waynelambright

Hello, friends. It's been a while. I'm finally starting to work on the 1986 Auto 928s with 180,000 miles. I had the car towed to my place. Previous own said it ran with starting fluid.

I tried some starting fluid and it fired up a few times, so we have SPARK!

Car is also stuck in Neutral. Also, indicated on dash as neutral. Foot on brake while cranking.

First I discovered after applying voltage to the fuel pump, it was frozen.

I put in a pump from one of the other 928's I have after testing it worked. Turns out, the seals were dry, so it was leaking. Came out today, the leak was almost gone.

When I crank, I don't hear the fuel pump. So I jumped the relay, and now I hear it.

I tried replacing the relay with another one. Still, the relay is not initiating by itself.

What might cause that?

Also, this weird noise when I pull out the key.

I also from drives door with the long key, locked and unlocked the car just in case the immobilized was doing something.



Thanks again for any help.

I love you guys.









90% of the drip went away in 24 hours, the seals are starting to swell. I'm hoping it all will be sealed tomorrow.







Her she sits, I love the sun influenced patina in the paint.

dr bob

The pump banjo "seals" are metal, so they don't "swell" with time. Folks might remember the vintage Prestone coolant TV ad where the metal can is ventilated with an ice pick multiple times. Coolant runs out the holes and eventually the flow stops. Is it prestone's amazing stop-leaks technology? No, they explained in court, the coolant level dropped due to all those holes.

The sealing washers really need to be replaced each time they are tightened and loosened again. Tightening them more just galls the faces and makes the leaking worse. Use A Torque Wrench with new washers.

Related: Puffing starting fluid into a 928 (or any engine) risks a backfire into the intake manifold. Besides popping manifold connections and vacuum hoses apart, the big risk is that the crank will turn backwards and cause the timing belt to jump around the crank gear. On a good lucky day, the cam timing will be off. More common is broken driver's side cams, and sometimes broken belts if they are less than new. Yours is less than new.

The fuel pump is powered via a dedicated feeder directly from the battery positive terminal. Your test light says that the wire is still attached. Spend a few minutes cleaning and tightening those connections at the battery to be sure there's power available when the load from the pump is connected. Know that the relay also supplies the heater in the oxygen sensor, so damaged wiring there canl keep the pump from running.

The pump runs based on a tach signal from the EZF (ignition) controller passed to the LH (fuel injection) controller. When the LH determines that the engine is spinning from that signal, it grounds one side of the fuel pump relay coil and powers the pump. Since you seem to have spark, you can next determine that the tach signal makes it to the LH, and then why the pump relay doesn't engage while cranking.

I shared some thoughts in your "stuck in neutral" thread.

Mrmerlin

someone gave me a 84 Euro after they caught the rear of the car on fire,
they sparked the fire by connecting a wire to the dripping fuel pump,

waynelambright

The pump is actually leaking. Not banjo bolt.


Day after, it sealed up.


Thanks for the help on the neutral question.





Back to no start:
When I crank. With relay installed. I see the tachometer bouncing. HOWEVER you won't see it bounce in the video because I'm using the jumper wire on the fuel pump relay.

I was very certian that the fuel pump does not power up if the relay is installed. I also tried other relays to but same no power results.

I'll put the batter on the charger and try more tomorrow and report.

Thanks again.

dr bob

Wayne --

Your test light is almost no load at all on the primary wiring to the relay. The pump and HEGO sensor load will draw that voltage down if there's any significant resistance in the supply-side wiring (battery connection I suggested in post 2). With a handful of little fabricated jumpers, you can connect the relay to the socket and test for voltage at the 30 pin while cranking. Use a DMM rather than your test light so you can see the actual voltage rather than guessing based on how bright the test light is. You can also connect the DMM (in voltage mode) across the relay coil and verify that there's a signal to close the relay from the LH.

Powering the fuel pump directly has absolutely relationship with the tach reading. We should see the tach bouncing as you crank, whether or not the fuel pump or video camera is running. The contact wiring is completely isolated from the LH trigger by the relay. With that in mind, it looks like you are powering the pump with jumper wires from the battery. Try putting a jumper in the FP relay socket between 30 and 87. Make darn sure you put the jumper in the correct socket connections. The pump should run continuously with that jumper in place. If it doesn't, you can start tracing voltage from the battery through the relay socket and fuse to the pump. Look for where the voltage stops and you'll find the fault.

waynelambright

OK, I'll test the voltage with a Multi meter and I'll also clean the grounds, they look good, but I'll do it anyhow. Today I put in fuel and it almost started.

Video shows lots of cranking and a few almost starts.

Video shows seepage of fuel engine bay.

Thanks again for the help, I would be lost without this help.

waynelambright

Good advice, I'll bring out the fire extinguisher next time.

nosnow

Holy batman. I think this was my old car. Is this an '85 with upgraded 86.5 suspension? Is this burgundy on burgundy with rear A/C lines crimped/cut? Wish I still had the VIN.

The beep noise is from a Sony head unit if memory serves me correct. pull the power or take the face off the radio and you shouldn't hear it. It will beep even if not turned on.

waynelambright

Do you live in farm country by Sacramento. The son shot out the driver window with a bbgun.




Previous owner.

waynelambright

Dr. Bob.

I cleaned up my battery cables, voltage is good. The relay is not working. I did a test and found two bad relays.

I jumped the connector. It ran for 15 minutes. I'm going to buy a soldering iron tomorrow and try to fix the relays.

I had the fire extinguisher handy :-)

While pushing in the relay the female part popped out of the fuse box. Have to fix that next. I fix one thing and two things break. LOL.

jetson8859

Love the look of the cars without the rub strips! Sounds like you are making progress. Those look like standard 53 relays so I would just go ahead and order 4 or 5 new relays, they are $5 or $6 a piece so not a heavy hit to the budget. I am sure that Mark at 928 Intl has them and he is relatively local to you.

nosnow

Nope not my old one.





I sold it to someone in the Peteluma area 6 or 7 years ago. Amazing given the production volume that two Burgundy on Burgundy of the same vintage in the same area.

dr bob

Wayne --

Those 53b-type relays are consumables. The "typical" failure mode is damage to the relay contacts inside due to overloading and/or arcing at those contacts. The little convex contact surfaces have a very thin layer of silver over a copper base. the copper carries heat away, while the silver carries the current and doesn't oxidize the way the raw copper would. Arcing is caused as the contact opens and and current still tries to flow across the small-but growing air gap. Since it's DC current passing through, the little arc moves metal from one contact to the other similar to DC arc welding. It's tempting to try and restore the relay by filing or sanding the contact surfaces smooth again, but that's a very temporary fix at best; the arcing will move the exposed copper a lot faster than the silver you remove with the file/sandpaper.

The Good News is that new good-quality relays are relatively cheap. Genuine German Bosch are often under $10 each, making them one of the cheapest and easiest "fixes" availale. Wizzdumb is to replace the fuel pump, injection and ignition relays as a group, and save yourself the agony of chasing the gremlins that come with failing critical relays.

You may not be the first person to discover this particular phenomena...

Also:

That ground strap you are dressing up has undoubtedly become corroded inside the plastic sleeve. Corrosive fumes from the battery wick up through the braided copper weave. As with the relays, the common wizzdumb is to replace rather than try and restore. While it may seem easy to get rid of the green chloride residue, that's really the reacted copper that's now completely gone. More Good News: Our better vendors offer a heavy-duty replacement strap, with marine-rated tinned-copper braid that's protected from the battery fumes. Another inexpensive "fix" that solves a slew of electrical symptoms, especially some charging issues you might not otherwise suspect.