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I mentioned this in another post but didn't get much response...

How do you adjust the throttle valve switch? My Clymer goes through it but neither of my throttle bodies match the one in the manual. Plus I don't get the correct reading with the volt meter like they show...Any help? Thanks!

Go to this site http://www.pelicanparts.com/techarticle ... switch.htm and click on the 1.7/1.8 throttle swtich adjustment and follow it. This is what I used to adjust mine.

thanks for link, I have haven't seen that one before. I'll have to make sure it is setup correct. Now that my car is drivable after today the problem i have is that you have to nurse the throttle when starting other wise it bogs down and almost kills... but then it is ok from a rolling stop or upper rpms...

That is generally not the throttle valve switch. It it was, it will drive poorly at any speed....anytime the throttle is all the way closed.....and then reopened. What you are describing is commonly caused by several otehr problems. Most commonly....a PCV valve that is causing the MPS to dump by opening early......an the next most common is the need for adjustment at the outer full load enrichment stop on the MpS. That is the outer aluminum plug that cover the main mixture adjustment. It must be screwed in a precise amount. Too far out and you bog down from too much fuel when you crack the throttle....too far in and you bog down (usually with popping) from teh mixture being excessively lean off the line.
Yes...of course the TPS can cause a small amount of this...but between the two adjustments...TPS and full load stop on teh MPS.....the MPS is teh quicker and more sensitive of teh two.

Also....I am assuming you are speaking of D-jet? The L-jet switch is totally different.
Also...teh VOM readings are only to tell you if the switch is worn out. If the resistance is very high...clean everything. The D-jet TPS does not work on resistance. It is simply a series of mechanical switches. But....what the book is getting at is that if teh resistance is waaaay too high....the signal is delayed.

Also do a search. I have detailed adjusting the TPS numerous times. All of the manuals are incorrect. Even teh Bentley...IMHO. Ray

Ok...I have a D-jet TB and throttle valve switch in front of me. First you must understand that most of what is in teh books is correct....but totally con-contextual and rarely specific to part #. Also....as with ,sot otehr D-jet parts.....the last books available were written in teh early to mid 70's at a stage when they still had no desire to really tell you the nuts and bolts of what and how to adjust. Just like tje MPS....there is no detailed 100% complete adjusting guide.

First...get familiar with teh guts of this thing. Take the TB off the manifold and out of the car. For the sake of this description...I am right handed. I hold the part with my left and do the checking and adjusting with my right. It make a difference.

First...just slightly loosen the screws. You want it to take a little effort to move the plate. If teh screws are too loose, just tightening them down will change the adjustment.

Lets see what we are looking at: at the 6 through 9 oclock position you see the double row of 9 contact fingers...18 in all. The outer set of 9 is pin #9 on the plug. The inner set is pin # 20.
Looking at the brown plastic "for" attached to the shaft...you see a pair of "whisker contacts....trapped between a pair of brass pins. One pin....the furthest aft in teh clockwise direction....is going to pin # 12 or 47...or 12/47 both. By the way....this is a five pin connector...but all of this is the same on the four pin connector basically.
The forward post of pin on that brown fork....goes to the whisker switch that drags across teh 18 pairs of contacts. Each time the switch crosses from one contact to the other.....all of your injectors get a "bump"....or an injection. The throttgle valve switch is roughly equivalent to the accelerator pump of a carburettor.

How this thing works: When the TB plate is closed tightly and you are off the gas.....and the TB is adjusted properly.....you should see two very important things. (1) That forked brass switch in the brown plastic arm attached to the shaft.....should be IN CONTACT with the brass pin/post....that is furthest toward clockwise or 12:00. This is the closed position. Tha brass pin/post.....goes to the wiper arm that is attached to pin # 20 on the plug.
The foward end of this little brass fork switch in the plastci fork arm....MUST be OUT of contact with the other brass pin/post. That would be the post /pin that attaches to the wiper arm that drags the accelerator/injector contacts. Are we oriented now?

The object of adjustment is this: When the TB is closed tightly......the fork switch....must be in the rear stop position as described in teh paragraph above. The whsisker contact that drags the accelerator/injector contacts....MUST....MUST be on the contact strip......that is conected to pin # 20. This is the INNER row of contact teeth not the outer. BUT.....BUT........when the switch is properly adjusted....................the whisker wiper must be only a few thousandths from dropping into the next void space bewteen the two dircuit paths. In other words......you want the whisker switch to be contacting metal on teh inner circuit path of #20....while the TB is in closed position......but you want it incredibly close to dropping onto the next ciruit path (outer ring of teeth pin # 9).
When the TB is closed...and the "fork" switch...is against the rearward post/pin......the wiper that runs over the accelerator/injector grid is disabled.
The object here is sensitivity. Ant minute throttle movement....unseats the fork switch from the rear post/pin.....and switches it to the forward pin that now makes the wiper that goes across the accelerator contacts.....live. The object is that the split second the fork switch moves....the whisker/wiper must be in contact with the metal of one of the two circuit paths.....of there will be a lag. This is why you "park" it on the first....or inner path attached to pin # 20.

Still with me?

With the TB in my left hand...and my fingers pushed into the plenum side of the plate.....and the TPS with black cap off facing me....with plug going to the right. Attache the voltmeter terminals....(set the meter to continuity...not ohms....those are meaningless here)..to terminals #12 and # 20.

