mercedes 190E starting problem

I have a 190E 2.0 (1990) which was running perfectly until 2 days ago, when I tried to start it and the engine just cranked and cranked without even a cough or splutter. I immediately suspected a fault in
the ignition system but checked this only to find the plugs are sparking (cheked by holding HT leads a short distance from earthed metal). I changed all four plugs anyhow - stilll no start. Then i suspected a fuel pump or relay problem, so i bypassed the relay by bridging the 30 and 87 sockets on relay with a piece of wire, and the pump whirs away fine. what is the most likely solution considering the plugs spark and the fuel pump and relay are fine? Any help would be vastly appreciated before I spend a fortune getting out a mobile mechanic
Thanks
tom
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Overload relay?
How old is the fuel pump relay?
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I am thinking another possibility of fuel enrichment problem... similar to choke for the colder morning.
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Cheers for the suggestions - if the pump is pumping and the plugs are sparking and the car still wont start isnt the overload relay ruled out? Not sure when the fuel filter was last changed, Iv'e only had the car a couple of months in which time its been running fine. Is the fuel pump easy to change? Also I am concerned as to why it is not starting atall - I have seen loads of problems posted on these pages where the car starts and then dies, or has trouble cold starting etc, but mine wont fire atall. Does this change the diagnosis?
Thanks
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I would start with simple diagnostic first... then continur crossing off potential problems. Another possibility is factory alarm if you have one... I would unplug it if you do have one.... easy way to test for this is to simply leave the window down... lock the car... and then pull up the door lock plunger... and open the car... if horn beeps and light flashes... you got alarm.
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The car has an aftermarket alarm and immobiliser that was already fitted to the car when i bought it. I did suspect an immobiliser fault but ruled it out as firstly the immobiliser light goes out when you unlock the car, and secondly i have tried starting the car with the alarm on and the starter will not turn, proving that the imobiliser is working where supposed to. Plus why would I get a spark?? I have read many stories about the OVP relay on these cars - is this a likely cause - and if so is there a way i can test this (eg bridging the pins like i did on the fuel pump relay)? Finally, my OVP relay seems to be loose - i.e. it is not plugged into anything like the fuel pump one is - it is sort of attatched to the car by wires but not actually plugged in - is this normal?
PS - already checked 10A fuse on top and its fine
Thanks
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OVP is supposed to be plugged in like the fuel pump relay... actually, they are supposed to be next to each other if I remember correctly.
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You do not report wet or damp spark plugs. The fuel pump may run but is fuel getting into the cylinders? Probably not.
When was the fuel filter last changed?
Been buying fuel at a different station? (May have water in the fuel.)
The next test is the fuel pressure.
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I think the plugs were dry but I wasnt really checking al that intently. Doesnt fuel evaporate quickly anyhow? Another thought, what is the relay behind the fusebox? It is the same size and shape as the fuel pump relay - part number 201 821 00 47. Cheers guys
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Thought id update you on the situation. Today I had a mechanic round and we carried out lots of checks on the car. Number one was to see how far fuel was getting so we undid the inflow pipe to the fuel distributor and found there was fuel getting there at high pressure. Then we checked each injector outlet on the top of the fuel distributor in turn, only to find that none of them had any fuel coming out!
So... we took out the fuel distributor and dismantelled it only to find a large blockage of gunk inside it. After careful cleaning and putting back together we returned the part. However, concerned as to where the gunk was coming from we checked the fuel filter, which looked pretty new, but we changed it anyway. My guess is that on old filter wasnt working properly and that was the cause of the crap getting to the fuel dist. in the first place. Having replaced it we ran off a bottle of fuel from the inflow to the engine to check it was clean - which it was.
So, with the fuel dist cleaned out, we checked the injectors again - and found great fuel pressure on each one. Great news....except the engine still would not start. Each of the plugs was wet when removed, and on testing each plug a fat blue spark was found.
AAAArrrggghhh - help me please - - it has compression, fuel and spark - so why wont it run!!!??
