I have been searching but not finding.

I am almost finished with my 2056 with D-Jet. I know there MUST be some minor adjustment to the MPS but I cant find how, where, why etc ???

Can someone explain to me what I need to do, how to do it or just point me to the million threads on here somewhere

Thanks

you need to calibrate it with a wide band oxygen sensor
if you can't use a wb, then leave it alone....

I personally would NOT try to tweek one with out the WB

Geoff on this board used to do this service very reasonably
or buy... borrow a WB and do it yourself under load

I've tweeked a couple of them for a 2.0 under load with a WB
(not a 2056 yet though)

brant

brant

so what exactly will the engine run like before the tweek??
Can I cause damage on engine break in before i can drive it to a local shop for calibration??

a lot of shops traditionally have just "tweeked" these for the last 20 some years by ear...

I would never trust an adjustment not done with true data and a WB readout.

otherwise their guess is not much better than anyone elses guess
this is one of those things that can be done on a dyno, but otherwise if a shop wasn't willing to put it on a chassis dyno and do it right I would walk away...

doing it under load is ok too
and sending it to someone that has a similar engine spec would be ok too.

if you run it with a stock MPS it will be lean and could miss alot. Drive it and it will be really lean maybe burn a hole in a piston.

By ear its usually too rich which will wash the oil off the cylinders and you'll toast your rings.


What cam? If its a stock grind you can sneak by until you adjust it.
Raby cam or something else its time to adjust it.

If you are really careful you can remove the epoxy off the WOT stop and pick it out of the threads. This way you can unscrew the WOT stop to access the inner screws without taking the damn thing apart.

Rabby cam 9550

So what is the solution? I dont have a Wideband or Dyno in my garage lol

I need to send the mps out?
Who wants to adjust an MPS for a fellow teener??

Engine is a 1973 2.0 with 96mm jugs, keith black pistons, chromoly pushrods, 9550 cam, Djet

When I did my 2056 after break in it was soo lean that I feared what Jeff said. I started with NGK's 10(very cold) started to try to richen it up but it was a long process even with an LM1. When you tweak those screws it makes an enourmous amount of defference. A 1/16th of a turn is probably 3 heat ranges of spark plugs. You will be looking for a AFR 12.8 at the bottom and 13.8 on the top. The best way I found to adjust was to have someone else drive me around at 3500 rpm and watch the LM1. When you are getting close you will start to get a jump in power above 4K that will give you a nice smack in the ass.

Jo, pm Geoff (Bleyseng) and send your MPS to him. I have a variation of your build but very close. After a few pm's to Geoff w/ my engine data he dialed in an 051, which I had, for my needs. Works perfectly. Appx $100 + shipping. Allow him a few weeks as he likes to test drive his creations before sending them out.

I f your mps has the epoxy removed, you have access ti the outer plug/screw. It is the full load stop. Id f you back it out count how many turns out it takes. From there you will see an inner and outer screw. Turning the inner screw by itself without moving the the outer counterclockwiseplug/screw or out, will richen it across both idle and midload. If you get a broadband a/f meter from summit for $200, you will know exactly where you are.
Get on anders site and Bowlsby's. Print out the bosch stock info and ut will twllyiu exactly how ti do this.

I just did this wit a stock 2.0 stock setup. The mps was set exactly to factory setting g but when installed on my engine it was way lean. Once it was readjusted it is running perfect, but it was adjusted richer a out 1/2 turn out. You will have to recheck it and verify it in your engine to make sure it is right.
And yes all my other components are correct. Timing is spot on, cht is the correct one and it was tested to verify correct resistance.
Good luck.

Doesn't anybody remember that you can put a resistor in line with the head sensor to richen the mixture up across the entire rpm range? You are tricking the brain into thinking the engine is colder than it is. The factory did it. You may still be able to buy one. I think its about 250 ohms. That may not be enough. I did this with an adjustable potentiameter to find the best mixture, but I had an oxygen senser/bung in my exhaust to dial it in. My 2270 needed 425 ohms resistance with a bone stock untouched mps. My car was dynoed after this and I didn't need to make any adjustments. The mixture looked great throughout the rpm range. I built my own oxygen sensor from plans off the pelican site. I imagine you could put an adustable inline with the head sensor and do some acceleration runs and pull the plugs and check if their rich/lean. Do a search on our lovely site and see what comes up.

reading plugs is not wise with modern gasoline.

