bureau13

I don't really know anything about the 16V cars, my experience is just with my S3. That said, I'm pretty sure a good CPS is required, and the tach should bounce a bit when cranking. There's sort of a daisy chain of things that need to happen before your injectors pulse, if my recollection is correct, the EZ sees the CPS report, and in turn activates the LH, which sends the signal to the injectors...that is of course way over-simplified, and the details may even be incorrect for your car...but on mine, there are a several relays controlling those various items, and they all need to be working to get the car to start. I'm guessing something in that chain is not working (maybe more than one something).

Socal_Tom

Hi there-thanks for the response. It does appear at this point that you've gotten to the heart of it, I've got power where I believe it needs to be it's just not getting told to do anything with the power it has.

I need to spend some time researching the CPS and how that's all supposed to work on an 84, but I'm running out of other things to replace!

hwyengr

No CPS on an '84 unless it's a twin-dizzy Euro. The green wire is the equivalent of the CPS on the 16v cars.

Socal_Tom

Well there you go, shows you what I know. This is not a dual distributor car. I have replaced the green wire with a brand-new one from one of our supporting vendors. I believe I have done that correctly, and the car fires off the cold start so the timing is OK.

I need to put more work into searching from this but does the tach get it signal from the ignition control box? Does that same signal tell the injectors to do something?

.

hwyengr

Also, have you thought about just getting new relays instead of your jumper wires? Much less chance of error.

hwyengr

When you jump the relay terminals, are you getting 12v at the injectors? Just in case you aren't super familiar, the injectors batch fire by pulsing the connection to ground. You should always have power on the hot wire at the injector. If not, the harness could be bad or your jumpers could be off.

bureau13

Lol, shows what I know. I still suspect the computers (please don't tell me the '84 doesn't have those ) or more likely the relays that enable them...

Socal_Tom

Agree, and the new relays should be here tomorrow

Socal_Tom

Yes, I do have 12v at the injectors. Didn't test all of them but I pulled one from each side and confirmed voltage.

This could be wrong, but I'm starting to sketch out that despite having a new green wire the ignition / injection system isn't seeing the engine turning and therefore isn't pulsing the injectors. Could just be the flux capacitor for all I know.

Socal_Tom

More ground tracing and I discovered that whoever was in here last skipped connecting this ground (note - not my car, image taken from a Pelican thread on grounds which helped me realize I had not checked this one yet).

EDIT - just looked at where this leads and it appears to connect into the 14 pin and ignition control box as a ground, I don't want to get too excited here but missing a ground at that set of electrical components clearly would mess things up.

GT6ixer

Have you replaced the coil and or plug wires? Also may be time to pull the fuel rail and do the injectors. Witchhunter is a popular place to have them refurbed. Also have you done a fuel pressure check?

I don't know this for sure but if you are getting proper fuel pressure and spark to all 8 plugs and 7 of your 8 injectors are getting pulse, the engine should still run on 7 cylinders, albeit rough. The fact that it keeps dying to me suggests it's not getting enough fuel (i.e. clogged injectors).

Or alternatively you could have flooded cylinders. This happened to me when I was trying to get mine started. Apparently the 928 engine is prone and sensitive to flooding. If you can smell raw fuel in the engine bay then it's likely flooded. To clear, remove all of the plugs and pull the fuel relay. Run it on the starter for a few seconds at a time to expel any excess fuel. I put some paper towels around each plug hole to absorb the fuel. After you reinstall the plugs try to start it with the fuel relay still disconnected in order to burn up any left over fuel that may have not been pushed out.

GT6ixer

Oh, also have you verified that the timing is set correctly? Double and triple check this. Visually confirm the notches in the cam gears are aligned with the timing marks (i.e. TDC) and that the rotor is pointing to the line on the distributor housing. This was the final piece in my no start puzzle.

Socal_Tom

Good morning Nate, hope you are having a good day. This thread has become fairly long already, and my somewhat task oriented updates or likely hard to follow,. The primary issue I'm dealing with right now is that I don't have few injection pulse, although she will fire and run for a couple seconds off the cold start valve. It's quite likely that my injectors or if he given how long the car sat, but without the proper Ignition pulsing the injectors are not going to do any good anyway. Grin.

I am cautiously optimistic that I found the missing ground earlier today and that once properly cleaned and reassembled she'll be better off for it.

Thanks for the ideas, and I will check out the injector rebuilding company that you referenced.

hwyengr

You mentioned the dead #1 injector, are the others good or did you just check #1?

I'm a little less optimistic about your found ground, not a lot of the fuel injection-specific stuff goes through the 14-pin.

I'm not a 16V guy, but for the 32V you can put an oscilloscope on the LH pin from the CPS to see if it's recognizing the engine rotation. Is there a similar test for the green wire distributor pickup? Isn't that just a Hall sensor that can go bad?

Socal_Tom

Your pessimism was well placed-no change in my condition. She still only fires off the cold start valve - injectors are not getting a pulse.

I about to replace the engine to chassis ground cable but look what I found when I pulled the front passenger wheel off. Yikes, that side of the sway bar is just dangling in thin air.