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Dirtracer 619

Well-Known Member
Hey all im back for some help, My old school small block ford 5.0 with obd1 computer
After making the wire harness for the truck and hooking it to a painless wire harness
I have ben having an intermittent electrical gremlin. Random little pops while on and off the throttle
while racing this is unnerving, Then all of a sudden it will shut off or run like crap. Then just as sudden run like a raped ape

I found the wires that go to the ECC relays are supposed to be hot always.
And hooked to the ignition switch. My switch is just a toggle. And
when i shut the Batteries off there is no juice at all

I think the computer is losing its memory,

So can i jumper in at the relay with a hot wire?
Im worried about where it feeds back. Right now
I have been leaving the battery switch on.
But that makes everything hot and i dont like that to much.

Not sure which direction to go here.
So any help or ideas would be appreciated


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manicmechanic

Well-Known Member
I don't think loosing adaptive memory would cause this, it trims fuel and timing to try to bring the O2 sensors into into the happy zone.
High power settings are open loop and are not affected by adaptive.
Seems like a connection somewhere.
Are you able to access fault codes.
Also ground is as important as power supply.
Brain farts are usually loose connections.
 
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Dirtracer 619

Well-Known Member
one fault code 15 intermittent power loss to ECC
I am almost back together so will test soon I also have a 20 yr old distributor in
there but it looks fine the TFI has been changed but not the Magnetic pickup so will replace as funds become available but its like throwing money at a ghost I don't mind paying to fix just hate paying to guess
thanks Manic,mechanic guess i will keep looking.
 

Dirtracer 619

Well-Known Member
Any ideas. Does anyone know for sure on my OBD1
Computer. What happens if you kill the battries each time you shut it off
Is this practice ok?

I know they are supposed to have constant power
And mine does not. Is this the problem?



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philofab

Powered by Optima
It's very unlikely that you shutting the power off to ECM is causing issues. I unhook the batteries on all of my 90s Fords while they are parked without issue.

The problem sounds like a harness connector issue or possibly a broken solder joint on the ECM (unlikely).

If you have a Mustang style harness the two main disconnects for the harness (round plugs) behind the intake are notorious for holding water and corroding.
 

Dirtracer 619

Well-Known Member
I wish i did have disconnects, Mine are hardwired from ECC to injectors
Using a painless FI harness. Then custom wire on rest of race truck

I have been checking and ohming wires checking grounds. Over and over
I just dont see it.

Im gonna go out test what i have done If its still doing it, i will replace the distributor and wires

And of course go over it one more time to check for wire non conformaties


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philofab

Powered by Optima
In that case... check ALL of your grounds... that is where most of the electrical issues I find are.
 

green787

Well-Known Member
Hey all im back for some help, My old school small block ford 5.0 with obd1 computer
After making the wire harness for the truck and hooking it to a painless wire harness
I have ben having an intermittent electrical gremlin. Random little pops while on and off the throttle
while racing this is unnerving, Then all of a sudden it will shut off or run like crap. Then just as sudden run like a raped ape

I found the wires that go to the ECC relays are supposed to be hot always.
And hooked to the ignition switch. My switch is just a toggle. And
when i shut the Batteries off there is no juice at all

I think the computer is losing its memory,

So can i jumper in at the relay with a hot wire?
Im worried about where it feeds back. Right now
I have been leaving the battery switch on.
But that makes everything hot and i dont like that to much.

Not sure which direction to go here.
So any help or ideas would be appreciated


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The symptoms you describe would make me look at the throttle positioning sensor....
 

Dirtracer 619

Well-Known Member
Thanks yes i did and i had raised the idle to 1000. And found the TPS was .75v So re set to .96v
Still putting the suspension back so test soon. Keep the ideas flowing fellas, I will try any ideas to get racing again


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Dirtracer 619

Well-Known Member
Does anyone think it could be the distributor? What im using is a stock ford TFI.
I have changed the TFI module. But not the thing inside that i think is the magnetic pick up.
There is no play side to side on the rotating parts. But this thing is what 25 years old

I have an MSD distributor and plug wires on my wish list. Just have a little more saving to do

Again. Just a slight popping coming from what sounds like the intake side not loud at all
And some times just shuts down motor under load. Shut down. Turn on and it starts right back up
Makes it difficult to try and be a competitive racer:(


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green787

Well-Known Member
Blow the distributor out with compressed air to get any metal fragments that could be shorting the stator.... WD-40 everything electrical... Check for fuel pressure next time it dies.... an old distributor won't make the engine run bad if it is working properly...
 

Dirtracer 619

Well-Known Member
Well. Thats one I dont think I have tried yet,
But as soon as the compressor is charged going to
Do that. Sure cant hurt,

The funny part is the motor does run great. Except when that pesky miss pops up.
Should have her back on the wheels soon. So we can go test our progress.
Dam thing has always ran great in the garage

Hope she don't think she a garage queen. Haha

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