1990 300SL with starting/fuel problem

[Rodger2119]

I have a 1990 300SL with about 99k miles. I turn the key and the car will not usually start right away it just turns over and chugs like it wants to start but then doesn't. It will finally start, but when i press the accelerator the car chokes and stops. If I let it idle it will run for a while (maybe as long as 5 min) but usually shuts off again. If I get it started and it idles ok, I can sometimes get it into gear and move it, but it usually stalls.

Car has been sitting in inside storage for about 12 months. I had been having a problem where the car would just stall out (very seldom) on the road and then would take about 15 minutes before it would restart. It would just turn over and turn over but no start. It also happened when I would drive it (sometimes for hours) and then shut it off for 5 or 10 minutes (stop at a store) - It would not restart for another 15 minutes. I have had car for about 3 yrs but have only put about 5k miles on it. Can anyone help me???

 

[Stevie A]

Start with changing spark plugs. Cheap and easy. Next if no improvement replace or check distributor and rotor arm. Hard starts and stalling can be caused by a well known faulty OVP relay. But try spark plugs first.

 

[Rodger2119]

1990 300sl starting fuel problem

What about the fuel filter, Could that have anything to do with it?

 

[Rodger2119]

Jumped right to the OVP relay and checked it. looked all over the car for it and finally found it hiding under the cover on the passenger side of the engine compartment near the firewall. The old relay had a blown fuse, but I replaced it with a new one (in case there was more then just the fuse broken). Turned the key and the car is running like a real car again. Going to take the advice and change out the plugs anyway, But I think the problem is fixed for right now - Thanks - Total cost $89.00 USD

 

[television]

If you know someone in electronics, it would pay you to have the OVR re soldered, its one of the weakest parts on the car.

Malcolm

 

[Stevie A]

Change fuel filter too. Only about £10. The pump runs lots more than it needs to if the filter is not clean. Glad your running well again.

 

[Rodger2119]

I kept the old, one I was going to replace the blown fuse, but I will look into the resolder thing too. Replaced it with new though to keep from trying other problems. also am going to replace the fuel filter once I get the battery idiot light problem fixed.

 

[Rodger2119]

300SL Starting Problem

Replaced the OVR sensor and the car started right up. But the battery light was on and the car battery kept draining, So I had the alternator checked and it was shot - so i replaced that too. Car started right up again - Charged ok, and I let it idle for about 10 minutes. It started to run a very little bit rough. So I shut it off so I could move some thing and take it for a spin around the airport I store it at.

It wouldn't start. it just cranked over and over. Kind of seemed like vapor lock or no fuel, I tried pumping the pedal and that did no good. Kept trying periodically to start for about 20 minutes with no luck. I checked the OVR and the fuses were still ok.

Anyone have any advice?? I suppose I can break down and take it to the dealer, But my ego is not letting me do that!

 

[Myros]

if it's easy to do

whip out a plug and see if it's wet with fuel. unlikely to get vapour-lock in a fuel injected system, much more a carburettor problem.

 

[johnnycapone]

I had a similar problem on my 200te, it turned out that the fuel pump was running continuously instead of "pulsing". Had the fuel pump relay looked at and it has been ok since.
regards
John

 

[Rodger2119]

thought I would add another piece of information. In the past I have occasionally had a problem where the car ALWAYS started immediatly. If I drove it for an hour or two and then stopped for dinner it would always start again when I got ready to come home.

But if I took the car to the car wash, or took it to the gas station, If I shut it off, and then tried to restart it, it would just crank and crank and crank but not start. If i let it sit for about 30 minutes - it would start right up.

 

[Myros]

I remember some one in a ME article

talking about R129s and their moisture attracting distributors. These symptoms sound like those associated with a damp dizzy. Perhaps you should check there as well.

 

[davidsl500]

My V8 was like that - started immediately when cold, drive a few miles then it wouldnt restart - also started to cough and splutter if driving round town after a couple of miles. Turned out to be the Distributor Cap seals. Mine were like hard plastic/bakelite rings when they are supposed to be rubbery ( no chinese jokes pleease!). Moisture was condensing on the HT Posts in the cap and thus no spark. Would always start a few hours later. Weird problem, 2 tons of metal stopped by £5 worth of seals.

 

[Rodger2119]

I know this is going to sound stupid, But I am assuming that the distributor is the area int he front of the block where the plus wires go into? Can someone please confirm the postion of the Distributor? Or maybe send a url to a schematic?

I went out to start it again, and it started right up, ran great for about 4 minutes, but then slowly began running a little rough. Put it in drive and it stalled. Started up but then would run rough and stall again after a few minutes.

 

[television]

I know this is going to sound stupid, But I am assuming that the distributor is the area int he front of the block where the plus wires go into? Can someone please confirm the postion of the Distributor? Or maybe send a url to a schematic?

I went out to start it again, and it started right up, ran great for about 4 minutes, but then slowly began running a little rough. Put it in drive and it stalled. Started up but then would run rough and stall again after a few minutes.

This will help you find it.

http://www.detali.ru/cat/oem_mb2.as...GM=717.434&CT=M&cat=505&SID=15&SGR=060&SGN=04

malcolm

 

[davidsl500]

On Malcolms link Number 17 was the cause of my problem ( well 2 number 17's on mine obviously - one each bank)

Take the cap off and check to see if it's wet in the cap and also check the condition of the terminal posts. Dry the cap thoroughly if it is wet, clean up the terminals and as a temporary measure spray some WD40 in the cap, replace it and start her up again. Mine ran for a week with some WD40 in with no problems whilst I awaited the Seals - if the seal is like plastic then replace it.

I also suspected that one of the HT leads into the coils was not home fully as well - needed a good shove to get it in fully.

Good Luck and please report back !