Runs for a second, then immediately shuts off

[defeat54]

420a turbo fresh rebuild. forged internals, Eagle Rods, Wiseco Pistons, Polished Factory Forged Crank, Acl Race bearings, Arp head studs & main studs, Supertech Valves, Springs & Retainers, mild port & polish.Sard fuel pressure regulator -Walbro 255lph fuel pump--Apexi Safc NEO A/F -650cc inj-controller/tuner-HKS Turbo Timer with Multi Functions and V. display and a bunch off other stuff.

Car ran perfect for 3 days,I dropped it off at a friends house to have him tap into the 3 wires at the ecu to get my speed sensor to work since I went from auto to manual. He couldn't get it to work and just soldered the 3 wires back together. Black/green, yellow, yellow with white stripe are the 3 wires.

The problem:
Car runs for a second and than immediately shuts off. Compression test shows 150 on all four, I changed the spark plugs and fuses, and I have checked the relays.

 

[XiKeiyaZI]

Pull the ECU.

 

[gusu]

420a turbo fresh rebuild. forged internals, Eagle Rods, Wiseco Pistons, Polished Factory Forged Crank, Acl Race bearings, Arp head studs & main studs, Supertech Valves, Springs & Retainers, mild port & polish.Sard fuel pressure regulator -Walbro 255lph fuel pump--Apexi Safc NEO A/F -650cc inj-controller/tuner-HKS Turbo Timer with Multi Functions and V. display and a bunch off other stuff.

Car ran perfect for 3 days,I dropped it off at a friends house to have him tap into the 3 wires at the ecu to get my speed sensor to work since I went from auto to manual. He couldn't get it to work and just soldered the 3 wires back together. Black/green, yellow, yellow with white stripe are the 3 wires.

The problem:
Car runs for a second and than immediately shuts off. Compression test shows 150 on all four, I changed the spark plugs and fuses, and I have checked the relays.

Are you sure the wires that were soldered back together were done correctly and they were properly insulated? I'd check those first... a bit obvious but sometimes you overlook things because you assume they were done correctly. Even when dong your own work I'd honestly NEVER do that. No matter who did it. I don't care if God himself did it, you should still check it.

 

[turbotalon31]

Check to see if you have good fuel pressure , and as said above check the wiring, and the ecu but the ecu is a pain to check since it is jelly filled.

 

[XiKeiyaZI]

Are you sure the wires that were soldered back together were done correctly and they were properly insulated? I'd check those first... a bit obvious but sometimes you overlook things because you assume they were done correctly. Even when dong your own work I'd honestly NEVER do that. No matter who did it. I don't care if God himself did it, you should still check it.

Missed one, ole' Pal

This is exactly correct. Another thing with the 420a ECU's is they truly are fragile. Not sure if you've ever seen one with all of the rubberized insulation removed, but they are more-so easily damaged by heat ; Thus the coating to keep them protected and to dissipate heat.

If the wires were soldered back together, there is a possibility that the circuits on the ECU board were over heated or overloaded if the soldering was done with the Battery still active on the vehicle.

The only other things I could think of would be the ASD, but that would cancel Fuel/spark (Can't remember which), or something simple is unplugged.

I'm going to go with damaged ECU, however, based on the information given.

 

[defeat54]

I looked at the wires any they are on there but he has yet to insulate them due to us trying to figure out the problem. If the wires don't have a good connection why is the car even running for a few seconds?

If it is a damaged ecu can it be fixed? and what about the tune I have on it?

 

[XiKeiyaZI]

I looked at the wires any they are on there but he has yet to insulate them due to us trying to figure out the problem. If the wires don't have a good connection why is the car even running for a few seconds?

If the wires are truly well soldered in place, correctly, then it has nothing to do with the wiring that was cut. Read a few posts up about the ECU.

420a ECU's are extremely easy to come by. Borrow one from a friend, plug it up, and try to start the vehicle.


