77broncodriver
Full Member
- Joined
- Nov 21, 2009
- Messages
- 344
Hey guys I am trying to get my bronco running right after swapping to mustang EFI a few years ago. It has always had this issue but after a while I just lived with it and it was parked for about a year. Now I done a lot of other work to it and have been driving it a lot and now am noticing the problems of the EFI again.
Main issue:
It starts up perfect overtime no matter how long it sits. Driving around town, it has no issues but once I give it some gas it will hesitate when under load. Its not like it is bogging down but more that the spark cuts off for a split second. I really notice it when Im on the highway, it will constantly buck and hesitate cruising when I have the throttle more than 20% down.
This makes me believe that this is a spark problem and not a fuel problem
Here is the parts list I have for the EFI:
- 5.0 crate engine from ford (306 with aluminum heads and cam ~20k miles)
- explorer intake
- 30lb injectors with matching pro m maf sensor (previously had stock injectors and stock maf with same problem)
- RJM harness
- Replaced all other sensors including o2 sensors
- New MSD distributor
- New coil
- In tank fuel pump
Issues Ive had and fixes Ive tried
- First I thought the injectors so I got the 30lb injectors (what ford recommends for this engine) with matching maf
- Then I got a new distributor, spark plugs, wires, and coil
- Then I thought I needed a tune so I had it dyno tuned which was a waste of money. It ran really strong but still hesitated, turns out my harmonic balancer spun on crankshaft so after putting a new balancer on the tune wasn't right anymore so put it back to stock tune
- Converted my inline fuel set up to intank set up
- Checked timing
- Checked fuel pressure
There are probably another couple things I have tried but I've been tracing this down for several years so I probably forgot a few things.
I am thinking this has to be an electrical issue but don't know where to start looking. If anyone has experienced this and has any ideas let me know!
I really want to get this thing running right, Im really temped to sell all the EFI parts and buy a holley EFI unit or one of the other new TBI packages.
- Evan
Main issue:
It starts up perfect overtime no matter how long it sits. Driving around town, it has no issues but once I give it some gas it will hesitate when under load. Its not like it is bogging down but more that the spark cuts off for a split second. I really notice it when Im on the highway, it will constantly buck and hesitate cruising when I have the throttle more than 20% down.
This makes me believe that this is a spark problem and not a fuel problem
Here is the parts list I have for the EFI:
- 5.0 crate engine from ford (306 with aluminum heads and cam ~20k miles)
- explorer intake
- 30lb injectors with matching pro m maf sensor (previously had stock injectors and stock maf with same problem)
- RJM harness
- Replaced all other sensors including o2 sensors
- New MSD distributor
- New coil
- In tank fuel pump
Issues Ive had and fixes Ive tried
- First I thought the injectors so I got the 30lb injectors (what ford recommends for this engine) with matching maf
- Then I got a new distributor, spark plugs, wires, and coil
- Then I thought I needed a tune so I had it dyno tuned which was a waste of money. It ran really strong but still hesitated, turns out my harmonic balancer spun on crankshaft so after putting a new balancer on the tune wasn't right anymore so put it back to stock tune
- Converted my inline fuel set up to intank set up
- Checked timing
- Checked fuel pressure
There are probably another couple things I have tried but I've been tracing this down for several years so I probably forgot a few things.
I am thinking this has to be an electrical issue but don't know where to start looking. If anyone has experienced this and has any ideas let me know!
I really want to get this thing running right, Im really temped to sell all the EFI parts and buy a holley EFI unit or one of the other new TBI packages.
- Evan