abs relay and a sensor

joeys928 · 07-21-2014, 10:06 PM

So I have had a problem with a really bad drain on my battery. it would go from fully charged to dead within a couple of hours. so when I checked for some shorts I found 2 large draws in the A/C and radiator fan circuit as well as the abs circuit. on further inspection i found that i have the wrong relay placed in the abs slot so thats my draw there. i also have two leads near the radiator that are wired directly together. i think the sensor has something to do with the radiator fan since its always on as soon as the ignition is turned on. so I'm not sure which sensor that would be or even where it is since the wires seem to be moved. I need to know where the best place would be to find the abs relay, and if anyone can help me with the sensor that'd be a huge help. thanks in advance.

Danglerb · 07-22-2014, 08:14 PM

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Landseer · 07-23-2014, 02:29 AM

A picture would help to identify which leads are tied together. The cooling fan circuit on 85 car is pretty simple and it has 4 activation methods as I recall.

joeys928 · 07-24-2014, 11:40 AM

I have found the relay. the cheapest i saw it for was used on 928intl. that was still around $70. i got a picture of the leads in question and also another i found that im not sure what its for or where it goes. both are in the front passenger side of the engine bay.

Also, i changed my plugs yesterday since i had one cylinder not firing. that fixed my problem and its now firing however, when i took it out for a drive, i got about 3-5 minutes down the road and the engine just shut off completely. I pulled of to the side and my battery was to dead to start. also the warning light in the instrument cluster was flashing. My belt tension light does come on however thats just a bad sensor because i relplaced the belt when i first got it. I know i have some vacuum problems that im trying to sort out but im not sure why it would have shut down the way it did. It started up and drove back just fine on a jump. any ideas would be greatly appreciated. thanks.

joeys928 · 07-24-2014, 11:45 AM

here are those pictures

Landseer · 07-24-2014, 07:26 PM

You've got some electrical work ahead.
Might be best to park the car until you've been able to trace and repair stuff.

In the last picture, the 14 pin connector is missing its snap-on backing cover that retains the eletrodes, some of which are hot. That should be repaired first, before driving this car again.

Regarding the battery / stall / jump start to return ---- My suspicion is a bad (internally corroded ) negative battery strap that, when manipulated a bit, randomly works for a while. When 85 and 86 loose battery during operation, as when alternator isn't charging the battery and battery depletes, the circuit is designed to flash all the dash lights. Were all the lights flashing?

The bad sensor for the timing belt is, forgive me, bad workmanship. The sensor is simple. If you missed a spacer washer when reassembling it, then it will always show the light. One has to remove the center cover again to get at it and straighten-out the problem.

The jumpering --- looks like the top of the AC pressure switch has been broken-off on your car. It normally has a pair of leads that plug into the jumpered plugs.

joeys928 · 07-24-2014, 08:16 PM

thanks for the help. All the lights were flashing so ill look more into that cable. I do have it parked now as i just removed the air intake since its in need of a cleaning. also when i was removing it theres a lead on the top housing where the throttle connects and i have the plug but no wires. not sure what it is or where the wires go so i can complete that. ( i have a picture if needed)

about the jumpering, what can i do to fix that problem, its a constant drain and with the winters here i dont want that fan to be on all the time. all ive been able think of is putting a switch in that i can just flip when its needed, but id hate to do that.

about the sensor, when i had taken everything off to get to the belt i did find that the current belt was in great shape and looked pretty new (i changed it anyway). and part of sensor was broken, i only mentioned that in case the computer reads that as a red flag and shuts it down.

im in the process of taking things apart to clean and repair any problems i find ( which i have found way to many already) any insight as to what else i should be looking to do would be appreciated greatly. thanks again

Danglerb · 07-25-2014, 12:24 AM

Lots of farmer fixes, I would suspect and inspect everything previously done on the car. If they messed up such simple items, the likely list of important things messed up is too large to ignore.

The pressure switch bypass should not make the fan run all the time, its to protect the compressor from engaging and burning out the clutch on the AC compressor when the Freon pressure is too high.

