engine and drivetrain Which Tii Throttle Body Is Early And Which Is Late?

[jgerock]

I've got to agree with Matthew on this.  Since your engine is tired and the KF pump recently rebuilt (along with the distributor), then the other engine components are not up to what the injection system is looking for.  I try to use my AFR gauge as a baseline for troubleshooting and note if things don't seem quite right, then drive the snot out of the car and enjoy it just as the engineers designed it.  I eventually found a bad plug and coil wire and thought my fuel pump was bad (that made the car run lean, "swinging the AFR gauge around"). 

 

As long as you have a good, constant fuel pressure and good spark and the engine runs strong, I wouldn't worry about it until you decide to tear it apart (slippery slope). 

 

My question to you Rob: Will you bring the tii or the Coupe to Vintage?

Edited May 2, 2013 by jgerock

[thehackmechanic]

Jim, I am trying like hell to get the tii sufficiently well-sorted to take, but if I have to take the E9, it ain't hardship.

[thehackmechanic]

Update:

 

The spare throttle body I bought on eBay arrived. It's the newer "less sensitive" style with the shorter arm. I cleaned it up. Though I couldn't get the butterfly unscrewed and thus couldn't pull and directly clean the throttle shaft, I oiled it with enough Silikroil that the shaft moved freely. I made a new gasket, put the TB on the car, put the "correct" Jack Fahuna linkage rod back on, and sync'd the TB to the pump by the book.

 

No change; the AFM still reads 15 at WOT. I didn't expect a change, but hell it was something to try.

 

I put the original TB back on and set it back up. Again, no change.

 

I sighed, thoroughly documented the original setting on the verboten screw (again, I just had Hans Utke rebuild this pump), and began turning in the screw and making WOT runs. At about 1.5 turns, I'm finally getting sub-14 readings on the AFM. By diddling with the idle air mixture screw, I was able to get to run acceptably lean at idle and other non-WOT conditions. I did not have to offset the cam relative to the hole in the tuna can or change the length of the linkage rod. Go figure.

 

The engineer in me really wanted to have that "eureka" moment where I figured out what was wrong and got correct WOT AFM readings without having to futz with the verboten screw, but this is good enough.

 

I do have a life, ya know.

 

:^)

[jgerry2002]

How old is your fuel pump? I had a "rebuilt" fuel pump that tested fine at idle at 28psi but obviously had issues under load and I fought the SAME 15+ WOT AFR for a long time until I finally swapped it for a fresh fuel pump. In my case I installed an in tank pump per the FAQ. I finally started to make headway and the AFR improved bigtime.

 

The only way to test was a second gear WOT pass and wind it up. Or go to a track day with some place that has a long straight.

 

Though in my case I did change the verboten screw (there are no issues adjusting this when you have a wideband, it just fattens up the mixture across the whole range), and I do have the Wes Ingram "sport" linkage for a top end kick to match the 2.2L Metric motor.

 

I'm at ~13.0 AFR now. It'll stay that way even on the track.

 

The other thing to consider, fuel is NOT the same as when these cars were introduced. That summer blend does seem to have an effect on AFR (slightly leaner).

[thehackmechanic]

Justin, several steps back I replaced what was possibly the original fuel pump with a brand-new E28 pump.

[ray_]

Rob, I didn't see if you mentioned that your lean readings at WOT are throughout the rpm range. I wouldn't be too concerned with 15:1 at 3500 rpm at WOT.

 

GL,

[qworld]

After months of chasing the same problem ( too weak at speed too rich at idle) in my 73 Euro Tii I stumbled across this topic.

 

My otherwise standard engine  has 180psi even  compressions, correct distributor and every conceivable service part has been checked , measured , measured again and /or renewed ( eg fuel pump, pipework, filters, cold start linkage, etc etc) with reference to every manual publicly available. The only remaining items outstanding are the Kugel itself ( which shows signs of having been rebuilt in the past) and the throttle body.

 

I read about some guys  who solved this problem with a change of throttle body due to wear of the cam , but my (later type) shows no obvious wear to speak of.

 

Now I have fitted a wideband AFR gauge/ lamda probe and was shocked to discover I have AFR of 18+ at highway speed and yet 12 at idle. The ONLY way I can get the speed reading down to something  anywhere near to 14 is too enrich the verboten screw considerably but then idle looks terrible. 

 

However adjusting idle also presents a problem.  If I attempt to lean the idle mixture screw,  rpm increases to the point where I can no longer get it down by backing off the idle adjustment screw.. because it no longer touches the cam. To get a reasonably smooth 950rpm tickover I therefore have to resort to enrichening the mixture. Another catch 22. And in case you are wondering the linkage/kugel/throttle body adjustment  has been checked again and again. 

 

I would love to hear if Mr Hackmechanic managed to resolve his issues longer term or if anyone else has dealt with this problem since the topic first arose?

 

In previous 30 years  of fooling with carbs I never had a problem like this , but then this is my first Kugel . 

