PID Question - 96' Procharged Cobra WOT cut-out

01silverstang

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Long story but hoping yall can help, I just picked up my Cobra in January, it’s a 1996 with the following known engine mods:

- Procharger P-1SC with Open Race BOV and 3 Core Intercooler

- 42 lbs/hour injectors

- VMP blow through MAF

- Unknown Fuel Pump

When I purchased the vehicle, I replaced the pulley seal on the P-1SC and got it remounted with a new Gates belt as the previous owner advised the last belt had shredded. I have since replaced spark plugs with NGK TR6 gapped at .030, replaced the IAC, installed brand new OEM NGK 02 sensors, a new Bosch 4.2 wideband sensor for the AEM AFR gauge, as well as replacing the Fuel Filter.

I took it for a test spin and it pulled hard in second gear, but I noticed it had no turn signals or brakes lights. The car sat for about a month while I resolved that issue (clutch arm wore through the brake/turn signal wire causing a short to ground blowing fuses). During this time, I discovered an old Viper Alarm under the dash and removed it, the only issue I had was using a butt connector to reconnect the ignition so I could start the car. I also at this time replaced my fusible links between the voltage regulator and the under-hood fuse box. They were replaced in the Ford (Warranty) approved manner, of using a non-insulated butt connector and high-quality heat shrink.

I then proceeded to fill the car with some 93 (from Speedway) which I now know is not optimal, will be using Shell from here out. The car drives great and low and part throttle, so after cruising for a little bit I decided to try a quick pull in first gear… as soon as I went WOT the car just shut down like fuel or spark was completely cut. It’s not a breaking-up or just down on power, it’s like a complete cut… however, the car doesn’t die. I immediately let out thinking I had blown a coupler from the charge pipes. However, my vacuum was good and upon inspection I found no-couplers loose. No CEL’s or codes even after multiples pulls exhibiting the issue. If I stay at part throttle, I have gotten past the cutout rpm of 3k to 3.5k and gone up to 4k in second gear with no cut. It drives smooth with no bucking or misfires at part throttle, it’s only at WOT that it cuts (see attached videos).



While waiting for my new laptop to arrive so I can update the SCT X4 I purchased and start data-logging, I replaced the fuel filter and used live data on my Autel code clearer and got:

Spark Advance at idle: 16.0 to 19.0

MAF: .01 to .03 (lbs/s)

02B1S1: 0.955

02B2S1: 0.910

Fuel Trims were all zero

Monday, I checked fuel pressure at the rail, and at key on engine off I had 30 psi, 35 psi at idle holding, and with the vacuum line detached from the regulator it jumped to 45 psi. The 5 min leak down held 35 psi, though the gauge didn’t drop when it was removed until I disconnected the lines so maybe I didn’t do something right? I’m going to see if the gauge is long enough to run it under the cowl, and tape it to the windshield to see what fuel pressure does while driving and under a pull as well. I suppose if the fuel pump is starting to fail, and can’t keep under WOT that might explain the issue.

So, the laptop arrived last night and in anticipation I was hoping you could identify which PID’s would be helpful for figuring out why I’m having the cut-out at WOT.
 

robvas

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Does it cut at WOT or does it cut when you see positive boost pressure? (Do you have a boost gauge?)
 

01silverstang

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Does it cut at WOT or does it cut when you see positive boost pressure? (Do you have a boost gauge?)
I do have a boost gauge and the cutout occurs as it goes from vacuum to boost, no substantial boost has built when it happens.

I would have to check tonight to see if I can build boost at part throttle. I was going to drive in a higher gear to put load on the engine without WOT to see what happens.
 

decipha

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DO NOT UPDATE THE XCAL!!!!

Here is my cdan4 configuration file for livelink.

Usually when you get a hard cut like that its ignition related.
 

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01silverstang

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DO NOT UPDATE THE XCAL!!!!

Here is my cdan4 configuration file for livelink.

Usually when you get a hard cut like that its ignition related.

The X4 was already on the most current software when I connected it, and did not require any further update.

The only thing throwing me off about ignition is there isn't a single coil to go bad, so even if one of the two coils was bad... you would think it wouldn't shut off entirely. This is why I didn't think it was plug wires, I would have expected more constant misfires and eventually a CEL and/or codes.

I added the configuration file in Live Link, I'm new to all of this... so when I set the X4 to data log what else do I need to do to generate a good log for review?
 

decipha

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get the engine up to operating temp, start the log then go flog it where it acts up

stop and save the log and send it to your tuner. They will give you further instructions.
 

01silverstang

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get the engine up to operating temp, start the log then go flog it where it acts up

stop and save the log and send it to your tuner. They will give you further instructions.

I haven't decided on a "new" tuner yet, as the car should already have a custom tune from DynotuneMP in Hampshire, IL. I'm mainly hoping to identify a mechanical failure with the logs, be it sensor, ignition component, or fueling. I was hoping if I posted the logs here, someone more knowledgeable would be able to see what looks off and point me in the right direction.

In the future I would like to have the car gone over by a good tuner, however, I'd like to not waste that time and money chasing issues and instead have a solid tune done without side issues interfering.
 

01silverstang

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Ok, so I did a 3 min idle log... and then did a rev log going from 1,500 rpm up to 3,000 rpm for 15 second intervals. Any feedback would be appreciated!
 

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  • Idle datalog1.csv
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  • Rev datalog1.csv
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01silverstang

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You need to log the issue. If it's acting up at WOT a log at idle won't give the needed info.
It didn't feel right at idle either… if something is wrong at idle it may just be worse at wot. Ill get the other logs tomorrow, but I wanted to get these before dinner and my sons bedtime routine.
 

robvas

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I can see the CSV's just fine
 

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01silverstang

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I can see the CSV's just fine

I sent a screen shot to DynotuneMP and the only thing he said looked off about the log was the battery voltage which he confirmed is measured at the PCM. I pulled the carpet and kick panel and took the bracket off last night so I can try to measure the pin's for "vpwr" to see if I can isolate why the PCM power is low.

Before I go further, friend who is a Ford Mechanic wants me to check PCM power relay output from the CCRM, pin 24, to see if maybe the CCRM is the cause. Now the only thing throwing me off about this, is why there isn't a check engine light if the PCM is only registering 7.94v...
 

01silverstang

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I e-mailed SCT as the more I looked at the log the more that PID seemed "off," you would expect to see some variance over the course of the log but it was the same number constantly. They think something is off too, as the X4 displays within a 1v of what is measured at the battery on the X4.

Double checked the CCRM PIN 12/24 last night and they both measured the same as battery. So if the PID was a red herring, and my voltage is fine... then I'm back to fuel and spark... wish I had the money to sell this thing and just buy a new muscle car that works lol.
 

DSG2003Mach1

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I e-mailed SCT as the more I looked at the log the more that PID seemed "off," you would expect to see some variance over the course of the log but it was the same number constantly. They think something is off too, as the X4 displays within a 1v of what is measured at the battery on the X4.

Double checked the CCRM PIN 12/24 last night and they both measured the same as battery. So if the PID was a red herring, and my voltage is fine... then I'm back to fuel and spark... wish I had the money to sell this thing and just buy a new muscle car that works lol.

can you not just log fuel pressure on that car?
 

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