Anyhow, my mechanic rekons the car was flooded prettly badly and to leave the plugs out for 2-3 days to dry out the engine/cylinders/manifold, so im going to chek it again in a few days. Is that a fair suggestion??
Finally, is it possible that too much fuel is coming through and flooding the spark plugs before they have a chance to spark??
Any help greatly appreciated
tom
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I think yes after reassembly, too much fuel. You need to lean out the mixture... do 1/4 turn at a time and see if you can start the car up.
There is also a possibility as you disassembled it...it won't work as something is not adjusted right. This is a highly technical job as Bosch said... I never took one apart yet.
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Uh...
When I bought my first Mercedes about 10 years ago it was a real ratbag poor excuse for a euro 70 280SE. It wouldn't start when I went to test drive it so the guy pulled the plugs, fired a propane torch on them to burn away the gas and oil and then it started.
Waiting 2-3 days seems kinda lame.
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Need Mercedes parts? http://parts.mbz.org
Richard Sexton | Mercedes stuff: http://mbz.org
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Sounds like your man knows what he's doing so go with his suggestion.
I'm a bit skeptical that the fuel distributor mess caused an otherwise well running motor to suddenly quit - gradually yes, but suddenly ??
If there's further difficulty:
Check the spark's timing vs. the crankshaft
Open the oil filler and watch that the cam turns while the engine is cranked - If it doesn't, that's for sure THE PROBLEM!
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Cam turns when the engine is turned over, so thats not the problem.
I let the car dry out for 5 days and still nothing. So....
Its not the distributor, becuase I replaced it. Its not the coil, leads, or plugs, bcause they work fine and the plugs are sparking with fat blue sparks. Its not the fuel pump or relay because plenty of fuel is getting to the cylinders as the plugs are wet when removed, and each injector has been tested and is working fine. So what can it be!!!!???
Could it be a blown OVP relay that is the problem - i.e can this prevent the car from starting completely? But then if it is that then why does the fuel pump deliver fuel to the cylinders and the spark plugs spark? Also are there any other fuses/relays on the car that could have blown besides the ones in the fuse box under the bonnet?
none of this makes sense. In my opinion it is something very stupid that i must be missing, as the car has gone from a great runner to a complete non-starter with absolutely no symptoms in between - how bizarre!
Any help much appreciated
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Thought id update you on the situation. Today I had a mechanic round and we carried out lots of checks on the car. Number one was to see how far fuel was getting so we undid the inflow pipe to the fuel distributor and found there was fuel getting there at high pressure. Then we checked each injector outlet on the top of the fuel distributor in turn, only to find that none of them had any fuel coming out!
So... we took out the fuel distributor and dismantelled it only to find a large blockage of gunk inside it. After careful cleaning and putting back together we returned the part. However, concerned as to where the gunk was coming from we checked the fuel filter, which looked pretty new, but we changed it anyway. My guess is that on old filter wasnt working properly and that was the cause of the crap getting to the fuel dist. in the first place. Having replaced it we ran off a bottle of fuel from the inflow to the engine to check it was clean - which it was.
So, with the fuel dist cleaned out, we checked the injectors again - and found great fuel pressure on each one. Great news....except the engine still would not start. Each of the plugs was wet when removed, and on testing each plug a fat blue spark was found.
AAAArrrggghhh - help me please - - it has compression, fuel and spark - so why wont it run!!!??
Anyhow, my mechanic rekons the car was flooded prettly badly and to leave the plugs out for 2-3 days to dry out the engine/cylinders/manifold, so im going to chek it again in a few days. Is that a fair suggestion??
Finally, is it possible that too much fuel is coming through and flooding the spark plugs before they have a chance to spark??
Any help greatly appreciated
tom
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Thought id update you on the situation. Today I had a mechanic round and we carried out lots of checks on the car. Number one was to see how far fuel was getting so we undid the inflow pipe to the fuel distributor and found there was fuel getting there at high pressure. Then we checked each injector outlet on the top of the fuel distributor in turn, only to find that none of them had any fuel coming out!
