Another rough idle thread - Tii with 123

[pehlivanov_tii]

I will definitely check with a timing light and different distributor if I have to. The mechanic didn’t use a timing light. Honestly when he was mounting the 123, he set the engine on position, waited for the light and then only loosened the bolt and turned it forward and backwards, without much difference in the engine work… 

[pehlivanov_tii]

I didn’t have much time recently to try new things and the mechanic was very busy, but we ran some new tests after all with different distributor. We used stock distributor (refurbished it before) not a tii, but just to see if there is a difference how the mechanic thought and there wasn’t a difference.

Another two things I noticed:

1. Something’s up with the “D” cam settings. The engine just doesn’t want to work/start unless the “D” cam is set to an unusual, very advanced position for idle rpms. I used a pinch in the hole to set the D cam position for idle according to the manuals, but the car just doesn’t start unless I turn the 6mm screw almost to it’s end. See in the photo the advanced position that is the least possible for the engine to start. The butterfly is set to match the hole in KF pump body.

 

2. My linkage is sloppy, please see the video. But is that play could cause this rough misalignment? Is there a link for the bushings that I can get? The length of the rods is checked too.

 

 

P.S. The “clank” noise is still there, the more I turn the 6mm screw to more advanced position the less I hear it. 
 

Do you think it is a more linkage issue or is the KF pump itself? Or both? 😀

 

Edited July 28 by pehlivanov_tii

[dlacey]

Agree that D cam position seems way off for idle...that's entirely a linkage issue. If you setup the linkage 'by the book' the D cam should be at the 4mm hole when the pump is pinned at idle.

 

But avoid too many changes at same time...get the ignition stabilised first.

[pehlivanov_tii]

@dlacey thanks for your opinion, I appreciate it! I agree I have to start from somewhere i just don’t know from when. Everything is new, the cables, plugs, coil, distributor, cold start valve and relay, rebuilt engine and injectors and when I set the linkage by the book it’s just not starting.

[0257]

On 5/19/2024 at 5:46 AM, zinz said:

You must confirm your 123 timing with a timing light.  Finding the green light on the 123 during installation is simply not going to be spot on TDC. I’ve installed many 123s over the years and they all need a bit of tweaking to get them correct. Once the 123 is confirmed to be delivering spark at the correct advance/rpm, then you can lock it down and trust the curve numbers. 
 

Ed

+1, and what Mark92131 said.  You can’t trust the 123 installation manual.  Set static timing with a timing light and eliminate vacuum leaks before tuna can adjustments.  

 

My ‘74 runs best with the 123 set pretty close to the standard curve.  Trying to dial in more advance didn’t get me much, and it seems the fuel system responds best to that curve.

[gambitpaul]

On 7/28/2024 at 1:31 PM, pehlivanov_tii said:

I didn’t have much time recently to try new things and the mechanic was very busy, but we ran some new tests after all with different distributor. We used stock distributor (refurbished it before) not a tii, but just to see if there is a difference how the mechanic thought and there wasn’t a difference.

Another two things I noticed:

1. Something’s up with the “D” cam settings. The engine just doesn’t want to work/start unless the “D” cam is set to an unusual, very advanced position for idle rpms. I used a pinch in the hole to set the D cam position for idle according to the manuals, but the car just doesn’t start unless I turn the 6mm screw almost to it’s end. See in the photo the advanced position that is the least possible for the engine to start. The butterfly is set to match the hole in KF pump body.

 

2. My linkage is sloppy, please see the video. But is that play could cause this rough misalignment? Is there a link for the bushings that I can get? The length of the rods is checked too.

 

 

 

P.S. The “clank” noise is still there, the more I turn the 6mm screw to more advanced position the less I hear it. 
 

Do you think it is a more linkage issue or is the KF pump itself? Or both? 😀

 

 

The bushings you need are here:

 

BMW 2002 tii turbo Throttle Linkage Pivot Bushing 1971-1975 - rogerstii

WWW.ROGERSTII.COM

---

BMW 2002tii turbo Bushing

You need two.

[Einspritz]

Also get the bushings for the bell crank at the firewall.

 

Check the axial play on the D Cam shaft in the throttle body, the bushings may be worn. This may prevent (along with the plastic bushings on the two bellcranks) and return springs (you should get a new one for the TB) from returning to idle smoothly. If the bearings and seals for the throttle plate are worn, the grease is stiff, this too will affect the system.....or if there is air bypass there, it will affect your idle. The system is VERY sensitive in this regard.

 

Also check to see if there is a plastic cup at the bottom of the intermediate shaft at the WUR. You'll need that too.

 

The clunking sounds to me like it's under the valve cover or timing chain cover..... Yes?

[pehlivanov_tii]

I'm in kind of a dead end, really. 

To confirm the timing I decided to remove the factory distributor that I used for test purposes only and to bring back the 123, because it would be easier for me to follow the rpms on the app when using the timing light at the same moment. And also because it was confirmed that the distributor wasn't the issue.

 

So I followed the steps, but the car is not starting:
- turned the engine to TDC (I checked the camshaft, crankshaft and KF pulley, the KF pulley was off with few tooth by the way, but I removed the belt and set back the pulley to the correct position).

- wired the 123, except the black wire (i left it for right before trying to start, once everything is in place)
- I tried set the distributor rotor to point to cable for cylinder one and turned CCW until the green light was on, although i don't find it easy to point the rotor exactly to cyl 1 cable while the green light just light up. If I wan't it to point the rotor exactly to cyl 1 cable the green light was not just lightened, I have to turn a bit after it just lightened up. From the instructions I left with the impression that you turn the distributor and right after the green light shows you stop to turn it and put the cap. Anyway, tried both ways and it didn't work

- Fixed the distributor after putting the cap and everything is in place and connected the black wire to the coil.

- Checked the app, I am not in immobilise mode, there is a map loaded, etc.

- cable order is 1-3-4-2

 

My guesses:
- the wiring must be ok, because I removed the cable to the coil and once turning there is spark.

- when connecting the cables to the cap does it matter to which of all 4 ports of the cap you start connecting the cable for cyl 1, or as long as the rotor points to the cyl 1 cable it doesn't matter to which of all 4 ports you have connected it? I tried to look under the cap, but I couldn't find any markings that tells me something that there is some order from which port you have to start...

 

Meanwhile at least I got I think all replacement part of the linkage system - bushings, linkage spring next to the firewall, new spring for the throttle, but I'm waiting to start the car first before moving on...

Edited August 26 by pehlivanov_tii

[dlacey]

52 minutes ago, pehlivanov_tii said:

as long as the rotor points to the cyl 1 cable it doesn't matter to which of all 4 ports you have connected it?

Correct, as long as cylinder 1 lead is plugged in where rotor arm is pointing and the leads follow the Zundfolge then all should be good.

 

If you have HT sparks then it must run..or at least misfire a bit if there's any fuel. I assume you've checked for compression (zero valve clearance could cause zero compression).

 

I would try two things in desperation:

 

Swap plug leads 1&4 and 3&2 (if it runs then your initial timing was 180degree out).

 

If not, revert plug leads, loosen dizzy and  rotate it +/-45 degrees while cranking.. if it fires/runs then fix it wherever it is and then try to understand why timing is way out.