise as an indicator that you need to check your fuel pressure.
I've owned several SHOs and non-SHOs in which you could never hear the fuel pump - engine running or not. My current SHO, I could not hear the fuel pump until changing to a used pump from another SHO (the sending unit began acting-up). That pump I could hear, and that pump failed four months later. I took the "silent" pump and mounted it with the good sending unit and continue driving on it to this day.
If you have one of the "noisy" pumps that you hear everytime you start your car, then you can use the lack of pump-noise as an indicator that you need to check your fuel pressure.
OhioGuy82
New Member
I'm going to have it towed home this morning to see what I can do with it. Hopefully I can get it running. If not, I'll have a listing in the F/S section. I can't have 3 cars.
projectSHO89
SHOless In St L
A dim CEL usually means the PCM is not being properly powered. If the PCM isn't being powered, the fuel pump will never work. So, even if you hot-wired the pump, the engine still won't start or run.
One of the more common reasons for a dim CEL is a corroded ground wire connector that connects the negative battery terminal to the passenger-side strut tower. Install a jumper to see if the problem resolves.
Steve
One of the more common reasons for a dim CEL is a corroded ground wire connector that connects the negative battery terminal to the passenger-side strut tower. Install a jumper to see if the problem resolves.
Steve
Storm-Chaser
New Member
In both cases I have experience with, I had no fuel pressure with the "dim" Check Engine light. And in both cases changing the CCRM (ie. contains fuel pump relay) corrected both the no-start and "dim" Check Engine light.
James (St Louis SHO) first told me about this, and in both my cases his reasoning/experience proved correct.
James (St Louis SHO) first told me about this, and in both my cases his reasoning/experience proved correct.
Storm-Chaser
New Member
OhioGuy82
New Member
Well, finally the SHO is home. I did some investigating and found my ignition fuse holder was apart and empty & the inertia switch was disconnected and it seemed to be jumper. So I took the jumper off and connected it back. The bad is my battery is dead and I can't test anything. HOWEVER my friend who happens to have a 91 is going to swap his CCRM out with mine.
Let's hope that will resolve my problem.
Let's hope that will resolve my problem.
OhioGuy82
New Member
I connected the battery, no fuel pump prime. So I checked to see if I had any fuel at the rail, pressed on the schrader valve and sure enough, fuel shot straight up and hit the hood mat. Apparently I fuel, I'm stumped more now than ever! My fans are still on, and I still have a dim CEL light when cranking. I still do not have the "CLICK CLICK" I'm used to. I hope it's the CCRM.
I just had a CCRM from a running 91 in my SHO. It still will not start. Even with the good CCRM installed my fans are still on and the CEL light is still very dim. We tried running a jumper from the connector to a ground and the fuel pump will not turn on. From the CCRM connecter, he jumped pin 1 and 5 and the fuel pump energized. What else is there that is making my CEL light dim and the pump not to energize? I'm leaning now towards ECM.
The Red wire on the CCRM connector is measuring around .46-.50 volts, while the yellow is getting 12V+, I found that a bit odd.
I just had a CCRM from a running 91 in my SHO. It still will not start. Even with the good CCRM installed my fans are still on and the CEL light is still very dim. We tried running a jumper from the connector to a ground and the fuel pump will not turn on. From the CCRM connecter, he jumped pin 1 and 5 and the fuel pump energized. What else is there that is making my CEL light dim and the pump not to energize? I'm leaning now towards ECM.
The Red wire on the CCRM connector is measuring around .46-.50 volts, while the yellow is getting 12V+, I found that a bit odd.
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projectSHO89
SHOless In St L
Fix the dim CEL first. Ignore everything else until it is resolved, otherwise, you'll be wasting your time.
The RED wire (pin 24) is the output of the PCM Power Relay. If it doesn't have power on it, the computer (and almost everything else) won't work. Your PCM is probably not the issue. The yellow wire is a supply into the IRCM module, not an output.
Again, we've already told you what causes a dim CEL: Either a faulty ground or power lead to the PCM. This may be due to a fault either inside the IRCM or due to external wiring issues.
The PCM Power Relay in the IRCM must have:
Good ground - IRCM pin 15. Check continuity to battery negative terminal.
Good supply to be switched - IRCM Pin 8. Always Hot via EEC Relay fuse in engine compartment fuse box. Hope you already checked that fuse.
