hard start rough idle
#1
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1992 xj6 92,000 miles
This car doesn't get used everyday. Typically once or twice a week. It has had a slow battery drain since it was purchased about 10 years ago. That's a question for another day. Right now it has a starting issue.
New battery. Car will turn over but not start. Hasn't had a tune up so I replaced the distributor cap, rotor, spark plugs, wire set, air filter and fuel filter. The car did start after doing so but only after I held the pedal all the way down. Ran very rough and only smoothed out when the RPM's were over 2k. Once they dipped below 2k, it became rough again and by the time it dropped to 8k, it would stall out.
I started it again and placed the transmission in neutral with no change (same RPM conditions as above). When I put the car in drive and let off the break, nothing happened. I had the pedal all the way to the floor and the car just sat there. After about 30 seconds, it started to crawl forward but never more than a crawl. About 10 feet later it stalled again.
Just to clarify, there is no option to scan this car (I have an OBII scanner) is there? I didn't see a schrader valve on the fuel rail - is there one in the engine compartment that I can use a fuel pressure gauge on to see if I'm getting enough fuel in the engine?
The fuel that came out when I changed the fuel filter did not appear to have water in it. I checked the container before I put everything away and did not see any separation.
thanks in advance for any help.
This car doesn't get used everyday. Typically once or twice a week. It has had a slow battery drain since it was purchased about 10 years ago. That's a question for another day. Right now it has a starting issue.
New battery. Car will turn over but not start. Hasn't had a tune up so I replaced the distributor cap, rotor, spark plugs, wire set, air filter and fuel filter. The car did start after doing so but only after I held the pedal all the way down. Ran very rough and only smoothed out when the RPM's were over 2k. Once they dipped below 2k, it became rough again and by the time it dropped to 8k, it would stall out.
I started it again and placed the transmission in neutral with no change (same RPM conditions as above). When I put the car in drive and let off the break, nothing happened. I had the pedal all the way to the floor and the car just sat there. After about 30 seconds, it started to crawl forward but never more than a crawl. About 10 feet later it stalled again.
Just to clarify, there is no option to scan this car (I have an OBII scanner) is there? I didn't see a schrader valve on the fuel rail - is there one in the engine compartment that I can use a fuel pressure gauge on to see if I'm getting enough fuel in the engine?
The fuel that came out when I changed the fuel filter did not appear to have water in it. I checked the container before I put everything away and did not see any separation.
thanks in advance for any help.
#2
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Welcome to the forum. You should go introduce yourself in the new member section.
You have lots going on with your car. Focus on one thing at a time. After a few more posts, you can use the search function within the XJ40 section and go through each issue. Water is a major issue, and even the littlest bit can play havoc with your car and mind.
I would suggest getting a Haynes Repair Manual.
To address a couple issues. Your fuel pump is in the gas tank in the trunk, that could be having issues. Did you check the tranny fluid, while in neutral and the car warm?
Yes, you can check fuel pressure in the engine compartment on the rail.
Your car uses OBDI. There is also a VCM on the drivers column. Is your check engine light on? Put the key in the second position, right before starting and press the key "VCM" it will give you a code on the dash within the speedometer.
You have lots going on with your car. Focus on one thing at a time. After a few more posts, you can use the search function within the XJ40 section and go through each issue. Water is a major issue, and even the littlest bit can play havoc with your car and mind.
I would suggest getting a Haynes Repair Manual.
To address a couple issues. Your fuel pump is in the gas tank in the trunk, that could be having issues. Did you check the tranny fluid, while in neutral and the car warm?
Yes, you can check fuel pressure in the engine compartment on the rail.
Your car uses OBDI. There is also a VCM on the drivers column. Is your check engine light on? Put the key in the second position, right before starting and press the key "VCM" it will give you a code on the dash within the speedometer.
#3
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Picked up the haynes manual - thanks for the suggestion.
Checked the fuel pump - getting power and the psi rating is within spec on the rail.
Drained the fuel tank, put new high octane with some dry gas in the tank and the car ran much smoother. I could idle down to about 5-6k rpm's and the car did not stall. I could also move it when in forward or reverse. Still a little rough at the lower end of the rpm's.
