SH4DY

The basics: 1992 CX chassis, 1994 B18B1 motor/tranny/engine harness, OBD-1 P72 ECU.
Getting the motor physically in took all of 30 minutes. But then it went to hell. For some reason I need to get an integra throttle cable because there's no way mine will work but that's not the big issue...
I've got spark, verified firing order/ rotor button are correct, fuel pump primes, I've got fuel at the rail, but in several tries to start it, there was not one single combustion event. The plugs are still minty fresh... i.e. I think the injectors aren't spraying. The only codes it's throwing are for the VTEC solenoid, and the O2 sensor heater (neither of which are hooked up/there).
Possible causes: I used the LS engine harness as to make my life easier for converting to a 4-wire O2 and it was on the motor. Maybe something has gone awry in the loom? I know the ECU is good because it ran a friends ITR swapped VX not 2 weeks ago.
Solution: checking voltages at the injector harness when cranking, and try the olds cx harness in the same fashion.
Am I missing something? I thought the LS harness was just plug and play? Or are some wires switched? I also think it's odd that there's no code for the Knock sensor, VTEC oil pressure, or for the butterflies because those sensors simply aren't there.
HELP

klungemonger

Yeah that is weird I'd think you'd be getting just a ton of codes. Although one thing that comes to mind is, didn't teh CX come with a 1-wire O2 sensor, at least for that first year? So the 4-wire setup of the LS motor would require some harness mods to the chassis side of the engine harness.

Try unhooking the fuel line from the rail and hold it in a cup while someone turns teh car to on for a couple seconds. If it spurts out good then you're getting fuel to the injectors. So then get a multimeter and test injectors for resistance values to make sure they are high impedance and have continuity.

I assume you've pulled all the plugs and held them to ground while cranking the car so make sure they are firing? If so, check to make sure the wires are on in correct order. Then put engine at TDC on cylinder 1 and take dist cap off to see of rotor lines up at the #1 firing position in the cap.

And definitely try to score a P75 asap to rule out all those other ECU issues. All I can think of for now...

skunkcoupe

ls ecu FTW

SH4DY

I agree that the LS ECU is the best option for this motor/swap but it shouldn't effect it enough to where it won't even start. I know another guy thats using an ITR ecu on his LS swapped EG and it runs... pretty well actually.
But, I have verified firing order/TDC/rotor button etc... and i cracked open the cap on the end of the fuel rail and it's definately got fuel to the rail. Spark plugs spark like hell on the valve cover... It's just not spraying any fuel.
I'm going to compare the CX and LS harnesses today.
Also: since I've got a 92 it already has the wires run for the 4 wire O2 set-up (and VTEC and VTEC oil pressure) run to the bulk head connectors on the passenger side....

EDIT: It didn't occur to me until just now that the fuel pressure gauge (mounted on the rail) should be reading something other than 0 after the pump primes . I think something is messed up with the banjo bolt and fuel isn't able to pass from the line into the rail. I'll try to mess with it when I get home today...


Modified by SH4DY at 8:53 AM 11/13/2006

klungemonger

Well if you know for a fact that all the ignition is set up correctly and functioning, and you are getting fuel pressure at the rail, that narrows it down quite a bit.
Definitely check for continuity and resistance in the injectors, and in the connectors themselves to ensure signal is getting sent to them.
The only other thing I can think of is if maybe rings are bad and cylinder pressure is so low it can't make enough combustion pressure to stay started as it would just push past the rings.

SH4DY

OK im at a loss. if the banjo bolt on the fuel rail isn't all the way tightened it will spray fuel when cranking so its getting gas. The fuel pressure gauge remains at zero (could be because its a B&M). At this point I think the culprit may be the fuel pressure regulator (once again... B&M). any one know how to test the regulator? Maybe vice grips on the return line? But the plugs still look like no fuel has ever been sprayed on them.
I checked the harnesses and they are identical as far as the injectors go (the one 4-wire bulk head connector), I tried switching main relays as well as putting back in the CX ecu just for grins all to no avail...
dammit
EDIT: I think I've got it narrowed down to the distributor, we shall see this evening.


Modified by SH4DY at 3:30 AM 11/14/2006

SH4DY

I think the fuel injectors simply are not spraying. I thought it was due to a bad sensor in the distributor but all the resistances check out (~360ohms) for the TDC. CYP and the other one. I even replaced the distributor and still nothing. With the key "on", the harness side of the injector plugs see battery voltage like they should. I still have yet to try cranking it and seeing how the voltage behaves but my guess would be that it does change.
I mean even if my timing was fubared it would still spray fuel correct? I checked TDC via the notch in the crank pulley and a long extension in the cyl and it looked correct. the notch on the intake cam also coincides with the others...
I don't understand how a plug and play swap can go so wrong

EDIT: I checked the voltage at the injector harness when cranking and it drops to around 9 volts... so I'm thinking that they are getting a firing pulse. I need to verify with a noid light though...


Modified by SH4DY at 5:46 PM 11/15/2006

SH4DY

Just an update: I tried using the old CX harness and it behaves the same so I can rule out the LS harness. I'm going to try yet another distributor this weekend and see if its that...
still open to suggestions

klungemonger

It's not voltage you need to measure on the injectors, its resistance. If the resistance is outside the tolerance allowed by the ecu they will not fire even if power is coming into one side, because the ecu won't ground them out. Some possibilities are: 1) you have low-impedance injectors so ohms are too low, or 2) you have saturated injectors but inadvertently have a resistor box also, making ohms too high. Just an idea. Just measure ohms from one terminal to the other in the injectors.

Another idea is if the pressure regulator reads zero, maybe it is either blocked somehow, or cranked so high that the pressure won't allow the pintles to open in the injectors and the guage can't read right. Or it's turned so low that nothing squirts out when they open, or it just dribbles into the intake manifold and doesn't reach the cylinders.

SH4DY

I finally got a hold of a Honda Tech (actual Honda Technician) that owns a shop and he said that with most just yard motors (which this is) if they sit too long the injectors will get gummed up and suggested lightly tapping on the injectors with a hammer to try and free the internal mechanism while cranking. It's worth a try, so we'll find out tomorrow.... woste case I can try to swap the injectors.

PS. klungemonger: seriously, I can't thank you enough for bearing with me and continually trying to help out. many e-beers for you...

EDIT: it turned out to be the injectors. They were completely clogged. So, I would suggest that if you are unsure about how long the motor has been sitting have the injectors professionally cleaned or use injectors that you know work.


Modified by SH4DY at 2:59 AM 11/17/2006

klungemonger

All good man, happy to help...or at least try!
Hope it all gets worked out. Didn't realize you had some spare injectors, yes definitely toss those in there and test it out. Quick and easy to rule that out.