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Post by cla on Apr 13, 2010 23:47:15 GMT -5
What would cause 84 svo(all stock except K&N air filter) to hesitate when accelerating and not build any boost? If I accelerate very slow it will not hestitate, but it will not build any boost.
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Post by Stinger on Apr 14, 2010 1:49:25 GMT -5
A million different things on the hesitation. You need to start by scanning for codes to see what the computer says is wrong.
As for the boost issue, is this verified with an aftermarket guage? The factory gauge may just not work and it's making some boost. One way to know would we whether it is pegged at below 0 at all times or if it does climb slightly but doesn't move much past 0.
What's the history of the car? How long has it done this?
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Post by oneowner88lx on Apr 14, 2010 18:52:00 GMT -5
After you pull codes I would hook a fuel pressure guage up.
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Post by cla on Apr 14, 2010 20:21:48 GMT -5
I just bought the car the previous owner told me it was doing this and he thought it may be due to bad gas. I pulled the fuel tank found the short piece of hose in the fuel tank that runs from the in tank fuel pump cracked. I replaced hose emptied tank of old fuel but problem not any better. Tank was very clean but fuel smelled very old and bad. I also replaced fuel filter and made sure fuel pump in running. I will get gauge to check fuel pressure. What pressure should it run? What type brand name etc. tester should I buy? Thanks for your help. Under slow steady acceleration it will get upto 70 mph. If I accelerate slow it will turn 4200 rpm sitting in neutral. Factory boost gauge will rise a little then go back to zero. I took inlet off turbo and cool air side of turbo spins free and it does not appear to have much slack. What should I look for when checking for play in turbo?
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Post by Stinger on Apr 14, 2010 23:19:48 GMT -5
You just need a universal efi fuel pressure tester. They are as cheap as $25 or so. It should run about 32psi at idle with the vacuum hose on the regulator or about 38psi with the hose removed and plugged temporarily. Under load the fuel pressure should rise 1psi for every 1psi of boost (when you get it).
As long as the turbo spins free and doesn't drag on the housing with very little force, it's fine.
How old are the plugs/wires? Those are VERY common wear items on high specific output engines like these. Be sure to use Motorcraft factory replacement wires and plugs. Gap the plugs down to .030" (very important as they come out of the box over .040").
Also check for any leaks in the system between the turbo outlet and the throttle body inlet. A boost/vacuum leak will cause problems very similar to what you are having. This would include a ripped coupler, loose clamp, etc.
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Post by denz on Apr 15, 2010 16:43:41 GMT -5
also take the down pipe loose, and run it . It could be clogged verter if you have one.
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Post by oneowner88lx on Apr 15, 2010 18:00:54 GMT -5
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