Durbo20vT

Car is a 1989 300sel, but I figured since the w124 guys are more knowledgeable with the m103, I'd try my luck here...

I've been battling for quite some time now what seems to be a rough cold start issue and high idle only after the engine is fully warm. First start of the morning the car will fire right up and rpm raises to ~1300 then starts to immediately settle down. Once rpm start to drop, car falls on it's face and dies. Car cranks right back up and does the same thing every time, but when holding the gas pedal down ever so slightly for 10-15 seconds then release the pedal, the car holds idle on it's own. OK let the car warm up on its own to the water temp mark above 40 and on my way i go... no driveablilty issues whatsoever and idle is ~8-900 in Park (6-700 in drive). For the record, fuel pump primes with key every time.

After my commute or ride around town after engine is fully warmed, the rpm in park raises to 1300 and ~900 in drive. After the fully warm engine, i can shut down & start the car without hiccup every time. The idle drops to normal after every restart, then slowly creeps up to above 1000 mark where it settles to ~1200.

My dmm is missing at the moment, so I cant check the duty cycle @idle or 2500rpm. I searched for vac leaks, but didnt find any (sprayed carb cleaner around the inj, replaced hoses... no luck). I also tried unplugging the cold start injector, no change. Unplugged the ICV , no difference. I swapped the ICV out with another spare i had lying around, no change. I soaked them both out with carb cleaner and threw the original back in... no change.

The list of replace components over the last few months also didnt help with the symptoms I am having:

Fuel Distributor
EHA & o-rings
NEW Non-Resistor plugs/cap/rotor/wires
NEW OVP
NEW coolant temp sensor
Fuel pump relay not too long ago

I've searched for hours and hours for fixes to similar symptoms others had, but I seem to be overlooking something crucial to this mystery I can't solve. Last thing I want to do is bring it to an indy, so I'm hoping one of the guru's here can chime in on where else I can look to solve this issue...?


Fast forward a week or so since the above was mentioned...

Decided to throw in a few bottles of chevron techron and drove it for a week where the driveability was great (besides the higher than normal idle and cold start)... Until yesterday.

To recap yesterday's issue, I cold started the car and held the pedal down slightly for 15-30 seconds to get the idle to stabilize, then let it warm on its own. Waited until the temp on the gauge got to above 40 and went on my way. Once the car got to temp, every time the car came to a light, it shut off while the car was in D. Put the car in park, restart, and idled fine until It was put into drive where I stalled every time. If I touched the gas ever so slightly while in drive, I can keep the car alive and get it moving slightly. Once the car crawled enough to get to 2000 rpm, it would accelerate fine like nothing happened as long as I kept it moving. Slowing down again lead to another stall, so basically I kept it moving to get back home.

Once I got in the driveway, when I revved the car it would stop at 5000rpm and start popping and misfiring like all hell. The pipes had a funny smell and let off some gray smoke only when the pop-misfire occurred. the stalling issue when put into D or R was still present, so I am lead to believe it's fuel related rather than a clogged cat. The vid posted below is near identical to what I am experiencing. I feel this issue is related to the one described in my original post... just magnified now.


Any input from the veterans who may have experienced something like this?

QVHK

Hi, you must read about my other post on similar stalling and occasional high rpm problems. I consulted some folks in Peach Parts and got a list of potential suspects: #1. Unregulated air leak. * Failed hose MB# 1030941382 * Failed hose MB# 1030940482 * Failed hose MB# 1030940082 * Cracked MB# 1031410090. * Failed intake manifold gasket MB# 1031411180 * Failed seal ring brake master cylinder to power booster MB# 0014313360 * Failing - leaking brake power booster MB# 0044303130 #2. "Gummed up" idle speed actuator MB# 0001412225. #3. Failing voltage regulator #4. Failed thermal sender, continuous injection system MB# 0065427717 or MB# 0085423217 #5. Failing OVP MB# 2015403745 #6. Failing head gasket MB# 1030161120 #7. Failed Valve guides = worn out Anyway, as explained in my post, I still had the problem after replacing the fuel pumps, fuel relay, OVP, EHA, spark plug wire set, fuel filter, etc. Washing the ICV showed some improvement but the problem recurred after a week. My problem was less frequent than yours and strangely after two more weeks, the problem suddenly disappeared entirely. Anyway, think of possible causes due to air flow, fuel, fuel supply, ignition and/or electrical issues. Read some previous posts in other sites and many were fixed by simple solutions w, hich we tend to overlook, e.g. dirty fuel (water and precipitate in fuel tank), overdue fuel filter, weak electric fuel pumps, non-OEM air element, wrong use of spark plugs (the basic ones are best), but if temperature is an issue try replacing the engine temperature sender (on engine cover near the firewall). Six months ago I only had stalling problem, and replacing the engine temperature sensor fixed it. Good luck.

Dads72saab

I have w124 300te my problem is it seems to hold back between 40 and 60 Celcius and now the check engine light has come on once it warms up it it runs great but at idol it has started to run rought at idol. this car has 375.556 miles on it I take good care of my car its been very good to me. I've change plugs cap rotorinner and outer covers and o ring when I bought the car it had 295.000 miles I'am the third owner and have 35 years of mechanical expierents as automotive mechanic. But this one has got me going in circles. Maybe you can point me in the right direction I also have change the injectors