CPUNeck
Member
- Joined
- April 11, 2009
- Messages
- 23
- Reaction score
- 0
- City, State
- Fort Campbell, KY
- Year, Model & Trim Level
- 98' 4x4 XLT Rescue Squad
Hi all, obviously new here... ya'll have a good thing here, LOTS of smart guys!
Good trouble shooting I've read through here. Sorry, I post long and detailed, so be forewarned. Been stationed at Ft. Campbell about a year now and finally go on the local Rescue Squad. Low and behold, they have a (mfg 2/98) "red headed stepchild" Explorer XLT w/SOHC 4.0l 4x4 unit! Well I've been turning wrenches for a long time and am die hard Ford guy (albeit from the oil burner side
) No one really likes this truck because it's crap (their words) in reality it's because at close to 112k, there has been no maintenance done to it! Here are the symptoms.
Cold:
Starts good, idles ok, no clunk when engaging the tranny, but if you put it in any gear and power brake, after about 20% throttle travel, engine starts missing (read same feeling you get when you hit the fuel/ignition cut off on later model cars), it's bad.
Up to Op temp:
Starts good, idles up and down ~250-350 rpm from 750. No clunk when engaging the tranny. Same hesitation under load though.
Driving:
If I pull out from a stop and apply the throttle as the truck accelerates (slowly) NO problem. Accelerates smoothly, and no discernible shifts from the tranny. If I try to pull out like into traffic, major hesitation... and it won't go. I'll have to back off until the engines settles back down and gradually reapply throttle. This shift between smooth and OMG is abrupt, like a switch is flipped.
Underway:
If I wait until I'm going say ~30mph or so, I can mash the gas all I want. No hesitation and it runs out fine. Still no discernible shifts. So what here's what I've done so far.
Other symptoms:
SES light on (reset computer and light came on after idling long enough to go into closed loop. I can't reliably get the O/D button to activate the dash light. Works sometimes, not others... seems no difference in the gear ratio though.
Changed fuel filter, cleaned MAS, throttle body, and plumbing, quick check for vacuum leaks (brake cleaner to running engine)
Tried:
Unplugging TPS, idled better, no change in condition though, unplugged MAS, no change, checked middle plug on driver side... LOTS of carbon, not wet, but close. Noted wires look OEM, plugs were autolite platinums (electrode looked good with no visible pitting or wear. Fuel pressure at port at idle was ~30psi and rose to about 40psi while blipping the throttle. Air filter is in good repair. Alt is weak @ 14v and 31amps at idle no acc. on. With the full shabang going (lights, A/C, emergency indicators, take down lights etc. it was 13.4 and 84amps) We have to keep a trickle plugged in or the batt (new) will drain down in a week or so. Tried to listen for the fuel pump, but could not hear it at all. Tested pressure before the filter and had a static pressure in the 82-88psi range. But it only cycled for a few seconds (like 2-4) kinda short I thought, but gassers are kinda new again to me. ODB-II was only a pipe dream when I was working on gas engines
Unrelated:
Severe cupping to both inside front tires, harsh, banging/bumping while under way from up front. Enough play in lower BJ's when lowering the vehicle you can see vertical movement at the joint. I couldn't "feel" any movement when attempting to detect horizontal play while jacked up on the 12 and 6 O'clock on the tires though. Noted the front drive shaft seems to be "hard" locked to the front hubs. (My F-250 Powerstroke Diesel(PSD) is selectable)
Ok I'm done for now... hope that wasn't so much info. I'll report back later with the SES codes and how the wires and plugs impacted the problem.
Good trouble shooting I've read through here. Sorry, I post long and detailed, so be forewarned. Been stationed at Ft. Campbell about a year now and finally go on the local Rescue Squad. Low and behold, they have a (mfg 2/98) "red headed stepchild" Explorer XLT w/SOHC 4.0l 4x4 unit! Well I've been turning wrenches for a long time and am die hard Ford guy (albeit from the oil burner side) No one really likes this truck because it's crap (their words) in reality it's because at close to 112k, there has been no maintenance done to it! Here are the symptoms.Cold:
Starts good, idles ok, no clunk when engaging the tranny, but if you put it in any gear and power brake, after about 20% throttle travel, engine starts missing (read same feeling you get when you hit the fuel/ignition cut off on later model cars), it's bad.
Up to Op temp:
Starts good, idles up and down ~250-350 rpm from 750. No clunk when engaging the tranny. Same hesitation under load though.
Driving:
If I pull out from a stop and apply the throttle as the truck accelerates (slowly) NO problem. Accelerates smoothly, and no discernible shifts from the tranny. If I try to pull out like into traffic, major hesitation... and it won't go. I'll have to back off until the engines settles back down and gradually reapply throttle. This shift between smooth and OMG is abrupt, like a switch is flipped.
Underway:
If I wait until I'm going say ~30mph or so, I can mash the gas all I want. No hesitation and it runs out fine. Still no discernible shifts. So what here's what I've done so far.
Other symptoms:
SES light on (reset computer and light came on after idling long enough to go into closed loop. I can't reliably get the O/D button to activate the dash light. Works sometimes, not others... seems no difference in the gear ratio though.
Changed fuel filter, cleaned MAS, throttle body, and plumbing, quick check for vacuum leaks (brake cleaner to running engine)
Tried:
Unplugging TPS, idled better, no change in condition though, unplugged MAS, no change, checked middle plug on driver side... LOTS of carbon, not wet, but close. Noted wires look OEM, plugs were autolite platinums (electrode looked good with no visible pitting or wear. Fuel pressure at port at idle was ~30psi and rose to about 40psi while blipping the throttle. Air filter is in good repair. Alt is weak @ 14v and 31amps at idle no acc. on. With the full shabang going (lights, A/C, emergency indicators, take down lights etc. it was 13.4 and 84amps) We have to keep a trickle plugged in or the batt (new) will drain down in a week or so. Tried to listen for the fuel pump, but could not hear it at all. Tested pressure before the filter and had a static pressure in the 82-88psi range. But it only cycled for a few seconds (like 2-4) kinda short I thought, but gassers are kinda new again to me. ODB-II was only a pipe dream when I was working on gas engines
Unrelated:
Severe cupping to both inside front tires, harsh, banging/bumping while under way from up front. Enough play in lower BJ's when lowering the vehicle you can see vertical movement at the joint. I couldn't "feel" any movement when attempting to detect horizontal play while jacked up on the 12 and 6 O'clock on the tires though. Noted the front drive shaft seems to be "hard" locked to the front hubs. (My F-250 Powerstroke Diesel(PSD) is selectable)
Ok I'm done for now... hope that wasn't so much info. I'll report back later with the SES codes and how the wires and plugs impacted the problem.
