what is this thing?

joshl1978 · 04-16-2009, 12:40 PM

early 85 944 starts runs 20 secs then dies suddenly the exact same way every time.
replaced dme relay and fpr still the same.

what is that round part attached by a wire to the dme plug? that thing fell down and was hanging by its wire the day my car began having trouble. Its been a great car otherwise usually runs great and mechanically sound.

callmethewander · callmethewander's Garage

Got pics?

Slam · 04-16-2009, 02:47 PM

AFM unplugged?

joshl1978 · 04-17-2009, 07:49 AM

i believe the alarm system has something to do with this. how can i tell?

thekidd · 09:40 AM

If I think I know what you are talking about, it is the altitude sensor. I had no idea what that thing was either, untill the other day. "A Little Fun" there is a picture of it in there, postes by Techno, 5th picture down. It is from his Turbo, dont know if it is on same side as the earlys, but it looks about the same. Heres the thread- a little fun
My car 924S was doing that before the fire a few times. The wireing harness was loose, blue block? IDK?, I would just wiggle it, and the car would start and run. Try wiggling some wires behind the fuse box, maybee take the battery cables off, and give it a shot. If it works, get it fixed. Whenb I parted my 924S, the blue block- red wire, was melted and possibly the cause of my engine fire.

alantica · 04-17-2009, 10:38 AM

joshl1978, is there any specific reason you think this may be caused by the alarm system? An alarm status should result in a no-start. The alarm unit provides the DME a signal that stops voltage provided to the coil. Therefore, you should not even be able to start the car.

This can be checked by bypassing the alarm.
http://www.clarks-garage.com/shop-manual/elect-23.htm

The great thing is that it is running! That indicates that everything on the electronic side is probably good unless a chip or other component is heating up very quickly and drops the circuit, ending in a shut down.

Go to Clark's - http://www.clarks-garage.com/shop-manual/repair-procedure-index3.htm

This sounds like a no fuel condition. Your fuel pump may not be pumping enough fuel to keep the engine going or it may be that the fuel flow is being held back by clogging in the fuel filter. Does the car seem like it is gasping for air and shaking before cut off?

http://www.clarks-garage.com/shop-manual/fuel-03.htm

I also remember before from somebody on the forum having this same sort of problem and it was the wiring going to the mark reference and speed sensors - corrosion. Unplug the connectors and look at the contacts. The corrosion will usually look like a white or greenish powder, also wiggle the wires around to dislodge any corrosion that you can't see beneath the wire's plastic covering. Be careful with those plugs because they are very easy to break and those sensors are not cheap.

http://www.clarks-garage.com/shop-manual/ign-02.htm

Good Luck!

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joshl1978 · 04-18-2009, 01:55 PM

thankyou verry much that is exactly the part in the picture. I dont quite understand what your suggesting to do. could you explain more? where do I look on Clarks Garage? Thank you for taking the tiime i really appreciate.

eddied · eddied's Garage

I had the very same thing happen to me at work(60 mi from home)fuel psi regulator was the culprit.disconnect 1 inj. wire.car should stay running,but on 3 cyl."FUEL-07, Fuel Pressure Regulator - General Information and Replacement"
that is clark's page.

joshl1978 · 04-19-2009, 05:32 AM

What is the IDK? Blue block?

thekidd · 04-19-2009, 08:29 AM

behind the fuse box. There are a ton of wire that go to the fuses, about 10-13 or so to each fuse. But the wire lead into a little box with pins that connect to the fuse box. I just wiggled the one with the blue box, dont think it will fix yours, but give it a try. Just touch some of the witres back there. It is an old car, and maybee some water leaked in through the fire wall and corroded some of the connections.

joshl1978 · 04-27-2009, 05:19 AM

i changed my ignition coil had a jacob's high energy coil i replaced with stock used coil. car runs great now until i turn on the headlights she immediately shuts down. is it coil? altenator? computer?

Arizona_928 · 04-27-2009, 06:24 AM

You can get your altenator tested for free at autozone. That would be my next choice.

joshl1978 · 05-01-2009, 04:54 AM

would a weak altenator cause hesitation I believe my ignition coil is causing hesitation under hard acceleration also looking to remount ignition coil from exaust side

alantica · 05-01-2009, 06:15 AM

Quote:

Originally Posted by joshl1978

i changed my ignition coil had a jacob's high energy coil i replaced with stock used coil. car runs great now until i turn on the headlights she immediately shuts down. is it coil? altenator? computer?

Quote:

Originally Posted by joshl1978

would a weak altenator cause hesitation I believe my ignition coil is causing hesitation under hard acceleration also looking to remount ignition coil from exaust side

joshl1978,

Isolate each of these problems. If the 944 runs correctly until you turn on the lights - that is a pointer. There may be a ground in the switch,wiring or light that draws the current when the switch is turned to the "on" position. The result is not enough current to the rest of the system causing the electrical system to shut down and cutting the car off.

Your gauge should show the current reading at a steady voltage somewhere between 13V & 15V with 15V being nominal. You will have a drop in voltage when the lights are on {15V down to 14V}, hold the brakes and voltage will decrease some more {14V down to 13.5}. If the drop in voltage is below 12V with accessories turned on and the alternator does not pick up the load, you do have a problem with the alternator.

Take a look at this thread 457934. Don't concentrate so much on the coil. The coil takes a regulated current in (controlled by the DME) no matter what the speed of the engine. Increasing or decreasing the speed of the engine makes no difference, there is not a jump or drop in current to the coil. Think of the coil as an amplifier. The voltage coming in is amplified to supply correct current to the spark plugs determined by the speed of the rotor button. If the coil is messed up, it would show up on a resistance check.

Ignition Coil Resistance Check
In addition to the test above, you may elect to perform an ignition coil resistance check as confirmation of the coil's condition.

Check the ignition coil primary coil resistance by connecting an ohmmeter between the positive (Black wire) and negative (Green wire) terminals on the coil. The resistance should be 0.4 to 0.6 ohms.
Check the ignition coil secondary coil resistance by connecting an ohmmeter between the coil output terminal and the ignition coil negative terminal. The resistance should be 5000 to 7200 ohms.

Get the alternator checked. If it is working correctly, the next item to check is the DME. Hopefully that is not the problem, but the symptoms you are describing are pointing toward the DME.

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