Misfire Cylinder 7 and "Tappet Noise" any connections?

Disclaimer : sorry rather long post

Hi everyone,

I have another question. A long time ago (6 month) I checked with a Bluetooth OBDII Reader my car and saw a Misfire Warning on Cylinder 7. Went to the garage and they cleared this fault.
The people at the garage disconnected a spark plugged show me how the engine behaved and how the steering wheel was checking when a misfire happen. But I never had such experience until today (noise and checking steering wheel).
Still the car when the weather is cold (Around 5 Celsius or below) the engine, while running smoothly, does not make the same "sound" has when it is warm or in summer. Personally it never really bugged or sounded odd, the car is from 1995 after all.

However today I checked the ODBII Reader and had the same Cylinder 7 misfire on ECU. I cleared the ECU and will check in the future.
The error they show is P1316 - Jaguar = Injector Circuit / IDM Codes Detected

Still I have a few questions for you guys.

First the Spark plugs and cables are only one year old, I changed the battery a few month ago (did not check ECU at this time).

Now on top of that I have a "Tappet Noise" that only come when car is cold and noisy on cold weather/engine and that later disappear when hot.

I went to the garage yesterday and the tappet noise was rather low but they immediately identify it anyway. The noise is located on the side of the engine where the EAS Pump is and correct me if I am wrong the Cylinder 7 is also on this side of the engine.

The garage will take the car soon, but they figure it could be the rocker arms shaft, a rocker itself or worse case a tappet. Luckily this won/t be that expansive to fix.

Still, having this noise located in the area of the cylinder could there bet any connections with the misfire? Misfire can come from many thing but Spark plug and cable are new, it also could be an injector, but again any connection between the both?

What is the common culprit of a Misfire?

Thanks guys and sorry for the long thread.

Cheers

Note : P38 Range Rover 1995 4.6 HSE fuel only 87,000Km
Note : They tried the first time I show them the Misfire to swap MAF, no changes or effects on the engine, they cleared the MAF as a culprit.

PS My car does NOT behave like this (Hot Missfire) :
http://www.youtube.com/watch?v=d7xZvOUzmwk

Range rover isn't OBD compliant. You need specialist diagnostics, so your error code could be mis-leading you.

The Mad Hat Man said:

Range rover isn't OBD compliant. You need specialist diagnostics, so your error code could be mis-leading you.

Click to expand...

I agree with you, and this error is for a Jaguar, however, the Garage that take care of my P38 and that only deal in LR cars checked with their reader and also read a misfire on Cylinder 7.

V8 engine ECU can be read by OBDII but with limited functionality i believe. You may have a couple of problems a dicky tappet that is being picked up by a knock sensor, which would have to be pretty bad to cause a miss fire or uneven running. And the intermittent actual miss fire itself that causes the engine to run rough will more than likely be electrical.

Thanks Wammers

When I drop the car the 21 I will tell them about the error message that showed up again, it may help them to locate which tappet or the area where to look.

But what bother me in this is that the tappet noise is only loud when cold, since the past two days we have 25 to 28 here in Japan when last week-end we had 4... And yesterday due to the hot weather it is barely audible.

One more question, should we ONLY replace the tappet that is noisy or should they replace them all?

SpacePig said:

Thanks Wammers

When I drop the car the 21 I will tell them about the error message that showed up again, it may help them to locate which tappet or the area where to look.

But what bother me in this is that the tappet noise is only loud when cold, since the past two days we have 25 to 28 here in Japan when last week-end we had 4... And yesterday due to the hot weather it is barely audible.

One more question, should we ONLY replace the tappet that is noisy or should they replace them all?

Click to expand...

Find out what is wrong first you are speculating at the moment.

wammers said:

Find out what is wrong first you are speculating at the moment.

Click to expand...

I will then bug you again the 21 soon after dropping the car.

To be continued....

If the misfire is caused by the valvetrain than do a compression test to prove/disprove it - or you are wasting your and everybody else's time. Error codes are often symptoms not causes of a problem.

Regarding OBDII compliance, as the US (Land Rover's (then) primary market) forced compliance from 1996 onwards - practically all petrol P38s should be compliment, the EU dragged their feet on this one, however diesel compliance for P38s (not mandatory during its production run) was implied by the necessity to make as many common components as possible (what's the point of building two types of engine management/BECM interface?) So the diesel gained limited ODBII compliance for fuel and emission systems via forced (petrol vehicle) compliance in the US.

So after a few days with a FT-86 I am now back driving my good old girl. So the tapping noise as been indetified : Fuel Purge Valve.

They, my Land Rover specialist, did not change it but just cleaned the connectors and "voila" no noise so far.

Simply put, when the noise starting we just disconnected the Fuel Purge Valve and no more noise, connect it back : noise, off again : no noise

I will see if cleaning the connector is a long term fix or not, but they told me that I could change it If I really wanted to but if it were them they would not even bother. It seems that only UK and JP P38 runs with this valve while in Australia for example this vavle is no installed (according to them, my garage)

Now you guys are my safety net so what would U do if the noise come back? Did any of you had such experience in the past with a noisy Fuel purge valve on cold start?

This part is rather cheap : Britcar (UK) Ltd > ESR3001 FUEL PURGE VALVE ASSY NRR (G) and my garage will source it from Brit Car anyway.

The Mad Hat Man said:

Range rover isn't OBD compliant. You need specialist diagnostics, so your error code could be mis-leading you.

Click to expand...

The engine ECU is, can be read with ELM.

My purge valve has made a clicking sound since i've had the rangie. I don't think it a big issue.

martynv8 said:

My purge valve has made a clicking sound since i've had the rangie. I don't think it a big issue.

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Hi thanks and just for curiosity how long it has been clicking?

I've had mine for over a year now & it's always done it. TBH i thought it was normal?

martynv8 said:

I've had mine for over a year now & it's always done it. TBH i thought it was normal?

Click to expand...

I have been seeing this issue since the past 6 month, and started to freak me out this winter where the noise was at its loudest.

This morning I could not hear any ticking/tapping since they "lubricate" the connector, I will have a look again tonight when cold and see or next week when we will go hiking in the mountain.

You should maybe give it a try as well, they removed the connector that was plugged where the metallic mount fix the valve, maybe it will fix yours as well. I do not recall the brand they used to clean/lubricate the connector but it was also designed for spark plug connectors.

Also, does your Valve always tick or like mine only when cold and will vanish with time when hot (30m to 1h)?

Hi,

I'll give it a try. Mine starts clicking intermittantly. I first thought i had a slipped sleeve until i put a hosepipe to the valve to locate the sound.