sixpoint9kPa

Here's another fangled quirk for the technically inclined...

I've got a gremlin in the electronics of my '86 951 when attempting to start the car. Ponder this...

First, here's what's new:
starter
battery
RPM sensor
crank position sensor

Other things tried:
removed junk stereo
removed amplifier
removed non functional legacy alarm system
cleaned up wiring mess under dash and in front center console

By removing the alarm (and the starter kill relay), the no start / no draw issue seems to be fixed.. yet one other issue remains.

Every once in a while I'll go to start the car, and the battery has drained just enough to keep the starter from engaging. There's a draw on the battery and the starter won't... start. However, you can hear the solenoid plunging with each key turn by the click it makes. After a week vacation, the battery had drained to just over 5 volts... it's a slow trickle. Another week without starting the car after that incident the car started without a problem. It's more/less random.

I can jump the car and it will start.. about 99% of the time. One of the last couple times I had to jump the car, it wouldn't start with the jumpers on until I lowered the e-brake. Fancy that. Jiggling the e-brake has even kept me from getting stranded without jumping the battery. Granted, I know of no correlation between the e-brake wiring and the car starting, but this odd trick does work when all else fails. Just for grins, I disconected the e-brake signal wire.

There has to be a frayed wire, or malfunctioning electronic component somewhere... but where to look next?

streckfu's

Sorry I can't help but that is very curious.

Sam Lin

Take an ammeter and go through your fusebox with the car off - find what's drawing the current.

How old is your battery?

Sam

Jason_86_951

There is a bundle of wires that runs right along the side of your E-brake. There could be a short to ground in that bundle, jiggling the E-brake could be moving this around just enough.
Just a guess.

M758

e-brake also contols a light on the dash that turns off when fully released. It may be link to you issue.

sixpoint9kPa

Sam: The battery is new, and has a higher CCA rating than the stock requirements. I've had the 'ole multimeter in amp mode and can't seem to find a significant draw. But it is relatively random, so it may have been hiding at the time.

Jason: I've taken the rubber strip off that bundle of wires, and they all seem to be shielded well enough. Last weekend that wire bundle was my last hope of an easy fix.

Sam Lin

You need to pull each fuse and bridge the contacts with the DMM, can't just probe them while they're in. You can start first by pulling negative battery terminal and just seeing the total draw there between terminal and clamp - that'll let you know if it's hiding at the moment.

Sam

sixpoint9kPa

The e-brake wire to the light on the dash was my last ditch effort. It's disconnected, and I haven't used the e-brake in a while just in case it's touching another wire under the carpet somewhere. I drove it to the office today and yesterday after having disconnected that wire over the weekend, and it's been starting fine. But it has "started fine" for weeks before. Eighteen year old electronics are evil, and therefore cannot be trusted... but I remain optimistic.

Thanks for all the quick responses everyone! ...I could kill a whole day of productivity posting in here.

josephsc

Yea, Rennlist could be bad for your job.....

One thing I did when I had a slow drain issue last year was to get a solar-panel charger that goes into the cigarette lighter. It's not a cure for your problem, but may prevent you from getting stranded.

sixpoint9kPa

Did your slow drain issue ever get resolved? Or do you still carry a spare cig light charger with you? ....or did you end up using explosives? ...something I'm about to consider.

Peckster

[QUOTE=sixpoint9kPa] Eighteen year old electronics are evil, and therefore cannot be trusted... but I remain optimistic.
QUOTE]

I've never had a problem with my electrics. Most of the problems I hear about are grounds or aftermarket wiring. I'd suspect your battery connections or maybe the main ground or the starter itself. I doubt the emergency brake has anything to do with it.

tazman

Sam is on the right track here but when you go to pull the terminal off of the battery you have to have one probe touching the post and one touching the terminal while you pull it apart. You have to be sure that the car never looses power while you do your test because there are things that will turn off when they loose power. You should see a current draw with the meter between the terminal and post then you start pulling fuses until the current draw drops.

One of the popular things that can cause this is the relay for the windows that allows them to work after you turn off the car before opening the door. So for a quick test on that turn the key off operate the window a little, then open the door and see if the window still operates.

josephsc

Yes, I did resolve it -- turned out that the new battery was defective. In my case, I bought a brand new battery that was leaky (you pick it up and next day your clothes melts away). I replaced the defective battery under warranty and has had no problems since. I also moved to a warmer climate, which requires less juice to start up the car...

sixpoint9kPa

I'm leaning towards a previous owner's hack job, or a poor ground. I doubt the e-brake has anything to do with it either, but it's been a consistant quick fix.. as strange as it sounds. I've heard on more than one occation to have the new battery checked also.

sixpoint9kPa

You're not the first to mention the new battery. Worth a shot to have it checked and/or repaced under warranty.