Running problem when restarted from hot

[mec]

ok guys cool, well i have just fitted the new frequency valve which chris gave me and that is now definetly working, i am going to take it out for a run tomorrow and see how it goes then i need to get it back on the co machine, what i cant work out is my C0 was fine but the C02 reading was 12 + % so im not sure whether it was running wrong or not, it did stink of petrol all the time though !

mike

[Dan6457]

I didn't think gas analysers measures CO2. They certainly don't need to for MOT tests. Its just CO and HC thats measured.

[mec]

thats what i thought maybe he was reading the screen wrong ! DOH ! :lol:

[NickT]

NickT Wrote:...........
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.

Now you have the frequency valve working the fuel system will now run better instead of very rich running. Do as I said in this earlier post and then post your results here.

NOTE when you connect the Oxygen sensor the results should be between 0.7% CO to 1.5% CO. If it goes too lean or richens the fuel mixture then the oxygen sensor is contaminated, probably by the excessive fueling previously. You can run the car without the oxygen sensor connected (as it defaults the frequency valve to 50% duty cycle anyway) until you have chance to change it.

On a 4 gas analyser (MOT Spec.)

CO2 (Carbon Dioxide) is usually between 11 and 14% if everything else is set up ok.
CO (Carbon Monoxide) is the gas you measure - 0.7 to 1.5% CO
HC (Hydrocarbons) is unburnt fuel/oil and ideally should be <200 ppm (1200ppm MOT limit)
O2 (Oxygen) Oxygen content.

As Dan said, for the age of our car it's only CO (<4.5%) and HC (<1200ppm) that is measured for the MOT Test.

NickT

[mec]

Hi Nick

well i took the car out today for a quick spin around the block, got it nice and hot and it ran 10 times better and seems to be nearly back to normal, i have adjusted anything else as yet, thanks for all the advise you have given me! , got another question for ya ! can i clean the lamda sensor as it only had a new one last year i believe when alan owned the car he changed it?? i will try and take it back into work maybe this weekend and get it back on the emissions machine and see what we got fingers crossed a! :lol: :wink:

mike

[Dan6457]

If I get bored in the week and its sunny I might pop round on my new motorbike for a look mike.

[NickT]

mec Wrote:Hi Nick

well i took the car out today for a quick spin around the block, got it nice and hot and it ran 10 times better and seems to be nearly back to normal, i have adjusted anything else as yet, thanks for all the advise you have given me! , got another question for ya ! can i clean the lamda sensor as it only had a new one last year i believe when alan owned the car he changed it?? i will try and take it back into work maybe this weekend and get it back on the emissions machine and see what we got fingers crossed a! :lol: :wink:

mike

I have heard that you can clean them in an ultrasonic bath but for the price of a new one in my opinion it's not worth the effort. However, you can check the operation using an oscilloscope on the single wire (and earth) and see if you get a sine wave with peaks at 0.2v and 0.8v at 1 Hz at idle and at least 2 Hz with the engine at 3000rpm (assuming base CO is set in my previous post). If you get this signal then the oxygen sensor is working OK. You may be lucky.

Any 18mm thread (spark plug) ZIRCONIA 1v Single wire oxygen sensor would do.
You could also get the 2 wire version too and connect the earth cable to the engine block.

I have a 4 wire version in mine (still ZIRCONIA 1v) that incorporates a heater circuit which helps rapid heating and temperature stabilisation. Works great !

NickT.

[mec]

rather good nick think i mite have to get one of them !

Your more than welcome to come over dan drop me a txt when your about ! i see you bought a new car to ! you should put some pics on of the two !

mike