dale53

Here goes, I have a 97 sc400 76K on the car, no start but I have injector pulse, fires up when fuel poured into intake, blue spark at both coils, new fuel pump, and filter, had the ecm rebuilt and checked, the only code to pull is misfire on cyl #8, can hot wire the fuel pump and feel and hear fuel moving in the lines. Had a no start about 6mos ago but time i pushed into the shop it started, no newbie to EFI but new to toyota, so what the heck is left? pressure reg? don't have a pressure gauge that fits this, I have the factory manuals and have at this for 3 weeks now reading a lot of good info on this site but still need help, any ideas ?

dale53

what the heck, just replaced the press reg to no avail, 90 people have looked at this and no replies? not even a question

gerrb

iTrader: (34)

you said that it fires up when fuel is poured into the intake ...

once you hot wired the fuel pump , you said fuel was going through the lines ... did you try starting it and did it start ?

dale53

yes tried to start with pump hot wired no go

gerrb

iTrader: (34)

based on those info , fuel pressure is not enough so it can be injected by the injectors .

And that pressure is controlled by your fuel regulator .

Ali SC3

iTrader: (10)

how do you know you have injector pulse? if the pump is hotwired and you do have the right injector pulse it should fire up if it is firing up when you put fuel in the intake (meaning the ignition is working). the pulse could be off due to ecu, or the ecu also cuts it out if there is no spark confirmation signal from the ignitor. the fact that the ecu is rebuilt still makes me suspect it, also that the regulator was replaced. make sure the vac hose is on the regulator.

dale53

update, replaced press reg, have power to one side of injector and ground pulse to the other when cranking, no start, pump is hot wired, pour a little gas into intake and starts then stops when fuel is gone, sounds like it is running good on all 8 only for a few seconds, has to be not getting fuel but how?, is rigging a press gauge that difficult?

dale53

maybe I should start over, the car sat for about 2 mo, then battery was almost dead but at last sec it started and ran rough but had always ran good, and set a code for #8 cyl misfire , the scan tool will not link to ecm when engine not running, drove it and the code reset, then parked in shop and now the no start, that is where i started and sent the ecm out for repair, maybe this will help

dale53

got a press gauge on it and at 45 psi with pump running, shut off pump and holds press at about 42 psi, could this be an injector pulse timing issue?

gerrb

iTrader: (34)

you got fuel , it starts with starter fluid / fuel on the intake ...

injector pulse problem -> can be ecu but if you say that ecu has been reworked .. then wiring issue like voltage to the injectors or bad ground

dale53

I have checked all wiring I could get to and the grounds, injectors are getting battery volt while cranking and what appears to be a good ground, the ECM still will not communicate with the scan tool, has to be ECM?

dale53

update: I manually grounded 2 injectors with press in lines and they deliver fuel and car tries to start, so I am not getting enough ground through ecm though it shows ground pulse with test light, the question is, where does the ecm ground to, I have the manuals and they are no help finding the grounds on the car, I talked to the guys who rebuilt the ecm and they have never heard of such a thing, could it still be a and ecm, can anyone tell me what wire off the ecm is the ground, I fell like I may not have to shoot this thing after all, I hope.

dale53

more digging found injector circuit on page EG-328, now where the heck is ground EE on the car? can I just jumper a wire off of terminals #79 and 80 to ground to test it?

Ali SC3

iTrader: (10)

maybe some "genius" before you pulled the ground strap. try running a thick gauge wire from the cylinder head to the negative battery connection. sounds like you can also try what you mentioned check the resistance on the wires coming out of those pins back to chassis ground.

I don't always trust rebuilt ecms unless the problem was minor in the first place, maybe see if you can find someone with a running car that is willing to do a test, normally bad ecu's cause overfueling... but it is a fueling issue generally so its a small possibility.

dale53

UPDATE: after about giving up on this, went out and found no injector pulse, pulled the ECU and sent it back to place that "rebuilt" it and after a few days called and said indeed there was a part that had failed and was not available so they have ordered me a new ECU, as of today still waiting for it , will post results, one good thing that has come out of this is I know more about that car than I ever thought possible. and thanks for all your input.