Hello,

This is my first time posting here.
I bought a xj8 about two weeks ago and the person I bought it from said it was good except for the fuel pump.
So I trailered it home and I then changed the fuel pump and fuel filter but the idle was still the same. Really rough and down to between 300-500rpm.
I took the throttle body off and cleaned it and the idle control valve. I also cleaned the MAF with the proper MAF cleaner.
It did nothing
I also changed all the coils and spark plugs but that did nothing.
I've tried to find a vacuum leak by spraying start gas around the vacuum lines but nothing.
I'm running out of ideas and need help.
Should I be worried about the timing chains?
I know they have the good aluminum tensioners but how is it with the guide rails and all of that.

Thanks for your time!
Will

 

Being a 2003 it should have the newest timing chains.. No, actually it WILL have the newest, as the change was 2001.

Reset the ECU. Remove a battery pole, hold it against the other for a few seconds and done.

When reset, give it a good drive and check.

 

Just because you cleaned the MAF doesn't mean it isn't broke. Mine was running rough and I tried to the cleaning method first also (makes sense, its quick, easy and cheap), but to no avail. Got one off Amazon and she screams again. Also, make sure your vacuum is hooked up to your MAP sensor. Technically said, its easy to knock off if someone was fiddling around by the throttle body.

 

Hello,

I forgot to say that the obd2 showed misfire on all but the number 2 cylinder.

I checked that vacuum hose and that was on properly.
I disconnected the MAF sensor to se if it worked and I believe it does because the engine starts to "shudder" and act funny when I take it of. I also get restricted performance when its disconnected.

I forgot to mention that sometimes stalls when I'm in drive and reverse.

Thanks again and thanks for the replys !

 

I also forgot to say I checked the fuel pressure and it was steady on 41. Is that where it's supposed to be?

Thanks

 

Yes. Fuel pressure is fine at 40 -41 psi. BTW, fuel pressure is seldom the problem for rough idle. The car is using little fuel at idle!

Exactly which codes do you have? Can you chart your LTFT and STFT?

 

Is this it?<br/>

 

Fuel pressure sounds good, I believe 42 is the naturally aspirated rate.
Ok, I'm not trying to scare you, but it sounds like you need to check the timing. When you take your valve covers off you'll see your cams. On those cams are a flat spot for setting timing and also to keep timing (with lock down bars) when disassembling that area. You don't need the lock downs, your just viewing it. So, with the covers off, hand rotate the crank until they all show the flat spot on top. All 4 should be flush at the same time, if not, then timing is off.
I'm real sure what Daim says is correct and you should have metal spring loaded tensioners factory. That being said, check the tension on your chains, they should be fairly rigid. I say check this because a member from Ontario recently had to fix what the previous owner supposedly fixed on his tensioners and it was a botched job that cost him part of his vacation for him to get repaired properly.
Another check would be a compression test, its another cheap test that will reveal issues without breaking down the motor.
Here's a link that is very highly recommended... JagRepair.com - Jaguar Repair Information Resource ...it has many articles, pdf's, training links, repair guides and details for your vehicle provided by those on site here with vast knowledge.
Keep us posted, be sure to check the codes after clearing them and doing a test and refiring her. We need to see if these change or stay constant.

 

I don't remember the codes but there were about 15 of them and I erased them all. They still haven't come back.
But it was:
P0301
P0303
P0304
P0305
P0306
P0307
P0308
P1314
P1316


I do always have the p0100 when I hook it up though.

Thanks

 

1316 is Misfire Excessive Emissions Fault....this is the Jaguar specific code read
1314 is Misfire Catalyst Damage Fault (Bank B or 2)...this is the Jaguar specific code read

....here's a page from the link I gave ya...

 

There is a good chance you have a major vacuum leak. Check the intake plenum, especially near the resonator stub. Check the full load and part load breathers (the tubes running from the top of the two cam covers) CAREFULLY for cracks- the lengthwise ones are difficult to see at first! I know you have sprayed, but some vacuum leaks are hard to find.

It was not clear to me what happens after you rev from idle. Does it settle out a bit?

Also, after sitting, there might be come contaminate in the fuel, like water. Did you get rid of the old fuel when changing the pump?

Before you tear the engine apart, you need to get a OBD reader which will chart the fuel trims so you can see trends. A smoke tester is the perfect tool for looking for intake leaks.

Keep monitoring the codes. Some will almost certainly return pretty soon.

 

Thank you for all the responses.
I'm gonna see if I can get out there this afternoon to see what I can do.

If it is the fuel trim is that because of the o2sensors on the cat or what does affect that.

Thanks

 

No, the fuel trim is adding fuel, most likely due to a vacuum leak of the MAF is sending low air data.

 

Ok, lets try something simple, how old was/is the fuel in her? How much is in there now and will she idle and/or rev?

I want to eliminate an possible bad/cheap fuel, which would cause massive misfires. No matter how much fuel, hopefully not a lot, run a can of Sea Foam or octane boost through her...preferably the Sea Foam. Let her run for 20-30 minutes, occasionally trying to rev her to burn off any contamination.

 

Hello again.

The fuel is all brand new v-power. I have put a bottle of fuel injection and fuel system cleaner in it but nothing.

I erased all the codes that was in the computer and then I drove her awhile but now that I get to a stoplight she dies. Before she was just on the verge of dying.

I had 13 codes when I got back and during my ride sometimes engine fail safe came on and sometimes restricted performance came on.

But to the codes. Here they all are:

P0300
P0301
P0302
P0303
P0304
P0305
P0306
P0307
P0308
P0506 x2?
P1000
P1316

Since all of the coils and spark plugs are brand new I have a hard time finding that accurate.
The battery I use was fully charged and fairly new.
I did the reboot with the negative and positive cable.

When I started it today it was at a fairly good idle speed but it was still a very lumpy idle.
When I pressed the accelerator it hesitated a little and then started revving and when it came back down it almost died.

Thanks!

 

So, you have good fuel pressure and misfires on all cylinders. The timing is suspect, but not likely a problem since you have the upgraded engine. I would look to the MAF at this point since your trims are showing lean readings, but only if you are sure you have no intake plenum leaks. You still have not reported CAREFULLY examining the intake for leaks.

 

Hello.

I don't really know how to search for intake leaks. I tried the smoke method but with a cigarette and I did not see anything. Maybe not enough smoke?

And the code P0506 says something about the IAC valve.
Could it be that valve even though I cleaned it properly?

 

That 1316 is your next chase and probably your cure for the rest since we can eliminate the fuel.

 

So this is how the latest readings look
Don't really know what to make of it. Though maybe some of you can get a clue from that.

 

How do I chase that?