St185 Gt4 Running Issue - Advice Desperately Needed

[Gavin J]

Hi i'm new to this forum and registered hoping you can provide me with a much needed solution to my problem!!

Basically my ST185 GT4 developed a misfire last week, loss of power and loads of grey smoke out the back so i managed to limp it home.

When running the fumes stink of unburnt fuel - so initial reaction was that either a plug or lead had gone down.

Checked the leads and all were showing a good spark, took the spark plugs out and the plug in the cylinder closest to the cam was soaked in petrol. So assuming that the plug was starting a to fail a replacement set was fitted. Still no difference, so i've got a good spark at each plug, rotor arm and dizzy cap is fine. But the plug is still getting soaked in petrol and not firing.

So i called the RAC as i have home start and he was pretty baffled aswell and the only fault he could find was that the lamda sensor was a open circuit and not working properly and could be causing it to overfuel? but i thought this would cause it to overfuel on all cylinders and not one? but i replaced it anyway and the problem still persists!

Now my next theory is that the injector is knackered and possibly stuck open causing it to overfuel? so today i unplugged the injector from the problem cylinder and started the car and it was obviously misfiring but it was no longer throwing loads of unburnt fuel out the back.

So now my question is, how easy is it to remove the throttle/inlet manifold in order to give me access to the fuel rail/injectors? or does anyone have any other suggestions?

Cheers

Gavin

[dawesy]

have you changed the plug leads? could be a lead thats gone down, just because it fires in open air dosnt mean that it will fire correctly in the cylinder.

doubtful that the injector is at fault as the tend to fail in the closed position.

check all vacumme hoses and inlet pipes as an air leak can cause a similar issue.

[reena187]

Hi i'm new to this forum and registered hoping you can provide me with a much needed solution to my problem!!

Basically my ST185 GT4 developed a misfire last week, loss of power and loads of grey smoke out the back so i managed to limp it home.

When running the fumes stink of unburnt fuel - so initial reaction was that either a plug or lead had gone down.

Checked the leads and all were showing a good spark, took the spark plugs out and the plug in the cylinder closest to the cam was soaked in petrol. So assuming that the plug was starting a to fail a replacement set was fitted. Still no difference, so i've got a good spark at each plug, rotor arm and dizzy cap is fine. But the plug is still getting soaked in petrol and not firing.

So i called the RAC as i have home start and he was pretty baffled aswell and the only fault he could find was that the lamda sensor was a open circuit and not working properly and could be causing it to overfuel? but i thought this would cause it to overfuel on all cylinders and not one? but i replaced it anyway and the problem still persists!

Now my next theory is that the injector is knackered and possibly stuck open causing it to overfuel? so today i unplugged the injector from the problem cylinder and started the car and it was obviously misfiring but it was no longer throwing loads of unburnt fuel out the back.

So now my question is, how easy is it to remove the throttle/inlet manifold in order to give me access to the fuel rail/injectors? or does anyone have any other suggestions?

Cheers

Gavin

check the oil and see if the petrol is mixing with it. have you checked compression on all cylinders?

[GTForbes]

i'd replace the leads, i know their not a cheap part but mines would give a fine spark untill under load then would fail. there's no point in upgrading so i'd just get another standard set