So I just bought a non-running 1990 E350 with a 351w and 127000 miles. Thought it would be pretty simple to get going! It starts, barely, but won’t idle or rev up without constant pumping of the gas pedal. Put in new plugs, rotor, dist.cap...checked firing order... thought of insufficient fuel, but all three pumps seem to be working, and I have about 40-45 psi of fuel pressure at the back right fuel rail. Disconnecting the vacuum line to the PRV makes almost no difference.... I have not messed with the dual tank selector/filter yet, because of the good pressure readings... i have looked for major vacuum leaks like a disconnected hose, but everything seems to be together exception a1” hose off the air pump (lower right front of engine), but closing it off made no difference...??

original air cleaner assembly is gone, replaced with a K&N type cone filter, with direct lines to the throttle body. There is no maf sensor that I can see... is this year van supposed to have one?
I have also not addressed the throttle position sensor yet
And for extra Diagnostic info: i can get it to run by continuously spraying gas onto the air cleaner surface,and she purrs happily!!

Ideas??

 

Hi,

• Make sure your TPS is within specs. When it goes bad it causes a few driveability issues.
• Another item you should check is your fuel injectors(power, ground, and they are spraying fuel)
• IAC Valve.
• MAP. Manifold Absolute Pressure sensor. Passenger side of the engine above heater fan. The computer uses the data on this sensor every time you start the engine. It has a vacuum line attached to it and a harness.

Good luck!

 

Thanks for those ideas! Nice rainy day to see what I can find....

 

How long has it been sitting? The first thing I would do is to drain the tank, change the filter, and get fresh gas in it.

 

Hi... it was “running fine” as recent as 2 months ago. Hasn’t run right, certainly not driveable, since she had some work done to it (new battery and alternator)
The tank was almost empty, and is now half full of fresh gas.
What I just found about an hour ago is a bad MAP sensor... it’s got a bit over 5 volts and a good ground, but failed the hertz measurements badly. It was a fairly smooth decrease in frequency, but way low, like less than 1/2 of the spec values....so I will get unit tomorrow and see what happens.
thanks for any thoughts you might have! Stay tuned......

 

Thanks handyAl.... haven’t replaced it (tomorrow!) but the map sensor failed the test frequency outputs. I’ll replace it tomorrow and see what happens

 

WooHooo! The van is up and running! Turned out to be the map sensor. Thanks all for ideas and thoughts! Now I can start on all the other things that need fixing, like rear main seal, sliding door, front fuel tank leak.... and lots more! AllGood!

 

Thanks for letting us know!