Mrmerlin

were any of the relay pins corroded?? if so then reread post 13

Madmarek

No I never really found anything that looked obviously bad.

If I remember correctly I replaced the fuel pump relay.

Mrmerlin

whats the condition of the hot post, and is there a cover fitted??

Madmarek

Hot post looks ok but i will clean up tonight
no cover but the car never sees rain.

billtool

In my two months experience...I'd say tighten up the hot post. Solved my mystery dying issue two weeks ago.

Mrmerlin

if you dont have a hot post cover then the 14 pin connector just above it will get wet and corrode.

You should make sure to fit a cover before you wash the car as there is electricity going through the 14 pin when the battery is connected.
Inspect the 14 pin connector for corrosion

SteveG

He says it never gets wet. Cover or not, it will corrode underside. I would get it covered anyway, as that is a "HOT" post and you don't want to accidentally ground that OPEN connection.


"Also cleaned and retightened every ground I could find on the entire car." While it sounds like a relay, I would check this indefinite statement against Wally's list. Esp. coil connections and grounds from coils. These seem to attract moisture even through the rubber boots on the coil wires.

Madmarek

Didn't get a chance to do anything last night except turn the key. Weather was in the 70's and the car started right up no problem.

Cold weather coming tomorrow so It looks like I will be cleaning and tightening this weekend.

Madmarek

Ok so its been around 70 degrees everytime I go to start the car.

Last time it started, and shut off. Left ignition on and tried windows etc. and all worked.

So I dedided to clean the hot post. Did that and all seems well. Not cold yet but I will try and the temperature drops.

I hope that was it.

Madmarek

Its been hot, its been cold, I even left the car out overnight and all is well.
Cleaning and tightening the Hot post seems to have cured the problem.

Thanks for everyones suggestions.

Mrmerlin

get a hot post cover order one for a 1988 S4 it fits you may have to drill a hole in the end of the hot post if yours doesnt have a threaded stud on the end of it, JB weld a bolt in the end then cut off the head of the bolt with a dremel then you will need a threaded cap and the hot post cover

Madmarek

Great, thanks for the tip

Madmarek

Now that the weather is cold all the time the car dies all the time. I am curious to see if this is a low voltage problem. Next time I go to start the car I will check to see the standing voltage. See if the car dies, Fully charge the battery and try again. Maybe its low voltage and one of the coils is dropping out.

Landseer

Next time, try taking a volt reading from the postive battery terminal to a ground, say, the bolts on the top of a rear shock tower. Then across the battery itself. If different, then you have a ground strap gone bad. Sounds unbelievable, I know, but can happen. Check out this picture, 85 car. https://rennlist.com/forums/928-foru...rap-issue.html And the Wally Plumly observation --- essentially: its possible for a continuity test to show OK, but the ground strap not be able to pass the quantity of current during actual use.

Also, on 84, if you haven't done it already, replace thermo/time sensor and temp II and ignition switch. If you haven't done it, just do it.

Ignition switch has multiple contacts. Its possible for it to work the accessories but not provide enough power consistently to keep relays triggered. Ask me how I know that.

More about thermo/time: https://rennlist.com/forums/928-foru...testing-2.html (Read also the link embedded at post #20 ). This thermo/time sensor in particular is a problem when it goes bad for cold starting the 84 car. Note that somewhere in the link its pointed out that the WSM test values are wrong. Just replace.

Madmarek

Warm weather is here but the car is still flaky.
Noticed the following relay chattering. 928 612 473 00 bridge for starter M/T
What does this do?
What holds it in?
I removed the cover with the relay still in service.
When I hold the relay closed the car seems to run fine. If I push the relay contacts open the car dies immediately.