SC: Yesterday no starter, today no fuel pump??

[hilandscott]

I've checked the threads that deal with general "not starting" tips, and in looking over the electrics on the left rear of the engine compartment I've changed only one thing by checking the 14 pin connector-- the starter is turning fine (dead yesterday) and the fuel pump is dead (hummed right along yesterday waiting for starter).

I was thinking that the old, loose ignition might be a factor, but I doubt the symptoms now match. It seems electrics. I have looked at all the fuses in front and rear and nothing is blown. Also swapped the fuel relay with another and no luck. As it could be a bad connection or intermittent I'd like to get to the bottom of it. Right now I'm just hoping to get it started...

By the way, there is a red cap covering a coil/switch that looks rusty, near the rear fuses. Anyone know the function?

Thanks for any suggestions. The car was just rebuild 2K ago, but the wiring harness and other connections are 24 years old.

[hilandscott]

I swapped in a new ignition switch (the existing is worn enough that the key can be pulled out from any switch position -- no luck with that.

Still not sure how fuel pump okay yesterday and now dead today...

[hilandscott]

Apparently not all relays are created equal...

I worked again through the wires, fuses, and relays. I swapped the window regulator relay with the fuel relay (both black). No difference. For whatever reason I then swapped in the only red relay "rel. air conditioning" (and I don't have air conditioning on the car) AND THE FUEL PUMP CAME BACK TO LIFE.

I then started the car to find that it was smoking excess fuel (whitish) and running very rough. So, the mystery continues, and I have discovered that not all relays are created equal.

Any ideas?

[hilandscott]

Found the earlier thread on SC fuel relay problems related to alarm and how to jump #30 and #87a.

Jumping had no effect. The alarm is a not-so-nice hack by a PO with a horn in the smuggler box and splices into the fuse panel near the fuel. The alarm control unit is not as Warren's pic showed: it is much more simple, like a four post black plastic block with only two leads attached.

So, as I replaced the fuel relay (black) with the horn and window regulator relays, no current to pump. But, with red relay... and wiggling the *defective* black relay that was in place, I can get current to the pump.

The red relay is a different part number, and is in the slot at the end (closest to front bumper) labeled "rel. air conditioner"

Any ideas??

[stormcrow]

The red relay is used primarily for the fuel pump. The white smoke is probably oil in the combustion chamber burning off. Start the engine and run it for awhile to see if it clears up. Black smoke indicates a rich mixture.

The red relay has a blocking diode across the coil which is used to provide voltage to the fuel pump terminal both when the key is turned to the start position or to the on position when the engine is running. The reason for this is that the fuel pump relay will stop the fuel pump if for any reason the engine stops running with the ignition key in the on position.

Steve

[hilandscott]

Okay, if the red relay is supposed to be associated with the fuel, then it is in the wrong place and the car was running fine with the black relay prior to today!! Don't know what to make of that.

Measured resistance across 85 - 86 posts of relays: 75ohms on black (defective relay?) and open (no continuity) on red relay.

Could it be that both are working but function differently?

When I only partially replace the black relay (that was running the fuel pump until today keep in mind) the fuel pump hums away when 30 and 87a are contacted. When the relay is placed completely the fuel pump stops again...

[Early_S_Man]

The fuel pump relay is the rearmost location -- closest to the dash. My spare red relays measure in the 84 Ohm to 85 Ohm range, and NO, they don't operate differently than the black relays!

It sounds like somone previously found out that your red relay was bad and changed it out with the A/C relay ... and NEVER bothered to replace the red one!

I sounds as if you may have a corrosion or warpage problem with the relay socket! Try cleaning the socket receptacles with a pipe cleaner and vinegar, followed by a thorough rinse with isopropyl alcohol.

[hilandscott]

So, I checked and cleaned the relay positions as suggested, also using an exacto knife to widen the relay poles slightly for better fit. (Thanks Warren).

The black relay that was controling the fuel pump must be bad, while the red relay in the A/C space is indeed a spare and works.

So, the engine was a little rough in starting but runs fine and has good power. I think I can declare vistory in time for Monday morning...