88 E350 rebuilt engine skips
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88 E350 rebuilt engine skips
I have a 1988 E350 Ford van with a 351 5.8L Windsor, rebuilt. Less than 500 miles on rebuild. The van sat for 2 years. As it stands, it starts good, idle's a little lobby, and about half way to the floor it skips and has no power, however if you drive the loud pedal to the floor it'll come out of it. But its always in the same spot and only at speeds less than 45 or so. Anyone have any ideas? I was thinking maybe TPS or dirty fuel.
Thoughts are appreciated.
Thoughts are appreciated.
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From: Jasper, MO
Double check spark plug wires. These dang things have the worst wirepath I have ever seen and leave you wide open to spark plug wire failure, not to mention the ones I have purchased had a tendency to "slip off" the plug, usuall toward the rear of the engine, lol. But the symptoms you describe are classic of that... or possibly even crossed wires. All else checking out OK, I would say TPS is your next bet, but check the basics before throwing parts at it.
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Spark plug wires are all okay. Replaced the coil as it was pretty burnt up. Spark plugs are also okay. It acts like it has no advance, and when its warmed up is the only time im having the problem.
If its in park, it goes from idle to full throttle without any glitches at all. Fuel pressure is okay, tested at 70 psi.
If its in park, it goes from idle to full throttle without any glitches at all. Fuel pressure is okay, tested at 70 psi.
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Well, your throttle position sensor may just be it, then. These glitches can be tricky. I had one problem with MY 5.8 (89) where it would hack and cough and gag in gear. In neutral it would idle and rev fine. In reverse I could smoke the tires, but go right back to drive and it would get sick all over again. This wound up being the wire connector TO the coil. It had seperated at the molex plug but you couldnt tell without inspecting it closely, up inside. I had thrown countless hours and dollars at that thing. couldn't get a read off the computer and THAT is what made me chase down that connection, because that lack of communication on a running vehicle usually indicates a broken wire somewhere, lol
Good luck!
Good luck!
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Well it wasn't timing, its dead on. But, the throttle cable doesn't seem to be opening the butterflys on the throttle body all the way. Gotta replace that next.
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Lead Driver
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Ok, you have a 351w. If your fuel pressure is 70psi you have either a faulty fuel pressure regulator, or a clogged return line. What's happening is the engine is flooding itself. The TPS is BAD. Check for vaccum leaks, and make sure the intakes (upper to lower, and lower to heads) are all tight. Make sure the throttle body and the IAC are tight, and the gaskets are good.
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Sorry about that, The fuel pressure was tested at around 60-65 PSI.
All the intake components, including idle air control are tight. IAC is new, so I've ruled that out as a potential problem.
I've played with the timing, both retarding and advancing. The only thing I achieved by either of them was spark knock and no power. The problem is starting to sound more and more like TPS.
Are these TPS' adjustable or are they just a replaced item, and voltage is regulated by the computer? Any details on the TPS you can give is appreciated. I know the TPS is on the bottom of the throttle body, so whats the replacement procedure?
All the intake components, including idle air control are tight. IAC is new, so I've ruled that out as a potential problem.
I've played with the timing, both retarding and advancing. The only thing I achieved by either of them was spark knock and no power. The problem is starting to sound more and more like TPS.
Are these TPS' adjustable or are they just a replaced item, and voltage is regulated by the computer? Any details on the TPS you can give is appreciated. I know the TPS is on the bottom of the throttle body, so whats the replacement procedure?
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From: Jasper, MO
I have been told you can clean the Shi'ite out of them and that fixes many problems, but I, not being a patient man, usually opt for the safest footing and buy new. It IS a common problem so the odds are in your favor.
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Just thought of another thing.... disconnect the vac tube to the Map sensor and make sure it's getting vaccuum. if it isn't, follow the tube to the port and see if it's still connected. I've had these come off too, with similar results...
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Get a good flashlight and pull the connector off the front of the coil. see if the contacts are clean, and that the wire hasn't corroded inside the plug. this is sounding more and more like the ghost I had.
I know you said the coil was new, but remember my problem was a bad CONNECTOR PLUG, not so much the coil itself
I know you said the coil was new, but remember my problem was a bad CONNECTOR PLUG, not so much the coil itself
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Won't run at all any more. I had it sitting idling in the driveway while I went into the house to fetch something and it died, wont start. Acts like a dead battery, but the battery has plenty of voltage.