Right turn stalling!! 420

[884201972]

OK, My 1988 420 is still being troublesome. Minimal use for last 3-4 years before I purchased in August. I have replaced fuel filter, fuel inlet line, spark plugs, rotor and distributor cap, idle air valve, fuel pump relay. The pump relay got the car running down the road again. Now, as long as you stay easy on the gas, below 30 mph, the car runs great. Step on it to go above 30 and the engine wants to stall out--like running out of gas. Let up on the gas and everything is fine again. Also at issue--since I have had the car--it WILL STALL when you make a right turn, and only turning right. Shove into neutral, the car restarts instantly, and away you go--till the next right turn. I am thinking the sock/filter in the bottom of the tank? Crud in the bottom of the tank? Fuel guage fluctuates between empty and full--never know what it is going to show until I start the car, and then that might change while drving. Can the sending units be cleaned/repaired? I am new at Mercedes ownership and repair, so please help! Thanks, Steve

[HarryM]

This problem is very simple to fix, and has nothing to do with filters, spark plugs or rotors.

Clean the battery terminals, and check the ground cable connection to the body, and the live cable connection near the engine.

Post back if this fixed the problem.

[884201972]

Thanks for suggestion. I got to check all of these connections and they are nice and clean and tight--no corrosion at all. I drove the car again--temperature here about 63 so no cold wet weather to do deal with. 9 out of 10 times the car will die on right turn, shove into neutral, and will restart instantly while you are rolling out of the turn. Cruise at 20 or 25 mph she runs great, step on the gas to go 30-40 and the car bucks like a bucking horse, but does not die. Slow back down and she runs fine again. Fuel tank is about 3/4 full, so not low on gas. It always starts instantly--hot or cold. It never fails to restart instantly. It just does not want to run. It will sit and idle effortlessly for as long as you want. I am stumped and really need the brain input on this one. Thanks, Steve

[RKreutzer]

Hi there,
to me that looks like the engine is not getting enough gasoline in order to rev higher and maybe something gets squeazed when making the turn restricting the flow.
When I replaced my fuel pumps, I routed the fuel hose wrongly and it was a bit constricted. It ran fine until I accelerated. Once re-routed, everything ok.
There are also 2 check valves that help to keep the pressure up and I believe they are only 13.50 or so each. You might want to replace those.
I believe the dealer has a contraption to measure the fuel flow.
Good luck