I bought a chipped p28 a couple months ago and the car ran great on it. No problems or anything. I put a/c and powersteering on it and a week and a half later the ecu won't start my car. It seems that it isn't sending gas anymore. I put my messed up p30 in it and it starts right up so I know it's the other ecu. My question is, how do you know if it's the ecu itself that has gone bad or the chip? I opened the ecu and didn't see any scorch marks or anything out of the ordinary. I put a second chip in it that is mapped for a turbo car and it didn't start the car either. Is it my ecu or could it be the chipping kit? Could it be the chip? Is there any way to test it all to see where the problem is?

Key points that might be helpful in diagnosing:
Cranks like crazy but doesn't start
Since the a/c and ps was put on, it has fallen on it's face 3-4 times
Idles have been steadily decreasing from around 1000 down to about 550
Starts on another ecu
Neither chip will start the car
No scorch marks inside the unit

Can anyone help meh? Thanks for any input.

 

Does it throw any check engine lights and do you hear the fuel pump prime with the suspected bad ecu?

 

Never threw any cels. I never heard the pump prime either but I live on a busy road so I can't say with confidence that the pump didn't prime. I did listen for it and didn't hear it.

 

No one else with any input?

 

sounds like ur main relay. if its hot outside that happens. ur soldering joints need to be fixed. or try giving ur relay a good kick. thats what i did. worth a try!

 

It does sound like the main relay and maybe its just coincidence that when you put in the other ucu it starts up take out the main relay and resolder the all the points. look at them and see if you can see any cracks in the solder,

 

Sorry I haven't checked this thread in a while. I lost hope that there would be help on Honda Tech.

Main relay? In the ecu or somewhere else? I've put the ecu in a couple times since and it still doesn't work. My car starts fine off the other ecu everytime so I'm going to rule it out as a coincidence.

 

I am also having somewhat of the same problem. My car ran fine on a Neptune tune, then one day the car started running like crap and would barely start. I would put in another ecu with a lower boost tune and the car would run fine. I have several chipped ecu's and have tried the chip in all of them and the car still won't run right. Is there a possibility that the chip went bad?

Sorry if you think I'm thread-jacking, but I believe this falls along the same lines as your problem.

 

Generally the chip won't "go bad". But it could have bad connection or possibly a bent pin.

If you are having problems with the car starting and/or having problems with the fuel pump priming then the capacitor in the ecu will more than likely need replaced.