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1987 300E 90K miles, starting problem

Yesterday, I went out to start it after it had been sitting for a few hours and it cranked, almost started for a couple of seconds, but died. After repeated attempts it turned over but would not start. I tried starting with the accelerator pressed, but no luck. I waiting about about 15 minutes and it started, I drove it 5 minutes to the store and after sitting for 5 minutes, had the same problem. Over an hour period of retrying, allowing 15 minute intervals, it still didn't start. I got a ride home and went back after dinner and after running for a couple of seconds, it died. This time, after about 15 minutes, I got it started and drove it home.

I have had this happen maybe a dozen times over the last year, but it always started after a short rest. If it means anything, yesterday, it was over 100 degrees in the sun when I was having problems. This morning at 6:30 AM, it started right up.

The car, owned by my father who purchased it new, has been well maintained but has not had a tune up for a while. It sat in a garage for 6 months last year until August and also, I stored it in a garage over the winter until April. I started it up every couple of weeks during the winter. Last month I had the air conditioning converted and also replaced the compressor. The only other problem I have is the blower always pushes air out of the upper vents, even when I select the button for the lower vent. I don't know if that could be related.

Thanks for any ideas. Steve Canham

Reply to
Steve.Canham
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After failing to start, when it does start, does it start normally or with stumbles and misfires?

If "normal" I believe the fuel pump relay is the prime suspect. That relay is the switch for the car's electric fuel pump and such relays fail with age so the electric fuel pump doesn't run and there's no fuel to start the engine.

If it starts with stumbles and misfires the fuel system on the engine needs work.

The heater - a/c air distribution is due to one of the ducts' vacuum powered air distributors being broken or disconnected.

Reply to
T.G. Lambach

When it DOES start it runs normal, so I will look at the fuel pump relay. Also, will look for problem with the air distributors, but that in itself is not a major concern for me. Thanks very much for the help.

Reply to
Steve.Canham

Went home for lunch (92 Degrees) and she started right up. The fuel pump relay could fail intermittently? Is the heat related to the problem?

Reply to
Steve.Canham

Classic symptoms of hot start problem... basically you got internal fuel pressure leak. Most culprit is the fuel accumulator... one side has rubber hose... pull the hose out... if fuel keeps coming out of the accumulator... it is defintely bad.

Another source of leak is on the top of fuel distributor... called compensator piston... there is an oring in there that will wear.

Last possibility which is also high... fuel pump relay... look at the date stamped on it... if it is same year as your car, replace it... they usually only last about 14 years...

Reply to
Tiger

Relays become intermittent - as yours has. Many also fail while driving

- motor suddenly quits and may restart normally - or not!

Reply to
T.G. Lambach

Thanks for the help.

Reply to
Steve.Canham

I replaced the fuel pump relay and it has started fine for the last 2

1/2 weeks until 2 days ago.

Now I have another problem. When the engine is cold, I must hold the accelerator to the floor for the engine to start. This morning on the way to work, after about 4 miles, the engine died as I turned a corner, but I was able to restart it without pressing the accelerator It has been running rough intermittently and almost died one other time, but pumping the accelerator kept it going and then it started running smoothly again.

Reply to
Steve.Canham

When is the last time you changed the O2 sensor?

Reply to
Tiger

Sorry to but in. I've recently replaced the valve guide seals on my '89 300e that had been starting perfectly to that point. After the change, now oil fouling on plugs hugely reduced but have noticed (my wifes car so that I don't know if it was an 'immediate' consequence) that it is 'harder' to start now. I mean, one has to crank a few seconds before it runs - before it started essentially immediately. could the O2 sensor be responsible for this somehow I wonder? the sensor is about 150k miles old BUT when I checked the 'readout' under hood the sensor seemed to voltage 'cycle' as is to be expected.

cheers, guenter

Reply to
Guenter Scholz

I don't have a service record prior to buying the care months ago.

The car died 3 time on the 10 mile trip home from work yesterday. I have it parked now until it is repaired.

I posted this same question on the MBCA forum and someone asked the same question about the fuel filter.

Thanks.

Reply to
Steve.Canham

There are a couple of things that affect this... so you can't simply just swap parts because it gets very expensive.

I would start out by inspecting the fuel system first... is there enough pressure? Possibility of fuel pump going bad... Fuel filter can do the problem but is very rare... you really need super dirty fuel to do this. The fact that you couldn't start when cold is the key symptom... so I'd suspect the fuel pump... but I would check with fuel pressure gauge to validate this diagnosis.

Reply to
Tiger

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