(1) Hold the plate closed tightly with your left fingers......rotate the switchplate counter clockwise. the fork switch will be against teh most rearward pin/post. There should be no "beep" of needle movement....whichever you are using....no contact. You will see the fork switch on the rear post. This is off position and in teh fuel cut-off models...anytime teh fork switch comes out of contact with teh forward post and into contact wit hthe rearward post....the injection cuts off.

(2) slowly....carefully....holding the plate tight shut.....turn the switch plate clockwise.....in increments of just a few thousandths at a time.

(3) When the forks switch moves to the forward post...the needle should swing...or the meter beep...whichever you have...singifying contact. This means that the wipe rarm is now live.

(4) the thing to verify....is the little contact "tit" on the end of the wiper arm. If the adjustment is correct.....it should be just a few thousandths from sliding off of the copper circuit path of the inner ring of teeth...into the void between the inner contact path (terminal 20) and teh first tooth of the outer path connected to # 9.
If it is too far from teh edge....move teh plate clockwise a few thosuandths at a time until it is just so.

Lock the plate down. Open and reclose the TB...to reset teh fork switch. Close teh throttle and check that in teh closed position the fork switch is again on teh rearward post only.

The only point of the 2* BS in the boks...is that each contact on the wipe rstrips represents about 1.5 degrees of spacing. If you were not exact....generally a furether 2* movement would get you into a proper useful position for teh wiper start point. Crude...but sufficient for most people.

There is more to this...but it depends on the part # of the switch. There are also ways to increase the sensitivity. Send me a PM and I can send you pictures. Ray

Thanks for the detailed instructions, they help alot. From the info i got from the book along with some common sense after figuring that thing out that's how I have mine setup. Luckily I have two of them and am able to "play" with one. I've taken them apart, cleaned them up, used a small amount of di-electric grease, and set them up about how you described. But, I'm gonna go through it one more time to double check now that I have your instructions.

I did as you said and put a 3.5mm fixed orifice in the PCV and that really helped with the bogging from a stop. I have the MPS from the motor I put in that I am gonna try too. Since the one I am using was for my 72 I think the matched MPS for my 73 motor may help. We'll see. As for other things I have been driving the car around town seeing if any other bugs need to be worked out... You're help is much appreciated

By the way...please do not put any dialectric grease or any kind of oil on the contact plate where the wipers cross teh enrichment contacts. It would seem logical to do so to keep weardown....but what it causes...is skipping of the wiper contacts across the circuit pattern. Its like hydroplaning.

Also....there are a great many switches...even brand new...that cannot be exactly adjusted properly.....either ith teh simple factory method of waiting for the witch to open when turning clockwise and them 2* more...orwith opening up and doing a detailed adjustment. This is because of tolerance/slop in teh build of each fork switch in teh brown fork. There are ways to greatly enhance the accuracy of the throttle valve switch. Very simple and no-invasive. They make adjustment much much tighter. Send me a PM and I will e-mail some macro shots. Ray

Thanks for the tip. I only put a small amount of di-electric grease on them because there was some on it before I cleaned it with an electrical cleaner...PM sent for the macro shots

I am putting together a simple word document that has about a dozen close up imbedded photos. It is an adjustment "how" to for the TPS. It will be e-mailable but probably be about 3-4 megabytes. I should have it done by monday. Ray

Thanks Ray, I'll keep an eye out for it

hi Ray

Do you still have that document on your PC ?

/ Ploug

I will check. Ray

Ray, a way to check that the throttle switch is correctely adjusted, without having to remove the throttle would be:

1. Turn the ignition on (motor off)

2. Slowly by hand move the trottle from closed to open, listen and count for 20 injector pulses.

3. Release trottle, check that 1:st injector pulse comes as soon as trottle leaves the fully closed position (with no actual delay/play).

or?

/Lars S

Lars S wrote:Ray, a way to check that the throttle switch is correctely adjusted, without having to remove the throttle would be:

1. Turn the ignition on (motor off)

2. Slowly by hand move the trottle from closed to open, listen and count for 20 injector pulses.

3. Release trottle, check that 1:st injector pulse comes as soon as trottle leaves the fully closed position (with no actual delay/play).

or?

/Lars S

Lars....yes...I can do that...but....hat will only do if the TVS is in perfect condition and has no manufacturing slop which is very common.. That only checks for function.
The problem here that none of the manuals describe at all...is that you are simultaneously adjusting the relative position of the forked micro-switch and the exact starting position from throttle closed point...of the wiper arm on teh enrichment circuit track. When you move the throttle less than 2*...preferably 1*....the forked switch must simultaneously contact teh forward pole....connecting the wiper arm to the circuit....and the wiper arm must instantly make contact with the first enrichment track of the 20 on the plate.

The problem is that there is typically excessive slack between the poles for the forked switch....and there can be excessive float to the throttle shaft connector bushing. What this leads to is delay between the synchronous connection of the forked switch and the wiper contacts at the right moment. It means that perfect factory adjustment will always leave either the wiper or forked switch...on of the two...out of adjustment by a minute amount.

While you are correct...that someone paying attention can "check" their adjustment in this manner....they cannot see which part is the problem when the switch does not adjust...without removing the cover. In my experience...they can all be quickly fixed.....and fully 50% of all switches I have found since the mid 80's ...have this probhlem. Ray

I did a check on my 412 today (adjusted the switch a year ago by instructions from the book), there was now approx 4o (degrees) play before th 1st acc pulse came on. This does nott feel much when turning the throttle, about 3mm at the outmost end part of of the gas wire bracket (the part of the bracket which is farmost from axle center), however I guess it is to much.


/Lars S