Gate valve installed after being modified to fit.
From a cold start, idle went to ~1Krpm and stayed there, stable.
Running up to ~2500rpm and releasing caused the idle to drop to
about 700 and instantly go up to ~1Krpm.

The gate valve is quite sensitive with all the adjustment being in the
last 1/8th turn prior to fully closed. Again darkness got me before I
could play with it much. No other tests were done as I got a late start.

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Well that's interesting.

But is sounds like you need to have more control of the gate valve at certain times.

It also sounds like you do have a CIS related problem with the original set up. Have you tried to see what the engine does with the CIS ECU unplugged yet?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Nope, no other tests done, yet.

It was dusk when I finally fired it up. ECU seemed to respond quite quickly to any gate valve adjustment.

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Bob,

I've been playing with my CIS today and because the ambient temperature is so much colder than it was earlier this year I'm noticing a greater effect of the "warming up phase". I get the feeling that your resistor shunt of the coolant sender has had a big effect.

I'm going to spend a bit more time tomorrow sending in different resistance values to check what is going on.

What was the value of the resistor you added again?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

39 ohm resistor is whats on there now.

What has really truly frosted me is that Im sure not the only one who has worked on this issue with most being more than 'handy'. No one including MB has come up with a decent system test procedure. EVERY forum post Ive read and there have been many constantly suggest ... change this or that ... to the point I keep expecting to read ... 'add nitrogen to your tires'.

To think that a >$5 gate valve with barbs has done more to 'fixing' this issue than anything else is just flat mind boggling. Living with a just under 1K idle is sure not acceptable to me

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

How are you getting on with this Bob?

I was speaking with the chief mechanic at the dealership the other day and he thought that my stalling could be due to wiring being wired to the wrong sensors. He had me thinking for a while but then I realised that on my later style plugs what he said isn't possible...

...but...

...it might be for you.

Anyway it goes like this. He was saying the three pin plug for the air flow potentiometer can be swapped (by accident) with the air idle control valve (if that is also of the 3 pin variety). Now I haven't seen a 3 pin air idle control valve before (mine's 2 pin) but it got me thinking =>

Have you got a three pin air idle control valve? Have you checked the wiring from each of the plug ends to the plug that goes onto the ECU?

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Bump 4 Bob!

__________________
1992 W201 190E 1.8 171,000 km - Daily driver
1981 W123 300D ~ 100,000 miles / 160,000 km - project car stripped to the bone
1965 Land Rover Series 2a Station Wagon CIS recovery therapy!
1961 Volvo PV544 Bare metal rat rod-ish thing

I'm here to chat about cars and to help others - I'm not here "to always be right" like an internet warrior



Don't leave that there - I'll take it to bits!

Nice suggestion but the way my wiring is routed, not at all possible.
Cold and wet here so nothing new to report

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

jesus this is quite a thread. In post # 56 Stretch shows the location of X11. This is where you need to go.

Put the IAC valve back on and get the engine to operating temp. At X11 check voltage readings at terminal # 3 with your ground probe in terminal # 2. Voltage should bounce back and forth +- 0.5 volt variance. Avg. voltage should be 6-8 volts.

If voltage is constant, that means you have a fault with one of the sensors. This test is easy and can confirm a fault or eliminate a lot of suspects.

At operating temp of ~80C, X11 Pin 2 / 3 reading is : 11.8 to 11.3vdc

At startup, voltage was 11.66vdc

Suggestions now ?

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Bob
Is that reading of 11.6- 11.3 with engine running? If it is, that is a problem,
the reading at x11 between #2 and #3 should fluctuate and average slightly less than half of running battery voltage.
Also 11.6 volts DC is low and will cause problems.

Reading was with engine running. Solution ?
What would cause the low voltage?

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

Bob,
I have been following this since it's inception because I own two M103's.
I'm not an expert but I am learning.
The reading at #2 and #3 should fluctuate from 6-7v Dc
11.6v DC is nearly dead battery, put it on a charger.
What spark plugs are you running?
Do you have continuity at the micro switch, and to test TPS, continuity at terminal #2 and ground on the 4 pole above the coaxial on the EZL?
Check the wiring at the TPS.
Were the injectors replaced with the seals, if not how old are they?
What vacuum is present at a manifold nipple?
I just went through this on my 92, wanted to roll it outside and shoot it.
Fixed it, TPS misaligned.
I feel your pain.
Don't give up

Paul

I will check the startup voltage across #2&3 ... weather kept me from working for bout a month.

Dont remember which brand but they have less than 500 miles on new plugs.
Micro switch checks good. You are referring to the one on the firewall side of the fuel distributor ?
TPS ? Unit on the front of the fuel distributor is brand new. The one under the intake checks good at the cable end, meaning the line is good too.
Not sure what you mean by th coax on the EZL ??
Injectors were not replaced. Car starts very easily, 1-2 starter seconds.
Havent measure the vacuum.

__________________
1985 300D 198K sold
1982 300D 202K
1989 300E 125K
1992 940T

"If you dont have time to do it safely, you dont have time to do it"

"The democracy will cease to exist when you take away from those who are willing to work and give to those who would not."

After reading the entire thread I have a couple thoughts.

Your car has fault codes, they are read though the lambda reading. Fixed value equals a fault, oscillating lambda equals no fault.

There is no normal condition where 1200 RPM idle is correct. The resistor didn't fix anything. At best it masked a problem and caused another. Undo it and start over or you will never fix the problem.

I didn't see confirmation that the air flow pot was adjusted correctly. The low voltage pin must have .7 to .9V when idling with hot engine and no additional load. This has to be right.

__________________

90 300TE 4-M
Turbo 103, T3/T04E 50 trim
T04B cover .60 AR
Stage 3 turbine .63 AR
A2W I/C, 40 LB/HR
MS2E, 60-2 Direct Coil Control
3" Exh, AEM W/B O2
Underdrive Alt. and P/S Pulleys,
Vented Rear Discs, .034 Booster.
3.07 diffs 1st Gear Start

90 300CE 104.980
Milled & ported head, 10.3:1 compression
197° intake cam w/20° advancer
Tuned CIS ECU
4° ignition advance
PCS TCM2000, built 722.6
600W networked suction fan
Sportline sway bars
V8 rear subframe, Quaife ATB 3.06 diff