Main Menu

928s that won,t start


Vehicle Information: Year: 1984 928S US; Engine (size, modifications): stock 928S; Total Mileage: 75,000; Transmission type: Manual;

I last e-mailed you in 11/02 for the same problem, car will not start. You responded on 12/1/02, thank you. I have gone through the troubleshooting AFC on page 24-21 of the workshop manual and found two items (ohm readings) that contradict the information in the manual. First, the temperature time switch (TTS) for cold start value; terminal "G" to ground is indicated to be "0 ohms", I got a reading of "37.6 ohms" at about 55 degrees F. "W" to "G" was correct at "36.7 ohms" and "W" to ground was good at "0". So I jumped the connector plug with a wire and the car started for the first time in 6 months, but ran very poorly, like 6 cylinders firing. I proceeded to order and install a new TTS and then I started the car again, still the car ran poorly. Checking the plugs and wires several times during this process, I found that the 5 and 6 wire had been reversed and I thought that I most likely found the problem. On the next try a few days latter, the car would not start again. So I checked the ohm readings again and found that the new TTS had similar readings to the original TTS, specifically the "G" to ground read "32.4" ohms, when the manual said it should be "0". Question: do you think the manual is wrong? The second incorrect reading occurred when I got to the Auxiliary Air Regulator (AAR). The resistance across the two terminals is supposed to read 40 to 75 ohms, but the reading I took said 17.4 ohms at about 50 degrees F. So then the manual says to do a power supply check with fuel pump relay jumped and I found this to be good at 12 volts. The manual also says to do a visual check of the AAR, so I took the AAR out and found the spring-loaded closure plate within the housing to be about 70% closed. The manual says the Cold engine -the valve open; Warm engine -the valve should be closed. With the AAR out of the car I examined the sliding plate and found the plate to be spring-loaded and only partial open. The plate moved freely when probed with a screwdriver; but is apparently set in this 70% closed position. I also ran a 12-volt current through the terminals of the housing and the valve did not move. Do you think that this could be the problem, and should I purchase a new AAR? Again could the ohm readings in the manual be in error? By the way, all ohm readings were checked with two different meters. I also replaced the coil during this time.

You must log in to view answers associated with technical questions. Join PCA to participate in our community.
No votes yet