924Board.org

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

I'm currently troubleshooting a start but no idle issue on #196, Its been a while coming but I finally have it all together.

Both fuel pumps are working, the relay is jumpered for now with a fuse. I can get the car to start when flooring the gas pedal / key to start position. It catches and revs up to 2-3k but as soon as I put the key to position 3, the engine dies.

My next line of attach will be to evaluate the WUR override a PO put in and possibly return it to stock.

I wish I had my multi-meter, but its at my apt an hr away, so diagnosis will be limited... I'm wondering if this could be an issue with the starter solenoid.

I will keep this thread updated as I keep troubleshooting, but advice would be surely appreciated.
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1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

Sounds like an ignition switch failure.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

Hmm, I will have to explore that option as well. Are the early 944 ignition switches the same part as ours?

Could I jumper the ignition switch to test the rest of the system?

Edit: To answer my own question, yes 944 ignition switches are interchangeable.
Now just gotta go pull it and try it out.
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

It's worth a shot as the symptoms sound exactly the same as others have described.

Don't forget jumpering the boost switch too, though that doesn't sound like a possibility in this case, it could help eliminate another variable.
_________________
Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

Jumpered the ignition switch, The car starts up, and runs, but dies as soon as I take the starter off.

To jumper the boost switch, do I run a positive charge from the battery?

I'm at a loss to what it might be if I'm overriding the ignition switch...

Please help?
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

fiat22turbo · Joined: 18 Jan 2006 Posts: 4040 Location: Portland, OR

http://www.924board.org/viewtopic.php?t=22724
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

I've been reading that thread. This part doesn't make sense tho:

ideola · Joined: 01 Oct 2004 Posts: 15550 Location: Spring Lake MI

Here's another thread with a more systematic approach:
http://www.924board.org/viewtopic.php?t=28790
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erstwhile owner of just about every 924 variant ever made

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

Thanks Ideola, that write up was most helpful. Im glad it does not assume the reader knows anything. I've gone down the initial check list, the last item I need to test is the igition control unit...

If I'm interpreting this scematic from haynes correctly... when the starter is engaged the ignition control unit is overriden? And you have current going from #6 to #5 to # 4 to the spark plugs?

Now when the stater goes offline, the current goes from #1 to #2 to #3 to #5 to #4 and then the plugs?

Im thinking I need to test the ignition control unit, I know I'm getting fuel, so I must be losing spark when I take the starter offline... I'll probably not get to testing it until later in the week, if at all before the weekend...
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

I finally got a chance to get at the car with a Multi-meter tonight.

I started by resetting the timing. The crank / cam marks were slightly (1-2 teeth on the cam) out of sync. I set it properly and re-tightened the belt

There were no resistors as per the haynes manual to test. Is this something absent on the Turbo?

I proceeded with the haynes procedure to test the the ignition coil. The PO installed an aftermarket coil, and the readings were as follows:
resistance between terminals 15 and 1 - 1.6ohms
Resistance between terminals 1 and 4 - 9.94 Kohms
these seem a bit high to me, but the real problem came next:

I tested the battery voltage - 12.35v
turned the ignition to the on position and proceeded to test the voltage at terminal 15 on the coil.
my first reading was 1.99v, which is much lower than the 5v in the haynes manual. then subsequent readings were around 0.16v

I also jumpered the ignition switch to rule this out as a variable, and I continued to get readings of 0.16v.
Haynes is telling me to check all the wiring for the source of the voltage drop, now I'm not good at doing electrical work, but I'm trying to learn as I go here. Is this where I start checking continuity on all the wires?

Any suggestions?

Should I ditch the aftermarket ignition coil and get a OEM replacement? Are the resistors something that was removed by a PO?
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

It seems my multimeter may have been giving intermittent fault readings... the display is missing pixels on certain settings, making 6s look like 0s, 9s like 7s and all such fun. I guess thats what I get for using a cheapo harbor freight multimeter...

Borrowing a multimeter from work, and I'll check the voltage at the coil again tonight.
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

Rasta Monsta · Joined: 12 Jul 2006 Posts: 11733 Location: PacNW

Check fuel pressures and smoke test the intake
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Toofah King Bad

WeiBe (1987 924S 2.5t) - 931 S3

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

where can I get a Bosch CIS testing kit? the one linked in Ideolas write-up is NLA.

I was using the borrowed multimeter, and confirmed my readings from yesterday. I also tested the voltage at the ICU and the voltage was not sufficient. I guess I'll be learning the wiring diagrams thoroughly in search of the source of the voltage drop.
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

I should have started with this, but I'm an idiot, so I was looking for bigger problems. The GF and I cleaned up all the grounds last night. The 3 in the trunk were atrocious...

I have the battery on a trickle charger right now, and I'll start testing the all the electrics again, maybe even get to starting her up tonight. More updates to come...
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car

Knz · Joined: 05 Mar 2014 Posts: 105 Location: Sparrow Bush, NY

Issue was resolved. It wasn't the grounds as much as there was no current running through 15 at the fuse box. Thank you MrPink for sorting that out. Now just to sort out the timing, and a few small issues and this car will finally be ready to get on the road again.
_________________
1980 931 (#185) for sale
1980 931 (#196) engine rebuild
1983 928S Project
1983 944 Summer Car
2002 BMW 525i Winter Car