Need some help
 

Im kinda stumped right now. One of my current cars will not run on a stock ecu but will fire right up with a PFC. While the stock ecu is hooked into the car the injectors will not get a signal from the ecu. However, as soon as you plug in the PFC it gets a signal. What sensors would cause the stock ecu to not send signal to the injectors, yet at the same time the PFC will overlook and still send signal?

Appreciatte the help in advance.

i think it may have something to do with Injector Resistors.
i think you need them for the pfc and you dont for the stock ecu.

I think you are thinking about the 1680cc debate whether you need the resistors so it doesnt kill the injector drivers in the PFC.

Either way, I appreciate the guess. Keepem coming.

David

David, I'm assuming you have ruled out that the ECU itself is defective?

Yea, I have actually tried 2 ecus and then put them back in another fd and it will start? I really dont know what could cause this?

That's odd. Does the PFC sensor display show anything odd when its hooked up? IIRC, there are quite a few sensors that the PFC reports on, but aren't necessarily used (sort of like the knock sensor).

It may be a reverse situation, but I know one guy who had a car that ran fine on a stock ECU but not on a PFC. The front pulley "teeth" that go by the crank angle sensor were bent, and one ECU was pickier about it than the other. Worth peeking down there to make sure the teeth don't look jacked up.

Do you have stock injectors/fuel system on the car?

Dale

do you get any codes?

Here is the kicker and I forgot to mention it earlier. It ran yesterday on the stock ecu, but today it will not. It is a fresh rebuild and I threw in some used plugs because I knew they would foul anyways. Well I let it idle in the driveway yesterday for about 20 mins and moved it around the driveway a couple times(which is probably how I fouled the plugs). So I put in new plugs this morning, keep in mind nothing else has been touched, and when I go to start it I get no fuel. Used a node light to check the injectors and they are getting no signal, thus I throw in the PFC and they get signal and the car starts right up? I really dont see what could cause this. I have tested both the stock ecus adn the PFC in another car and they all work fine. Im so tired of changing plugs and ECUs its ridiculous.

Its not pulling any codes except the ones it should for the non-seq conversion. I have resistors in line so the CEL isnt permanantly.