So close but no buzz (electrical experts needed!)

[jjcollier]

Hope I'm not abusing the system here by essentially reposting, but I've been able to rule out a bunch of potential no-start issues and frankly I'M JONESING TO DRIVE!!!

Here's what I've got(BTW, it's a euro '79SC with CIS):
-Spark (nice and blue on fresh plugs)
-Gas in the gas tank
-No requisite fuel filter buzz just prior to start up.
-Fuel at the (new) fuel filter (checked by loosening the lower attachment and noting seapage)
-The smell of fuel in the engine compartment, but dry injectors after multiple attempts to start
-Power at the fuel filter during turn over, but no vibration/pumping. (checked with volt meter) Yes I've tried tapping it too.
-I assume a good red fuel pump relay (I've tried switching others out)
-New fuse at #16 (and I've tried switching it out with another 25 amp fuse and cleaning the connection area)
-I have tried disconnecting the safety switch in back. No change.

Based on the above, I believe that my fuel pump has died. However, we did have it pulled a few nights ago and it ran when disconnected from the fuel lines (note sure how/why it worked then as the absence of the buzz was the first thing I noticed when trying to restart the car after it first died a week ago). Once reconnected, it would not pump during start up or when tested using the key on run/lift the sensor plate method. I have been back down there to clean the terminals and double check connections. All seem to be fine.

I have checked the relay connections with a volt meter and get a reading at 86/87, 86/30, etc., but NOT when checking 86/87a.

What else could be the issue here?

[ianc]

Hey JJ,

It sounds like you're suspecting your fuel pump now. Your steps above are a little confusing to me (do you mean 'fuel pump' when saying 'fuel filter'?), but just step back:

The fuel pump is a dumb electrical device. Relays, safety switches and complex wiring issues aside, if you put power and ground directly to it and it doesn't run, then it's toast.

Jump it with a known good power supply and ground. If it doesn't spin, it's dead, so get rid of it and try another.

ianc

Edited to say: I think I read another post of yours a few days ago where you may have run the pump dry while testing. If you did this for any length of time, it's entirely conceivable that you may have burned the pump, making replacement all the more likely. Bottom line: put power across it and see what you get.

Edited yet again: (I'm up late) I also don't understand your testing of the relay terminals above. Here is a little primer on the relay terms:

30 - Switched (load) current in
85 - Switching current in
86 - Switching current out (ground)
87 - Switched (load) current out

87a - Current from 30 with no switching voltage applied across 85-86 (unused mostly).

Essentially, the relay completes the 30-87a circuit with no power applied through 85-86 (no switching current). When power is applied to 85 (and 86 grounds it), power flows from 30-87 instead of 30-87a. 87a is largely unused, so the relay becomes a simple on-off switch, with switching current supplied through 85-86, and load current from 30-87.

[jjcollier]

Ianc:
Very cool of you to continue commenting on my problem here.
-When I say "fuel filter" I mean it. Despite not hearing the fuel pump, I wanted to check and see if fuel was getting to the rear of the car at all, so I loosened the fuel filter connector to see if there was any gas there (as there had been when I pulled the old one). So it appeared there was something in the system, but not the pressure to get through the injectors. Considering the state of the pump, it's probably a moot point.
-We only ran the pump "dry" for a few seconds.
-I'm an electronic cretin. I checked the relay circuits because someone suggested that if there is no power at 86/87a then the fuse is bad. Considering, though, that I have power at the pump during turn-over, I suppose the fusese, etc. are okay.
Thanks again. 'Sounds to me like a toasted fuel pump...

[Joeaksa]

Quick test for this is to get some starting fluid. Squirt just a bit into the intake of the engine and try to start it. If you get some coughs or it fires once or twice, then the ignition and all inside is working and you have a fuel problem.

Which fuel problem needs to be worked with as noted above. This test is just a quick way to see if the engine is ready to run but has no fuel. You can also use gasoline to do this but the starting spray is more concentrated (do not use much!) and works well.

JoeA