/Background: 1990 560SEC Euro, had been running somewhat rough, econ gauge not pegged to left as it should have been @ idle, hard to start.

I found a handful of vacuum leaks, around some of the intake ports, the base of the air flow meter housing, and a few lines/hoses. I pulled the intake and replaced all rubber /plastic bits, all 8 injectors, and new gaskets.



I turned the key to prime the system a few times, then went to each injector and loosened the nut to look for fuel flow. A few did not have any, so I tried to prime a few more times, with success, except for cyl #5. I then proceeded to loosen the nut at the fuel distributor, and all had fuel except for #5. I tried to prime a few more times and then saw fuel at #5.

Tried to crank the motor over, and it would sputter, and almost catch, but never really run.

Sprayed some carb cleaner into the airflow meter, and on the next attempt it fired and ran for a second or two, then died.

After reading some other threads, I have turned the 3mm adjuster in by 2 full turns (8 steps at 1/4 turn each), and I think it sounds worse now than before as it tries to fire.

I have double checked my spark plug wires, cap and rotor as well (all are new). Unless I have the cylinder numbering wrong (1-4 on RH side, 5-8 on LH side)...

Not sure where to go next here, feeling a bit frustrated as I was hoping for a nice smooth startup.

Thanks
Andrew

reset the fuel dist. remove a fuel line from the dist. jump the fuel pump relay so the pump runs. when fuel reaches the top of the port and not run over the side, the 3mm allen is set close enough to run. any more, turn it down. 2 full turns from who knows where sounds like WAY too much. good luck, chuck.

thanks. Will give that a try tomorrow, gotta get ready for work soon.

I'd expect you to have to adjust the mixture screw out.... not in.

__________________

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

That is what would make sense to me as well -- with vacuum leaks resolved, there should be a need for less fuel, not more.

When I primed my 560 after doing the same repairs, I just jumped the pump relay to let the pumps run for a few minutes to burp the air out of the system. Seems to me it was still a bit of a nuisance to get the car fired up due to the CO tower being pretty far out of adjustment.

I also had a dead CIS ECU, so that was preventing the CSV from helping.

Also, verify all the big items are snug such as the brake booster. I have left those loose in the past or disconnected.

__________________
I'm not a doctor, but I'll have a look.

'85 300SD 245k
'87 300SDL 251k
'90 300SEL 326k

Six others from BMW, GM, and Ford.

Liberty will not descend to a people; a people must raise themselves to liberty.[/IMG]

Good to know. I was hesitant to keep the pumps running very long with the jumper wire, but I suppose there's not much risk involved with that.

OK, I think I figured out the problem. I believe I will receive the dumbass of the year award for this one.

I never removed the blue shop towels from each intake port before placing the intake manifold back into position.

Yes, you read that right. Each intake port has a blue shop towel in it - not real towels, but the thin ones that come on a roll.

I will pull the intake and hope that there's no damage to the intake valves as a result.

Just wanted to follow-up with a conclusion to this issue:

I pulled the intake again, removed all the blue shop towels, rotated the crank by hand and used a long forceps to extract bits of towel from the valve seat area in each intake runner. Then replaced the intake, and all is well. My M117 is running great now.

the important thing is that you figured it out and fixed it. -CTH

__________________
- cth350@gmail.com
http://www.111lakeside.com/

There are better ways to clean the top end

__________________
Prost!