Running problem when restarted from hot

[mec]

Hi Guys

Well after driving all the way to norfolk and back this weekend without a problem through rain and thunder and everything else that could have be thrown at it, i got home swithed off the engine for 5 mins, then came out started it again to put in the garage and it was running realy lumpy again same as it was on the MOT ramp on monday. after thinking it was a charging issue i now think its gota be fueling problem. anyone got any ideas what this could be?
It seems like it only does it once you have stopped the engine when its hot and then restart it again. I drove 140 miles without stopping coming up to norfolk and it was faultless and then today i drove 110 miles back and it was perfect weird one a
Any help is very much appreciated !! :lol: + thanks all for a great weekend it was a laugh especially that dodgy picture dan took of me on the forum lol :lol: car looked good though !!!

mike

[bozzzydmc]

Mike

Sounds to me like an electrical fault caused by water , perhaps your spark plug wells have a bit of water in them?

Maybe pop one or two boots off and take a look..

Mike

[NickT]

May be accumulator but a fuel pressure test should show that.

Nick.

[mec]

hi guys
thanks for the thoughts, i will have to check both these things out, also i know its running very rich at the mo do you
think this could cause it ? maybe it just needs a good service and tune up ??

mike

[bozzzydmc]

Perhaps your rich running and the journey has fouled/ blackened your plugs so one is missing slightly ? Taking one or two out will see how your plugs look, they should be a light shade of brown if the fuel mixture is set right ...





As MrT has said a fuel pressure test and air / fuel tune up is a good way forward.

[NickT]

One quick check is to disconnect the oxygen sensor electrical connection. Rear bulkhead near rear drivers wheel. Follow the single black cable from the oxygen sensor.

On a poor setup engine the oxygen sensor will get contaminated. This false reading will instruct the fuel computer that will in turn alter the duty cycle of the frequency/ bleed valve causing it to run rich. By disconnecting the oxygen sensor it will default the duty cycle to 50%. This will run at base fuelling setting.

Simple test to do.

NickT

[mec]

that sounds like a very good idea nick ! i think im gona have to get out there and have a look at the plugs and unplug that sensor to we will see!!!
its funny you should say about that sensor actually because when i was under the drivers wheel arch some time ago when i first got the de i noticed that this wired had been cut/torn so i reconnected it maybe this was a mistake !

mike

[NickT]

mec Wrote:that sounds like a very good idea nick ! i think im gona have to get out there and have a look at the plugs and unplug that sensor to we will see!!!
its funny you should say about that sensor actually because when i was under the drivers wheel arch some time ago when i first got the de i noticed that this wired had been cut/torn so i reconnected it maybe this was a mistake !

mike

Did the trouble start once you did this?

NickT

[Dan6457]

I have just remembered that when Allen bought the car he had to fit a new oxygen sensor to get it to pass its mot. So it must have been working then and running well enough to pass emisions and that was only a year ago.

[mec]

hi guys

well nick the problem didnt happen straight after i re connected it but i hadnt used it much since the until trying to get it through the mot, as for whay dan said thats very interesting that it needed new sensor for the mot, it didnt pass the emitions this year either even though it evetually passed the mot wink wink say no more!
as i say maybe it needs a damn good tune up and service, it does seem like it holds back slightly when you floor it maybe it chokeing itself up ?? :?

[Tourettes Tony]

maybe the mot stations should check their emision booklet, as the Delorean is not in there and should only be a visual. TT :x

[Rich H]

mec Wrote:hi guys
thanks for the thoughts, i will have to check both these things out, also i know its running very rich at the mo do you
think this could cause it ?

mike

"over rich mixture" "potential CPR issue perhaps or maybe VAC leak"...gee...déja vu :roll: :wink:

viewtopic.php?f=9&t=2684

[Dan6457]

I think someone who is familiar with these type of injection systems needs to give it a good going over as it could be any number of things When you were at the mot, did you try adjusting the mixture at all?

What tony said is right, but the emissions should be correct if the engine is running right, even if it doesn't have to be checked by law.

[NickT]

Dan1986 Wrote:I have just remembered that when Allen bought the car he had to fit a new oxygen sensor to get it to pass its mot. So it must have been working then and running well enough to pass emisions and that was only a year ago.

A new oxygen sensor may correct the fuelling to make a pass but if the base fuelling setup is too rich it will soon contaminate it.

Disconnect the oxygen sensor electrically to make the computer operate the frequency valve to 50% duty cycle.
Take care to garage/ mot place.
Check emissions. It should be between 1.0 % CO and 2.0 % CO. (1.5% is ideal).
If it is more than this then the base fuelling is way off and assuming all ignition components are in order and the vacuum pipes are connected the correct way round, may need a slight adjustment and/ or may need fuel pressure testing (inc CPR)/ injector spray pattern testing, cold start thermo time switch testing.
Adjustment is done with the engine off, removing the bung near the fuel distributor, inserting a long 3mm allen key and turning it no more than 1/8th of a turn at a time. re-insert bung and Re-start engine, wait for a minute for idle stabilisation then re-take a reading.

REF cold start injector, try disconnecting the electrical blue plug and seeing if it makes a difference. It shouldn't.

NickT.

[mec]

right guys heres the deal, today i took the de back to work toput on the co2 machine to adjust the mixture and it was running at 11% ! We tried adjusting it down and got it down to 7% and it ran like crap ! so we had to put it back up
So after this i took a ride down to chris @ gradys in canvey and he has come up with a few theorys and also given me one of the parts i need that may help Top Bloke !
I had a nice long chat with him and had a good snif around and saw pilot 20! and Jez's new beast its looking good matey !!
So watch this space, any other theory with the fuel set up is always welcome ! :lol: :wink:

mike