Help Troubleshooting EFI Start Problem

[Jambi]

Since installing my EFI, I have had an issue starting the engine to where it typically takes 4-5 turns of the key to finally start the engine. This typically occurs with a cold start. Once the engine has been running for a bit and warmed up, the engine will start at the first turn of the key. It's just starting from a "cold" state, where it consistently takes 4 - 5 turns of the key before it finally cranks over and holds idle.

Codes pulled from my code reader in order are 81, 82, 85, 84, 10, 11.

Fuel pressure reads between 35-40psi at first turn of the key and beyond, including when running. Don't know that it's necessary, but I have a new in-tank fuel pump that I will be installing soon to see if that makes a difference.

I did get a new TFI module.

Once the engine does start, I've noticed the first couple times I feather the gas pedal, I hear a "pop" type sound that sounds like it's coming from the cold air intake, but it only occurs with the first couple pumps of the gas pedal, after that it's fine.

 

[SevenT]

EFI Start Problem

Jambi,

Who made your harness? Are you modern 5.0 firing order or legacy 289/302 prior to '87?

Codes 81 and 82 are the smog pump solenoids. Soft codes, no impact on performance. Code 84 is the EGR and 85 is the CAN-P. Once again soft codes.

Code 11 means the test passed. Code 10 is a separator code and means nothing in KOEO tests.

Everytime you turn the key on, the fuel pump cycles to pressurize the fuel system. Does it buzz for a few seconds before you turn all the way to start?

v/r,

SevenT

 

[Dylan_Shaffer]

Since this happens when it’s cold my guess would be your starter is pulling too much power away from the efi system, causing enough of a voltage drop to prevent it from starting properly. This was happening on my bronco. I made a new battery cable (old one was getting corroded) and cleaned any corrosion off any other contacts. Started just fine thereafter. An old Worn out starter will cause an excessive power draw as well.

 

[Jambi]

Jambi,

Who made your harness? Are you modern 5.0 firing order or legacy 289/302 prior to '87?

Everytime you turn the key on, the fuel pump cycles to pressurize the fuel system. Does it buzz for a few seconds before you turn all the way to start?

SevenT

The harness is a Ron Francis harness and my 302 is pre-1987.

Yes, I let the fuel pump buzz for the few seconds until it clicks off then I try to start the engine.

 

[SevenT]

EFI Start Problem

Jambi,

Your firing order is 1-5-4-2-6-3-7-8 and the harness is 1-3-7-2-6-5-4-8. I do not have a wiring harness that is different than my firing order, so I don't know what the implications are there.

Check your start system wires like Dylan_Shaffer said. The ECU needs a clean 12V to work correctly and if the start system is pulling it down, that could be a contributing factor in the lack of start. Good luck.

v/r,

SevenT