Switched 12V from ignition switch - IRCM Pin 13. Should be HOT in START or RUN.
Those are the prerequisites for getting power to the PCM. You still need to get a good ground to it. That is the above-mentioned ground lead. You can do a quick test by using a battery jumper cable to from the battery's negative terminal to the ground stud on the firewall (the one the rear intake is attached to) to see if the PCM then powers up correctly.
This is not rocket science, don't make it harder than it needs to be. Just follow directions and it will be solved readily.
Steve
The RED wire (pin 24) is the output of the PCM Power Relay. If it doesn't have power on it, the computer (and almost everything else) won't work. Your PCM is probably not the issue. The yellow wire is a supply into the IRCM module, not an output.
Again, we've already told you what causes a dim CEL: Either a faulty ground or power lead to the PCM. This may be due to a fault either inside the IRCM or due to external wiring issues.
The PCM Power Relay in the IRCM must have:
Good ground - IRCM pin 15. Check continuity to battery negative terminal.
Good supply to be switched - IRCM Pin 8. Always Hot via EEC Relay fuse in engine compartment fuse box. Hope you already checked that fuse.
Switched 12V from ignition switch - IRCM Pin 13. Should be HOT in START or RUN.
Those are the prerequisites for getting power to the PCM. You still need to get a good ground to it. That is the above-mentioned ground lead. You can do a quick test by using a battery jumper cable to from the battery's negative terminal to the ground stud on the firewall (the one the rear intake is attached to) to see if the PCM then powers up correctly.
This is not rocket science, don't make it harder than it needs to be. Just follow directions and it will be solved readily.
Steve
OhioGuy82
New Member
I performed the tests above. Everything checks out as described. What is my next step?
projectSHO89
SHOless In St L
You already reported you had nothing on the red wire, now you do?
Report actual readings pin-by-pin. I don't accept glossed-over reports.
OhioGuy82
New Member
Pin 15 = 000. Grounded to the battery as advised.
Pin 8 = 12.25Volts. Always.
Pin 13 = 11.25 Volts in the "RUN" Position. 9.89 Volts in the "START" Position
Pin 24 = 1.9-2.5Volts. It kept fluctuating.
Pin 8 = 12.25Volts. Always.
Pin 13 = 11.25 Volts in the "RUN" Position. 9.89 Volts in the "START" Position
Pin 24 = 1.9-2.5Volts. It kept fluctuating.
projectSHO89
SHOless In St L
Based on that, I'd say your PCM power relay inside the box (or an attending internal PCB trace) has failed or that one of the loads is dragging it down.
I'd check resistance between pin 24 (power OFF) and ground first.
If the pin circuit is not shorted to ground, you can connect a fused (10A or 15A) jumper from the battery positive terminal to pin 24 to bypass the relay and see if the system now works. If so, that confirms the internal relay has failed.
Make certain you are using the correct letter version of the IRCM box. In the case of the 91, it should be an "M".
Steve
I'd check resistance between pin 24 (power OFF) and ground first.
If the pin circuit is not shorted to ground, you can connect a fused (10A or 15A) jumper from the battery positive terminal to pin 24 to bypass the relay and see if the system now works. If so, that confirms the internal relay has failed.
Make certain you are using the correct letter version of the IRCM box. In the case of the 91, it should be an "M".
Steve
OhioGuy82
New Member
Pin 24 = 1.25K Ohms resistance when grounded to the chassis.
I took a test light out and checked for voltage with the IRCM plugged in and sure enough, it lit up. I have voltage going to the PCM. Any good approach to checking voltage going into the PCM? Besides tracing out the route to the PCM?
I took a test light out and checked for voltage with the IRCM plugged in and sure enough, it lit up. I have voltage going to the PCM. Any good approach to checking voltage going into the PCM? Besides tracing out the route to the PCM?
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projectSHO89
SHOless In St L
Your previous post indicated only 1.9-2.5 volts, now you "have voltage going to the PCM"?
?????
Either you have the correct power out of the IRCM or you don't.
If you don't, it's probably bad. If you were to have full battery voltage out of it on pin 24, then, and only then, to you have correct power available for the PCM.
Steve
?????
Either you have the correct power out of the IRCM or you don't.
If you don't, it's probably bad. If you were to have full battery voltage out of it on pin 24, then, and only then, to you have correct power available for the PCM.
Steve
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