walrus108
NAXJA Forum User
- Location
- Charleston, SC
Just found this site and signed up! My recent problems led me here. I used to be a regular on an old XJ forum that no longer exist. Howdy Y'all!
I have a stock 2001 XJ 4.0l 4x4 that has always ran perfectly. It's at 135,000 now and the MIL light recently came on. With my scan tool I initially got 2 codes. P0304 (cylinder #4 misfire) and P0174 (2/1 Fuel system lean). It also began surging and idling rough when this code was thrown. The p0174 has never reappeared since it was first cleared. It still runs and drives just poorly. It hasn't ever stalled.
I started with the basics and replaced the plugs with the OEM type Champions and checked all the gaps. The coil pack had some signs of arching in the boots so I decided to replace it too. Most of you know there are no distributor cap, rotor, or wires on this year. I cleared the codes and started it. This did not change a thing. Same symptoms, same code minus the P0174. The p0174 has never reappeared since it was first cleared, as I said. Still #4 misfire though.
Next, I removed the fuel rail and cleaned the holes in the manifold and the spray ends of the injectors with brake clean. I switched #4 and #1, cleared the codes, and started it. Still ran the same but now it gave me #1 misfire code. Bingo!(So I thought). Bought a new injector and replaced the #1 that seemed to be faulty. Still the same symptoms, only now I'm getting P0300 (random misfire), P0302 (#2 misfire), and P0305 (#5 misfire). I was ready to shoot the thing at this point, but I love it so!
Then I found #1 TDC and removed the camshaft sensor and checked alignment with a toothpick. It was dead on as best as I could tell. Just like in the books anyhow. There was pleanty of wear on the sensor and some dust in the bottom so I blew that out and cleaned it and replaced the actual sensor on the top with a new one. I'm sure I fixed something that was soon to wear out but nothing changed symptom wise. Same codes.
Here are some things (clues) that I know about it so far.
1. My scan tool shows that at operating temp, both banks of O2 sensors are sweeping. Next, I will put my volt meter on each one to double check.
2. On the scan tool, the TPS seems to move smoothly, but it reads 17.9% at idle. Is this normal? I will also be putting my voltmeter on that fist light tomorrow.
3. The plugs that came out of it were the same Champion, looked very normal, good color, no signs of carbon, oil, or detonation. The cylinders looked very clean through the plug holes.
4. I see no cracks under the valve covers at all. No coolant in the oil and no oil in the coolant. It still runs at 195 max like it always has and there's been zero coolant loss ever. I really don't think that there's the known carbon build up problem and if there was, I doubt that it would have occured on at least 3 cylinders simultaniously. I will be checking compression though but it's really not likely IMO.
5. It runs the worst when it's cold and you try to accelerate. When it's warm it seems to run pretty much normal just off idle @ 1500 rpm, esp after the light comes on. Maybe the computer's compensating for something and it gets better?
6. The MIL light has flashed, when it is cold, during acceleration, but just for a short time.
7. Fuel pressure at the rail is a constant 46psi at idle and at a load. It never waivers.
8. There is no noticable egg smell at the exhaust and it doesn't sound like any clogged cat I have ever heard. Doesn't mean it isn't that for sure, it just doesn't seem likely in my experience.
Here are some questions that it would be really helpful to have the answer to before I throw anymore parts at this thing.
1. Can a Crankshaft position sensor cause misfires? Keep in mind that it still starts fine. It just runs like crap when it does.
2. Can IAC cause random misfires?
3. How likely is a vacuum leak to cause this? There are no definite leaks but I have not eliminated this as a possibility. This also would relate to the IAC, unmetered air. But is that a likely cause for a problem like this?
4. How about TPS? Could this possibly be the cause of random misfires?
I consider myself a fairly competent mechanic. I have worked as a Volvo mechanic for over 5 years, have done all my own repairs since I was 16, drag raced, rebuilt engines, etc. I just have never had to learn newer Jeeps and this one has me stumped. Many of the problems on newer Volvos that come up really puzzle us at first. We might see a new problem and it mike take a week to figure it out the first time. Like chasing a ghost. But then we solve it. Then we start getting in 3 per week with the very same thing and we look like Einstein for solving it so fast! I'm hoping there are a few of you that know much more about Jeeps than I do that have seen this a few times and regularly SOLVED it more than once. Using the search on here, I found many somewhat similar problems to mine, but none just like it, and no real answers to the dilemma.