Thats not accurate. The ballast resistor on TS2 only affects warm-up. Once the engine reaches operating temp, the ECU takes over and the ballast resistor has no effect.

Seems to work extremely well for me.

I have never tried it but PBAnders says the TS2 is only in effect during the warmup. I have used different ohm resistors to get the cold idle mix correct.
Its so easy to adjust a MPS to set the AFR "IF" you have the correct tools and time.

If you are indicating TS2 as the head temp sensor, you need to refresh your memory of Brad's site. The resistor in line with the head temp sensor affects the signal to the ECU all of the time. He states that resistance of up to 150 ohms is good for the warm up mixture and resistances of more than that will affect the operation after warmed up.
I think Andy is correct.
Tom

Before I adjusted the mps, I had a potentiometer and it took quite a bit to fool the ecu, but it did change the richness across the board. I had a lean running condition so idle was way fast. Of course the better long term fix was to adjust the mps so that the a.f. ratio is consistent in bot partial and full load.
Get an a/f meter and follow anders.

I also got a n mps that was super rich, when they fail the default is rich.

jsayre914,
I guess if the 2056 is going to run lean, you could put in resistor temporarily just so it wouldn't be too lean. Eventually you need to get the MPS adjusted.
I exchanged PM's with Brad some time back about this issue of adding or lessening the in-line resistance of the CHT circuit and he said then that he had often thought of putting in a multiple position switch to modify the mixture from the driver's seat. I guess then you would need to have some way of telling if you needed a richer mixture or leaner mixture, either some kind of meter or experience in conditions that would require a different mixture.
Tom

so it is not ok to break in a 2056 without adjusting the mps first. and you cant adjust the mps unless the car is running




Walk me through this step by step. (shortbus style)

1) borrow a tool from a friend (what the heck is a lm1?)

2) remove the goop out of the mps and back out the screw (refrence pbanders site)

3) follow normal engine break in procedure while adjusting the mps??





p.s. Bleyseng is currently south of the border and is willing to help me out in a month

What is there to misunderstand? Its pretty clear:

"Warm-Up Transition: When the engine is below its normal operating temperature, more fuel is needed to account for condensation and incomplete mixing until the engine is fully warmed up. Engine temperature is sensed by the TS2 sensor. The ECU has a warm-up enrichment circuit that senses the resistance of the TS2 sensor and corrects the mixture for the engine temperature. When the value of TS2 drops below a threshold value (typically 300 ohms), the warm-up circuit in the ECU has a cut-off characteristic, so that no additional decrease in TS2's resistance will affect the mixture (i.e. the engine is fully warmed-up)."

From here: http://members.rennlist.com/pbanders/djetfund.htm

And:

"These data also have application for using ballast resistance for tuning. It has been a common practice to add ballast resistance to the TS2 sensor to increase the richness of the mixture to accommodate larger displacement and other modifications. The problem that the data above point out is that if you do this when the motor is fully warmed-up, the amount of ballast you need to add will need to be such that the combined resistance of the ballast and the TS2 sensor exceeds about 300 ohms. Since TS2 drops to as little as 50 ohms when the motor is hot (head temps of 300 F, for example), this means that the ballast will be more than 250 ohms. But because TS2 resistance increases rapidly as the engine temperature decreases, the proportional effect on Vout decreases. This means that for cold and cold-cold start conditions, the mixture will not be rich enough for a large-displacement motor for good characteristics. As a result, using ballast resistance to increase the overall mixture will likely lead to drivability problems.

Using ballast resistance to improve warm-up characteristics, however, has some good potential. If you are experiencing problems with a lean mixture during warm-up, a modest amount of ballast resistance (e.g. 50 ohms) will produce a richer mixture, but will not affect the mixture when the motor is fully warmed up. This permits, within a range, the independent adjustment of warm-up mixture, idle mixture, and hot mixture."

From here: http://members.rennlist.com/pbanders/ecu.htm#CTC

I've use a 480 OHM resisiter connected to the head temp senser with very good results on three of my 2056 engines. Give it a try--you can buy them at Radio Shack for a few dollars.