qxx
Member
- Joined
- June 7, 2011
- Messages
- 16
- Reaction score
- 0
- City, State
- Boston
- Year, Model & Trim Level
- '98 Sport V6 4.0L SOHC
I'm going to try and provide as much detail as possible because I am sort of at my wits end and running out of possibilities quickly. So any feedback is appreciated.
Specs:
1998 Ford Explorer Sport
4WD
4.0L SOHC
226,000 miles
The Beginning
Got into the beast in the morning, drove 17 miles to work, parked and was idling having my morning cigarette; nothing unusual at this point. About 5 minutes later the Explorer just stalls. No sputtering or any signs that something was awry, the engine just stops as if it was shut off. I tried starting her back up and she cranks but won't turn over. I try this one and off over the course of a few hours and nothing. I tow it to my garage and naturally it starts up fine at that point and runs good enough to go up the drive way. Once up there, I turn it off and try to start it again and it won't start; cranks but won't turn over.
Current Status
Since then, it behaves in a variety of ways. If it starts, it's usually when it is cold (usually but not always). It struggles to idle when cold, sputtering somewhere between 500 and 1000 RPMs poorly. Once warmed up, it doesn't want to idle at all. I have to rev it way up and if it drops below 2000 RPM, it just tries to die out never stopping as it plummets to 0 RPMs.
Once it is warm [it seems], the only way to start it is so keep the key turned and cranking while giving it gas, holding the pedal to the floor. While doing this, it has a bunch of *almost* starts and if you get lucky it will finally start and even though it revs up to 4000 RPM because you have your foot on the gas, it will try to stall our right through that basically revving right up to 4000 and promptly descending to 0 RPM even though you have the gas pedal floored. When this happens it makes a deep, sad noise like it is getting no fuel (not saying that it is not getting fuel, just saying that is the sound).
Most commonly, when warm, you can eventually get it to start by cranking the key, flooring the gas and revving it up to around 2k, if you let your foot off it tries to die and you have to give it more gas to keep it running. Once in a blue moon, after enough revving, it will hold idle seemingly normally at around 1000 and sound great. Then, if you put it in reverse or drive, it immediately dies.
There has been once or twice where I've revved it warm and it has behaved normally; it'll idle normal, it'll go into reverse, drive and you can drive it back and forth normally. If you shut it off, you can restart it. But eventually, it goes back to it's broken type behavior outlined above.
The Troubleshooting
Because of the behavior above, I've done a lot of reading and digging around.
The first thing I did was put a pressure gauge on to check the fuel pressure; that checked out OK; it held pressure just fine.
Since then, I've replaced the MAF (Mass Air Flow sensor) and I've replaced the IAC (Idle Air Control valve).
Previously, I had a code indicating a bad O2 sensor; Bank 2, Sensor 1 so I replaced that too just because.
Also, I checked for vacuum leaks and found a slightly torn rubber gasket on the brake booster so I replaced that and also there were 2 loose screws where my upper intake manifold and I tightened those. Still, there could be a vacuum leak somewhere as we all know, but aside from those 2 spots I couldn't easily find any after much searching.
None of the replacement or fixes above have changed the way the truck behaves; it is still broken and showing the same symptoms.
At this point, I've taken the entire upper and lower intake manifolds off just to clean them while I try to figure something out (much carbon build up inside of them). The EGR tube is also filthy as hell and covered in carbon. Not sure if I should clean or replace that or if it's dirtiness even makes a difference.
So, with all that in mind, can anyone please help point me in the right direction? Anyone experience something similar or the same issue? Is there anything else I should logically check into as possible fixes?
Thanks, I'll keep a close eye on this thread and happy to answer any questions that may help lead to an answer.
Specs:
1998 Ford Explorer Sport
4WD
4.0L SOHC
226,000 miles
The Beginning
Got into the beast in the morning, drove 17 miles to work, parked and was idling having my morning cigarette; nothing unusual at this point. About 5 minutes later the Explorer just stalls. No sputtering or any signs that something was awry, the engine just stops as if it was shut off. I tried starting her back up and she cranks but won't turn over. I try this one and off over the course of a few hours and nothing. I tow it to my garage and naturally it starts up fine at that point and runs good enough to go up the drive way. Once up there, I turn it off and try to start it again and it won't start; cranks but won't turn over.
Current Status
Since then, it behaves in a variety of ways. If it starts, it's usually when it is cold (usually but not always). It struggles to idle when cold, sputtering somewhere between 500 and 1000 RPMs poorly. Once warmed up, it doesn't want to idle at all. I have to rev it way up and if it drops below 2000 RPM, it just tries to die out never stopping as it plummets to 0 RPMs.
Once it is warm [it seems], the only way to start it is so keep the key turned and cranking while giving it gas, holding the pedal to the floor. While doing this, it has a bunch of *almost* starts and if you get lucky it will finally start and even though it revs up to 4000 RPM because you have your foot on the gas, it will try to stall our right through that basically revving right up to 4000 and promptly descending to 0 RPM even though you have the gas pedal floored. When this happens it makes a deep, sad noise like it is getting no fuel (not saying that it is not getting fuel, just saying that is the sound).
Most commonly, when warm, you can eventually get it to start by cranking the key, flooring the gas and revving it up to around 2k, if you let your foot off it tries to die and you have to give it more gas to keep it running. Once in a blue moon, after enough revving, it will hold idle seemingly normally at around 1000 and sound great. Then, if you put it in reverse or drive, it immediately dies.
There has been once or twice where I've revved it warm and it has behaved normally; it'll idle normal, it'll go into reverse, drive and you can drive it back and forth normally. If you shut it off, you can restart it. But eventually, it goes back to it's broken type behavior outlined above.
The Troubleshooting
Because of the behavior above, I've done a lot of reading and digging around.
The first thing I did was put a pressure gauge on to check the fuel pressure; that checked out OK; it held pressure just fine.
Since then, I've replaced the MAF (Mass Air Flow sensor) and I've replaced the IAC (Idle Air Control valve).
Previously, I had a code indicating a bad O2 sensor; Bank 2, Sensor 1 so I replaced that too just because.
Also, I checked for vacuum leaks and found a slightly torn rubber gasket on the brake booster so I replaced that and also there were 2 loose screws where my upper intake manifold and I tightened those. Still, there could be a vacuum leak somewhere as we all know, but aside from those 2 spots I couldn't easily find any after much searching.
None of the replacement or fixes above have changed the way the truck behaves; it is still broken and showing the same symptoms.
At this point, I've taken the entire upper and lower intake manifolds off just to clean them while I try to figure something out (much carbon build up inside of them). The EGR tube is also filthy as hell and covered in carbon. Not sure if I should clean or replace that or if it's dirtiness even makes a difference.
So, with all that in mind, can anyone please help point me in the right direction? Anyone experience something similar or the same issue? Is there anything else I should logically check into as possible fixes?
Thanks, I'll keep a close eye on this thread and happy to answer any questions that may help lead to an answer.
