89 won't start after long drives

shdtreemech · #1 03-25-2006, 12:29 AM

Problems starting after engine run for long time (1+ hrs). Recently had fuel filter changed. If it sets for awhile it will start and idle rough for a minute and be okay until cycle is repeated. Released pressure from fuel rail at test fitting and got a lot of air. After bleeding pressure a couple of times it started right up. I am getting plenty of pressure to the fuel rail so I don't think the pump is the problem. Could fitting on fuel filter allow air to be sucked in? Or is fuel vaporizing? What should I check? Car runs great while its running. It's just a problem getting it restarted once it is well heated. Coolant was flushed and new thermostat and radiator cap at same time as fuel filter. Engine does not overheat and fan does cycle on and off when engine temp comes up.

maxwedge · #2 03-25-2006, 07:20 AM

Get a fuel pressure gage on it when it won't start, pump could failing a 17 years.

shdtreemech · #3 03-25-2006, 02:05 PM

Fuel pressure if fine. Within the tolerances. It just seems to be getting air in the fuel rail once it gets warmed up and sets for a short time. Wondering if it could be in the evap system. Funny thing is, the air is under pressure also.

maxwedge · #4 03-25-2006, 04:31 PM

Take the gas cap off see if the tank is under pressure, so you have 40 psi at least when this happens?

shdtreemech · #5 03-25-2006, 06:19 PM

Fuel pressure, yes. Just got back and tried it again, and no start. Bled a little pressure off fuel rail, and no air. Tried to start and it did. I am now suspecting the fuel press regulator? What do you think. I have yet checked the fuel pressure when it does this. The problem is that when I hook the gage up it bleeds off a little, so I won't know what the actual pressure is when symptoms occur.

Thanks for your assistance, let me know if you think of anything else.

maxwedge · #6 03-25-2006, 08:50 PM

Turn the key on and see what it builds up to, before the start attempt.

shdtreemech · #7 03-29-2006, 02:09 AM

Ended up being fuel pump after all. Checked fuel pressure before start of problem and pressure was ok until start attempt. Seems that the fuel pump would not repressureize system after start attempt. Took to a garage for replacement and they even said "the fuel pump normally just quits and is not intermittent". Well, they proved themselves wrong.

Thanks for the assistance.

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