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· Registered
1988 300TE 217K miles and counting.
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175 Posts
Discussion Starter · #1 ·
Alright,

Well. my 300te has seen better days. About a month ago after installing a new radio the car was turning over but wouldn't fire. I pulled the spark plug wire and found that it was sparking but wasn't getting gas. I then went to the fuel pumps and found out they weren't getting power. I then did the troubleshooting and found out the fuel pump relay was bad. I jumped pins 7 and 8 in the relay and the fuel pumps ran and then I got the car to start. HOORAY. But then I was looking under the hood while the car was idling and I pushed on the air flow sensor. As soon as I touched the sensor the car shut off, and then I couldn't get it to start again.

I figured I'd wait until the new relay came in to proceed hoping that the problem wasn't anything major. I put the new relay in and I can hear the pumps running so that problem is solved. But the car STILL won't start. I pulled the spark and it was very wet with gas.
 

· Premium Member
About a dozen 1988, 1989, 1990, and 1991 sedans, wagons, 4Matics and 1 coupe
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5,524 Posts
When you pushed down on the airflow sensor plate you instantly mega-flooded the engine. That's why the plugs are wet with gas.

You have a couple of possible paths to follow at this point.

1) Gently push the airfow sensor plate down and spray some starting fluid down there. Release the plate and immediately start the car. Starting fluid (ether) is a lot more volatile than gasoline and it will ignite with the smallest spark.

or

2) Hold the throttle to the floor and crank for 15-20 seconds letting air flow through the cylinders evaporating the excess gas. This may work but be ready to release the throttle as soon as the engine fires.

or

3) Install a fresh set of spark plugs and the engine should start.

Good luck.
 

· Premium Member
About a dozen 1988, 1989, 1990, and 1991 sedans, wagons, 4Matics and 1 coupe
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5,524 Posts
I still say its flooded. Try #2 or #3. Make sure that the battery is fully charged too. You'll need maximum spark power.
 

· Registered
1988 300TE 217K miles and counting.
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175 Posts
Discussion Starter · #6 ·
its possible.

If I let it sit overnight should it be able to start tomorrow if it was just flooded?

I'm kinda frustrated right now, I don't want to have to get the car towed and admit defeat.

I was looking into replacing the spark plugs with beru ultra-x spark plugs. They look pretty nice but I can't find any place that sells them. BERU Ultra-X — the spark plug innovation that unites current OEM technologies
 

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About a dozen 1988, 1989, 1990, and 1991 sedans, wagons, 4Matics and 1 coupe
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5,524 Posts
I'd find a way to keep the accelerator pedal pressed down overnight and leave the air cleaner off too. That should do it for you.
 

· Registered
1988 300TE 217K miles and counting.
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175 Posts
Discussion Starter · #10 ·
I think you're right about it being flooded. I put the throttle all the way down and I took the spark plugs out for 24 hours.I put the plugs back in and I couldn't get it started, so I was kinda annoyed. But I noticed after cranking for a couple seconds with my foot to the floor, it would fire just a little bit but die. So I continued to crank it in short 3-5 second burst until the car almost started.It would start to fire a few times and then die. Finally when cranking it would fire and die fire and die. By this point in time the battery was drained. So I put it on charge for the night and I'll try again in the morning.

Question... Is it bad for exhaust fumes to come out of your intake?
 

· W124 Moderator
86 190E 2.3L 16V, 95 320TE 02 S500
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13,365 Posts
Exhaust fumes or un-burt fuel? Exhaust fumes usually indicate the engine it trying to fire on an exhaust stroke rather than compression... Any chance you had the engine at a high, hard RPM just prior to this "no start" problem? It could, and I am just guessing here, have jumped time due to a bad timing chain. If so, there is work to be done. Just my 2 cents.

Good Luck,

Jayare
 

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65 Posts
In searching the archives I found this post about flooding the engine. The symptoms cited are the same as mine - get spark, have fuel but won't start. It all started when the car died on the freeway. I've installed two new fuel pumps, filter and OVP relay. I get fuel out of the injectors when I test them outside the cylinder and depress the air flow sensor plate.
I've pulled the plugs and found the wet with fuel. Can I dry them out with a match and re-install? The mystery is that I have fuel, good spark when removing the plug and shorting it to ground, tried starting fluid but the car won't start.
HELP.
 

· Registered
W124
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6,604 Posts
In searching the archives I found this post about flooding the engine. The symptoms cited are the same as mine - get spark, have fuel but won't start. It all started when the car died on the freeway. I've installed two new fuel pumps, filter and OVP relay. I get fuel out of the injectors when I test them outside the cylinder and depress the air flow sensor plate.
I've pulled the plugs and found the wet with fuel. Can I dry them out with a match and re-install? The mystery is that I have fuel, good spark when removing the plug and shorting it to ground, tried starting fluid but the car won't start.
HELP.
Take the plugs out and let them air dry or use a hair dryer on them (or better yet a can of compressed air). To make sure there is no fuel pooled in the cylinders, while you have the plugs out crank the motor for ten seconds or so. Have someone watch what comes out of the sparkplug holes while you do this and make sure they aren't standing in line with the spark plugs when you do it.

If your engine was flooded, there's no way it will still be flooded unless there is fuel pooled in the intake manifold. I just noticed that you have a 103 motor. The idle speed actuator (some call it the idle control valve) could cause the problem you are having. Its located to the front of the fuel distributor and is mounted in a rubber clamp held to the intake manifold by two 10mm bolts. It has a two lead connector at the very front of it and two rubber hoses running into it from under the intake manifold. If you don't make progress with any of the above suggestions, pull the ISA out of the car and run a piece of small hose (3/8 maybe) in place of the ISA. Shove the hose into both of the rubber hoses that ran to the ISA. You're messing with vacuum here so make sure they are pushed into the hoses snugly. This will eliminate the ISA as a source of the problem - its a cheap way to do so since they cost $300 (ask me how I know) Good luck.
 

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"Gretchen" my 1986 300E 286000 km+ (RIP) August 2015
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1,097 Posts
My 2 cents, I had a very similar problem.
My fuel pump was on the fritz, replace it no more problems.
It was only pumping
a small amount of fuel, I could hear it run, cranked well,but no start. Try it as a last resort if you want.
 
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