Transmission fluid checked out. I also ordered some cables that should allow my obdII to work with this car's obdI.
While it was running, some smoke started coming out near the rear tires. I turned the car off and found that a rubber buffer near the exhaust (it's right beneath where the emergency brake splits) was getting burned as the exhaust heated up. I checked this out in the manual but couldn't find anything. Any thoughts on why this is happening?
Checked the fuel pump - getting power and the psi rating is within spec on the rail.
Drained the fuel tank, put new high octane with some dry gas in the tank and the car ran much smoother. I could idle down to about 5-6k rpm's and the car did not stall. I could also move it when in forward or reverse. Still a little rough at the lower end of the rpm's.
Transmission fluid checked out. I also ordered some cables that should allow my obdII to work with this car's obdI.
While it was running, some smoke started coming out near the rear tires. I turned the car off and found that a rubber buffer near the exhaust (it's right beneath where the emergency brake splits) was getting burned as the exhaust heated up. I checked this out in the manual but couldn't find anything. Any thoughts on why this is happening?
#4
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Exhaust burning rubber at the rear would tend to indicate either a problem with the exhaust or a problem with a rubber mount.
You don't say what the rubber is.
But I would be inclined towards a problem with the exhaust, it should not be hot enough to burn rubber at the rear. Nor should it be touching anything rubber.
You don't say what the rubber is.
But I would be inclined towards a problem with the exhaust, it should not be hot enough to burn rubber at the rear. Nor should it be touching anything rubber.
#5
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I agree that the exhaust should not be in contact with the rubber buffer. I'm trying to did a pic of that area so I can compare it to what I have. Seems like the rubber bumper would be in contact with the cross piece that ties the two exhaust pipes together but it's a good 3 inches from that bracket.
Just picked up a code 26. Manual says oxygen sensor circuit: lean exhaust/vacuum leak. I'll start checking vacuum lines - anything typical of this code that I should be sure to check?
Thanks
Just picked up a code 26. Manual says oxygen sensor circuit: lean exhaust/vacuum leak. I'll start checking vacuum lines - anything typical of this code that I should be sure to check?
Thanks
#6
#7
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Yes I would say inlet would be intake gasket. Another thought on the smoking rubber-typically the only part of the exhaust that can get really hot would be the converters if they are getting plugged or loading up with gas. You may want to check the converters while the car is running and see how hot they are getting before driving it any distance.
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#8
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Did the following:
Changed plugs, wires, rotor and cap
Drained existing gas, changed fuel filter and puts in fresh high octane gas with a bottle of dry gas
Replaced the intake manifold gasket
Turned the key and the car fired right up and ran as smooth as can be...
The exhaust issue was a piece of rubber that had come loose and made contact with the exhaust pipe. This piece was reworked and that has fixed this problem as well.
Thanks for all your help.
Changed plugs, wires, rotor and cap
Drained existing gas, changed fuel filter and puts in fresh high octane gas with a bottle of dry gas
Replaced the intake manifold gasket
Turned the key and the car fired right up and ran as smooth as can be...
The exhaust issue was a piece of rubber that had come loose and made contact with the exhaust pipe. This piece was reworked and that has fixed this problem as well.
Thanks for all your help.
#9
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92 sovereign 96k
Car has run great since this initial problems was fixed
This has been a daily driver over the past few months.
In the past few days, I have noticed the car running rough at idle (when stopped in drive, in neutral or in park) and it has gotten progressively worse. It is only an issue at idle and doesn't matter how long the car has been driven. I had it on the highway for 25 minutes at 80 mph and when I got off and stopped on the ramp, it was a problem.
No codes yet.
After searching, I have found some potential problems that might lead to this issue:
- lose/broken wire on sending unit at the front/top of the engine
- o2 sensor
- idle control needs adjusting or replaced
I did not see a problem with the temp/sending unit wire.
Anyone know the ohm resistance for an o2 sensor for this vehicle?
From reading, it doesn't sound like adjusting the idle control can be done by a diyer as it requires some special equipment? Any way to test this unit or clean it?
Any other thoughts until a code shows up?
