ECU issue

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rt louis

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I have an Mopar performance conversion kit installed for over 15 years and it has worked fine until recently. Sometimes not starting, other times shutting off when idling at stops.
Changed to an Advance auto one and also one I purchased at Carlisle USA made one. Both do the same thing ( Starts fine runs fine but if I rev up to 3000 it sputters and won't go past that. 318 4 speed. I have been told it could be a bad pickup in the distributor but am at a loss. A I said with the orange box when it worked it ran great with no issues.
What is the deal?
Thanks,
 
If All Three do the same thing it must be something else... The Pickup would be a pretty suspect too!
 
have a similar issue. changed pickup and still does same thing
 
Could be a bad coil or a bad ballast. Short the ballast temporarily & see if it improves.
 
FBO with recommended coil.

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Had a similar issue on my '64 Dodge 440.. wouldn't start heat soaked and missed at times. Always started cold so threw a new ECU at it, that changed nothing. Turned out that the rubber plug was getting soft when hot and one of the terminals female ends was like throwing a wiener down a hallway and would disconnect from the ECU pin. Squeezed her tight and not an issue anymore...
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Check that you have good solid voltage to the system, IE 12-14 to the box, and "about" 10-12 to the coil with alternator running 14V

You've already "guessed" at two possibilities the pickup is certainly one. When I say "pickup" I mean EVERYTHING in that SYSTEM. The pickup, the pickup connector, the gap, dist. wear, debri and junk in the reluctor/ pickup, and the connector on the ECU and physically eyeball the pickkup/ reluctor for damage
 
Ok, maybe we have problems run together here.

First problem - Dies or won’t start.

Second problem- Sputters over 3000 rpm.

Did these both happen in the beginning at the same time, or did changing the ECMs fix problem #1 and start #2?

Problem # 1 sounds electrical, but could be fuel.

Problem #2 could be a lot of different things.
 
If you have had the vac adv hooked up, it is probably the p/up that is bad.
Vac adv moves the p/up plate & flexes the wires, which eventually break.
To check: disconnect p/up & connect an ohmmeter. Should measure 150-450 ohms. Flex the wires; if the reading changes, wires are broken.
 
Also check that the mechanical advance is working. easy check take the cap off and see if the rotor will turn a bit. Can be the issue also. You have oiled it in 15 years ?

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Start checking and running grounds . Battery to block, Block to firewall/Heater fan, Control box to heater fan, Also Ballast or Harness may have gone bad.

I pulled my hair out on a couple one was a ground others were wiring gone bad from heat. Space the control box off the firewall so it can cool behind it same for the regulator.

There is a factory adapter used on some models depending on where it is located. Behind the engine above the firewall is not a good place to protect it from heat. The biggest long term destroyer of electronics and wiring is heat.
 
The e bodies used a spacer on the ecu's. No idea why all of them did not have them.

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from classic


A-Body

  • 1971-72 Demon
  • 1971-76 Dart, Swinger, Duster, Scamp and Valiant
  • 1973-76 Dart Sport
B-Body

  • 1971 Coronet, Super Bee and GTX
  • 1 971-74 Charger, Road Runner and Satellite
E-Body

  • 1971-74 Barracuda, 'Cuda and Challenger
 
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Agree on grounds.

Jumper from clean (wire brush) mount hole on brain to known good chassis (or battery) ground.

I've also had more than once, the pickup plate or wiring inside the distributor be bad or broken.
That was a SOB to figure out.
 
I make a stand-off plate that creates a gap behind the brain for added cooling, and also has a trough lip at the bottom to catch any brain goo that starts dripping. It also makes that real easy to see before it f's up the paint on the firewall.

A friend of mine taps the 5v line and mounts a computer CPU fan on the heat sink.
 
Agree on grounds.

Jumper from clean (wire brush) mount hole on brain to known good chassis (or battery) ground.

I've also had more than once, the pickup plate or wiring inside the distributor be bad or broken.
That was a SOB to figure out.
Your best friend when it comes to grounds, always used them on aircraft daily
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