Pedrothecobra
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- Dec 22, 2021
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will update once i try it. still need to know where the signal to open and close the relay is fed from
Yes, at least on the couple fabricated hangers I’ve made there is a special Teflon insulation on the in tank wiring. It’s been many years since I’ve done that stuff lol.specialized wire?
ECU is newHave you looked at the capacitors in the computer? Two of them. I replaced mine when I did my intakes and never looked back.
You can get them off eBay
what do you mean in circles? i mean systematically going through and troubleshooting to rule out each system and its components isnt going in circles its basic troubleshooting 101. and when you say your car was doing the same thing, you were losing fuel pressure at the rail? along with not seeing full body voltage at the pump in the higher rpm range? also what do you mean by manufactures numbers? i probably have the info if you can be more specific as to what your referencing. have you read the recent post where im finding a slight short to ground through my pcm or are you just reading the initial post? im not trying to come off as a dick but i dont really understand what your comment is eluding to or how its informational to the issue im having. im trying to not continue throwing parts at an issue and actually understand how the system is supposed to be working so i can fix it. if you go back and read this entire thread youll read how ive found bad splices (repaired them) throughout this entire troubleshooting process"
ECU is new
So. New doesn't mean anything.
Did you check it?
From what you've written, all you say is what you have? All You have told my electrics guy is you are going in circles. He read your posts and said that exact thing. Going in circles. You have no manufacturer numbers.
You done a Gas Cap yet?
MAF?
Trans speed sensor?
PCV Hose?
This is all a problem I had before - target the hierarchy. Also, we have the same manual Pedrothecobra.
Go to town then:
Throttle Position Sensor
Mass Airflow Meter
EGR Valve Position
Heated Exhaust Gas Oxygen
Air Charge Temperature
Engine Coolant Temperature Sensors
Vehicle Speed Sensor (VSS)
Idle Air Controller (IAC)
Relays
Thermactor TAB/TAD and EVR Solenoids
Canister Purge
All the SMOG Stuff
thats what we were thinking last night while we were rd testing. but it never changed state, i know im getting a good tach signal from what i can see on my data stream. but if you follow the red wire out of the CCRM it goes to the other side of that relay and also the injector circuit. i did find a wire spliced into my CCRM on the AC field coil wired back to my heater controls. im wondering if the CCRM has an issue or could be causing the PCM to not remove voltage at the fuel pump relay in the higher RPM range.according to your diagram its the white/red wire that goes to the pcm that triggers the relay
I agree, your methods are sound from where I’m sitting.I watch a mechanic on tictok. Trouble shooting a new chevy truck lead to the computer being the problem. Pulled the computer noticed oil in the comp harness. Turns out the oil sending unit sensor diaphragm broke within and was applying oil psi to the wire which eventually traveled through 5ft of wire into the computer!!
I think your troubleshooting process is on par. Keep up your spirits and dont give up!
I did that a few times already, but at this point it doesn’t hurt to check em out againJust to be stupid, its been a while and you have been in the wiring, make a run through your fuses and make sure they are all good.
Yea that’s kinda where I think this is leading to. I’ve been keeping the level low for that reason lolI agree, your methods are sound from where I’m sitting.
I know it’s supposed to be new but I think you should drop the tank and inspect the pump, related hoses and wiring in the tank. I would also replace the entire sending unit unless you can be sure everything is holding pressure in the line.
At this point, even though a stock pump isn’t up to a power adder, if you can get the problem with cutting out to change, you’ll know where the problem lies. I’d bet that someone here has a stock sending unit you can try out. I know dropping the tank is a PITA but it sounds like you’re up to the task. My $0.02
I get what you’re trying to do but I think you’re going a little overboard. The wiring is fine. Looking more into it, it’s normal to see around 1v to 1.5v of voltage drop across the fuel pump circuit.
Yea I haven’t ruled that out but that’s an expensive work around for an issue that will still be there. I want to fix it before I run out of motivation and just bypass the whole system lol
was just replaced with a factory cobra pump, about a month ago at a shop. I haven’t physically verified the new pump with my own eyes. But I’ll probably be dropping the tank this weekend to check it out. And blow at the lines out while it’s down and disconnectedI don’t remember if it was ever determined but what pump is in there? It could be drawing too much current resulting in lower output. Or it could be a bad pump.
I get what you’re trying to do but I think you’re going a little overboard. The wiring is fine. Looking more into it, it’s normal to see around 1v to 1.5v of voltage drop across the fuel pump circuit. Regardless, it’s rated at 12v so a little lower isn’t going to kill it’s output like that. I think you have another issue. I think it’s relegated to the pump itself. If you’re na I wouldn’t run anything over a stock replacement pump.
Yea I haven’t ruled that out but that’s an expensive work around for an issue that will still be there. I want to fix it before I run out of motivation and just bypass the whole system lol