If any of you have the diagnostic flow chart for this problem and could email it to me, that would be a HUGE help.
Thanks to any of those who can offer any advice at all.
I have a stock 2001 XJ 4.0l 4x4 that has always ran perfectly. It's at 135,000 now and the MIL light recently came on. With my scan tool I initially got 2 codes. P0304 (cylinder #4 misfire) and P0174 (2/1 Fuel system lean). It also began surging and idling rough when this code was thrown. The p0174 has never reappeared since it was first cleared. It still runs and drives just poorly. It hasn't ever stalled.
I started with the basics and replaced the plugs with the OEM type Champions and checked all the gaps. The coil pack had some signs of arching in the boots so I decided to replace it too. Most of you know there are no distributor cap, rotor, or wires on this year. I cleared the codes and started it. This did not change a thing. Same symptoms, same code minus the P0174. The p0174 has never reappeared since it was first cleared, as I said. Still #4 misfire though.
Next, I removed the fuel rail and cleaned the holes in the manifold and the spray ends of the injectors with brake clean. I switched #4 and #1, cleared the codes, and started it. Still ran the same but now it gave me #1 misfire code. Bingo!(So I thought). Bought a new injector and replaced the #1 that seemed to be faulty. Still the same symptoms, only now I'm getting P0300 (random misfire), P0302 (#2 misfire), and P0305 (#5 misfire). I was ready to shoot the thing at this point, but I love it so!
Then I found #1 TDC and removed the camshaft sensor and checked alignment with a toothpick. It was dead on as best as I could tell. Just like in the books anyhow. There was pleanty of wear on the sensor and some dust in the bottom so I blew that out and cleaned it and replaced the actual sensor on the top with a new one. I'm sure I fixed something that was soon to wear out but nothing changed symptom wise. Same codes.
Here are some things (clues) that I know about it so far.
1. My scan tool shows that at operating temp, both banks of O2 sensors are sweeping. Next, I will put my volt meter on each one to double check.
2. On the scan tool, the TPS seems to move smoothly, but it reads 17.9% at idle. Is this normal? I will also be putting my voltmeter on that fist light tomorrow.
3. The plugs that came out of it were the same Champion, looked very normal, good color, no signs of carbon, oil, or detonation. The cylinders looked very clean through the plug holes.
4. I see no cracks under the valve covers at all. No coolant in the oil and no oil in the coolant. It still runs at 195 max like it always has and there's been zero coolant loss ever. I really don't think that there's the known carbon build up problem and if there was, I doubt that it would have occured on at least 3 cylinders simultaniously. I will be checking compression though but it's really not likely IMO.
5. It runs the worst when it's cold and you try to accelerate. When it's warm it seems to run pretty much normal just off idle @ 1500 rpm, esp after the light comes on. Maybe the computer's compensating for something and it gets better?
6. The MIL light has flashed, when it is cold, during acceleration, but just for a short time.
7. Fuel pressure at the rail is a constant 46psi at idle and at a load. It never waivers.
8. There is no noticable egg smell at the exhaust and it doesn't sound like any clogged cat I have ever heard. Doesn't mean it isn't that for sure, it just doesn't seem likely in my experience.
Here are some questions that it would be really helpful to have the answer to before I throw anymore parts at this thing.
1. Can a Crankshaft position sensor cause misfires? Keep in mind that it still starts fine. It just runs like crap when it does.
2. Can IAC cause random misfires?
3. How likely is a vacuum leak to cause this? There are no definite leaks but I have not eliminated this as a possibility. This also would relate to the IAC, unmetered air. But is that a likely cause for a problem like this?
4. How about TPS? Could this possibly be the cause of random misfires?
I consider myself a fairly competent mechanic. I have worked as a Volvo mechanic for over 5 years, have done all my own repairs since I was 16, drag raced, rebuilt engines, etc. I just have never had to learn newer Jeeps and this one has me stumped. Many of the problems on newer Volvos that come up really puzzle us at first. We might see a new problem and it mike take a week to figure it out the first time. Like chasing a ghost. But then we solve it. Then we start getting in 3 per week with the very same thing and we look like Einstein for solving it so fast! I'm hoping there are a few of you that know much more about Jeeps than I do that have seen this a few times and regularly SOLVED it more than once. Using the search on here, I found many somewhat similar problems to mine, but none just like it, and no real answers to the dilemma.
If any of you have the diagnostic flow chart for this problem and could email it to me, that would be a HUGE help.
Thanks to any of those who can offer any advice at all.