I would disconnect the battery and stop driving the car until you know what all of the dangerous poor repairs are and have fixed them.

Somebody local that knows the 928 could be a big help to you, or take lots more pictures.

Landseer · 02:05 AM

Agreed. And good quality pics of the CE panel and other wiring issues are critical for narrowing down an approach if asking for online help.

Regarding battery strap, no way really to check it, best to replace, can use a generic supplied by 928sRus. I've experienced a few complete failures of them, and so have at least 20 others here, that part is reaching end of useful life. Might have a bad alternator brushes as well. If bat was deeply drained, enough to bring car down, a simple jump start is unlikely to get it running again, at least not for long, which is why I bring up replacing strap as a good first step. Manipulation of ground strap during a jump start can indeed be difference between running and not running. One way to check is having 12.5 volts across battery, but say 3 to 11.5 volts from pos bat term to nearby body ground point, like a shock tower bolt.

These things are a good puzzle but doable; You are going to need the electrical diagrams.

Removal, inspection and cleaning of CE panel at passenger footwell, along with scrutiny of all wires on the panel, and leading to the panel, and the wires inside the console area where radio resides, are the places I start. Most of the time if there are shorts in the car wiring system, there will be tels throughut that mass of wires. Clean and re-fuse the panel; replace the 10 or so regular relays.

ABS is a whole nother animal, I woudl want to solidify the basics first.

BTW, me and others have collections of spare parts and wiring and relays for these cars that we sometimes get tired of holding on to, so you have some options if parts are really needed.

joeys928 · 07-25-2014, 11:10 AM

the reason i think those wires are the problem is because when i disconnect the wires my draw is gone but the fan doesn't turn on.
for the abs relay i need a new one because the relay in place is the wrong one and i believe its my draw there.
ill look at testing the strap today.
Is there anyone in the area that would be willing to come down? it seems that would be the easiest way.

Alan in AZ · 01:45 PM

Quote:

Originally Posted by Danglerb

The pressure switch bypass should not make the fan run all the time, its to protect the compressor from engaging and burning out the clutch on the AC compressor when the Freon pressure is too high.

... when the Freon pressure is too low, to protect the compressor from damage (insufficient oiling presumably). An additional (series switch) over pressure cutout was added only on the factory R134a systems (late GTS) - that one does protect the clutch & belt.

Alan

Alan in AZ · 07-25-2014, 01:58 PM

Quote:

Originally Posted by Landseer

Regarding the battery / stall / jump start to return ---- My suspicion is a bad (internally corroded ) negative battery strap that, when manipulated a bit, randomly works for a while. When 85 and 86 loose battery during operation, as when alternator isn't charging the battery and battery depletes, the circuit is designed to flash all the dash lights. Were all the lights flashing?

For the car to stall while driving there would have to be intermittent alternator and battery operation - possible I suppose, and if the battery is drained enough to not be able to start the car after driving for a while - seems it may not getting charged very well while running. But this could be some other flaky thing too. New ground strap is good (cheap) insurance at this age.

I'd suspect by now given the symptoms that the battery is also toast (have it checked on a load tester at a battery store). Makes sense to resolve these current drain problems before you install another one though.

The fan is switched on at full power by the relay XVIII based on the two temperature sensor switches (low power) for coolant & for refrigerant (fuse #29 controls both these). The fan is also switched on at lower speed (via the resistor) directly by the thermal high power switch on the intake (Fuse #23 controls this mode).

Test which circuit consumes power by pulling these fuses

Alan

joeys928 · 07-26-2014, 04:18 PM

i didnt get to testing those relays today. other things popped up. I did get a closer look at that ground strap and it looks to be in poor shape, ill be getting a new one shortly.

I found out that its the tps that was not connected. I found the wires but i cant find anything that will tell me which wire goes to which slot. I would like to know if anyone can help me with that.

ill get on the relays as soon as possible, im also trying to sort the mess of vacuum lines i have.

thanks for all the help so far.