 

 

 

 

[thehackmechanic]

I never fully solved it. I more got to a compromise and moved on for reasons of my mental health. I got it so the reading was, to me, acceptable at WOT. (I don't remember exactly where it wound up; I haven't driven the car all winter; it was never as rich at WOT as others recommended, but it was no longer off the chart lean; perhaps 14 or so.) I then loosed the pinch point on the throttle body shaft and played with where the cam was over the hole in the tuna can until, at highway cruising speed, it seemed about right. Again, I don't remember exactly where it wound up, but somewhere in the neighborhood of stochiometric 14.7:1, maybe 15:1. I don't recall having a major problem getting it to behave at idle, as that's just the little adjustment screw in the tuna can.

 

But, no, I never got it as rock-solid foolproof dialed in as some other posters have reported.

 

I always wanted to try it with a tank of non-oxygentated gas (no ethanol) to see if that made a big difference. Just haven't gotten around to it.

[PaulTWinterton]

where the cam was over the hole in the tuna can

 

I think you nailed it.  Cam OVER the hole makes all the difference. As opposed to AT THE EDGE with the 4mm tool.

Only the Haines manual refers to this "non-factory" tuning scenario.  They show the cam at the mid-point of the hole.

[wegweiser]

Because there's really nothing I enjoy more, than helping Rob twist his mind in to knots... here are some other possible things to consider. I remember this, from my days of selling tii "linkage kits":

 

According to my white parts books, the bell crank bracket (the portion bolted to  the block, NOT the pivoting H shaped portion) has an early (up to US VIN 2761817) and late version... I suspect the "H" shaped pivoting bell crank may also have changed - but there's no notation of it in my book. Why the change to the bracket alone, in mid 72??? Beats me?

 

Also: The vertical rod at one end of  the "85mm - measured, adjustable rod" has an early and late version as well. (at US VIN 2762372). Also, there's a different return spring used, as I recall (too lazy to look up EVERY part, tonight). 

 

The clamping portion of the vertical shaft to the throttle body has an early / late / then re-used VIN range. Follow closely here....just reading what the book tells me. Please don't get angry:

 

clamp Nr 13 54 1 256 469 used until 2761944 then AGAIN (you heard me!) from 2762014 to 2762372

 

clamp Nr 13 54 1 257 036 used on all others and would be considered typically the "late" version. 

 

OK... are you in my taxi yet? GOOD! The SAME odd, back and forth VIN ranges affect plastic runners and 121 / E12 head vehicles, as well. I chalk it up to supply issues in Munich... Who knows?

 

Here are some photos.... hope they load. And yeah... I keep freshly plated tii linkage in my kitchen at all times. I'd have to look at my (theoretically unmolested) tii to tell you which one is used on my own car (27620XX)

 

I'm not saying this is the gospel truth... but I've spent DECADES looking at 2002 parts diagrams as a fiche jockey, and there's some cryptotii-ology afoot!

 

I hope this helps...really I do! maybe someone installed some combo of incorrect linkage parts on your car...or maybe it's just Ethanol poisoning. I might be facing the same dilemma when I start using an AFM/gauge.

[Jeff]

Don't be intimidated by the main fuel screw (verboten screw)on the Kugelfischer pump. It is adjusting an eccentric shaft that is changing the stroke of the fuel plungers (6.5mm pistons) in the pump. You can measure the stroke of the piston before you adjust the screw for a stock base line. So you will have the ability to adjust it back to the stock location that Hans set it up if you like.

 

If you remove one of the 6mm allen cap screws on the center line of the pump head, then remove the suction valve under it. You then want to mount a Dial Indicator on the Kugelfischer pump securely. You are going to measure the stroke of the Kugelfischer pump piston with the dial indicator just like you would time a Two Stroke motorcycle engine. You just need to turn the engine over by hand and record the stroke of the pump piston. Make sure the engine its fully warmed up before measuring. All this can be done with the pump mounted on the engine. 

 

Increasing the stroke of the piston will make the fuel mixture rich and deceasing the stroke lean.

 

But knowing the Stroke setting of the piston in thousandths of a inch will allow you to make precise adjustment and still go back to the magic spot the Han's set it up at.

 

-Jeff

[Jeff]

This is how to measure the piston stroke on the Kugelfischer pump using a Dial Indicator. I learned this technique from Preston Miller of Miller & Norburn. This pump stand use to belong to Preston and I acquired it when I picked up some racing Kugelfischer parts from him a while ago.  All of my experience has been on racing pumps with out the warm up regulator, but the theory is the same. Just make sure the engine is warmed up so the warm up regulator push rod is not lifting lever off the fuel stop.

 

This pump on the stand is a very used stock early B-1 pump that I had in the garage. at the Idle setting I'm measuring .029 of stroke at idle and at wide open throttle .053 thousandths of a inch of stroke.    

Edited March 17, 2015 by Jeff

[wegweiser]

I think it's time I made a Kugelfischer stand! That's a thing of elegant beauty.

Edited March 17, 2015 by wegweiser

[gallian93]

Sorry miss posted

Edited March 31, 2017 by gallian93