Big picture: recently swapped the cylinder head for a 7120 casting as part of a head gasket replacement due to an overheating issue a year earlier which left it with a slowly worsening idle - with a wet "putting" through the exhaust, especially when cold. At the time thought to be due to the head gasket, along with a broken exhaust manifold stud which didn't help. It was also stalling occasionally.
Did a full service at this point, including:
- oil/filter
- bosch platinum plugs
- O2 sensors
- coolant
- welsh plugs (don't get me started
)
- crank angle sensor (for good measure)
All was fine after first run, and the wet "putting" from the exhaust seems to have gone. Then decided to fit the new cap and rotor. After this, idle was very poor until warmed up. Took it for a good fang and found it wanting to stall on sharp turns - particularly to the left.
Re-examined the dissy as this was the last thing touched and noticed play in the shaft and a rhythmic knocking noise, thought to be from the dissy/rotor.
Replaced the dissy with a good used one (thanks JJ).
Quote:
Originally Posted by darksidecustoms
Took it for a drive from cold start this evening and while generally a lot smoother and idle was much better than before, still stalled a couple of times when pulling to a stop. Once when popped into neutral to recover a stall, it surged without any throttle and coincidentally had a 'sulfurous' smell. Also threw a CEL.
Will see if I can download the code this weekend and will start a new thread if it's nothing obvious. Curious if whether it's related to the MAP sensor or NSS codes I pulled last time, or possibly transmission - when pulling to a stop it's almost as if the torque convertor doesnt slip.
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Last time I downloaded the codes, I had P0107 (Map Sensor Voltage Too Low) and P1296 (No 5 Volts to MAP Sensor) - amongst other things such as NSS/trans and a short from the fuel level sensor, which drops out all the time anyway. This was 4 weeks ago and I have since adjusted the NSS so this should be OK.
Haven't had a chance to download the code from the current fault(s).
From cold start tonight, it was struggling to keep idle at all - slowly stalls over about 4-5 secs to stall completely. Unplugged the sensor, exactly the same - no change. Drove to the local westfield, it sat for about 20 mins while I was shopping. Drove home and running next to perfect - was even quicker 0-80 than a DC5 Integra Type-R. Let it idle outside the house and unplugged the MAP sensor while running, and it stalled just liked when cold tonight - over about 4-5 secs.
Thought it also may have been to do with the fuel pump as it was less than a quarter full, but filled it tonight with 98 BP Ultimate and no change.
Also checked the trans fluid today from the dip stick - just above full but looking a little yellow and smelling slightly burnt, but it hasn't been replaced in the 3 years I've had the XJ. I do have a new trans filter ready to go in though, just haven't been able to make the time. No slipping, firm shifts, starts in park/neutral, reverse lights work (but sometimes not from cold start).
Also recently replaced coil and leads (~9 months ago, MSD).
Feels like I'm on the right track with the MAP sensor - like it's only working correctly when it's had some heat soaked into it. Don't have a multimeter to test it, might need to buy one.
What do you think? Money's real tight at the moment and its been about 2 months chasing this with my wife unable to drive it so I need to finally hit the nail on the head!
Stalling, sometimes surging at idle, hesitation under load - MAP sensor?
