Cold Start problem on 190e

[duncane]

I've got a 1992 190e which has problems starting from cold. It takes about 10-15 seconds to finally catch. I've tried replacing the plugs and leads but this hasn't really made much of a difference. Reading various posts on the forums would suggest it could be a faulty OVP relay. It seems like quite a common problem. I have tried getting one from German and Swedish but they don't stock them. Are they only available from Mercedes dealerships? Roughly how much do they cost?

Another problem I have is the Headlight adjuster is hissing. I have tried briefly to locate the leak in the vacuum tubing but so far unsuccessfully. Any tricks to help identify where the leak might be? Is there any chance this could have something to do with my starting problems?

Thanks,
Duncan

 

[stwat]

Hello Duncan. The OVP relay has a fuse which sits on top of the relay and its usually that which has blown. Its on the left hand side of the ECU and is ****** hard to get to but that's the first thing you want to check. As an aside, the fuse itself is a spade connection type which i find very strange as the main fuse box uses the older bullet type fuses!! Very odd.

I recently had a hissing adjuster switch and found that a rubber connector was missing from where the pipe fits to the headlamp. Once i had replaced this the hiss went away. The problem i now have, is that when i rev the engine the headlights dip!!!!!!!!!!!!! So i must have another leak that needs finding somewhere.

Good luck and keep us informed with how you get on.

Stu

 

[duncane]

Thanks for you reply Stu.

I have checked the fuse on the OVP relay, which as you say is a spade type, but that looks fine. Would this suggest the actual relay itself might be knackered? Any ideas how much a replacement relay would cost?

Cheers,
Duncan

 

[duncane]

Got a new OVP relay from local MB dealership for £60 and fitted it on Saturday and it has sorted out the problem.

Now to track down the leak on the vacuum system...

Cheers,
Duncan

 

[duncane]

More cold start problems

I thought I had sorted out this problem by replacing the OVP relay. Unfortunately after 2 days of the car starting perfectly, the problem is back. I have checked the 2 fuses on top of the new OVP relay and these are fine. Is it possible that something else is causing the relay to fail?

Thanks,
Duncan

 

[anyweb]

what does the car sound like when it's having problems starting from cold ?

and how do you eventually start it ?

battery ok ?

 

[duncane]

Thanks for the reply Anyweb. The engine turns over, and then when it catches it sounds a bit rough for maybe 10 seconds or so, then it is fine. It always (touch wood!) starts eventually, it's just doesn't start straightaway.

Tha battery seems fine. I'm going to check over the leads, distributer cap today to se if there's any moisture got in anywhere.

Anyweb - Just been looking through your 190d renovation website. That looked one hell of a job. Since I bought my 190E in August I have replaced the rear diff, the front coupling, catalytic converter, new plugs, and now the OVP relay. Jobs left to do are:
Replace a worn track rod
Change front brake pads
Locate vacuum leak which is causing headlight adjuster switch to hiss
Sort out cold starting issue
Sort out problem with the fuel guage (seems to jump around all over the place)

I'm sure i'll get there in the end! If anybody has any advice on locating the vacuum leak and fuel guage issues i'd be grateful.

Thanks,
Duncan

 

[anyweb]

you might have to remove the dashboard to get a proper look at the (should be two, at least it was two on my old 190d) hoses going in to the light adjustment knob, and removing the dashboard is a bit of a pain to sy the least so only do this if you are really in the mood

alternatively get your front seat out, get down on your back and using a torch try and locate the two vacuum hoses and see if you can follow where they are going

i recall that when i had mine 'detached' from the adjustment knob, that my car would not 'turn off' even with the key out of the ignition, that gave me a fright i tell ya !

anyway, best of luck with your car, i would guess that petrol engines common failure points at starting are the distributor cap, the spark plugs, leads, petrol filter if any and the carbeurettor

cheers
anyweb

 

[paulcallender]

It sounds like the cold start valve (5th injector) isn't working - its not too difficult to test. firstly check there is 12V or so across its terminals, for 4-10 secs during startup. If that's all ok then take it out and observe the fuel spray when you try and start the car. For this test, its definitely worth disabling the ignition - eg take the wire off the + terminal on the coil. And being in the car when its done, but being able to observe it.

