924Board.org

[Smoothie]

I've had an '82 924 Turbo for about 8 years now. It has the expected 924 electrical problems - windshield wipers cycle on sometimes on a bumpy road (tried replacing and now have just removed the wiper relay to take care of this), other times they and the lights (all except the headlights) don't work until you reach down and jiggle the wires at the fuse box. Horn didn't work or worked intermittantly for years until I added a ground wire from the steering column to the chassis down near the firewall. Gone through too many batteries already due apparently to low output from the alternator. (I upgraded the battery ground years ago and have replaced the Bosch alternators' voltage regulator.) (I switched to a Delco 140 amp alternator a few weeks ago to correct the low output problem. There's no difference between German volts and American volts, right? . It fit with just a couple easy modifications. I was so happy with it, I sent the retailer pictures and an e-mail describing how I did it. If you're interested, see #17 on http://www.alternatorparts.com.)
Through all these problems I was always at least happy that the engine ran good and there were no electrical problems with it. Now gradually over the past few months the electrical gremlin has migrated to the ignition. I'll be driving along, engine running very smoothly, then suddenly it's missing, sometimes get a backfire, and the tachometer will be flopping around obviously out of time with the engine speed. When it first started happening, I would pull over (the engine would eventually stall anyway or would start to backfire so much as I pumped the gas pedal it would create a scene, so I'd just shut it off.) I'd let it sit for a few minutes, then start it up and it would run fine for a few hours or a few days again. I've been pulling connections, cleaning and reconnecting. Did this to the Fairchild ignition module on the front of the left wheel well, the two multiwire connections located between the coil and the firewall, of course the wires attached to the coil, the overboost safety switch, ignition switch (which was replaced about 2 years ago), all other wires connected around the steering wheel, ignition wires, distributor cap and rotor were replaced recently. It ran fine yesterday after all this was done. Drove about 10 miles then and another 10 miles this morning with no problems. This afternoon I start it up, runs good for a few seconds then the ignition misses start and the tach is flopping around. Tap the gas a bit to try to get it smoothed out and it revs, but misses some more and backfires a little. I turn off the ignition then turn it on without engaging the starter. The usual idiot lights light up, you can hear the fuel pump running, but; the tach is flopping around without the engine running. It jiggles around a bit near 0 rpm, then it might jump over and peg itself at the max rpm side, then fly back down to 0 and shake around between 2000 and 0 rpm - just bizzare.
I'm goin out to mess with it some more. If anyone has a clue - I'm hoping to avoid my usual hit and miss part replacement routine.
Thanks, Jim

[Pat]

I'm out of my realm here as I own an '80 931, but have you checked the timing sensor? My 924 turbo runs the timing off of engine vacum but I know the '81-'82 924 turbos used a timing sensor on the clutch housing to control timing. Also the distributor doesn't have the peizo electric sensors for that tach as in the '80 so the timing sensor may run both the ignition timing and the tach.

[Smoothie]

Pat - Thanks for the suggestion. That's something I haven't looked at. Not only is it logical to look at it for the reason you give, but; I've always suspected that as my cars (the Porsche and a Cherokee) are parked together on the driveway, they conspire against me to both break down at the same time. The thinking is to have two vehicles - that way if one needs service, the other is available, but; they always break down together. The freaky thing is: just a couple months ago I had to replace the crank sensor on my Jeep. I'm going out right now to park one on the street... Many thanks.

[larso]

i didn't read your entire post but how is the fuel pump relay..

If you are having all these bouncy lights on off problems and have fixed all the grounds have you thought of replacing the fuse box for the heak of it, some people have bad fuse boxes.

> Subject: Weather Forecast: Central Asia: Afghanistan: Kabul
>
>
> Forecast for Saturday, Sep 22, 2001
> Bright and sunny, temperature near 8,000 degrees F
> Winds approaching 750 knots--if going outside wear sunblock SPF 10 million
> or better
> Should be but one cloud in sky all day
>


lars

[Smoothie]

Thanks for the weather report. I'm sure it's accurate. I copied and sent that one to some bartending buddies that will really appreciate it. Thanks for the suggestions too and I don't blame you for not reading the whole post. I'm noticing my posts are more wordy than most.
Just had a look at the FAQ section of this site and found some more things there that need to be looked at: some ground wires behind the dashboard and the connector to the
control unit that's below the heater.
I'm hoping the problem isn't with the fuel pump relay. I've read they're made of unobtainium and gold plated and sell for about $80. If it's the fuse box, well that's a bunch of trouble I just don't want to get into. I've already been through that some years ago, cleaning and tightening contacts. I'll check those things from the FAQ first just because they're more fun and easy, then move on to the fuse box again when everything else has been tried. Thanks, Jim

[numbers]

Had a similar problem with my 931, and it turned out to be nothing more than a sulfated battery. Apparently, the sulfation would periodically cause the battery to short internally, loading the alternator, and droping the available voltage down to about ten volts. The taach flipping around was the key. The tach will only do that under a low voltage condition. Hope this helps.

