I started to get this hesitation problem with my car. When the car is cold it will start and rev normal but after a while when it gets hot, it starts to hesitate and backfire upon revving.

The car has a knightsports ecu, greddy front mount intercooler, air pump was removed,a new set of series 7 sequential turbos, full free flow exhaust, the engine was rebuilt a year ago, magnecor plug wires, new coil packs, new plugs, all sensors checked and changed where necessary, walbro fuel pump, aeromotive fuel pressure regulator, new fuel filter, new engine harness, apexi power intake, HKS grounding kit, koyo 3 core radiator, battery relocated to the trunk.

We swapped all the main parts on the engine and still could not solve this problem, the only item that was not changed yet is the ignitor and its harness. The car starts perfectly and revs but when it gets hot this problem starts. We even changed it back to the stock ecu as well and no progress.

Any ideas to solve this problem?

 

Hmm... Moving this thread to main forum.

 

Does it have issues at a certain engine temp or just when it has been ran for an extended period of time? Have you noticed if the problem occurs as soon as the coolant fans come on line?

And when in the timeline of all these upgrades did this hesitation problem start? How long has it been like this?

-J

 

I'd imagine it has something to do with the ECU. At least that would be a start. I'd get rid of em and at least throw in a PowerFC.

 

Could you describe when the problem first occurred?

 

I found the problem...its was the ignitor going bad, i cant believe i took so long to figure out this problem......a bad metering oil pump also sends the ecu into limp mode and causes the car to hesitation

 

Good to hear you found the problem. Thanks for posting the fix.

 

It's the "two's" that'll get you...

-J