I once failed an MOT on CO levels - Read how I passed haha
- Thread starter zcacogp
- Start date
Haha, I wish ! Just come down to see my very skilled mechanic mate, and thought we could plug in his fancy diagnostic device to check all is well with no fault codes etc. etc. but found that even with the mnassive box of leads he has, we don't seem to have one to fit - so I can't talk to my porker ! [8|] Am I right in saying that the diagnostic port is on the nearside inner wing just behind the suspension turrret ? 5 female pin job in a round connector ? Any ideas what pins are what between car and an omnitech scanner so I can make a lead up ? Long shot I know. . . . . . . . .[&o] Mike
Mike, To be honest, I'll be surprised if the car has any form of on-board diagnostics on it whatsoever. I don't know the port you refer to (it may be turbo-specific) but I'd be very surprised if you could get an OBDI or II to talk to it. It may be a simple flash-type readout (Mk3 Golfs had them) but even then I'd be skeptical. Oli.
1990 cars had a 'proper' diagnostic port under the dash, But I suspect when you change the chips this is lost as the Americans didn't really get any after 89 and the tuning chips mostly originate stateside. The under bonnet one flashes an LED and is basic - there is a guide somewhere on the net - clarks garage maybe, on how to make the circuit and what the flashes mean. Its also where you bypass the ISV for setting the idle mixture. The info for that is in the workshop manuals downloadable from Rick http://www.cannell.co.uk/ or promax Tony
Finally passed [
] Managed to get a slot for this morning. Poor dizzy cap and rotor arm was the culprit ! [8|] Can't believe I forgot to check them when I did the service earlier in the year - doh ! That brought CO level down from 9.42% at the first MOT to 4.9% today. We struggled to work out why it was still so high, when my very good MOT man had a little brainwave. Removal of the dipstick saw the level fall to 1.8% !!! Well within the limits. I asked with a puzzled look what was going on, and he explained that cos it had been SO rich for a while, there'd been enough bore wash to contaminate the oil (which is only a few hundred miles old). A quick sample check and indeed the oil stinks of fuel. So of course when this is vented back into the intake, it richens the mixture, plus confuses the engine management. So, an oil change to do (again) and we're back in business. Green MOT in hand, I'm off to tax it in the morning [] Many, MANY thanks to all those who helped out - really do appreciate it. A final request, where's the idle stabilisation valve on my car ? It idles fine, but it's still very low when cold for the first 20 secs or so - as if it had a cold start valve that wasn't working or something ? Cheers guys, Mike
] Managed to get a slot for this morning. Poor dizzy cap and rotor arm was the culprit ! [8|] Can't believe I forgot to check them when I did the service earlier in the year - doh ! That brought CO level down from 9.42% at the first MOT to 4.9% today. We struggled to work out why it was still so high, when my very good MOT man had a little brainwave. Removal of the dipstick saw the level fall to 1.8% !!! Well within the limits. I asked with a puzzled look what was going on, and he explained that cos it had been SO rich for a while, there'd been enough bore wash to contaminate the oil (which is only a few hundred miles old). A quick sample check and indeed the oil stinks of fuel. So of course when this is vented back into the intake, it richens the mixture, plus confuses the engine management. So, an oil change to do (again) and we're back in business. Green MOT in hand, I'm off to tax it in the morning [] Many, MANY thanks to all those who helped out - really do appreciate it. A final request, where's the idle stabilisation valve on my car ? It idles fine, but it's still very low when cold for the first 20 secs or so - as if it had a cold start valve that wasn't working or something ? Cheers guys, Mike
Great news always is when another one is on the road for another year! Mike
Exactly. Cheers guys, now enables me to get on with sortin real problems like 4 wheel alignment and making her go faster [] haha. There will be more mods, but probably not for a bit yet, though I think I'll push on tryin to sort the odd few niggly bits out while I have some momentum with it. Nick, sounds like a good idea to me. Mad busy for the next fortnight with mates wedding and work stuff (if my knee holds together long enough) but happy to sort something out for a couple of weeks time ? Mike
] haha. There will be more mods, but probably not for a bit yet, though I think I'll push on tryin to sort the odd few niggly bits out while I have some momentum with it. Nick, sounds like a good idea to me. Mad busy for the next fortnight with mates wedding and work stuff (if my knee holds together long enough) but happy to sort something out for a couple of weeks time ? Mike
Fat Albert
New member
I had a similar issue on my last SAAB Turbo, one of the Lambda sensors had gone over-richening the mixture, they changed it and it still failed, they did an oil change and it passed!
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