Rennlist save the day
02-19-2007, 05:02 PM
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Rennlist save the day
It has beem a bit cold in Minnesota the last few weeks- most mornings started below 0F. The '86 944 would hesitate/ cut out a few times from cold start then clean up and run. Finally, one night at work, it started but wouldn't break 1700 rpm- the motor cut completely. Once RPM dropped to around 1000, it would catch and run clean- as long as you didn't break 1700. The drive home was quite entertaining although I was dissapointed with Minnesota drivers' creativity. Of all the hand signals that may fit the occasion, most used the same 2 or 3.
A Rennlist archive search pinpointed the throttle switch. I cleaned it and went throuqh all the wiring, the AFM, solder joints, etc. I could hear the switch click when the throttle closed. A few hours later, I started the car and it still cut at 1700. I shut it down and opened the throttle by hand- no click. Apparently the super pig phlegm lubricant that got into the switch got stiff when cold.
I pulled the throttle body again and cut open the throttle switch housing with a Dremel. The idle switch is a standard microswith while the full throttle switch is an exposed reed switch. I used some old Freon degreaser and some Radio Shack tuner cleaner to purge the old goo. I reattached the switch top with silicone adhesive. Now everything works again.
I can't think of anything that would make a non-computerized car run like that. This make troubleshooting almost impossible without "inside info" about how the computer reacts to a switch stuck closed. I wasn't fixing a car, I was debugging the computer circuit due to some "too smart by half" programmers.
Anyway, thanks to the list, my car is back and I didn't buy a bunch of parts I didn't need.
Have fun,
Bill
A Rennlist archive search pinpointed the throttle switch. I cleaned it and went throuqh all the wiring, the AFM, solder joints, etc. I could hear the switch click when the throttle closed. A few hours later, I started the car and it still cut at 1700. I shut it down and opened the throttle by hand- no click. Apparently the super pig phlegm lubricant that got into the switch got stiff when cold.
I pulled the throttle body again and cut open the throttle switch housing with a Dremel. The idle switch is a standard microswith while the full throttle switch is an exposed reed switch. I used some old Freon degreaser and some Radio Shack tuner cleaner to purge the old goo. I reattached the switch top with silicone adhesive. Now everything works again.
I can't think of anything that would make a non-computerized car run like that. This make troubleshooting almost impossible without "inside info" about how the computer reacts to a switch stuck closed. I wasn't fixing a car, I was debugging the computer circuit due to some "too smart by half" programmers.
Anyway, thanks to the list, my car is back and I didn't buy a bunch of parts I didn't need.
Have fun,
Bill
03-05-2007, 11:23 PM
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Join Date: Nov 2006
Location: Elk Grove, CA
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Only 2 hours max, I just did that today to install my spare rebuilt throttlebody into my '83 944.
It would have only taken like 30 min, but I was trying to do something totally pointless. The large spring on the top of the TB under the throttle cam, doesnt need to be tensioned. The little spring that you stretch to connect to the arm forces the TB closed when the throttle is released.
I spent about an hour trying to figure out what the he** was going on. I finally gave up and just stuck it on with the spring installed like it should be and put the small spring on and then it tension the larger spring and closed the throttlebody.
I was so pissed that I wasted an hour on something totally pointless
It would have only taken like 30 min, but I was trying to do something totally pointless. The large spring on the top of the TB under the throttle cam, doesnt need to be tensioned. The little spring that you stretch to connect to the arm forces the TB closed when the throttle is released.
I spent about an hour trying to figure out what the he** was going on. I finally gave up and just stuck it on with the spring installed like it should be and put the small spring on and then it tension the larger spring and closed the throttlebody.
I was so pissed that I wasted an hour on something totally pointless