problems when warm

[kd19792]

have a 1990 mercedes 300e starts fine when cold, but once warmed up refuses to start i can here the fuel pump working when i turn ignition on and cant understand why only when warm. the battery will die before the car will restart if i just kept tring to start it. not sure where to start really as never had this problem ever with any other car if any one could point me in right direction it would be most appricated

 

[kd19792]

help please

 

[television]

I will read through the set up on your car.

Does it ever stop when warm or is it only the starting

 

[kd19792]

it runs fine untill the auto choke cuts off then thats it its dead just stalls and then wont start again im not realy familar with the set ups on mercs as this is my first one i bought it as to put on road for myself and absolutly itching to get it sorted and on road like a kid with a new toy. my mechincal knowleage is limit to vectras ect

 

[television]

This could be the crankshaft sensor

If you have a multi meter that measures ohms,,you could test it while warm,,it should read 1kΩ

It would be worth buying one for £5 to.£7 to test it

 

[kd19792]

i will give that ago tomorrow do you have any other areas i could take a look at many thanks for the advice

 

[television]

i will give that ago tomorrow do you have any other areas i could take a look at many thanks for the advice

I do have the whole injection sytem for your car in book form

I am trying to copy it if I can

The crank shaft senser is hard to measur if the test leads have safety shoulder as the connections are a little way down

 

[kd19792]

ok thanks i if you can get that to copy i will have a good look at it just want to get her back on road, always wanted one, my dream car i suppose been after one for year never been able to afford insurance untill now. so just like a kid with new toy. lol

 

[Xtractorfan]

Malcolm forgive me but it looks like you have got a page three model to pose for that pic with the sensor on her rump.. u have contacts we dont know about ...or is this the connections ur talking about

 

[television]

Malcolm forgive me but it looks like you have got a page three model to pose for that pic with the sensor on her rump.. u have contacts we dont know about ...or is this the connections ur talking about

Well it is a sensor

 

[kd19792]

right cant find my multimeter but start her up from cold started no problems until it gets up to about 40 degrees the when you touch acclerator it starts to cough and splutter unless you are very gental with acclerator the she revs up but bit bit heavey on acclerator she coughs and splutters if you dont touch the acclerator it just splutters and stalls

 

[ant500sl]

As the car fails at a given temperature I would say it might have something to do with the fueling side of things. Your car has the Bosch KE Jetronic system which is a mechanical system with the addition of electronic controls for warm up and acceleration enrichment etc.

With all the electronics disconnected the car runs with a perfect air to fuel ratio for a warmed up engine, this is one of the useful features of mechanical injection.

You can disable all the electronics by removing the two wire connector that attaches to the side of the fuel distributor. This is the block under the air filter that has 6 metal lines coming out of it which go to the fuel injectors. There is also a metal line in the centre which goes to the cold start injector which may also be a possible cause of your problem as if this leaks it will provide sufficient fuel to stop a warm engine at idle instantly.

If the engine runs ok then the problem is somewhere in the electronic control side. If not the fault will be fuel pressure/quantity or ignition.

This is a simple test and only takes 5 minutes with no tools required, its the one I always use as a starting point on the 5 cars I have owned with this type of injection.

 

[television]

Seeing your new post forget the CPS

Some more info here

http://www.mbclub.co.uk/forums/showthread.php?t=33066

 

[kd19792]

right will go try this help thanks for help from both of you it is greatly appricated

 

[mattkh]

the cold start injector which may also be a possible cause of your problem as if this leaks it will provide sufficient fuel to stop a warm engine at idle instantly.

Hi
Thank you for this excellent tip.
Just one question. How does a leaky cold start injector (overfuelling in other words) stop the engine idling ? In fact the revs should pick up.

 

[kd19792]

i suppose it could flood the engine is that possible

 

[kd19792]

tried removing the plug does not seem to make much differance it when it get inbetween 40 and 80 degrees it starts while it is cold it runs spot on i can even drive it up and down while cold, so where would i look next thanks

 

[mattkh]

tried removing the plug does not seem to make much differance

Hi
Which plug did you remove ?

 

[kd19792]

You can disable all the electronics by removing the two wire connector that attaches to the side of the fuel distributor. This is the block under the air filter that has 6 metal lines coming out of it which go to the fuel injectors.

this one as above

 

[Telegraph-Hill]

This could be the crankshaft sensor

If you have a multi meter that measures ohms,,you could test it while warm,,it should read 1kΩ

It would be worth buying one for £5 to.£7 to test it

The M103 does only have one CS sensor and it is wired to the test connector not to the ECU. There is one sensor at the flywheel going to the HV unit but never had problems with this.

The tip to disconnect the ECU is the right one but the better way to test it is to disconnect the whole connector on the top of the ECU (behind the battery) because the air flow unit is still connected. There is not THAT tip for this problem I'M afraid. The system needs to be tested and the ECU needs to be read out with an scope.

Greez,
Oli