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vibrations on idle engine mount?

pimgmx
Posts: 3289
Joined: Tue Jul 08, 2014 12:07 pm
Location: South East of the Netherlands

Re: vibrations on idle engine mount?

Postby pimgmx » Fri Oct 20, 2017 8:20 pm

Good shout, Carl!

the daily: 01 S8 http://bit.ly/2kIwP4m
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cedriccools
Posts: 26
Joined: Tue Sep 12, 2017 9:22 pm

Re: vibrations on idle engine mount?

Postby cedriccools » Fri Oct 20, 2017 11:28 pm

Elsa_jag wrote:Just thinking about the low rpm...

Does it only have the issues once warm?
And
Does the car struggle to run sometimes when you come to a stop (again only when warm)? Perhaps even cut out when you stop?

If so, it may be the coolant temperature sensor. It's a common fail and I've had mine go twice, when it happens the car runs like a dog, tries to drop the revs too low


Yes indeed. The check engine light only start to light when hot, not every time.

I started looking at the exhaust manifold today and discovered that few exhaust were leaking, so that will be fixed first, but i also ordered the sensor you mentioned, just as the o2 sensor

old del boy
Posts: 6929
Joined: Thu Jul 10, 2008 9:29 am
Location: Kent

Re: vibrations on idle engine mount?

Postby old del boy » Fri Oct 20, 2017 11:47 pm

cedriccools wrote:
old del boy wrote:
cedriccools wrote:Just did the compression test.
All cilinders are 7.5kg/cm2 except cylinder 5 and 6. Those are 9kg/cm2

I checked the plugs and cylinder 1 and 3 have an okay spark plug color.

Cylinder 5 has a dark/black color so is running top rich

Cylinder 2,4,6 are very light color, so are running too lean.

What can cause this? Faulty injectors? Will clean them out this evening


Those compression readings equate to 106.6 psi and 128 psi , Haynes manual suggests readings should be between 150 and 160 psi with no more than 10 psi difference between cylinders :?

Derek..


I have to say the compression tester was a bit of a prehistoric machine :-) today I will have a new one.

now, what makes it that some sparkplugs run rich and some run lean? I cleaned the injectors yesterday, without result


Misfires and air leaks , you really need to make sure your ignition system is not at fault and working properly , it's common for these cars to have been neglected , people seem to think ignition leads last forever but they will break down internally over time or absorb moisture , how old are yours ?
Then there's the distributor cap and rotor arm , the arm can leak down the shaft and cause problems , spark plugs , are they the correct ones ? gapped properly , once you have established these are all ok then you can think about the myriad of other things that could be causing rough running , a failing crank position sensor can cause weird symptoms while working intermittently , we have had a case whereby a fractured wire caused this to work intermittently , of course it is possible that the engine management ecu is not firing the injectors properly but it's more likely to be something else as these are quite reliable , a damaged wire to an injector for instance or a poor earth due to corrosion , it's a question of elimination i'm afraid ,

Derek..
'93 4.0L Daimler, solent blue,
'93 4.0L Daimler, Westminster,
'85 2600 Rover sd1 vdp oporto.

cedriccools
Posts: 26
Joined: Tue Sep 12, 2017 9:22 pm

Re: vibrations on idle engine mount?

Postby cedriccools » Sat Oct 21, 2017 8:54 am

[quote="old del boy"
Misfires and air leaks , you really need to make sure your ignition system is not at fault and working properly , it's common for these cars to have been neglected , people seem to think ignition leads last forever but they will break down internally over time or absorb moisture , how old are yours ?
Then there's the distributor cap and rotor arm , the arm can leak down the shaft and cause problems , spark plugs , are they the correct ones ? gapped properly , once you have established these are all ok then you can think about the myriad of other things that could be causing rough running , a failing crank position sensor can cause weird symptoms while working intermittently , we have had a case whereby a fractured wire caused this to work intermittently , of course it is possible that the engine management ecu is not firing the injectors properly but it's more likely to be something else as these are quite reliable , a damaged wire to an injector for instance or a poor earth due to corrosion , it's a question of elimination i'm afraid ,

Derek..[/quote][/quote][/quote]

I was afraid of this :-) where can I find the coolant temperature sensor?

old del boy
Posts: 6929
Joined: Thu Jul 10, 2008 9:29 am
Location: Kent

Re: vibrations on idle engine mount?

Postby old del boy » Sun Oct 22, 2017 1:00 am

Its just behind the thermostat , a brown top connector , this might help

http://www.jaguardriver.nu/manualer/XJ4 ... Manual.pdf

Derek..
'93 4.0L Daimler, solent blue,
'93 4.0L Daimler, Westminster,
'85 2600 Rover sd1 vdp oporto.