MPS Adjustment, It helps to have the right tools Options

[Mblizzard]

I post this only because I struggled to find the proper tools to adjust my MPS after going to a 2056. While I was able to make adjustments using standard tools, I could never get it exactly right. I asked several people about where I could get the right tools and could not find them. It is likely that this is well known to everyone but me, but I finally found what I needed at Tangerine Racing.

It is such a simple tool but without it you can't really be sure you are adjusting only one of the screws without changing the other one. So once again Chris is the man that can put the right tool in your hand. I have been close on the adjustment many times only to mess it up trying one more small change.

If you are playing with your MPS just get one of the MPS tuning kits from Chris it will make your life much easier.

[76-914]

Yep, got one with the kit.

[rick 918-S]

Anyone ever written a how-to for adjusting the MPS? Is it on the Brad Anders site?

[Dave_Darling]

Yes, it is.

http://members.rennlist.com/pbanders/manif...sure_sensor.htm

--DD

[Brian_Boss]

If you don't have the exact RLC meter that Brad used ( I forget the brand and model but it is no longer made) the values he gives are really more of a guideline.

I have a pro quality meter but not the specific one he used and the L values needed some tweaking.

[Mblizzard]

If you don't have the exact RLC meter that Brad used ( I forget the brand and model but it is no longer made) the values he gives are really more of a guideline.

I have a pro quality meter but not the specific one he used and the L values needed some tweaking.

Brian,

Are you saying you can set up a MPS using values? I have been trying to do it to A/F meter readings. I have an extra MPS that I may want to have someone play with.

[DRPHIL914]

I believe its called a wavetec . A member here did mine and his own but we both found those settings to be too lean (scottinnh) and so using Anders as the guide then gradually used my a/f meter to get it in good running . As I took it a bit more rich the idle smoothed out and now runs great. If you get a hunting its either vac leak or the mps is set too lean(if all other items are previously sorted)

[Brian_Boss]

If you don't have the exact RLC meter that Brad used ( I forget the brand and model but it is no longer made) the values he gives are really more of a guideline.

I have a pro quality meter but not the specific one he used and the L values needed some tweaking.

Brian,

Are you saying you can set up a MPS using values? I have been trying to do it to A/F meter readings. I have an extra MPS that I may want to have someone play with.

You can calibrate them using a meter that can measure inductance (usually called an RLC meter) and a hand vacuum pump. If the specs are not on Brad Anders web site, they are in an old post here.

The issue is that there appears to be some variation between meters. Unless you have the exact model Brad used, it will be a ball park setting. In my case, made the car driveable but needed fine tuning with a/f meter.

If you had a known good MPS, I'm pretty sure you could "copy" the calibration to another using any decent meter.

[JeffBowlsby]

There is more to it than that. Brad used a Wavetek LCR55 meter to develop his values...I agree with the above, I have found them to be lean, so I richen them up. The MPS calibration values are very delicate and significant A:F ratio changes can occur with only slight changes to the MPS. I have that same meter and have calibrated many MPS but have developed my own values, based on my location and the requirements of my personal 50KMI 2.0L. Values for your specific car will likely be different than mine. I also own a couple of NOS 043 MPS (Not for sale]...and guess what...their calibration is not identical to each other on the meter.

Be sure to index the calibration values to factor in changes in elevation from your location to Brads location in AZ, which affect atmospheric pressure as Brad describes on his webpage.

Even with that there are other variables - engine wear, timing, sensor variances, actual injector flow rates, barometric pressure differences due to local ambient weather, etc.

The published values should be close enough to get the car running, but the specific calibration needs fine tuning with an exhaust gas analyzer, WB02 or similar precision equipment to get it right on, due primarily to just too many variables with engines that are 40 years old. The old carb method of listen/drive/tune is laborious, but not impossible, just takes time. But there is a risk that if you don't understand or realize what changes you are making, with three different calibrations that are interrelated, you could potentially cause more damage and make things worse.

[Steve_R]

Can someone outline the steps to adjust the MPS using a dyno and an exhaust gas analyzer?

In my area there are several shops that have a dyno and can measure AFR (air-fuel-ratio).

Can I just record the AFR under full load, turn the engine off and make an adjustment.
Then, repeat until the full load AFR is at the correct value?

[Mblizzard]

Can someone outline the steps to adjust the MPS using a dyno and an exhaust gas analyzer?

In my area there are several shops that have a dyno and can measure AFR (air-fuel-ratio).

Can I just record the AFR under full load, turn the engine off and make an adjustment.
Then, repeat until the full load AFR is at the correct value?

I thought it was that simple but it is a little more complex. Read this 1000 times and you will get the hang of it. Well maybe you don't have to understand every word but you do need a solid understanding of the way the inner and outer screws work together so that you know what to change. Focus on understand what each screw does first then read the adjustment section.

[Bleyseng]

Can someone outline the steps to adjust the MPS using a dyno and an exhaust gas analyzer?

In my area there are several shops that have a dyno and can measure AFR (air-fuel-ratio).

Can I just record the AFR under full load, turn the engine off and make an adjustment.
Then, repeat until the full load AFR is at the correct value?

First remove the WOT stop without destroying it by heating the epoxy and turning it in so you can dig the epoxy out of the threads. Then back it out.
Now you can go on a dyno and run under load in 4th gear at 2500 or 3000rpms and check the AFR. 13.7 to one great onto the next test.
Run it thru the gears to 70 mph in 4th under load. What is the AFR on the dyne chart say? Should be pretty flat around 13.5 to 13.7 to one.

Now do the WOT test in 4th gear and it should start out at 2000 rpms at 11.5 to one and then climb to 12.5 to one at 5000 rpms. See your printout. If it's good install the WOT so it barely touches using a Wavetek to tell you when it hitting. If it's too rich install it and adjust to that spec using multiple dyno runs to do it.

Finished? Test drive it and it should be really smooth accelerating and have plenty of power until 5000rpms under WOT.
Now, epoxy the WOT stop so it doesn't move and make sure the vent holes on the MPS are facing down so water doesn't get into the diaphragm area. Too many MPS's are mounted wrong so water gets in and rusts em out.