Here is the issue that I am having - once warm the car only reves to about 1.5 rpm and starts to bogg down

video below

90 XJ6 rev issue - YouTube

Any help or suggestions would be appreciated

Just a note when cold it revs up all the way with no issues

 

I'm thinking timing chain stretch. I'd get a few more opinions before jumping in to that, but that's definitely what it sounds like.

 

bennkishh if it was timing chain then wouldn't it be happening even if the engine is cold? Also some times its happens at higher RPM like 3 or 3.5

Also is it hard to tighten the timing chain?

Anyone else have any suggestions?

 

My guess (and it's just a guess) would be a sensor problem or an intake vacuum leak/emission control system issue.
I'd start by making sure all the intake and breather hoses are sealing properly and that the hoses are sound.

No codes?

 

Have you got a Haynes Manual? For starters Refer to chapter 6 - Exhaust Gas Recirculation (EGR) System and also the Crankcase ventilation system... I'm thinking that your fault lays here.... if not then

Have you got the standard hydraulic brake set up? or has it been converted to a vacuum booster?
Have you checked for cracks in your manifold?
Have you checked your O2 sensor?
Have you checked the TPS?
Have you replaced spark plugs/wires/rotor/dizzy cap?
Have you tried disconnecting the air filter and running it?
Have you run a compression check?

You might also like to look at the TSB regarding NOT revving your engine above 2000 rpm in Park or Neutral... it can damage your transmission

It could be anything but these are good places to start...

 

While I've got my thinking cap on, it might also be worth checking and cleaning your Mass airflow sensor (MAF)... it's the big metal thing between the air filter box and the intake manifold... these gunk up with oil as does the crankcase ventilation hose.

Remove your MAF (but don't disconnect the wiring) and see if there is any improvement, if not, disconnect the wiring and try...

 

Thanks for all the suggestions I will start some troubleshooting tomorrow

 

Oh and no codes as you can see in the video

 

I just re-watched the video - it doesn't show any code check - you have to press the VCM button with the ignition key at position 2 (ignition on without the engine running) for the code to be displayed.

 

Thanks I will do that

 

So i had some time to take a look at the car today.

First of all my cap and rotor were replaced a couple weeks back and ignition coil was replaced when I purchased the car 5 months ago only things I have not replaced are wires and plugs but those both look fine

I have checked all the intake and breather hoses and they are all sealing properly no cracks etc..

Also checked to see if there are any cracks in my manifold - no issues there

Took apart the entire intake system from filter to the throttle body not dirty at all but still cleaned it all with throttle body cleaner

Issues is still there

Compression check also done and all is fine there

Checked for codes - no codes

Also disconnected the MAF with all the wiring still attached and ran the car - started for a second or two but then dies every time should that be happening?

 

Did you use a meter on the TPS and monitor the full range with the meter attached?

 

dwiniarz,

It doesn't sound right that your engine dies with your MAF disconnected from the inlet manifold with the wiring still connected. try leaving it in place, just disconnect the wiring, remove your air filter and report back with the result?

Have you got a Haynes manual? The procedure for testing it is in chapter 6

 

Jagfix38 I had a bit of time today to disconnected the MAF wire while still connected and once I disconnect the wire it dies.

The TPS has been tested and is fine

 

Also rechecked the for codes today and for the first time I get Fail Fuel 11 what does this mean?

 

According to Haynes, for a MY 90, Idle Potentiometer is not operating in range. I have never worked with it, so can't help with trouble shooting. The codes for the TPS are 17, 18 & 19, so this may be a different component, not sure which one though.

 

Hi - you should get the engine management .pdf, it's a must have for issues like this.

You can download it from the stickies at the top of the XJ40 forum page. It'll tell you how to approach your fail code and give you possible causes.

As Rob says, a quick look says fuel fail 11 on 90-92 MY engines is an idle trim issue.