Intermittent start, Supercharged

TylerM

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KB 2.6l Stage 2
52lbs injectors
DW300M fuel pump
Degree colder plugs
MSD coils
Triple Pass with GT500 pump
SCT Big Air
New 850 CCA battery.
New clutch

Coil packs are getting voltage. Fuel pump primes and pressure at the rails.

Car cranks

Car ran and idled for about 30 minutes on initial start. Dropped e-brake to do a datalogging run and car shut off. Has not started since. Car returned a pats code. Circumvented pats in the tune. Car will occasionally start and idle for 3-5 seconds then shutoff and not start. Code P0690 (PCM Power Relay sense high) appears randomly.

Cleaned PCM plugs with electronics cleaner. Pulled blower off and inspected. Bypass valve was stuck open in valet mode. Locked the bypass valve closed. Reinstalled blower. Car started and ran like crap until I killed it. Realized I forgot to bolt the blower back down. Bolted the blower back down. Car ran for 3 seconds and died. Car will sometimes start and then immediately dies. Sometimes just cranks. Not sure where to go from here. Cannot replicate a start condition nor will the car run long enough to find a vacuum leak anywhere. Any input?

Can smell fuel after attempting to start the car, smell dissipates after a few minutes.
 

Juice

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Is this a new install of the supercharger?
What is the point of the PATS bypass?
 

TylerM

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Is this a new install of the supercharger?
What is the point of the PATS bypass?
New install on this vehicle.

Keep the immobilizer from kicking in while we tune it. I have time set aside to troubleshoot it later.

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Juice

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There is no way the immobilizer to shut the car down once it starts. PATS only keeps the car from starting.
Since it is a new SC install and it never ran, I have to say you missed reconnecting something, lose ground, etc. Time to double check everything.
 

TylerM

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Idled for 30 and stalled you said. I would not call that running if you never got to drive it.
I apologize, I left information out. I drove it to the end of the block and back before hooking up my datlogging equipment. About 50 yards.

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DieHarder

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Did you remove/disturb any grounds/other wiring during your build? If so, recheck all of your grounds and every wire you've touched, moved, extended, re-soldered, crimp connected or otherwise disturbed. Try to do continuity checks end-to-end on any wiring you extended and check for shorts where appropriate.

Floating grounds will do a number on these cars; they're very sensitive that way and need good grounds to operate properly. In fact I had to add another ground (4 gauge wire) running from the passenger strut tower to one of the bolts on my new/expensive alternator to get it to output the correct voltage. Chased that one for two weeks (including dealer troubleshooting - wasted money) before I finally figured that one out. Kept thinking it was PCM alternator sense lines when it fact the grounds were the culprit.

P0690 comes up as PCM Pwr Relay high sense. That could easily happen if the grounds are floating. I would also check the output of the alternator when you get it running and record that voltage. In the meantime I would check all of the grounds, clean and put them back together. And it wouldn't hurt to add another ground from the body/negative terminal to the engine even if only temporary as a test to see if that helps troubleshoot your starting issue. Will assume that you have a decent VOM to troubleshoot wiring/electrical. Good Luck.
 

07 Boss

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Did you have to move the PCM during the install? Doesn't KB use the intake that goes down to the bumper?
 

Juice

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P0690 your pcm thinks it is having a power problem. Thats where you need to start checking. I do not know which is the pcm power relay.
 

TylerM

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Did you have to move the PCM during the install? Doesn't KB use the intake that goes down to the bumper?
They do. I went ahead and moved the BEC to the cabin and the pcm to the fender. I ordered the oem workshop diagrams for my model year.

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P0690 your pcm thinks it is having a power problem. Thats where you need to start checking. I do not know which is the pcm power relay.
I tested the relay and it works good. Waiting on the wiring diagrams for my car to chase it.

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Did you remove/disturb any grounds/other wiring during your build? If so, recheck all of your grounds and every wire you've touched, moved, extended, re-soldered, crimp connected or otherwise disturbed. Try to do continuity checks end-to-end on any wiring you extended and check for shorts where appropriate.

Floating grounds will do a number on these cars; they're very sensitive that way and need good grounds to operate properly. In fact I had to add another ground (4 gauge wire) running from the passenger strut tower to one of the bolts on my new/expensive alternator to get it to output the correct voltage. Chased that one for two weeks (including dealer troubleshooting - wasted money) before I finally figured that one out. Kept thinking it was PCM alternator sense lines when it fact the grounds were the culprit.

P0690 comes up as PCM Pwr Relay high sense. That could easily happen if the grounds are floating. I would also check the output of the alternator when you get it running and record that voltage. In the meantime I would check all of the grounds, clean and put them back together. And it wouldn't hurt to add another ground from the body/negative terminal to the engine even if only temporary as a test to see if that helps troubleshoot your starting issue. Will assume that you have a decent VOM to troubleshoot wiring/electrical. Good Luck.
I'll double check the grounds. The alternator is a high output. Roughly one year of use on it.

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Juice

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Something went wrong moving the PCM and BEC. Thats the most likely explanation.
Since it did run for a little, and now something has failed or a fuse is blown. Anything powered from a circuit coming from the SJB, the SJB has over curreent protection built in. Did you add any electrical componenets? Like an intercooler pump?
 

TylerM

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Something went wrong moving the PCM and BEC. Thats the most likely explanation.
Since it did run for a little, and now something has failed or a fuse is blown. Anything powered from a circuit coming from the SJB, the SJB has over curreent protection built in. Did you add any electrical componenets? Like an intercooler pump?
Intercooler pump, FRPP and triple pass, but I did not route the electrical through the boxes

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07 Boss

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Yep, I would bet money it has to do with wiring somewhere while relocating shit. One of the reasons I went Whipple. I would go through and check continuity on all of your soldered wires, check grounds, fuses, etc.
 

Pentalab

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They do. I went ahead and moved the BEC to the cabin and the pcm to the fender. I ordered the oem workshop diagrams for my model year.
The alternator is a high output. Roughly one year of use on it.

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What do you mean by a 'high output alternator' ?? (who makes it) Put a DVM across the battery terminals ..and with eng off, you should see like 12.2 to 12.5 vdc. With eng on, idling, you should see 14.75 vdc.
With eng on, idling, switch dvm to read acv. You should read just a few millivolts acv. If you are reading a substantial amount of acv, that's excess AC ripple, which will cause no end of grief. ( 1 or more of the 6 x diodes inside the alternator has shorted). You don't want to be pumping raw acv into the battery ( and the ecu, etc).

Several of the aftermarket higher output alternators gave folks grief. The vdc was not stable, and would wander and fluctuate all over the map.
 

07 Boss

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I had a brand new motorcraft alternator being installed under warranty by Ford that was bad out of the box, diode issues.
 

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