Classic Misfiring at 2-3000rpm

tarphenry said:

Hope so! would be good after all the searching

Click to expand...

The throttle potentiometer is supposed to read 0.32 -0.35 so that kind of reading would suggest that it's signal to the ECU is giving a wide open throttle indication, demanding more fuel and hence overfueling.

ukadamwest said:

Methinks me found the problem...

Click to expand...

Hi, I'm home (went to visit sis & bro in law).

Wow! The throttle pot... So, is it sticking at this or is that it full open or what have you found?

Don't leave me hanging

I thought you had already discounted this so it never occurred to me to mention it!!

So, is the butterfly knackered or is it the wiper inside the throttle pot or a bad solder or......



EDIT: Ok, ou replied while I was typing

Doo said:

I thought you had already discounted this so it never occurred to me to mention it!!

Click to expand...

snap
12% seemed high in the vid but as they aren't set at 0v. I would think that reading would prevent idle control.
However I think wot should read much closer to the 5v feed.

Either, he's still fixing it, or he's tore all his hair off in frustration and is too embarrassed to come on and show us

C'mon, did you fix her yet???

No no no...

I got a replacement throttle pot and fuel reg. They arrived in the post Thursday. Friday after work it was snowing. Saturday it was snowing today I have some people coming to look at the boxster as I've decided it needs to go as fatherhood is not conducive to two seaters...

And yes I had contemplated a RR sport to replace the boxster but having a selection of range rovers of various years would leave me tearing my hair out.

Back to the throttle pot.. I might go and do that now and see what happens...

It's not the tps

ukadamwest said:

It's not the tps

Click to expand...

So, back to looking for a vacuum leak then??

Don't know where else to look for a vacuum leak... only possible place left is if I put the dyson in it

Doo said:

So, back to looking for a vacuum leak then??

Click to expand...

+1

Does your model have a fuel vapour recovery system, the little knowledge I have of this is that the fuel tank vapour is displaced and pumped to a charcoal canister when you fill her up, those caught and stored vapours are then fed back into the engine at ordained parameters, probably temp and high engine vac. If you have such a set up, is it operating correctly or flooding the vapours into the engine at will?

From memory, Fuel Evap system was US models only....

Are you burning oil?

I once had an 88 Carlton, it had such a system.

I would of preferred the 90/91 Lotus flavour though.

Saint.V8 said:

From memory, Fuel Evap system was US models only....

Are you burning oil?

Click to expand...

Nope and oil is clean

ukadamwest said:

Nope and oil is clean

Click to expand...

Don't know if you have seen this, but lots of info here:

http://www.actproducts.co.uk/2011/l...n-system-–-installation-and-diagnostic-notes/

Could look at the Tune resistor as this will adjust fuelling, if it is faulty the system reverts to a rich mixture.

Also check the temperature sensors too.....

Hi saint
All the temp sensors have been changed.

Update.

Replaced coil today.. no change...

so pulled the MAF, the plenum chamber, the fuel rail.. replaced the fuel pressure regulator. put it all back together and...



wait for it.....








wait for it....










Solved. Just a slight lumpy run now most likely from the sooty plugs from the over fueling.. but took it for a run down the road.. yay !!!!!


Now the P38 is throwing a misfire.. but most likely plugs again as the LPG does eat plugs.

I may well stock up on BRP6ES plugs !

Well done, I like it when a plan comes together

Well done mate fuel pressure regulator don't think we had that on the list

ukadamwest said:

Update.

Replaced coil today.. no change...

so pulled the MAF, the plenum chamber, the fuel rail.. replaced the fuel pressure regulator. put it all back together and...



wait for it.....








wait for it....










Solved. Just a slight lumpy run now most likely from the sooty plugs from the over fueling.. but took it for a run down the road.. yay !!!!!


Now the P38 is throwing a misfire.. but most likely plugs again as the LPG does eat plugs.

I may well stock up on BRP6ES plugs !

Click to expand...

Excellent. drop the r from the plugs may help too

not solved..

misfiring again.

and the P38 is misfiring too.
can someone tell me why we like these cars ?