87 Ford TB Turbo Coupe

85000 miles. Stored under cover (outside) for 9 years. Started and driven up and down the driveway at least every three months or so. Started it today and it ran good for about 10 minutes then quit. On restart it will only run on idle. When power is required it kills. Added fresh gas with preservative although the gas in tank smelled fine. I am attempting to replace the fuel filter which is rusted on the underside of the car of course. Any suggestions other than the filter?

Thanks

Sounds like a boost leak. I would check your intercooler connections. I.e. turbo to cooler and cooler to throttle body.

Matthew

In addition to the above, look for loose / disconnected vacuum lines. Try unplugging the electrical connector from the VAM and see if it will run.

Thanks, I'll try the suggestions.

ruko

I unplugged the VAM. Is this also called the mass airflow sensor? The check engine light came on and the car runs. Not really that good but it has enough power now that I can move it from the middle of the drive way. What do I do next? Replace the sensor?

Thanks again,

ruko

You likely have a large boost / vacuum leak causing the VAM (which is kind of a mechanical mass airflow sensor) to send incorrect air flow info to the PCM. VAM operation can be chacked with a voltmeter. COnnect + to W/BK and - to BK/W wires. KOEO, about .4 V, HOt idle around 1V, goosing throttle jumps to 4V or so.

Thanks, going to try this. If I get normal voltage readings then it's most likely a vacuum leak? When goosing the throttle I do get some boost indication on the boost meter.

Thanks

ruko

Large vac leaks will result in VAM volts being low, as engine is sucking in unmetered air. Low volts = low airflow reported to VAM = PCM doesnt tell injectors to inject enough fuel.

VAM could be bad. You can hook up a DMM to BK/W and W/BK wires and manually push open the door to be sure volts increases smoothly. Uncommon, but VAM door can stick open. This = high volts = PCM thinks high air flow = lots of fuel injected = wont run.

Back to the turbo coupe. I get good voltage from the VAM when it's running: 0.4 volts with key on and 1.9 at idle. This agrees with AllData specs. It only runs for about 5 seconds however. Now it wont even run continuously with the VAM disconnected. If the VAM is producing proper varying voltage doesn't this mean there is air going by it? So if air is going by I wonder if the problem is a vacuum leak. I've checked all the hoses and they are not leaking. Any other suggestions?

Thanks

1.9V at 1000 RPM hot idle with AC and big electrical loads turned off is WAY too high. My experience, and that of others is 1V at idle. There is an adjustable air bypass to bring the idle voltage down to the correct range. Do a search here on how to do this.

If your VAM is a replacement from a parts store, it is VERY likely the air bypass is not correctly adjusted.

I have seen LOTS of incorrect info on Alldata.