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1973 C10 "The Purple Truck"

Basic build
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The only way I wouldn't have opened that up the day I got it, would be if I was incarcerated..
If I was in a full body cast, I would tear it open with my teeth, and the bribe someone to cover it up for me!
 
Scott, I am sorry this is happening to you. I thought they would take care of you faster than this.

My previous tech contact at Edelbrock is no longer with them since the middle of last year, but I just called my new contact and let them know they dropped the ball on this. They are going to get back to me, hopefully I can make something happen, I'll do my best and keep you posted.

I apologize I didn't do something sooner, you seemed to have it handled yourself, I didn't realize they would drop the ball like this, and I didn't know who my contact was with this whole Edelbrock move until last week, but now that I do and I saw your post I decided I better step in and see if there is anything I can do to help.

I agree with the guys, give it a chance with the fresh engine, it's possible the oil fouled 02 sensor could create a lot of tuning issues.

I don't want to go back to a carb, the EFI has too many benefits when correct.
 
skunked said:
Cam specs? Any plans to improve the exhaust?

IMO you need to give the bro flow a chance with this engine.
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220/224 @050 .495in/.502ex 110LSA
I'm hoping to have money for headers. At the barest minimum I was planning to put in dual exhaust.

Bent77 said:
And a fresh O2 sensor. Running an oil burning engine on an O2 sensor is a recipe for failure
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Yeah, definitely needs an O2 sensor.

folkenheath said:
UPS tracking they just gave me says your parts should be there tomorrow...I'll send a PM...
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Man that would be awesome!

I did get an email from tech just yesterday saying that mine was next in line but the tester dude is out with covid.
 
I'm also surprised because I figured part of the issue might be they didn't have spare ECU's.
 
No new motor but it is running and driving. Unfortunately I still have the TPS issue despite the new ECU & throttle body.

It's got to be something in the harness. I tried wiggling the wires and connectors throughout the harness and that had no effect.

As a long shot I ran a ground wire from the throttle body to the battery where the ECU is grounded. No change.

The next thing I can think is to pull the harness out and more closely investigate the wires and connectors.

I just can't think of what could cause the TPS signal to jump 13٪ with the linkage on the stop.
 
mrk5 said:
No new motor but it is running and driving. Unfortunately I still have the TPS issue despite the new ECU & throttle body.

It's got to be something in the harness. I tried wiggling the wires and connectors throughout the harness and that had no effect.

As a long shot I ran a ground wire from the throttle body to the battery where the ECU is grounded. No change.

The next thing I can think is to pull the harness out and more closely investigate the wires and connectors.

I just can't think of what could cause the TPS signal to jump 13٪ with the linkage on the stop.
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Does the signal jump with the key on engine off? Or only when running?
 
So you know its definitely a wiring issue at this point because everthing else with the TPS has been replaced, whether it be EMI or RFI issues, or a solid ground or power issue, etc. What about your battery, is your battery in good condition? I'd be looking at the connector for the TPS and ECU and any connector in between there, checking every terminal to make sure its "snapped in" and can't retract into the connector when connected, most wire terminals snap into the connector from the back.

I'd also be checking my ground connection, and my plug wires and coil wires for anything lose or not grounded there. There also should be a solid ground to the engine block.

Does it vary when the engine is off too, or only when it is running?

One thing I have noticed over the years, is most modern coils have at least 4 wires. The high side and the low side of the coil. The low side comes from whatever is controlling the coil, two wires. And the high side is the high voltage spark side. One wire is the plug wire, and most modern coils have another high side ground wire that usually says to go directly to the cylinder head for that coil in multi coil setups, or the engine block if it's a single coil.

My point is, without this "4th" wire, the ground of the high side of the coil must get back to the cylinder head somehow to create the high side "loop". And I wonder if they are more susceptible to causing electrical interference because the loop is larger and not as direct as right back to the cylinder head style. In an HEI cap, its vital that wire connects to the engine, I usually go straight to the intake or block. But where is that wire in a traditional external canister coil? Is it a common ground and it travels back through the coil? I don't know the answer, but I need to find out. Anyway, I am getting ahead of myself because I don't even know if it still does it with the engine off. And it obviously works for others so the ground is somewhere.

I also read previously the TPS relearns the low side every key on with the Edelbrock, which has pros and cons, but could be normal?
 
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I think I might have solved the problem. I was thinking of what could cause the TPS to not read correctly and I kept thinking it has to be reference voltage. So I was thinking of what could cause the ECU to get a messed up voltage signal. I was also thinking about how the Edelbrock tech had me try a bunch of the basic things and do stuff that was the "safest" setup, like putting the switched power on a wire straight off the battery thru a switch instead of relying on the factory ignition wire.

The one thing I had left that might be considered not to be an optimal setup is the fuel pump wiring. The PF4 instructions say that you can wire the pump directly off the harness as long as it pull less than 10 amps. I specifically purchased a pump from Edelbrock that was advertised to work with the PF4 and draw less than 10 amps. https://www.edelbrock.com/inline-fu...tric-fuel-pump-3594-regulator-1728-35943.html

pump-wiring.jpg

I was also thinking about stuff that could have changed after 6 to 8 months of operation. What if the pump was drawing more current because it was getting older? So I wired the fuel pump with a relay Sunday.

So far, so good. After I installed the new ECU and throttle body, it had been jumping the TPS every time I started it. Since rewiring the pump the TPS has been behaving itself. I have my fingers crossed the problem is fixed. I'm not totally confident yet because there were short periods before when the TPS operated correctly. If it's still working correctly by the end of the week, I should be able to call this case closed. :sign29:
 
It's also an interesting difference between the Sniper and PF4 because the Sniper harness comes with a relay for the fuel pump.
 
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