Xvetteowner

My car is a 84 Euro S, The meter is a Gunson Gastester, Not the best but from what I read its fine if you calibrate correctly Its a pain but I'm sure I got it right. I'm trying to figure out why I have a lean condition between 1000 and 2000 rpms. I read a post that Euro's will run best if set to 1.5 CO. What happens if you can't get there? I can turn the MAF screw either in or out and 09 is the highest reading I can get. Could bad wires or the wrong type of plugs (denso PW20TT's) be the cause. I've ordered new correct plugs and wires from two of the Rennlist supports and a min-vac to test the fuel presuure regs, and damper. Speaking of plugs, the way their burning is clean on the ground elector While 3/4 of the white insulator (surrounds the centre electrode) and centre electode is black and the other 1/4 looks new. Maybe its the flame travel. Thinking out loud, If the fuel pressurer regs and damper are good I bet a adjustable fuel pressure regulator would solve the problem

John Speake

The CO pot is a 20 turn adjuster, clockwise to richen the mixture..... no ed stops so don't keep turning when the CO stops changing.

Remove the 6 way MAF plug and on the MAF measure with a multimeter on resistance range between pins 6 and 3 (or 6 & 4) the max rich setting is 1000 ohms.

If you're at 1000 ohms with a very weak mixture then the MAF is shot or there's a huge airleak. Have you measured intake vacuum at idle ?

neilh

Gary. To add to what John said, above- CW richens, CCW leans - set the pot value to a starting value of 382 ohms before you reinstall, go from there.
Neil

Xvetteowner

Thanks...and to think I thought the adjuster was a "one full turn thing" since it had no stops. so after 20 turns in or out, it will just keep spinning and change nothing. If it wasn't 105 in the garage I would check the vacuum. I did the old fashion test of starting the car and spraying carb cleaner on every vacuum hose and fitting and was not able to change the idle....Just got my mini-vac so I could test the fuel pressure reg and damper, as soon as it cools in a few days . I'll be in my "summer home" as the wife and kids call it.

alabbasi

I know it's a euro but does it have a catalytic converter? If so, you're not going to get a higher CO reading no matter what you do as the cat will convert CO to CO2.

Xvetteowner

And air pump belt removed

John Speake

Good point, Alabbasi. So, has the car been Federalised ?

Xvetteowner

John,
At one point it must have been being its a CA car. I have confirm that the ECM brain is still the euro one that came with the car, How it was hooked up to the single O2 senser that was in the exhaust pipe beats me. ( If it was ever hooked out) It looks like it was plugged decades ago. ( But the car was in CA till 2003) so it must have passed inspection with the single "cat" that was in place

John Speake

Well, O2 or not, the cat is doing its job and holding down the tail pipe CO. To make a sensible reading you need a test port before the cat.

Many Euro's were Federalised with an O2 sensor and a "black box" to adjust the fuelling, I guess it was some kind of piggy back device.

Any extra boxes on your car ? Lots of people with these doctored cars often find the O2 sensor isn't connected to anything :-)

Xvetteowner

Must have had one at one point No extra box, The Plug for the O2 looks like its been there 10 years.