[Smoothie]

Thanks for the suggestion Numbers. Actually I don't have a voltage problem anymore. I still have a digital multimeter attached to monitor the car ever since I put the Delco alternator in. The battery has been reading about 12.5 volts after sitting overnight and the system reads >13.5v with the engine running. I've also checked the voltage a couple of times while the tach and engine were misbehaving and saw no voltage drop. I checked and cleaned the connectors on the ignition module that's mounted on the front left wheel well and the ICU that's mounted below the heater. The car ran great today, but; that doesn't prove anything - if it runs good now for a few days, then a few weeks, I'll be convinced that the problem is gone. The suggestion to check the ICU connector is in the 924.org FAQ under: "Car Won't Start/Run Properly: My 924 Turbo/931 is backfiring/running rough – How can I fix it?"

(next day)
The car ran good again today, maybe only because it knew we were going to an auto parts store. It did hiccup once on the way back though, but; it may have just been expressing disgust as the car ahead was driving slow. It would have burped, but; it has no carburator and it might have farted, but; it has no backfire valve. But seriously, thanks for the suggestion. If/when it starts acting up again, I'll definitely check the battery - it has a couple years on it at this point and must have been hurt some by the low voltage it was getting.

[ This Message was edited by: Smoothie on 2001-09-20 09:17 ]

[Vince Ponz]

I have a minor problem with my oil temp gauge. In the evening with the lights on the fuel pressure gauge can show up to 1 bar lower. I turn out the lights and it goes up 1 bar. I also switched from synthetic to regular oil to get the pressure up. The fake stuff is too thin for me. Any help would be appreciated. I changed all four of the grounds and they are still good. I wonder what causes the drop. Any leads?

[Smoothie]

I didn't realize I had a voltage problem until I hooked up that digital multimeter. I attached it through the cigarette lighter outlet. Voltage was acceptable with no accessories on - no lights, radio, etc., but; dropped quite a bit, especially when I turned on the radio, which suprised me. Here are some of the voltage drops I get:
radio -.50v
heater fan (high) -.25v
all lights -.45v
headlights alone -.25v
other lights alone -.20v
wipers (high) -.10v
wipers (low) -.05v
a/c low(1) -.15v
a/c med(2) -.25v
a/c high(3) -.40v
interior light over rear view mirror -.20v

- But never mind all that, I was about to suggest a higher amp alternator, but; I just went out to see exactly what my gauges do when different accessories are switched on. I don't have an oil temp gauge (do have water temp) and don't have one for fuel pressure (only oil pressure). When I turn on just the lights (no headlights) my oil pressure gauge drops by 1 bar, the tip of my water temp gauge shifts to the right by about 1.5mm and the fuel gauge (which is way off and reading low anyway) moves right about .5mm. Turning on the headlights and/or high beams has no additional affect on the gauges. These are insignificant problems to me. I know I have the right amount of oil and the effect to the other gauges is so minor...

Just for fun, check your voltage with headlights, the fan or a/c, and the radio switched on. See if you're still getting >12 volts with all that stuff on (engine running of course).

[Smoothie]

(day 3)
ran good
(day 4)
still good

[Smoothie]

On that oil pressure gauge reading - I read somewhere recently a solution to this problem, but; have not been able to find it again. If I'm remembering correctly, it involved rewiring the oil pressure sender (may have been the gauge). It's supposedly wired in series with something else and the solution was to cut one of the wires and run it somewhere else. If I find those instructions I'll provide the link. I'm pretty sure it was on one of these discussion groups or links from 924org.

[numbers]

Smoothie, I have run the delco alternator for several years now. I think you will find it much more reliable than the Bosch.

[Smoothie]

Most excellent! Smoothie likes to hear that. I have a Delco CS-144 (140 amp). I think they said these are used in Corvettes, trucks and some large cars. Before I went for it, I looked into having the Bosch alternator rewound and modified to increase its' output. The local generator shop could increase it from 75A to 90A for $135 - was glad to find the Delco.

[Vince Ponz]

I made a mistake and I meant to say the oil pressure gauge. Put the lights on and the pressure drops. I changed from synthetic to dino and it is a little better.
When hot I really get to worry. Uses no oil and runs great.

[Vince Ponz]

I made a mistake and I meant to say the oil pressure gauge. Put the lights on and the pressure drops. I changed from synthetic to dino and it is a little better.
When hot I really get to worry. Uses no oil and runs great.