hughandjen · Feb 24, 2021

1999 4.6 Thor engine
Hi guys as per my emissions thread my car failed it’s mot on emissions.
I have checked compression, plugs all good. OBD2 port not working.
I have quite a loud ticking under the passenger side rocker cover.
I’ve tried hydrolic valve lifter treatment in the oil to no avail, so I’m going to have to take off the rocker cover and have a look.
It’s a Thor engine so I’m going to take off the plenum first.
Is there any pitfalls or suggestions to make the job easier
Thanks

kermit_rr · Feb 24, 2021

this is my next job too.. been put off for a while.

pwood999 · Feb 24, 2021

I would get the Diagnostic port working first. Might save you time & money in parts if you read the ECU fault first.

First check you actually have 12V & ground on the connector.
Then check C0229-C0067 behind RH Footwell panel for corrosion (18pin rectangular).
Also check C0203-C0448 which is somewhere under the coolant header tank (big round connectors).

kermit_rr · Feb 24, 2021

OBD won't list mechanical problems though

pwood999 · Feb 24, 2021

@kermit_rr agreed, but it might help identify the fault.

hughandjen · Feb 24, 2021

I’m definitely getting a loud ticking noise using a stephoscope on the left hand rocker cover probably the third cylinder back from the front of the engine

kermit_rr · Feb 24, 2021

hughandjen said:
I’m definitely getting a loud ticking noise using a stephoscope on the left hand rocker cover probably the third cylinder back from the front of the engine

I'm also able to hear the same tick underneath, but louder. assuming its the lifter itself tapping inside the engine block

hughandjen · Feb 24, 2021

kermit_rr said:
I'm also able to hear the same tick underneath, but louder. assuming its the lifter itself tapping inside the engine block

Mines the same

kermit_rr · Feb 24, 2021

hughandjen said:
Mines the same

We can be camshaft replacement twins!! I'll show you mine if you show me yours

tomcat59alan · Feb 24, 2021

pwood999 said:
I would get the Diagnostic port working first. Might save you time & money in parts if you read the ECU fault first.

First check you actually have 12V & ground on the connector.

Then check C0229-C0067 behind RH Footwell panel for corrosion (18pin rectangular).

Also check C0203-C0448 which is somewhere under the coolant header tank (big round connectors).

View attachment 231718

Pin16 is power and pins4&5 are ground

hughandjen · Feb 24, 2021

tomcat59alan said:
Pin16 is power and pins4&5 are ground

I ran a power lead to pin 16 (brown) and got power to the port but the reader still couldn’t comunicate

kermit_rr · Feb 24, 2021

hughandjen said:
I ran a power lead to pin 16 (brown) and got power to the port but the reader still couldn’t comunicate

what diag tool are you using?

hughandjen · Feb 24, 2021

kermit_rr said:
We can be camshaft replacement twins!! I'll show you mine if you show me yours

Haha I’ll eat you know how I get in this wee

kermit_rr said:
what diag tool are you using?

i have a crappy VGate one but I took the car to a Landy specialist and he couldn’t get it to work.
So then I took it to a car electrical specialist and he said that even if it is working it won’t tell me much other than what I know already ie that the lambda sensor is picking up unburnt fuel.

kermit_rr · Feb 24, 2021

a " car electrical specialist" may not have the right tool either, but should get basic engine fault codes

pwood999 · Feb 24, 2021

If O2 sensors are showing rich mixture, it's most likely inlet leak somewhere. Could also be bad MAF or Engine Coolant Temp sensor (the one for the ECU, not the temp gauge), either of which can cause rich fuelling. Equally a faulty o2 sensor (reading lean) can cause the ECU to increase fuelling.

One ticking lifter should not cause rich mixture.

hughandjen · Feb 24, 2021

pwood999 said:
If O2 sensors are showing rich mixture, it's most likely inlet leak somewhere. Could also be bad MAF or Engine Coolant Temp sensor (the one for the ECU, not the temp gauge), either of which can cause rich fuelling. Equally a faulty o2 sensor (reading lean) can cause the ECU to increase fuelling.

One ticking lifter should not cause rich mixture.

She failed on high CO figures and definitely is not running on all 8. I need to sort the ticking noise anyway so will be getting spanner’s out this weekend

kermit_rr · Feb 24, 2021

A bit of a jump but bad lifter/cam, if the inlet isn't opening properly then it could have a rich exhaust. In my opinion

pwood999 · Feb 24, 2021

Maybe, but diagnostics would then show significant side-to-side differences in o2 & fuel trim readings.

Grab a cheap dial gauge on eBay, and measure the cam lobe lift before doing all the camshaft out work. Might save a bunch of work removing plenum bananas, manifold, rockers, lifters, water pump, front cover, camchain, radiator(s), etc.

pwood999 · Feb 24, 2021

or one like this digital gauge.

kermit_rr · Feb 24, 2021

pwood999 said:
Maybe, but diagnostics would then show significant side-to-side differences in o2 & fuel trim readings.

Grab a cheap dial gauge on eBay, and measure the cam lobe lift before doing all the camshaft out work. Might save a bunch of work removing plenum bananas, manifold, rockers, lifters, water pump, front cover, camchain, radiator(s), etc.

If a lifter is on its way out then you need to replace them all, camshaft included

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