96 cobra breaks up under WOT

[Pedrothecobra]

Expensive, sure. Work around for an issue that will still be there? Hardly the case unless you piggyback the CCRM. The best method, we found, was to yank the CCRM and use relays to run AC, fuel pump and PWM fan controller. The only caveat is getting the gauges to work as you're removing the factory sensors they're tied to. @lwarrior1016 monitors his with Autometer gauges while @ttocs and I are using the Holley dash.

yea i got this thing as a project about 2 months ago, i dont mind troubleshooting issues for now and im not sure what direction i want to take this thing. i havent ruled out a stand alone system yet. i was just trying to get it running 100% and drive it for a bit before i go crazy lol. i wouldnt mind swapping in a gen3 5.0 but they are pricey and the power you get out of a stock 4.6 with bolt ons from what ive been looking at hits the HP ceiling the 5.0 starts at. ive got a clean car to play with in terms of no rust and minor mechanical things that need attention.

 

[07GtS197]

I hear what you're saying, and I wouldn't have suggested checking the wiring if we didn't find the flying splices into the CCRM as we did. In my line of work, and with this car, I felt need to eliminate all variables and verify individual functions systematically. There is still an issue with the PCM not switching the state of the FPR. Since the PCM has been replaced, and the CCRM has been tampered with, is the CCRM failing? That's what I've been asking myself. Sure, you could make the argument that a 1 volt loss is negligible, and I wouldn't disagree too much. And the car may have a fuel delivery issue that hasn't been isolated yet. But if there is a PCM or CCRM issue, I'm curious if the other outputs such as injectors are affected. Is the fuel/air ratio accurate at >3250? How far off are the process variables from setpoint? If I knew what the permissive was that commanded the FPR to change, I would try to induce it as a test. I also ask, does that same permissive subsequently affect injector frequencies? I would think that if your RPM's reach >3250, the pump is stepped up to a higher output, the injectors are open at a different duration, probably a multitude of other changes are being made.

At the end of the day, if the fuel delivery checks out good, there is still that FPR not dropping out, and who knows what else is happening/not happening that we haven't identified.

Sorry for the ramble.

I get it I just think that you’re on a wild goose chase. Also, I’m not familiar with the cobra specific fuel system, but what changes at that rpm? The fuel injectors are controlled directly by the ecu via adding a ground so if that were as issue the ecu would detect it and throw a code. And if your afr is that far off the fuel trims would be positive at that rpm and may even throw a code if the ecu isn’t able to keep up with the fuel.

 

[Pedrothecobra]

I get it I just think that you’re on a wild goose chase. Also, I’m not familiar with the cobra specific fuel system, but what changes at that rpm? The fuel injectors are controlled directly by the ecu via adding a ground so if that were as issue the ecu would detect it and throw a code. And if your afr is that far off the fuel trims would be positive at that rpm and may even throw a code if the ecu isn’t able to keep up with the fuel.

My fuel trims are positive. They were 15-20 now they are sitting around 5-10 that’s the LTFT I haven’t looked at the shorts I’m a while since I’ve been chasing down the voltage/pressure issue

 

[07GtS197]

With the trims being that high it sounds like the pump can’t keep up so it’s increasing the injector pulse. Do you have a clamp style volt meter? You can clamp it on and see how many amps it’s pulling as the pressure goes down at higher rpm’s. That will tell you whether the pump is struggling or not or if it is a wiring problem. Have you checked the fuel pressure regulator on the fuel rail? It could be sticking open as well.

 

[Riles]

"

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

Just sit down. Your clueless ‍

 

[Pedrothecobra]

With the trims being that high it sounds like the pump can’t keep up so it’s increasing the injector pulse. Do you have a clamp style volt meter? You can clamp it on and see how many amps it’s pulling as the pressure goes down at higher rpm’s. That will tell you whether the pump is struggling or not or if it is a wiring problem. Have you checked the fuel pressure regulator on the fuel rail? It could be sticking open as well.

i do have a clamp style meter i can give it a shot. the regulator i replaced last week just for peace of mind. i guess i can try and clamp on at the kick panel and see what im getting while im driving. otherwise "adultingsucks" is gonna have to cram in the trunk lol

by any chance do you know what i should be seeing amperage wise in a good working system?

 

[Adultingsucks]

I have a clamp-on meter that will do AC & DC. I'll bring it home with me today.

 

[07GtS197]

I don’t know what the amperage should be but watch for amp spikes while it’s breaking up.

 

[96blak54]

One issue that i know that plagues are fuel tanks is the fuel return causing cavitation with in the fuel box(i cant remember the proper term for it). This is the box surrounding the pump to stablize fuel waving in the tank. Fuel thats returned to the tank needs a line that directs the fuel away from the pumps location because the returning fuel splashes around the pump creating cavitation. Your situation could be as simple as this but requires dropping the tank to check it. The return hose inside the tank is known for this problem. Simply redirection the hose. Sometimes the hose comes off and will most definitely blast the stable fuel supply for the pump.

I nominate dropping the tank

 

[07GtS197]

I think you’re thinking of the tank sump. Good call.

 

[Pedrothecobra]

One issue that i know that plagues are fuel tanks is the fuel return causing cavitation with in the fuel box(i cant remember the proper term for it). This is the box surrounding the pump to stablize fuel waving in the tank. Fuel thats returned to the tank needs a line that directs the fuel away from the pumps location because the returning fuel splashes around the pump creating cavitation. Your situation could be as simple as this but requires dropping the tank to check it. The return hose inside the tank is known for this problem. Simply redirection the hose. Sometimes the hose comes off and will most definitely blast the stable fuel supply for the pump.

I nominate dropping the tank

thanks. im hoping to get the tank down sunday. i want to inspect everything and blow out my lines while the tank is out.

 

[ttocs]

One issue that i know that plagues are fuel tanks is the fuel return causing cavitation with in the fuel box(i cant remember the proper term for it). This is the box surrounding the pump to stablize fuel waving in the tank. Fuel thats returned to the tank needs a line that directs the fuel away from the pumps location because the returning fuel splashes around the pump creating cavitation. Your situation could be as simple as this but requires dropping the tank to check it. The return hose inside the tank is known for this problem. Simply redirection the hose. Sometimes the hose comes off and will most definitely blast the stable fuel supply for the pump.

I nominate dropping the tank

if I am not mistaken this only really happens when the tank gets low? I thought this was the case and if it was we could test it by filling it?

 

[Pedrothecobra]

if I am not mistaken this only really happens when the tank gets low? I thought this was the case and if it was we could test it by filling it?

so i was actually going to say that but im hesitant to fill the tank if im goin to be dropping it. ive never filled the tank since i bought the car

 

[Notthenow]

I just had to drain my tank because I let it sit for 14 months on my estimated 3 month down time.... I used a cheap transfer pump and went through the fill vent on the side of the tank next to to filler tube. Very quick and painless, but helps if you have containers to store the fuel, of course.

 

[96blak54]

Transferring fuel is costly! Anything fuel related becomes painful.

 

[Notthenow]

And, it smells great.

 

[Notthenow]

Not sure on the fuel transferring cost that toy mean Blak, a $10 hand pump from Auto Zone and two 5 gallon gas cans I had on hand....

 

[ttocs]

just disconnect the line at the filter and use the pump to do it.

 

[Pedrothecobra]

I prefer to use some garden hose and my mouth lol

 

[Rons95GT]

Speaking of old fuel, how old is too old? I just got back from a long cross country trip in our travel trailer. I did put fuel stabilizer in before I left.