300E Cold Start Hot Start Resolved
 

After many months of replacing this and thinking it was that, I finally have my '91 300E starting like it was brand new ON THE FIRST TURN and catching on the initial crank like a NEWER car! Here is what I think has contributed to everyone's woes that I have repaired in mine:

1. Poor fuel pressure (Installed new fuel pumps, filter, accumulator and EHA Valve). Plenty of pressure the next morning and plenty of suction when removing that gas cap (was not like that before)

2. New Plug Wires and NGK Copper Plugs installed.

3. Flushed coolant and all the crud out. Put in Steel Seal ($80.00) with new coolant and ran in coolant per directions with heater on high for 60 min and let cool, etc.

4. Replaced all heater and radiator hoses and expansion tank as well as old thermostat that was corroded and stuck.

5. Installed proper 875 Amp Battery vs. the 610 Amp that PO had put in (what a spark and crank difference!!!)

6. Ran some more Liquid Head Gasket Sealant from BARS ($29.99 liquid stuff from Autozone that you can add to coolant and run for an hour with heater on high and then let cool overnight to seal any final cracks in block). This got rid of my smoke and the leaking coolant flooding into the cyclinders helping to create the hard starts! It works like promised and is still working and getting better by day.)

7. After installing new EHA valve I adjusted to correct duty cycle with Sears Duty Cycle Meter ($29.99).

8. Replaced o2 sensor prior to all of this and immedialtely noticed idle improvement.

9. Replaced coolant sensor on back of engine block and noticed even better idle back then.

10. Today, I replaced my thermostat which helps the engine get warmer faster during startup (upon examination my old one was all corroded and spring was jacked up for some reason) unlike my old one which remained stuck and kept the engine cool too long (engines like 90-95 degrees celcius temps to run smooth).

11. Replaced Cold Start injector with one from "Used-Bay" for $35.00. Don't know if it changed anything but now, freezing cold, warm, or sweltering, same start and idle, and temps (92-95 degrees).

12. Replaced Fuel Injectors for $25.00 a piece. Easy to do.

What questions do you have?

:) Happy Guy...for now:)

did any of these yield the most improvement???

Most likely the injectors.

On a 20-year old car, they're worn out.

Not necessarily, but the EHA Valve (very noticeable difference in idle), Injectors, and the $29.99 BARS Head Gasket Sealant (after a few days of running this, starts kept getting better). I think with that old block, that if you have good coolant pressure, coolant leaks into the engine block and causes the hard cold starts. When I flushed my coolant, I think I pressured the sealant particles out and had to redo the BARS treatment because it was horrible to start and I was smoking at startup for a while until it burned it all off. It does not clog up your radiator either. I have very good flow and coolant color. The proper battery for this car is also a must as it cranks very hard.

I am thinking about doing the eha valve then (first i would just replace the o-rings... i have been trying to resolve a slightly off idle when cold.... i have replaced motor mounts (big dif) spark plugs (no dif) cleaned icv (virtually no diff) changed fuel filter (no dif)

start isn't too much of a probably 90% of the time....use bg44k once a year.

I can't seem to find a vacuum leak anywhere, but have replaced some of the vacuum lines.

this is on the 89 300ce with 108k miles.

all of the other "repairs" are really maintenance items

i am about due for a coolant flush and change...no big deal.

Here's another one.

Make sure your T.P.S. potentiometer is set properly and doesn't have worn spots.

i have performed all of the above mentioned items except the coolant flush because my coolant is brand new anyway,and nothing has changed,my issue is the car wont start when the E.H.A is disconnected,so i conect it,it starts,then the car has to fully warm up to 80 celcius or it pops bogs and will not move out of its own way,so i end up disconnecting the E.H.A and it rund great,i replaced the E.H.A with a used one and still no im provement. all of my sensors have been tested and work fine,im baffled,the i njectors look new because there brass and on a 22 year old car i think the brass would be kinda corroded by now. there very shiny like new.

Brass injectors began on all models starting from 89 onwards. With a good pressure wash, the brass will shine like new, so keep that in mind.

#3 and #6 are redundant. But how did the Steel Seal work out?

Sounds to me like a $2K overhaul altogether, but if the car runs like new it was wirth the money.

Steel Seal worked great. I have no more coolant loss or oil burning and car starts right up and idles fast. No smoke anymore either. I was very skeptical but all is still good...

This weekend I am flushing coolant and replacing all coolant hoses and expansion tank. I have read a lot of good reviews of Steel Seal and will be adding that to the refill since I suspect I have one or more small head gasket leak(s) it could effectively plug.

It's too soon for a victory lap but I will report that steam, which I thought was just condensation (even after the engine reach operating temp), is no longer coming from my exhaust after using Steel Seal (added it last night).

I also had/have an issue with small amounts of oil in the coolant. If that has also stopped I will be delighted.

Keep your fingers crossed! If it works, you probably want to do a coolant flush and get all that oil and junk out of the cooling system. Pretty easy to do with a Prestone Flush kit from your local autoparts store. If it doesn't work, do the coolant flush, and try the K&W Headgasket Sealant treatment. Do a web search on it and you'll see how to do it. Thing is you can't add it to antifreeze but most users also say it works great (only about $8.00).

Do update us on the progress and if the coolant leaks have ceased .
Regards
mak