Super Spec Rover T Series, Misfire.

[Guest Peter Kelly]

When starting from cold the engine sounds sweet and pulls like a Rocket.

However as soon as the engine is warmed through it starts to misfire.

I have replaced all the H.T.electrics but the symptoms still persist.

I think that messages from one of the sensors is not reaching the ECU and the fuel mixture is becoming too rich.

But which sensor?

Any ideas?

 

Pete

[Guest Tim Norman]

Lambda?

[Grim]

well if it is ok cold and crap hot, i'd try the temp sensor.

[Guest Peter Kelly]

I have replaced the temp sensor with no improvement..

 

Pete

[Guest Peter Kelly]

Lambda?

Is the Lambda sensor the one on the exhaust?

[richyb66]

Is the Lambda sensor the one on the exhaust?

 

Yes.

 

You say it's mis-firing but you also suggest it might be running rich. Do the plugs look noticeably sooty of does the exhaust smell rich at all? I'd also be looking at the coil pack as that can cause mis-firing if it's faulty.

[Guest Peter Kelly]

Yes.

 

You say it's mis-firing but you also suggest it might be running rich. Do the plugs look noticeably sooty of does the exhaust smell rich at all? I'd also be looking at the coil pack as that can cause mis-firing if it's faulty.

Yes the plugs were very sooty after a fair run . The coil is brand new.

I do have concern about a multi point conector on the lambda cables situated in the passenger footwell.

Perhaps one of the cables could have come adrift?

Do you know any midgets who could have a look for me?

 

Pete

Edited July 12, 2013 by Pete the Dog

[Guest Peter Kelly]

I have just removed Lamba sensor from exhaust and it is thick with soot.

 

Pete

[Redspec]

The original lambda sensors fitted are known to fail / not work with the ecu even from new.

 

http://www.rhocar.org/index.php?showtopic=34958&hl=%2Bdredded+%2Bsuperspec

 

Mine has started to missfire / bog down yesterday - got to keep the rev's up above 3000 rpm or it has no power / misses

 

Idle seems fine

 

Steve

[Guest stevenkirk]

Which temp. sensor did you replace? - there is two on mine - on for ECU and one for gauge.

I used Rimmer Bros for my replacement -

 

http://www.rimmerbros.co.uk/?gclid=CNDTqMvQrLgCFdPItAodwTwAvw

Edited July 13, 2013 by steven

[Guest Peter Kelly]

I replaced the one that talks to the ECU, still misfires when warm.

[alanrichey]

Slightly off-topic here, as my Rover engine is running fine, but I am having trouble accessing the spark plugs (brand new owner of a built SuperSpec) to check condition. Do I need to remove the long plastic cover first, if so how, or can I just pull on one of the leads individually. I have pulled fairly hard with no success but did want to risk any more force in case I am missing something. Is there a trick ?

 

Al

[Guest Peter Kelly]

Just yank it off holding the plastic, not the lead.

When replacing the plugs use a piece of plastic tube to screw the plugs in up to finger tight before tightening down with plug spanner.

 

Peter

[alanrichey]

Many thanks, I'll give it a try

[bullfist]

So is an MOT pass any indication of how good the Lambda sensor is working? My Superspec passed with good emissions, so I assumed that the Lambda was in good condition. But I have noticed that the exhaust is a little sooty. The car seems to drive ok (lacks a little power at higher revs), but there is occasional (light) backfiring when taking foot off accelerator - I was led to believe that backfiring was air getting sucked into the exhaust somewhere (even though all holes - allegedly - have been plugged).

-steve