I am a new owner, 1991 3000gt sl, i bought this car 3 days ago not running. i have replaced the ecm, caps were toast. replaced the main fuel relay, it was clicking it arse off, replaced the CAS, wasn't sending a square wave on my osciliscope and i was not getting fire to the plugs.

i am now getting fire, the coils ohm within spec, the ignitor ohms within spec, and the CAS is functioning proper. what i am NOT getting is fuel from the injectors. i have pressure in the rails, fuel IS flowing. pump runs fine. i have pulled the rail from the front bank and turned it over, no fuel from the injectors. every fuse and relay in this car is fine. i put a multi-meter on the injector clips and i get continuity when grounded, the clips are getting power, they simply aren't firing the when needed.

i have exhausted all avenues i can think of. i have gotten the injectors to spray one time, and it tried to fire up, but nothing since that one time.

i am at a loss, this car s in pristine condition, white with red leather, the previous owner said it died on him about a year and a half ago in his driveway and he hasn't touched it since. i bought it from him for 600 bucks. i hate to turn around and sell it again without driving it.

maybe the injectors need to be cleaned

did you replace the whole ECU, or just the caps?

i replaced the ecu completely with a brand new unit. the injectors will spray when jumped with a power source, they aren't clogged, they simply aren't getting a signal to fire. i have traced the entire circuit for them and there is power throughout the system, it is grounded thru the system as well. i am stumped.

Check the ground wire that gets bolted to the firewall by the battery. It is attached to the engine harness and if not properly grounded it will cause that same problem.

ok, update.

i have run all new ground wires, i used 2 gauge cable and ran 1 to the firewall, one to the trans., one to the intake mani. and another to the exhaust, and one from the valve cover to the chassis.

i then ran my multi meter thru the ecu, checked everything against the ecu ground, everything checked out fine. all my injectors were recieving voltage within the spec range, all the sensors were within range, ad the mfi relay spec'd out fine.

i am still not getting an injector pulse. i am getting great spark, i am simply not getting any injector signals.

does the PTU have anything to do with injector signal? could it be giving me spark, but no injecotr signal? could the CAS be giving me a spark signal but no injector signal?

i am totally stumped

The CAS should be putting out 2 signals (through the blue wires... I believe that's the color). Make sure it is putting out a signal through both wires. It should have a positive, negative, and 2 signal wires.

I don't think the PTU has anything to do with injector control.

The ground I am talking about has a ring connector on it with probably 2 or 3 black wires coming from it. Make sure that is well grounded on the firewall.

Are you positive they aren't getting a signal to fire??? They could just be clogged up from sitting. Try starting it with some starting fluid. It might knock some sense into the injectors. I've had some of these cars do that.

The harness ground you are talking about is under the washer motor correct? if so, that is the one i hit with emory cloth and cleaned the surface on, i cleaned the contact surface of the firewall as well. i also replaced the ground strap from the battery on that contact point as well.

if i jump the injectors with a jumper wire they will fire with a consistent spray pattern. they aren't clogged.

the CAS is sending out its reference signals, the ecu is sending and recieving all of its signals, i checked against the ecu ground and measured all of the siganl wires.

my problem lies in the main engine harness, i got he car to start lastnight after removing most of the loom and tape from the harness, i freed up a short somewhere in it. but in the process i inturn shorted soemthing else out. i am picking up a harness at lunch today and installing it this afternoon.

hopefully it will finally solve the problem and i can take it to the upholstry shop. i need the rear panels, door panels, and rear seat backs recovered. the rest of the car is mint.

That was the ground I was talking about. Sounds like you have a rats nest in your wiring LOL. Is it auto or 5 speed? If the harness you get doesn't work, let me know. I usually have a few laying around.

Hans i sent you a pm.