Edit : Repairing the 420a ECU could be simple, it could be hard, or may not even be possible. Either way, it's more trouble than it's worth. Grab a new one.

Since you're using a Piggy Back tuning solution for you 'tune' and if so - swapping ECU's will not alter your settings in any fashion. That SAFC does nothing to the ECU itself aside from feed it information that is not true.

http://www.dsmtuners.com/forums/articles-tuning-ecu/406033-tuning-solutions-you.html

Now that you mention it - If the battery was unplugged for a good period at some point it is very possible your SAFC may have lost it's settings. Have you confirmed that nothing has changed with the SAFC? Inaccurate Fuel and Air Mixture will cause a car to die after a moment of trying to run. It can also cause backfiring, spitting, and no start conditions.

 

[defeat54]

I have good fuel pressure atm and nothing is unplugged.

 

[wranglerunner22]

Properly insulate the wiring and go from there... Your kicking a dead horse with things half assed from the gate.

 

[defeat54]

Properly insulate the wiring and its still doing the same thing.

 

[casuprock]

Use solder to make a solid connection and heat shrink tubing to insulate the connections. Spray the connector harness with Deoxit, these harness connectors are old and the contacts sometimes need cleaned.

Check to make sure the park/neutral position switch isn't causing you the problem since you did a manual swap. That could cause a problem.

Also check to make sure the closed throttle switch (idle switch) isn't your problem.

 

[XiKeiyaZI]

Properly insulate the wiring and its still doing the same thing.

I looked at the wires any they are on there but he has yet to insulate them due to us trying to figure out the problem. If the wires don't have a good connection why is the car even running for a few seconds?

If the wires are truly well soldered in place, correctly, then it has nothing to do with the wiring that was cut. Read a few posts up about the ECU.

420a ECU's are extremely easy to come by. Borrow one from a friend, plug it up, and try to start the vehicle.


Edit : Repairing the 420a ECU could be simple, it could be hard, or may not even be possible. Either way, it's more trouble than it's worth. Grab a new one.

Since you're using a Piggy Back tuning solution for you 'tune' and if so - swapping ECU's will not alter your settings in any fashion. That SAFC does nothing to the ECU itself aside from feed it information that is not true.

http://www.dsmtuners.com/forums/articles-tuning-ecu/406033-tuning-solutions-you.html

Now that you mention it - If the battery was unplugged for a good period at some point it is very possible your SAFC may have lost it's settings. Have you confirmed that nothing has changed with the SAFC? Inaccurate Fuel and Air Mixture will cause a car to die after a moment of trying to run. It can also cause backfiring, spitting, and no start conditions.

^ Read.

 

[MY1GDSM]

These quite a few things missing here first of all you just bought the Car an it had broken rings/ring lands something along those lines(I would imagine that the Stock Na Ecu with a Safc is a big part of that) you also made me aware that the car was running extremely Rich for a sort time that it did run before it was broke into...

An you ran into this Wiring problem from the Thieves that broke into it?

Im gonna have to go with keiya on this one from the limited info I have first guess would be the Safc isnt set up anymore or never was correctly

Can you confirm for us all the settings on it?

With brings me back to The state the car was in to begin with

If I was you before dropping another $4k into a motor I would seriously consider looking into some kind of Real engine management as A Safc isnt really safe with 650cc Injectors an Stock Na Ecu Sure you can get away with it in a Turbo dsm but we have 450cc injectors an fuel an timing maps designed for boost Not 240cc(U believe) injectors that the 420as come with there a big difference there I could only Imagine the Timing yould see even with the Safc setup correctly

Also OP
it helps alot if you fill out your profile with all your Mods

 

[defeat54]

I have zero shops in the montgomery area who can install megasquirt for me. I cant even find someone locally to help me with my safc settings.

 

[XiKeiyaZI]

Information is only a few keystrokes and a mouseclick or two away.