 

[stwat]

Thanks for the reply Anyweb. The engine turns over, and then when it catches it sounds a bit rough for maybe 10 seconds or so, then it is fine. It always (touch wood!) starts eventually, it's just doesn't start straightaway.

Mine has started doing this over the last week or so!!!!!!! :-x

One day its fine and then it just seems to have the odd bad day!!!!! The thing is mine smells strongly of petrol from the exhaust so its flooding for some reason. Weeping injector maybe???

Stu

 

[duncane]

Hi Stu,

Sorry to hear yours has started to play up. I replaced the air filter and HT leads on Saturday, but this doesn't seem to have had much effect.

I think it is time to take it to the garage to get the cold start injector tested.

I'll let you know how i get on.

Thanks,
Duncan

 

[duncane]

Problem getting worse

Hi everyone,

My cold start problem is getting worse, so I took it along to a local merc specialist. Unfortunately they couldn't book me in for a week or so to take a look at the car. The guy at the garage suggested my problem could be due to a faulty fuel pump relay and that I could test it by bridging sockets 87 and 30 (with the relay removed), so that the fuel pump is running constantly, and turning the car over. I have tried this and the car starts first time. Does this mean that the relay is knackered? I just want to be sure before stumping up the £130-140 to get a new relay

What do you reckon?

Thanks,
Duncan

 

[Stevie A]

I had a badly worn distributor cap which made the car difficult to start after it was left for a few days in damp weather. There was moisture in the cap too.

Try a scrappy for a relay.

 

[duncane]

The distributor cap looks OK, while I had it off I gave it a good spray with WD40 to get rid of any moisture.

Has anybody any thoughts on whether my fuel pump relay is likely to be the cause?

Thanks,
Duncan

 

[paulcallender]

The distributor cap looks OK, while I had it off I gave it a good spray with WD40 to get rid of any moisture.

Has anybody any thoughts on whether my fuel pump relay is likely to be the cause?

Thanks,
Duncan

Duncan, you've answered your own question in 3 posts above - bridge terminals 87 and 30 to eliminate it from your enquiries. If a fuel pump relay goes, it could prevent the car running at any time - not just non-starting. You can bridge the terminals (and put a switch in it) or substitute with a known good part, to test it.

With intermittent troubles, you really need to have the car in the 'fault' condition then do some diagnostics. For a fuel pump, the check would be to hear it running and/or test for +12V at the fuel pump, with a voltmeter.

I also reckon you could obtain a fuel pump relay for less than £130 - try www.eurocarparts.com or www.gsfcarparts.com, for example.

Also, have you tested the 5th injector yet?

 

[duncane]

Hi Paul,

Thanks for the reply. I bridged the terminal 87 and 30 and I heard the fuel pump working and the car started absolutlely fine, so i my thinking was it is a dodgy fuel pump relay, but I just wanted to confirm it with people are more experienced with these cars (I've only had my 190E since the start of august). So do you think i'm checking along the right lines and bridging the relay would suggest that the relay is faulty?

Anyway i bit the bullet this afternoon and ordered the merc part from an independant specialist which will set me back £115 (a bit cheaper than the main dealer) I did try German and Swedish, but they only do one for the pre-cat 190E, which actually made the starting problem worse.

I haven't tested the fifth injector yet, but I suppose that will be the next thing to check should the new relay not sort it out?

Sorry to sound a bit thick, but my last car was an old Golf and there was a lot less to analyse when something went wrong.

Cheers,
Duncan

 

[paulcallender]

Ironically, I now have an old Golf (as well as 2 Mercs!)

You really need to isolate whether its an ignition problem, or a fuelling problem, or something else (like compression, or valve/ignition timing). Have you owned the car for a while? Can you vouch for its pre-fault condition, which would rule out a lot of potential things wrong?

