'86 Graduate: no spark after reworking injectors

MrT · #1 (**permalink**) 02-14-2004, 05:21 PM

Simple if effective misery: We have a new '86 Graduate that ran (very) rough. Removed plenum, injetor rail, injectors and associated stuff. Replaced fuel lines rail-injector and cold start solenoid. Disconnected battery while doing this and did compression checks during project. (#3 cyl weak but comes back with oil in cyl: hoping for stuck ring that will break loose with MarvMystOil or similar).

Son reconnected ECU harness and fuel pump fuse, probably quire respectably. Car now has no spark. Cannot yet say fuel pressure is OK, as haven't measured it. Car used to spark, now doesn't. My Bosch fuel inj. manual doesn't help, nor do the other manuals I have. Is there a spark enable from the fuel or electrical system in the Bosch L-jetronic systems?

Help please.... A hint or a reference to a post would be welcome. I have tried there, but get nothing relevant on "no start" or even "no apark".

Thanks a BUNCH in advance.

Michael

Michael

**papajam** · #2 (**permalink**) 02-14-2004, 06:52 PM

Were all ground wires reattached? There are two at the back of the head on the intake side and a couple more to one of the bolts that holds the auxillary air regulator to the cam cover (I think). I'd also check the connections from the rev and timing transmitters that may have come loose during the surgery.
The Bosch L-Jet uses 2 ECUs; one for fuel and the other for ignition.

MrT · #3 (**permalink**) 02-14-2004, 08:35 PM

muchas gracias.

I know the (3?) wires at the aux. air connection are intact. I thought I had put all others back with the glaring exception of a single skinny braid under the plenum that I forgot. I think it is to connect the plenum in the presence of so many rubber isolators (bushings, air hoses, intake hoses, etc) to the block. But I tried to holding it against the plenum while Son#2 cranked the engine and found no joy. I took that to mean the spark problem lay elsewhere.

I appreciate the wire count, and indeed might have lost the crank sensor wire. I sure hope I wasn't so careless. In re-reading what I wrote, my typing is atrocious. I really did search on "no spark" instead of "no apark."

I quite possibly left off the wires at the back end of the head on the intake side. Hope springs ever. Maybe she'll be driving tomorrow....

Michael

MrT · #4 (**permalink**) 02-15-2004, 07:40 AM

Well, the two wires attached to the rearmost mounting point on the head on the intake side _are_ actually attached. I am not familiar with the wiring of the Spider, and would appreciate a count for the wires to be attached. I will look for the crank sensor wire. I don't look forward to pulling the plenum off again, and hope I don't have to do this.

[Addition: the crank sensor wire seems to have been the trick. Son#2 had not fully engaged the spade connector. When encouraged to go and verify his work, he found it independently, leading to much rejoicing and celebration. It seems still to run rough, though. Maybe needs a jaunt on the road with some MMO in the crankcase and enthusiasm on the gas pedal?]

Michael