Change fuel prime timer on $6E mask ecu

[bfsangli]

Im using a 1227165 ecu with the $6E mask and when i turn the key it only primes the fuel pump for a short time and it wont start off that, i need to turn the key off for a little and prime it a second time to get it to start.

Is the primer timer something that can be changed on these ecus/bins. I dont see anything in the 6e xdf that would allow me to change this.

I also am struggling to find any information about it online, if anyone can point me in the right direction i would appreciate it.

[dave w]

gearhead-eif link for $6E information: http://www.gearhead-efi.com/Fuel-Injection/showthread.php?366-1227165-ECM-Information-6E

dave w

[stew86MCSS396]

Try looking for crank pulse multiplier and increase the multiplier or frequency.

[1project2many]

I believe this value is stored in the code. It's been a long time since I've looked at this part of 6E...


30 seconds is enough on most vehicles to bring the fuel system up to full pressure. The early TPI units could develop problems with the injectors leaking after the engine was shut off which would completely depressurize the system. The system would fully pressurize within 30 seconds after the key was turned on. Once the ECM receives an ignition pulse it will turn the fuel pump on again, and the pump will remain running until 30 seconds after the last pulse is received. So cranking the engine will keep the pump running.


Unless you have diagnosed insufficient pressure during cranking I am tempted to suggest you look elsewhere for the cause of your problem. Too little fuel at crank can feel just like too much fuel.

[stew86MCSS396]

I believe this value is stored in the code. It's been a long time since I've looked at this part of 6E...


30 seconds is enough on most vehicles to bring the fuel system up to full pressure. The early TPI units could develop problems with the injectors leaking after the engine was shut off which would completely depressurize the system. The system would fully pressurize within 30 seconds after the key was turned on. Once the ECM receives an ignition pulse it will turn the fuel pump on again, and the pump will remain running until 30 seconds after the last pulse is received. So cranking the engine will keep the pump running.


Unless you have diagnosed insufficient pressure during cranking I am tempted to suggest you look elsewhere for the cause of your problem. Too little fuel at crank can feel just like too much fuel.
:thumbsup: Sorry...I usually associate this site as a tuning site and not a "my car doesn't run right, should I change my spark plugs, cap, rotor, wires...?" With that said, make sure everything is running to spec before diving into the tune. I do want to share that I have a super ram on a L98 with a cam and aftermarket injectors. After dialing in the idle cruise BLMs, I did notice that the engine takes a few more extra revolutions then what I think is necessary so I modified the above^^^suggested. Long crank times can be associated with a bad fuel pump relay something to check as well.

[1project2many]

Sorry...I usually associate this site as a tuning site and not a "my car doesn't run right, should I change my spark plugs, cap, rotor, wires...?"

I get that. We are focused on tuning but the rules here have never been rigid. There are quite a few "My engine doesn't run right and I don't know why" threads and we generally have folks willing to go above and beyond to help. I'm not afraid to suggest basics or changing direction if someone is asking to make a change that doesn't necessarily make sense. Doesn't mean I'm right or that I'm contradicting other posts.


I did notice that the engine takes a few more extra revolutions then what I think is necessary so I modified the above^^^suggested.
The value you modified increases crank fuel pulse width. It can certainly help with long crank times but I'm not sure how I'd know that increasing that value is the right direction to go without some testing or trial and error.