So... we took out the fuel distributor and dismantelled it only to find a large blockage of gunk inside it. After careful cleaning and putting back together we returned the part. However, concerned as to where the gunk was coming from we checked the fuel filter, which looked pretty new, but we changed it anyway. My guess is that on old filter wasnt working properly and that was the cause of the crap getting to the fuel dist. in the first place. Having replaced it we ran off a bottle of fuel from the inflow to the engine to check it was clean - which it was.
So, with the fuel dist cleaned out, we checked the injectors again - and found great fuel pressure on each one. Great news....except the engine still would not start. Each of the plugs was wet when removed, and on testing each plug a fat blue spark was found.
AAAArrrggghhh - help me please - - it has compression, fuel and spark - so why wont it run!!!??
Anyhow, my mechanic rekons the car was flooded prettly badly and to leave the plugs out for 2-3 days to dry out the engine/cylinders/manifold, so im going to chek it again in a few days. Is that a fair suggestion??
Finally, is it possible that too much fuel is coming through and flooding the spark plugs before they have a chance to spark??
Any help greatly appreciated
tom
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Thought id update you on the situation. Today I had a mechanic round and we carried out lots of checks on the car. Number one was to see how far fuel was getting so we undid the inflow pipe to the fuel distributor and found there was fuel getting there at high pressure. Then we checked each injector outlet on the top of the fuel distributor in turn, only to find that none of them had any fuel coming out!
So... we took out the fuel distributor and dismantelled it only to find a large blockage of gunk inside it. After careful cleaning and putting back together we returned the part. However, concerned as to where the gunk was coming from we checked the fuel filter, which looked pretty new, but we changed it anyway. My guess is that on old filter wasnt working properly and that was the cause of the crap getting to the fuel dist. in the first place. Having replaced it we ran off a bottle of fuel from the inflow to the engine to check it was clean - which it was.
So, with the fuel dist cleaned out, we checked the injectors again - and found great fuel pressure on each one. Great news....except the engine still would not start. Each of the plugs was wet when removed, and on testing each plug a fat blue spark was found.
AAAArrrggghhh - help me please - - it has compression, fuel and spark - so why wont it run!!!??
Anyhow, my mechanic rekons the car was flooded prettly badly and to leave the plugs out for 2-3 days to dry out the engine/cylinders/manifold, so im going to chek it again in a few days. Is that a fair suggestion??
Finally, is it possible that too much fuel is coming through and flooding the spark plugs before they have a chance to spark??
Any help greatly appreciated
tom
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Thought id update you on the situation. Today I had a mechanic round and we carried out lots of checks on the car. Number one was to see how far fuel was getting so we undid the inflow pipe to the fuel distributor and found there was fuel getting there at high pressure. Then we checked each injector outlet on the top of the fuel distributor in turn, only to find that none of them had any fuel coming out!
So... we took out the fuel distributor and dismantelled it only to find a large blockage of gunk inside it. After careful cleaning and putting back together we returned the part. However, concerned as to where the gunk was coming from we checked the fuel filter, which looked pretty new, but we changed it anyway. My guess is that on old filter wasnt working properly and that was the cause of the crap getting to the fuel dist. in the first place. Having replaced it we ran off a bottle of fuel from the inflow to the engine to check it was clean - which it was.
So, with the fuel dist cleaned out, we checked the injectors again - and found great fuel pressure on each one. Great news....except the engine still would not start. Each of the plugs was wet when removed, and on testing each plug a fat blue spark was found.
AAAArrrggghhh - help me please - - it has compression, fuel and spark - so why wont it run!!!??
Anyhow, my mechanic rekons the car was flooded prettly badly and to leave the plugs out for 2-3 days to dry out the engine/cylinders/manifold, so im going to chek it again in a few days. Is that a fair suggestion??
Finally, is it possible that too much fuel is coming through and flooding the spark plugs before they have a chance to spark??
Any help greatly appreciated
tom
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replying to tom.h.schofield, retroaddiction87 wrote: maybe you should try the cam sensor and or the crank sensor even though you have a spark it does need to be sparking at the right time. Sensor faulty,Water ingress in the connector or simply dirty well worth a check
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