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Hi I have a rough idle at start up but goes away after warmup only on cold starts. No check engine light. Only found the codes when I plugged in the code reader. It feels like it's missing on 2 Maybe 3 cylinders. Codes are P0300 Random misfire detected. P1316 misfire rate exceeds emissions.
This is a 1999 XJ8L
Work done
Timing chains/tentioners
Front/rear shocks
Thermostat/housing
Spark plugs when I got the car
Valve cover gaskets X5 and its still leaking on the exhaust manifold I'm about to gouge out my eyes. Do you know where I can get new valve covers and the bolts every time I reseal them I break the dam bolts and I torque them to spec.
Any help would be great
I could be the sensor on the fly wheel.. sits 6 oklock on the bell housing..
That sensor gives the "master sync" for ignition.. Maybe the signal from it is failing on lower rpm's.
Other than that you have the two ignition modules.. that sits on the wall next to the brakecylinder.. they dal with the ignition timing.. if they start to detoriate.. the will cause all sorts of engine misbehavior..
The upper right corner of your scanner screen indicates that there were three diagnostic trouble codes (DTCs) flagged. Do you know if the third one was a duplicate of P0300 or P1316, or was a different code altogether? It would be very helpful if the third code was a cylinder-specific one like P0301 - P0308, so it would be worth checking again.
You can download the DTC Summaries guide at this link:
When you look up each code in the guide, the right column gives some of the most common possible causes. Given the problems you've had with camshaft cover gaskets, one suspect would be oil leaking into one or more spark plug wells and causing random misfires. The ground path for the spark plugs is through the engine and ground strap, and any oil on the spark plug threads interferes with the electrical circuit.
The torque specification for the cam cover screws is just 10 Newton meters / 7.4 foot pounds, which is not much more than hand tight, so if you are breaking screws is it possible you are overtightening them? If so, that has the added consequence of distorting the gaskets and causing leaks.
Hi don the other code is p1000 I think it's the one that says the system test not complete so I didn't add it to the list. I'll pull the coils probably tomorrow afternoon when I get off work. I also torqued those bolts in the proper sequence and at 10 newton meters. After the 4th reseal with rtv silicon in the spots that were leaking all the time. They were still leaking even when I shoved rtv in the spots that were leaking after everything was put together. Thankfully when the valve cover bolts broke they were in spots that I could get a drill and tapp it out. I'm just afraid that when I go and re reseal it I'll get a bolt that breaks in the lower back if that happens I'm pulling the engine out and I'll clean the holy hell out of it. I still need to do the rear main seal any way.
The dtc codes updated to p0301 and p0307. So on Saturday I'm going to swap those coils to another cylinder and see if they move. And during that I'll also look to see if there is oil in the plug wells. It would be weird if oil is the cause of the misfire. When I first got the car almost every plug well had a good amount of oil in it and I never had a misfire problem.
One more thing is that my check engine light is not on at all with the misfire. I know the light works when I turn the key to the on position. Why would the light not pop on?
Looks like my misfire is being caused by excessive blow by. Clyinder #1 and #7 have oil covering the piston head and spark plug. Air filter and air intake are covered in oil along with the throttle body.
.. just curious.. How in the world does the engine manage to throw oil upstreams and wet the oilfilter while running?
How come its only two cylinders that have blow by and get wet from oil? I imagend that when an engine gets to that point, its more of an general wear in the egnine and not just two cylinders... stuck oil scraper rings is in my world more likely..
If you clean out all plug holes.. and clean the sparkplugs.. the engine should runs smoth as silk atleast for a few minutes... or?
Einhead what I think is happening is exhaust is blowing past the piston rings. Then the oil is being pushed through the breather hose that connects to the air intake tube a little past the mass airflow sensor. So when your driving the engine is pulling the air and thus the oil that is leaking from the breather hose is pulled into the throttle and to the cylinders. That’s what I think I might be wrong I’m not sure. But the jag is starting to get harder to start and the idle is getting rougher. So I’m going to pull the engine out and rebuild it.
Also I found the engine removal pdf on the form. But what about a manual for engine tear down? Also where would I look up the specifications for valve clearance/ piston to piston wall clearance. Or how much play things are allowed to have? I’m going to rebuild the engine myself.
Also I found the engine removal pdf on the form. But what about a manual for engine tear down? Also where would I look up the specifications for valve clearance/ piston to piston wall clearance. Or how much play things are allowed to have? I’m going to rebuild the engine myself.
Hi Belmon,
First of all, some oil in the air intake of Jaguar engines is normal, but I wonder if the oil in your air filter could be due to blockage of the partial-load breather. See the TSB I am attaching.
If that doesn't turn out to be the problem and you really want to rebuild the engine, you can download one version of the X308 Workshop Manual from this forum, at the link below:
First of all, some oil in the air intake of Jaguar engines is normal, but I wonder if the oil in your air filter could be due to blockage of the partial-load breather. See the TSB I am attaching.
If that doesn't turn out to be the problem and you really want to rebuild the engine, you can download one version of the X308 Workshop Manual from this forum, at the link below:
Hi don the first thing I did when I noticed the oil in the intake I cleaned the partial load breather around 2-3 weeks ago when I resealed the cam covers they weren’t blocked same with the hoses.
Belmon do you know if its a nikasil or steel liner block? Can you get a compression test?
I think its a nikasil block. I saw in a another post that when jaguar replaced to the steel liner they had a grey oil pan and mine has a black. But when I get a chance I’ll look for the engine code.
Also from what I read is that you DONT hone a nikasil bore. What I read from other sites is that you use a scotch brite pad and lightly rub the cylinder bore in a cross hatch pattern.
If the nikasil bore lining is bad/out of specifications you need to get the nikasil lining recoated. And there’s a place called millennium technologies they gave me a $1300 quote and a 21 day turn around. Also they have experience doing this engine.. But I don’t know what I’ll do yet.
Random misfire code
