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94 F150 4.9 Bad fuel replaced - wont idle

Old 05-21-2013
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Join Date: May 2013
Posts: 2
Default 94 F150 4.9 Bad fuel replaced - wont idle

Hello...... I am the new guy and looking for some ideas on how to get old blue running again.....Dallas TX.

Truck has not been driven much in 5 years. The last two years only started and drove on the farm a few times, never very far. Prior to my current issue it has always ran perfect. Only has 100k miles on it and purchased it new – it is a California truck btw. Wouldn’t start about 8 months ago and my automotive savvy Buddy replaced the front tank fuel pump. Started immediately and ran great for a quick 20 miles then sat at idle for an hr and seemed fine when I turned it off. Sat a few weeks and the next time I started it ran like it was on 5 cylinders; crazy amounts of blue smoke. No power, could barley move it 50 feet. Sat a few months and I took out the new fuel pump and reached in the tank and grabbed something thicker than oil/varnish smell obviously (apparently Buddy had not paid attention). Dropped tank and cleaned about a gallon of sludge and 8 hrs later re-installed. I changed the inline fuel filter, blew air through the lines and hooked it up. It ran exactly the same, maybe 10 min then when hot I can’t keep it going, crazy blue smoke.
Unfortunately I like overlooking the obvious and have changed in order:
• Plugs
• Wires
• Injectors
• Cleaned all parts attached to intake.
Changed Oil and Filter – all other fluids new
• Vacuum lines
• EVP Valve
• Battery
• Throttle Position sensor
• Idle Air Control valve
In between each step (few days, weeks) I would start it to see if problem solved. When it was cold I could start it only. There was a loud valve lifter/sticking type noise that started about the 4-5 time/part I tried. But knowing it was fuel that started the problem I dismissed the noise for the time.

Then I found a diagram online about how the duel tank system works on this truck and beat myself up pretty good for a few days.
So now I have:
• Dropped rear tank
• Cleaned patched and re installed
• New fuel pump ect ect
• HEET in both tanks
• Seafoam
• New fuel
No fuel leaks
Gas caps are fine
Hose clamps are tight

Started up better but now I still have the loud valve noise and the longer it ran the more it went back to its original problem but no smoke until the end (only run 10-20 min and dies when hot) and I noticed a lot of moisture out the tail pipe for the first time.

It won’t run long enough to go and try and drive it. Don’t think its gas now.

I speculate that when I installed the new fuel pump 8 months ago and let it sit and idle and it sucked all that bad gas throughout the whole system it ran ok because it was hot. Once it cooled off it had gummed up or clogged something in the gas delivery, emissions, or air department and that’s why I started at the tank and went forward. I would love to go drive it but have only made it a mile with the pedal pegged and not moving very fast before it warmed up enough to die. However that was before I did the rear tank this weekend.

Do you think that I need to drop the front tank again because it’s been running off and on 20 min at a time (10 times) for a couple months while circulating from the contaminated rear tank?

Kicker is I need this truck to drive on the regular and it kicking my butt!
constructionDAVE is offline  
Old 05-22-2013
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Join Date: May 2013
Posts: 2

PSI on both tanks= 50 and held.

Runs better before it warms up and progressively worse

First I removed break booster line and RPM + and smoothed out a bit. Reinstalled

Removed the throttle position sensor RPM increased and i left off

Removed idle air control valve - no change. reinstalled both and it idles rough.

Removed new ECP, valve on the throttle body side & engine RPm increased and smoothed out a bit. Left off

Removed break booster hose , throttle position sensor an it didn't die until I removed the idle air control valve........

cleaned out the vapor canister lines as well..............
constructionDAVE is offline  
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