Using LM-1 on CIS

[mca]

Just to follow up I have been running numerous tests with an LM-1.

I currently have my CO set at roughly 3%. While driving the car I watched my mixture numbers and liked what I saw. Nice enrichment on WOT.

One question remains though, at 2300-3000 RPMs I see my leanest condition at14.7 AFR.

Is that too lean or is it still ok?

[911pcars]

Originally Posted by mca

Just to follow up I have been running numerous tests with an LM-1.

I currently have my CO set at roughly 3%. While driving the car I watched my mixture numbers and liked what I saw. Nice enrichment on WOT.

One question remains though, at 2300-3000 RPMs I see my leanest condition at14.7 AFR.

Is that too lean or is it still ok?

I'd say that's ideal for fuel economy and emissions.

A/F at WOT is open loop. That is, sensor input is ignored in this mode and the default is what is allowed by the ECU.

Sherwood

[euro911sc]

Been folling this thread closely... What if you have no ecu?? like my ROW? All I have is the mixture screw...

Comments Sherwood?

-Michael

[Paulporsche]

Craig,

14.7 is stoich so your LM-1 would show it as "joosta right" for economy and emissions. More importantly, I think, is that stumbling you were getting. Has it disappeared w/ this setting?

Michael,

W/o an ECU you are relying on your mixture screw setting and the design of the CIS system to give you the best setup under all conditions. If you have an A/F meter you should find an idle setting of about 3.5% will give you best performance according to JW. I've always set mine by feel. I've found that if @ warm idle I get good pull up to redline and then the idle speed does not drop down before returning to the correct point, or if @ idle there is no hunting, then it's good. A recent test w/ an LM-1 confirmed this point is 3.5%.

[mca]

Originally Posted by Paulporsche

Craig,

14.7 is stoich so your LM-1 would show it as "joosta right" for economy and emissions. More importantly, I think, is that stumbling you were getting. Has it disappeared w/ this setting?

For some reason I was thinking that 14.1 was stoich. Good to know that I am ok at 14.7.

Still have stumble. My troubleshooting was on pause this weekend since I had to do my final valve adjust. This was my first solo valve adjust - between changing the oil, sump plate, checking my cam timing, and putting my muffler back on it took me all weekend to complete. Not as fast as others b/c I am a noob.

Next step is to swap coil then dizzy. Again, I am not too bothered by it. Just want to make sure that I am not running too lean where I would be damaging the engine.

Four of us in the area are going to split the cost of an LM-2. I have been borrowing the LM-1 and it sure is a nice piece of equipment to have on hand.

[Vereeken]

Originally Posted by euro911sc

Been folling this thread closely... What if you have no ecu?? like my ROW? All I have is the mixture screw...

Comments Sherwood?

-Michael

It is easier. You can play with the idle adjust screw and fuel mixture screw. I have an LM-1 but with RPM sensor and it tells me I am fine at idle anywhere at between 14 and 14.7 I tbelieve that that gives you 3% and not 3,5% co but maybe it has something to do with altitude. I have seen numbers on this site that I can not match from people in Denver and that is pretty high up.

Stupid thing is you do not really need the LM-1 on a RoW SC. If the idle hunts at warm-up you are to rich if it stalls at warmup you are to lean. If you are in between and your warm-up is smooth then believe it or not the LM 1 shows 14.x. I would say the differen is about 1/2 a turn on the mixture. Ofcourse this is when cold start valve , AAV, Thermo time valve all work well.

I am at sea level. Car is a 1983 SC RoW no Ecu no 02, no mods.

AT 6000Rpm you want to have 12.7 or somewhere around that. I run 98 Octane.

One thing that made me go around the block several times was the decel valve. I could not get my idle stabilized even though all my numbers where spot on; until I swapped the decelvalve and the tubing. Turned out the decel valve membrane had a hole in it and let air through once every so now and then ;o)

Also one for the books I believe your timing needs to be excellent before setting the mixture. I was trying to do mixture with timing fairly far off and I did not get good results. Now this could just be me being stupid.

Michel