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Gene in NC
06-12-2008, 10:09 PM
'89 525a,166k quit first on slow left turn in residential area (our street), and second on slowing on off ramp after 4 mi at 70 mph. No restart. Fire but not continue. Felt like fuel problem.

Both recovered after aprox 3 hr cool down. Started and ran cleanly.

Tested fuel pressure tonight. Idle and level hwy/street- 38 psi, accelerate from stop or other- jump to aprox. 42 psi, overrun- 33 psi.

Pinch return line- pressure jumps.

Fuel pressure gauge rigged to windshield under wiper arm for readings under way.

Dave M
06-13-2008, 10:53 AM
'89 525a,166k quit first on slow left turn in residential area (our street), and second on slowing on off ramp after 4 mi at 70 mph. No restart. Fire but not continue. Felt like fuel problem.

Both recovered after aprox 3 hr cool down. Started and ran cleanly.

Tested fuel pressure tonight. Idle and level hwy/street- 38 psi, accelerate from stop or other- jump to aprox. 42 psi, overrun- 33 psi.

Pinch return line- pressure jumps.

Fuel pressure gauge rigged to windshield under wiper arm for readings under way.

First, do you know the proper pressure for the M20?? No bentley here, so I'm only guessing that 33-38 is low and 42 is close to normal, but still on the low side.

When is the last time you changed the fuel filter?? If you can't remember, nows the time as it may be your cheap fix.

If its not your filter, your pump may be intermitently quitting on you. When attempting toe start did you happen to check if the pump was running? Have you checked the power wire in the wiring harness to the sending unit in the trunk?

There are a few potential culprits,

Dave