Tuning question

[col320ce]

I find the car hard to tune as once it's warm and I've parked it in my garage and set the CO sensor up I think it's starting to go back on warmup set up. So is it possible to fool the car into thinking that it's fully warm? My thought is that once the lever that the WRD actuates with gets to a certain place it has fully turned off the startup conditions of the FIP. If this is true, can I warm the car up then unscrew the thermostat and fully depress the FIP lever and block the WRD air intake and tune the car. I assume if I keep it idling when not adjusting the FIP then this would keep the car warm enough to tune it. Does this sound silly?
thoughts?

[ctaylor738]

Likely the opposite is happening.  When you shut the engine off, heat in the cooling system will rise, and the WRD thermostat is near the top. So I would think it would warm a bit waiting for you to start your testing, the drop a bit when you start the engine.

Easy to check with an infrared gun.

Cheers,

CT

[stickandrudderman]

Why not just remove the aux air filter and confirm warm up device is functioning properly. If it isn't you'll need to rectify that before you'll have any hope of correctly tuning the engine.

[col320ce]

WRD is running properly but just because it's not sucking in air doesn't necessarily mean the plunger has fully turned off the FIP warm up conditions.  Although not sucking in air is my best marker for the car being warm.
Another question to ask maybe: Can the car stay warm (WRD off) when idling after it's been warmed up. I don't think it does.
Part of my confusion is that I can tune it as I'm doing however when I drive it and re test it's not the same as the previous measurement (can be off by a lot).   I assume this is because I'm trying to tune it with part of the WRD back in a partial warm up state.

[Pawel66]

I remember that some of the troubles with tuning of my car were related to:
1. Warm up had to be done while driving, not just by reaching temperature while standing idling in the garage

2. It takes a good ride for the changed settings to get in place and start performing

Those took time and were difficult to plan due to weather on days I could devote to car.

[ctaylor738]

When I am messing with the idle mixture, I will leave my Gunson's Gastester hooked up to a 12 volt power supply so that I can do a tailpipe test with the engine running after a test drive.

Cheers,

CT

[Pawel66]

When I am messing with the idle mixture, I will leave my Gunson's Gastester hooked up to a 12 volt power supply so that I can do a tailpipe test with the engine running after a test drive.

Cheers,

CT

I thought it was only me.... I thought it must have been silly...

This is to have the meter ready, not to have to wait until it warms up and calibrates because during that time the car will chill down a bit, even idling... right?

[ctaylor738]

Correct.

CT

[dirkbalter]

When I am messing with the idle mixture, I will leave my Gunson's Gastester hooked up to a 12 volt power supply so that I can do a tailpipe test with the engine running after a test drive.

Cheers,

CT

How do you guys like the Gunson Tester? I am tempted to buy one but the reviews are mixed.

[Pawel66]

Fine for a weekend mechanic.

[col320ce]

I have a Gunson but I don't like it at all. I bought a Bosch MOT analyser (from the 1980's) that I think works well. It's massive and not very portable though.

[ctaylor738]

My Gunson has served me well. 

I think it's fine for the level of precision needed for cars without a catalytic converter.  I have a bud who does Virginia smog inspections that I use as a backstop when a car needs to pass the District of Columbia emissions test.  The Gunson has always been within .5% of his readings.  You need to know its limits and understand that it will drift and that you need to consider that when you get a reading.  And that you need to allow it to calibrate at the end of a tuning session and adjust the reading accordingly.

I have used it enough that I often don't wait for a final reading.  I put the probe in the tailpipe and if the reading jumps quickly to 5%, I stop and adjust.  And the same if it starts to fall below 2%.

The Split Linkage Test will almost always get you in the ballpark.

CT

[dirkbalter]

Fine for a weekend mechanic.

Thats me.
Thanks to all for the feedback.