When my 90 turbo wagon's main pump was on the way out, once in a blue moon it would die, like a lack of gas and start back up. One day it was rough to start and died a mile away and wouldn't restart. Got it home and it ran fine for about a month. Then it died after a long trip. It was like it could only coast - no power to the engine. It took a bit to trully "die" as the engine was still running.

A pressure check revealed it only had 20 PSI when it would start (it would not move) this was likely supplied by the prepump. I also confirmed the pump was getting voltage at the pump connector and current was not flowing into it.

If it won't start, check for noise from the pump when you first turn the key. It should run both pumps for a few seconds to prime the system. If you hear noise from the prepump and nothing from the main pump, the main pump is likely dead.

There is more detailed info in the FAQS for checking the pump.

If you need to replace the main pump, plan on replacing the fuel filter, short pipe between the fuel filter, and the clamp assembly that holds the pump as it is likely corroded.

BTW the 89 turbos have LH2.2 so there is no OBD and they have a Hall effect sensor instead of the RPM sensor. The 90 turbos got the LH2.4 system that has OBD-I and RPM sensors.

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Paul NW Indiana '89 744 Turbo 145K/ '90 745 turbo 127K