baronbob

Please let me know what you decide. My detonation detector went off twice, that I know of, and I am now in the process of a re-build as a result. If your ecu acts the same as mine (I started with a 7.4MPI not a 502 which has a different ECU) it shuts down TOO LATE and then keeps the retard in for at least a minute. I trust every respondent to your thread but I am going to install a an LM-1 O2 sensor to take the mystery out of what might be causing any lean conditions. I will be able to send Mark @ precision a data recording of F/A, RPM, and fuel pressure. The reason I have my problem is related to keeping the stock injectors (less than 30#s). The stock set-up (M-1 5PSI) did not lean out, but when I went to Gill exhaust, ported Merlin heads, with big valves, roller rockers and a mag cam, I needed more fuel. The injectors programed to 90% duty cycle @ WOT did not flow enough fuel. Mark warned me about this but initial plug readings seemed to be OK. My point here is to go to the basics A/F is what it is all about. You can make other changes such as line sizes etc but what you are trying to achieve is to keep the motor out of melt down. If your programmer can see the correct fuel pressure he can program the correct ratio to keep you out of trouble. If she runs good with the proper ratios then live with the hesitation. If you see damaging ratios under certain conditions then start chasing the various suggested fix's one at a time.

Pat McPherson

Hey Bob,
Sorry to hear that you have to rebuild again. I have been parting out my 7.4MPI and have a bunch of EFI parts I'd be happy to get out of my basement for a little beer money.
I do have a set of larger than stock injectors that came with a second MPI setup I bought for my 7.4MPI modifications.
Let me know if you are interested...

baronbob

Hi Patrick
Thanks for keeping in touch. I am interested in your injectors What size and how much? What about fuel delivery parts? [email protected]
Bob

Pat McPherson

Hi Bob,
I replied to your e-mail from a couple of days ago.
I'm not sure what size the injectors are, but I'll get you any info off of them I can.
Talk to you soon,