Hello everyone. I am a new owner of a 99 VDP 4.0 natural asperated. Well I think I really screwed up but we will see. So the car had a rough idle but ran well after about 900 RPMs accept once in a wile I would get a bump/misfire. Had a few codes P0171 P0300, P0307, P1316. P0332. Just a bit of back ground on me. I am a transmission builder and have great scanners. Way to many tools and access to some good info like Alldata and Identafix. So I pulled coils and found a split plug boot. Replaced that and cleared codes. Still idled rough but no more bump. Motor was nice and quite so I drove it for a couple weeks when one day on my way to work I heard pinging. Looked at the temp gaege and looked fine to me. Just barely over half. I had another 2 miles to go so I just went very easy. Big mistake!!!! When I pulled into the parking lot it shut off. There was steam coming from the hood. Let it cool and put some water in it and as soon as I did it ran on the ground. Found that one of the 2 hoses under the intake was split wide open. Pulled the intake and fixed it. Changed the oil and started the car. Now it sounds like I have a bad lifter!!! Its not a knock but a tap. Runs the same as it did but I know that tap cant be good. I know these motors have a lot of timing chain issues and am wondering if mabey when it got hot if it hurt a tensioner and maybe it was already bad which is why it runs rough at idle. Oh it has 141000 miles on it so its no spring chicken. But the rest of the car is in good shape. I would hate to have to put a motor in this car since the are not cheap. 2000$ for a used one and I am sure I would need to do some work to it before putting it in. Any suggestions would be great and thank you in advance.

 

reefkeeper,


First, welcome to the forum,


please use punctuation, and line spacing in a post! It makes it so much easier to read.


When it is all in one block, a lot of people(me included) cannot be bothered to wade through a lot of text speak.


Please do not get me wrong, this is advice, not criticism.


Second,( If not done so already) introduce yourself on the new member thread, and add your car year and engine/version to your signature, and where you live.


There is quite a lot of difference between a US spec car to a UK spec car, so putting where you reside does make it easier for us to give an informed answer.

 

Thanks Andrew. I will do as you suggested. I edited my sig to put year make and model

but it did not show up. I will look at that again. I will also go to the intro thread and

make a post. For anyone reading this thread I am in the US and it is a 99 VDP. Thank

you again.

 

If you are bothered about your timing chains and tensioners (and I would be) pull the cam covers off!


If the upper tensioners are an orangey brown colour, and plastic, at the very least, order up a new pair of metal tensioners.


Oh, and a new set of bolts for the metal tensioners, as they are a different length!


Best thing to do, use the search engine in the forum, (cam chain tensioners/ failures etc) ....


Now, after you have scared yourself shitless, and thought " WHAT HAVE I GOT MYSELF INTO" Remember, it is only an engine, just follow the many instructions, some with a video walk through, and she will purr again.

 

Have you cleared all of the codes and driven it to see if it has set new codes.
Since the hoses under the manifold was the one that let loose I would look at a bad knock sensor giving you a noise. They really don't like to sit in water.
Run the codes again and lets see what you have.
I have attached the codes out of the service manual for the ones you listed.

 

Thanks guys. Yes reset the codes and drove it. What came back was P0300

and P0171. I cleaned the MAF sensor which helped but I think the MAF sensor

is bad. I watch the MAF on a scanner and even under WOT It does not go

above 8 so I felt that was my misfire at idle. The little things like simple

misfires dont concern me much. My big concern is the "What sounds like" lifter

tap. Has anyone ever heard this before? Is it possible that the timing chains

and tensioners could cause a lifter tap? Before I go and put new timing

chains and tensioners in this motor I want to know my tap will be gone or

there is no point and get another motor. I thank everyone for the help

 

If you suspect the MAF just unplug it. The car will run on default settings but will have restricted performance (and a crap tickover!). However, the difference will tell you if the MAF is to blame.

 

Yes I am running with the MAF unpluged already. Tic is still there. Sounds like its in the valve train but who knows. I was also thinking that maybe when it got hot it broke some sludge free and the oil pump pick up is clogged and starving the lifters for oil. Sometimes the tic is not as bad and other times its louder. But if does sound like a lifter. To be honest I dont even know if an overhead cam engine has lifters. I am a transmission guy. LOL

 

The AJ27 DOES NOT use hydraulic lifters. Now, I guess it is possible that oil starvation could cause a noise from not lubing the cam, bit I doubt it.

Maybe it is just an enhanced awareness of engine sounds after the overheat?

I have had several "events" on both NA and SC XJ8s where I had a sudden and almost complete loss of coolant, with the temp gauge going pegged hot. None have caused an engine failure. On the other hand, I lost a head gasket with no overheat event in the recent past. I know that is contrary to the predictors of overheat doom, but it is my experience.

 

Thanks sparkenzap. You might be right about the over awareness but I dont know. Funny thing is I didnt loose much coolant. Maybe 3 quarts and the gauge never went up. I guess I am back to timing chains and tensioners. Going to pull it apart this weekend.

 

Overheating can result in a valve seat dropping, but I would expect more than just a tapping sound if that happened.

 

Not a leak at an exhaust manifold joint is it? They can tick.

 

Another source of ticking is the idler and tensioner bearings. I would elimanate them before jumping into the timing chains. It is best though to know for sure you have the upgraded secondary tensioners, so i would pull the cam covers.

 

Thanks for all the suggestions. I am not afraid to do anything on this motor. "No guts

no glory" I was hoping someone had been through this. I find that the best source of

information. I wonder if I can post a video link here??? If I can I will video the engine

running and post a link to youtube and then everyone can hear it. I am going to try

and pull the oil pan today just to check the pick up and maybe the oil pump.

I payed close attention this morning and the tic was louder wile the motor warmed up.

Once up to temp it is not as loud. Thank you all again. I hope I can help others with

transmission issues in the future.

 

You need to determine, immediately, which secondary tensioners you have. The secondaries rattle if failing.

For the codes, clean the part-load-breather (lots of threads); clean the electrical connections to the MAF; check for air leaks from the air filter housing to the throttle body; clean the throttle bore and plate. With air tube off the throttle body take the slack out of the accelerator cable (search for threads).

There are lots of threads on doing the secondary tensioners (at least two on this first page, alone). Given what you do for a living, this will be a piece of cake for you.

 

Thanks jhartz. Ya I saw plenty of threads about the secondary tensioners. I will look at the others you suggested. Thank you for saying the tensioners will rattle if failing. That was exactly what I was looking for. Some conformation. I will pull cam covers and see what I have.

 

P0300 is more likely a coil causing a misfire.

 

I missed that you had not checked the tensioners. I agree with Jim. That should be the very next thing you should be checking BEFORE you drive it again.

 

Thanks guys. Pulling the cam covers today. Been slammed at work last couple days so have not had time. Damm I didnt know I should not drive it. I have been driving it for a full week. Its only about 7 miles each way and I have not gone anywhere else but work.

 

reefer:
The reason is that a cam chain failure many times results in a piston crash which is almost a total loss for the engine and therefore the car.