Post queries regarding your Mk3 Cavalier's fuel system (including ECUs) and exhaust here
#162510 by cavalier1990
Mon May 15, 2017 10:12 am
Ok, another MOT another bodge pass for the emissions. High Lambda and CO at 3k revs, HC ok at 3k revs. I'm thinking next step is go for an original lambda sensor, but cheaper option first would be blank off EGR valve. Trouble is I don't have an emissions tester I can plug in and work away at the car trying different things without paying a garage and a mechanic to do it.
#162511 by Robsey
Mon May 15, 2017 10:39 am
Wow gas testers have gone expensive...
Well not really - I bought a Gunsons Gas Tester 2 professional in about 1990 for £80.

Just looking now, the cheapest I can find start at £99 for a standard model.

There are a few used Gas-Tester 2s for sale on ebay... currently about £50 each.
#162523 by cavalier1990
Tue May 16, 2017 9:13 am
Robsey wrote:Wow gas testers have gone expensive...
Well not really - I bought a Gunsons Gas Tester 2 professional in about 1990 for £80.

Just looking now, the cheapest I can find start at £99 for a standard model.

There are a few used Gas-Tester 2s for sale on ebay... currently about £50 each.


I was thinking along the lines of getting one of those, would be interesting for tuning purposes as well with my collection of cars!
#162686 by cavalier1990
Tue May 30, 2017 9:21 pm
Only thing is it looks like the Gunson ones, and ones around 100 quid mark only check for CO, need one that does lambda and HC as well. Think that would be one of those around the £1K mark, or at the very least 5-600 min.
#162690 by Robsey
Wed May 31, 2017 12:05 am
I suspect you are correct.

The sub-£150 units will do CO, RPM, Dwell angle and Voltage.

That is what the Gastester 2 Pro does.
Quite nifty 20 -odd years ago.
But not enough by modern standards.
#162723 by Cabletwitch
Sat Jun 03, 2017 9:21 am
Just a thought, because I'm having similar problems... could it be due to a naff fuel pressure regulator? If the springs become weak, wouldn't is allow too much fuel to be burnt for the volume of air it's taking in, leading to incomplete combustion and increased CO readings? I had that particular flash yesterday, I'm going to have a look-see at the vac line to it to start with, and see if it has any effect. But maybe replacing the whole thing might yield better results, if they're not too expensive?

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