Here are a bunch of zero-cost things you can to do eliminate some of the more common starting issues (assuming starter is spinning the engine okay, battery is good, fuel type and condition is good):

1. Bypass the fuel pump relay
2. Check delivery of fuel at the fuel distributor (take off the fuel line and observe the flowrate and cleaniness of the fuel).
3. Check operation of the 5th injector.
4. Do a test start with 'cold start' spray or similar.
5. Check and clean the air filter.
6. Check the security, and clean the contacts, of all electrical connections to the engine (eg water temp sensors, FI sensors, etc etc) and the coil.
7. Look at the condition of the spark plugs, and clean them if needs be.
8. Look at the condition of the ignition leads, and clean them if needs be.
9. Look at the condition of the distributor cap, and clean if needs be.
10. Reset the timing statically, if you are unsure if its correct or not.

PS If you're old Golf was fuel injection, then it should all look eerily familiar - they use basically the same Bosch FI system (KE-Jetronic).

 

[duncane]

My old golf was pretty basic with single point injection :-? .

On your check list i have:
1. Bypass the fuel pump relay Checked and starts fine when bypassed
2. Check delivery of fuel at the fuel distributor (take off the fuel line and observe the flowrate and cleaniness of the fuel).
3. Check operation of the 5th injector.
4. Do a test start with 'cold start' spray or similar.
5. Check and clean the air filter. Changed the air filter
6. Check the security, and clean the contacts, of all electrical connections to the engine (eg water temp sensors, FI sensors, etc etc) and the coil.
7. Look at the condition of the spark plugs, and clean them if needs be. Replaced the spark plugs
8. Look at the condition of the ignition leads, and clean them if needs be. Replaced the ignition leads
9. Look at the condition of the distributor cap, and clean if needs be. Checked and looks OK
10. Reset the timing statically, if you are unsure if its correct or not.

I have avoided getting involved with the 5th injector and fuel distributor as i'm a little wary of messing with the actual fuel delivery as i've no experience of this (paranoid of going up in flames!).

Hopefully the relay will finally sort things out, fingers crossed. If not I think it is time to stop the self diagnosis and take it the garage to sort out.

Thanks for your advice, I'm sure i'll be posting again soon as I work through the other problems on the car ;-)

Duncan

 

[paulcallender]

My old golf was pretty basic with single point injection :-? .

On your check list i have:
1. Bypass the fuel pump relay Checked and starts fine when bypassed
2. Check delivery of fuel at the fuel distributor (take off the fuel line and observe the flowrate and cleaniness of the fuel).
3. Check operation of the 5th injector.
4. Do a test start with 'cold start' spray or similar.
5. Check and clean the air filter. Changed the air filter
6. Check the security, and clean the contacts, of all electrical connections to the engine (eg water temp sensors, FI sensors, etc etc) and the coil.
7. Look at the condition of the spark plugs, and clean them if needs be. Replaced the spark plugs
8. Look at the condition of the ignition leads, and clean them if needs be. Replaced the ignition leads
9. Look at the condition of the distributor cap, and clean if needs be. Checked and looks OK
10. Reset the timing statically, if you are unsure if its correct or not.

I have avoided getting involved with the 5th injector and fuel distributor as i'm a little wary of messing with the actual fuel delivery as i've no experience of this (paranoid of going up in flames!).

Hopefully the relay will finally sort things out, fingers crossed. If not I think it is time to stop the self diagnosis and take it the garage to sort out.

Thanks for your advice, I'm sure i'll be posting again soon as I work through the other problems on the car ;-)

Duncan

Which model and year Golf? The Mk1 and Mk2 fuel injection ones all had multipoint injection. Up to around 1987 it was K-Jetronic, then they moved over to Digifant. I think single point injection came later on, say after 1992?

You could use 'cold start' spray as a very basic check of the fuel system - if it starts fine on the cold start, but not without, then it tends to be a fuel problem not an ignition one. You're going to have to get involved with fuel, eventually. Just take simple precautions like eliminating ignition sources and keeping a bucket of water, or hosepipe handy. You could even go all the way and purchase a fire extinguisher, as I have done (never needed it yet!)

 

[duncane]

Hi Paul,

The Golf was a very basic 1.4 MkIII (1994), a really nice car, very simple to maintain, but with it being the 1.4 MkIII was pretty underpowered. It was a shame to get rid of it in the end, especially considering the problems i've had with the 190e. The golf always used to start as soon as you turned the key Ah, halcyon days.

That said i'm sure the 190 will be fine once i've got all the niggles sorted.

Duncan