Great running 300E car just shuts off!!! - PeachParts Mercedes-Benz Forum

sptt · #1 09-18-2010, 12:34 AM

I'm driving my finally fine-tuned (what I think is fine-tuned) 300e down a busy street and I come to a stoplight and it just dies! All warning lights come on. I put it in park, start it back up first crank and no problem, and it hasn't happened again all day. Anything I should check? It was idiling soooo nice before and after it happened which is great I think! Some bad gas going through? Should I check plugs? OVP is new. Scared the heck out of me!

mak · #2 09-18-2010, 10:35 AM

I am quite sure it is the Fuel pump Relay acting up ,i had the same symptom and initially misdiagnosed it as a ignition problem.
With age these relays become erratic ,its best to replace them or re- solder the ageing joints inside .Best to replace it.
Next phase all the old fuses and if old, the fuel accumulator and rest all is reliable in the CIS system .
mak

sptt · #3 09-18-2010, 02:37 PM

OK. Sounds logical. I'll take out and resolder then order one in the meantime.

Thanks!

david s poole · #4 09-18-2010, 04:10 PM

what yr is your 300e?

sptt · #5 09-19-2010, 04:05 AM

1991. Hasn't happened since that one day and that one time. I know I need a valve job and whatever else should be done on my engine ASAP. Then, I want to get my trans fixed with those brake bands and pistons so I can shift smoothly into drive and reverse. I replaced the fuel accumulator and it starts hot or cold now no problem. I'm going to put in some injector seals since it seems easiest for me to do myself so I hope that helps even a little more. Any other suggestions Mr. Poole? I'm not losing coolant, a little oil is leaking around the manifold cover now but nothing major.

Thanks,

Steve

ps2cho · #6 09-19-2010, 01:26 PM

Quote:

Originally Posted by sptt

1991. Hasn't happened since that one day and that one time. I know I need a valve job and whatever else should be done on my engine ASAP. Then, I want to get my trans fixed with those brake bands and pistons so I can shift smoothly into drive and reverse. I replaced the fuel accumulator and it starts hot or cold now no problem. I'm going to put in some injector seals since it seems easiest for me to do myself so I hope that helps even a little more. Any other suggestions Mr. Poole? I'm not losing coolant, a little oil is leaking around the manifold cover now but nothing major.

Thanks,

Steve

If you are going to do injector seals, replace the injector too. You may as well. Sometimes uneven idles can be bad injector spray from age. Injector cleaners are no good at removing heavy tarnish with age. They are just a good short term cleaner.

mbzman · #7 09-20-2010, 02:08 AM

If the injectors are original I would go ahead and change them out. Because they are mechanical they are inexpensive to buy as opposed to the electronic type in newer cars.

sptt · #8 09-21-2010, 12:28 AM

Experts...Besides injectors and seals, is there anything else I need to replace the injectors?

mlozzi200478 · #9 09-21-2010, 05:42 AM

if you havent already i would def check/replace the fuel pump relay,make sure there is no cracking on the vacum line going to the fuel pressure regulator,make sure all the plugs/wires are new also cap and rotor is new,make sure all coil wire connections are tight.and i think you said the ovp was new right? and you replaced the fuel pressure accumulator?are the fule pumps new? you may want to have the fuel pressure checked at both fuel pumps at the check valve,while doing so i would replace both fuel pump check valces.

Ferdman · #10 09-21-2010, 06:34 AM

miozzi, while it's a good idea to make sure the vent line on the fuel pressure reglator (FPR) is intact I don't think a cracked vent line affects engine performance. AFAIK the vent line only comes into play if the FPR diaphragm fails ... it then directs fuel into the air filter housing instead of allowing it to spray on the hot engine and possibly cause an underhood fire.

Cal Learner · #11 09-21-2010, 08:34 AM

mlozzi, this is the second time I've read you refer to multiple check valves at the fuel pumps on a 124. The only check valve I'm familiar with is a single valve on the evaporative emission system return line, located just below the bottom left edge of the fuel tank. Not associated with the pumps at all. What valves are you referring to? Clarify please.

david s poole · #12 09-21-2010, 01:34 PM

if that is a 91 300e i think it has the MAS combination relay that includes the fuel pump relay.check out your ovp as well as the socket it plugs into.

sptt · #13 09-21-2010, 11:59 PM

David,

OVP is fine (2 months new...2 good fuses). Not sure how to check the MAS. I have a digital multi-meter.

Thanks,

Steve