FYI - the fuel pump was replaced a few years ago. I believe I have the paperwork and can check on the details if necessary.
thanks in advance for any help
Car has run great since this initial problems was fixed
This has been a daily driver over the past few months.
In the past few days, I have noticed the car running rough at idle (when stopped in drive, in neutral or in park) and it has gotten progressively worse. It is only an issue at idle and doesn't matter how long the car has been driven. I had it on the highway for 25 minutes at 80 mph and when I got off and stopped on the ramp, it was a problem.
No codes yet.
After searching, I have found some potential problems that might lead to this issue:
- lose/broken wire on sending unit at the front/top of the engine
- o2 sensor
- idle control needs adjusting or replaced
I did not see a problem with the temp/sending unit wire.
Anyone know the ohm resistance for an o2 sensor for this vehicle?
From reading, it doesn't sound like adjusting the idle control can be done by a diyer as it requires some special equipment? Any way to test this unit or clean it?
Any other thoughts until a code shows up?
FYI - the fuel pump was replaced a few years ago. I believe I have the paperwork and can check on the details if necessary.
thanks in advance for any help
#10
#11
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did some looking - Jagbits:
VACUUM SOLENOID VALVE, FOR CRUISE CONTROL OR EGR SYSTEM
Part #: EAC7905
VACUUM SOLENOID VALVE, FOR CRUISE CONTROL OR EGR SYSTEM, FITS 1988-1994 XJ6 AND 1989-1996 XJS.
does this mean that I can swap out the cruise control solenoid for the egr to see if that's the problem?
VACUUM SOLENOID VALVE, FOR CRUISE CONTROL OR EGR SYSTEM
Part #: EAC7905
VACUUM SOLENOID VALVE, FOR CRUISE CONTROL OR EGR SYSTEM, FITS 1988-1994 XJ6 AND 1989-1996 XJS.
does this mean that I can swap out the cruise control solenoid for the egr to see if that's the problem?
#12
#13
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#15
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Well yesterday the fuel fail 37 code cleared.
Now I have the transmission light with the x through it... Symptoms haven't changed - I just have a new light on. Did some searching and found the reference to the jag lovers ebook with a write up about this problem. Anyone have additional thoughts on this issue?
Can anyone tell me what "limp mode" actually is? I found a lot of references to it but never much in the line of an explanation. Thanks
Now I have the transmission light with the x through it... Symptoms haven't changed - I just have a new light on. Did some searching and found the reference to the jag lovers ebook with a write up about this problem. Anyone have additional thoughts on this issue?
Can anyone tell me what "limp mode" actually is? I found a lot of references to it but never much in the line of an explanation. Thanks
#16
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My understanding is that 'limp mode' is when the car locks the transmission into a singular gear, making shifting impossible, thus enabling the car to make it home or to the shop - but not fast. Indeed, not much over 40 mph. This always triggers the transmission fault code you described. I do not know, however, whether the tranny fault light can be triggered without the car being in limp mode.
Scott
Scott
#17
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Thanks for the reply. After the rough idle, I haven't moved it from the driveway. Not having driven it since the transmission light came on, I didn't know what to expect and most posts said not to drive until it was fixed. Now I have to get that figured out...
My understanding is that 'limp mode' is when the car locks the transmission into a singular gear, making shifting impossible, thus enabling the car to make it home or to the shop - but not fast. Indeed, not much over 40 mph. This always triggers the transmission fault code you described. I do not know, however, whether the tranny fault light can be triggered without the car being in limp mode.
Scott
Scott
#18
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I have changed the throttle position sensor and the transmission light is gone. I also changed the ignition coil (it was showing signs of going bad). Now all of the lights are gone but I still have the rough idle.
Considered the gas might have water and put some some Heet in the tank. Have only driven it a small amount but haven't noticed any improvement.
There is still a clicking sound that changes with acceleration. Does this sound like an exhaust leak from the manifold? If so, is there a way to check that?
thanks
Considered the gas might have water and put some some Heet in the tank. Have only driven it a small amount but haven't noticed any improvement.
There is still a clicking sound that changes with acceleration. Does this sound like an exhaust leak from the manifold? If so, is there a way to check that?
thanks
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