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This 2001 Ford Sport Trac SOHC 4.0L project started out with my wife calling me to say "the transmission had gone bad or something". The complaint was No Power, the vehicle would not go over 45 or 50 MPH unless you were driving downhill. I thought possibly fuel pump or Clogged Exhaust system without seeing it, didn't sound like a transmission problem to me from the way she described it. I brought home my fuel pressure gauge and Snapon Solus from work and when I found the time I started diagnosing the problem.
I checked the Fuel pressure and it was within Specification 30-65 PSI
Next, with some help from an assistant, Tommy J, we tested the Exhaust system back pressure with a gauge installed into one of the Pre Catalyst 02 sensor holes. It showed Zero or very little PSI's.
Then after reading some testimony's from fellow http://www.iatn.net/ members and even though my fuel trims were not incredibly high at idle, My short term fuel trim on bank 1 was only 5 with the rest being at around 0.
I took the leap of faith and decided it must be a failed Intake Manifold Gasket.
From: David from Washington
Date: Jan 3, 2007 6:15 PM
we have a ton of these with bad intake gaskets, has high
fuel trim at idle, more normal at 2500. If you have a smoke
machine, try smoking it when its cold.
Date: Jan 3, 2007 6:15 PM
we have a ton of these with bad intake gaskets, has high
fuel trim at idle, more normal at 2500. If you have a smoke
machine, try smoking it when its cold.
From: Jim from Georgia
Date: Jan 3, 2007 7:18 PM
I suspect you have a leak at the intake manifold gaskets.
This engine uses o- ring rubber gaskets. Have had to
replace quite a few. Test for a leak with smoke machine if
you have one.
Date: Jan 3, 2007 7:18 PM
I suspect you have a leak at the intake manifold gaskets.
This engine uses o- ring rubber gaskets. Have had to
replace quite a few. Test for a leak with smoke machine if
you have one.
I called a couple of after market parts stores in town a found that the gasket set was around $15 but decided to purchase the gaskets from a Ford Dealer, They were slightly higher priced at $20 but this way I was relatively sure I would have the correct gaskets and a good quality part.
It looks harder then what it really is...
I was able to remove the intake in about 75 minutes and once I had it out of the way I could see where it had apparently been leaking at the right rear corner, I cleaned the surface, replaced the gaskets and .....
The entire Job took me approximately 2 hours and went smoothly. I Went for a test drive to town and back to get some Jimmy Johns Sub's, The truck ran perfectly again like it did before the problem. Although I am not completely sure why the carb cleaner sprayed around the intake trick never works for me with this style intake or why the fuel trims did not indicate a bad intake gasket, I am glad the car is fixed and did not cost me a fortune.
myke
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