84 still won't run.....Loosing my mind HELP!

84toy · 11:14 PM

It's fixed!! See my reply. Thanks for the help !!

OK, Pease Help!! I'm ready to haul this thing to the scrap yard! I posted a week ago that my 84 won't run after having the engine\tranny out for a tranny rebuild. It will run if I put fuel down the throttle body. The DME was tested in another car and runs fine, the relay is replaced, the crank sensors are new and adjusted. I replaced the plugs (again). The fuel pressure is high and the spark is good. I have even pinched off all the vacuum lines but it still does the same thing. It will fire up for a few seconds (sounds good) and die. It is for sure not getting enough fuel. I can assure you that the vacuum lines are all correct.

The only thing I can think of is possible the Volume Air Flow Sensor. Will the engine will run at all if they are bad?? My understanding is that they will run but poorly. Anyone ever disconnected one and tried to run it???? Can you bypass it somewhay to make it run rich?

Or perhaps the injectors are not operating correctly?

Suggestions are appreciated.

Paul

Joejitsu · Joejitsu's Garage

Please don't haul it off the the scrapyard! Haul it to my house and I will "dispose" of it for you instead.

makaio · 11-10-2003, 08:37 PM

If it was running fine before the engine/tranny removal, then it has to be something simple. Did you remove the motor & tranny yourself, and re-install it? I know it it's not much help, but it has too be something simple, like a fuel return or vent or something.

AFJuvat · 11-10-2003, 08:57 PM

Go out to the auto parts store and buy yourself a "noid light" - any autozone has them. get the one for Bosch fuel injection systsms - this will set you back a whole $7 or so.

You will now test the injectors to see if they are getting a signal. Disconnect the wiring for one of the injectors and plug the noid light in and have someone crank the car - the light should flash. - no light means no signal to the injectors - Wiring or DME fault. A constant "on" indicates a DME problem.

Next, behind #3 cylinder, on the back firewall, there should be a connector - is it plugged in? (it is easy to miss as it "hides" behind the intake.)

Are you sure you have the crank and reference sensors the proper distance off the flywheel (0.8mm) and you have them plugged into the cirrect connector - if the sensors are crossed, the car will not start.

Is all of your wiring hooked up on the drivers side of the engine compartment? did you perchance knock any fuses aor cables loose? Did you reconnect your grounds to the Cyl #1 intake manifold?

Air flow sensor is unlikely cause - it worked before, and they rarely and I mean rarely) just "die" out of the blue.

AFJuvat

84toy · 11-10-2003, 09:10 PM

Thanks for the replies. Yes I am positive all the connectors and plugs are hooked up. The "noid light" is an excellent idea. The crank and reference sensors are new and set to the correct clearance but it did not help by changing them. Keep in mind that if I use fuel in the intake it will roar to life which means those sensors are working. Yes, the ball of grounds on the intake are all hooked up. Only reason I suspected the AFM is because I rinsed the engine down when I cleaned it and I thought maybe I shorted it out. Will it run disconnected? I took the small cover off and it was dry inside though. I appreciate the help.

One thing I was thinking is that if the fuel system is under static pressure with engine off, and I energize injector bank 1,2,3, or bank 4,5,6 at the DME, the fuel pressure should drop immediately if the system is not clogged. Anyone try this before? I would hate to hydraulic the engine!!

Thanks

Paul

Dan Owens · 11-10-2003, 10:47 PM

Paul,

I'm sticking to my original suggestion, and also one given by several others. Check the AFM. They do go bad from wear over 20 years and especially from water getting into the electronics box. You did say you "rinsed " the engine and that the engine ran prior to pulling it. It will not run with a bad AFM. By introducing fuel into the system manually and having it run that should be telling you loud and clear that fuel starvation is the problem. It wouldn't run at all if the sensors were bad, spark was missing, etc... If your pump is working and your getting fuel to the rails and injectors are firing it's a fuel control issue. I don't know why you're not checkin the freakin AFM, (said with a smile although very loudly) Just my .02 cents worth.

84toy · 11-10-2003, 11:12 PM

It's fixed!!!! and it runs!! I checked the outputs of the DME and then at the engine. No connection. It turned out to be a short at the connector in the engine compartment. Only thing I can think of is that it got torn while on the engine stand when I was moving it around. Right now I am a happy camper!!!!

Thanks to all of you for your help and suggestions

Paul

makaio · 11-11-2003, 08:17 PM

Glad it was something simple.