W163 ML270 cdi starts but stops instantly

[Hargy78]

Hi all,
I know there is a lot of discussions on cdi not starting and they’re prone to air leaks in the suction line between the tank and lift pump.
But mine seems to be a little different:

It starts easily but stops before it reaches idle.

I’ve put a 12v lift pump at the tank to overcome air leaks (before I go chassing air leaks) - it pumps freely but after trying to start the pump is dead-head. Fuel solenoid closing and stopping flow.
The tacho rises to about 1000rpm before it stops - crank angle sensor probably ok.
I’ve replaced cam shaft sensor and there is no change.
I’ve put a multi meter on the battery to check for high voltage - failed Volt Reg apparently can result in high voltage and shut the engine down. But no high voltage is recorded in the brief starting period.
The fob keys dont work the locks - immobiliser issue? But it does start briefly

So now for the history:
The vehicle is in a rough state. I was given it as it wouldnt start. Once home I tried to start it and it tried. I put about 10L diesel in it, it started and I drove off the trailer.
Took the engine covers off and found the wgr gummed up and black death over the injectors.
Cleaned up the intake, removed most of the black death carefully, unclipped injector 2 wiring and removed the diesel line. And of course the injector wouldnt come out. (#2 is leaking).
So I put the #2 injector back together, bleed the air and it starts but stops immediately.
Read about the fuel so filled the tank to full and tried lots of times but no joy.
Added 12v lift pump and found it dead heads when I try to start indicating a fuel valve is being closed.

So would you all be so kind as to offer items to check for?

Much appreciated,
Hargs

 

[oigle]

Perhaps you have wired the lift pump to an unsuitable 12V source.

 

[mersum1es]

Your tweakpump may now actually block fuel delivery so that pressure in rail drops immediately. Do you have a diagnostic device which could log rail pressure? It also could pinpoint is it fuel based issue or something else.

Another culprit could be that you injector connector pins has no proper contact (since you have played with them - pin withdraw/black death damage etc). Some engine models shut down engine if they found open injector solenoid circuit, can't remember if yours is one of them.

 

[M80]

Is it possible fuel rail pressure is too high, due to the additional pump?
Anyway it seems the start point is to disconnect that pump.
That assumes fuel can still be drawn with the pump disconnected.

 

[mersum1es]

No, pressure rises due to load (in this case pressure control valve), and function of in/out flow vs. rail volume. Increasing inlet pressure has very minor effect if system is at normal operating point. Another thing is that if there still is air bubbles in intake lines. that can cause fluctuation in pressure.

Now writing this, it occurred to me that is OP talking about W164 seen in signature? That car has OM642 engine, which already has tank primer pump. That engine does not suffer air leaks either. So if there now has some extra pump, it can be fully possible that tweak is actually causing lower primer pressure than original pump, and thus car dies at fuel starvation.

 

[M80]

Now writing this, it occurred to me that is OP talking about W164 seen in signature? That car has OM642 engine

The title is of the 163, 270 5 pot.
Pretty sure that's why he installed the lift pump.

One issue is that there isn't going to be the lift pump shut down by the ECU after (is it) 15 seconds?
But if it shuts down on a dead head that should serve purpose.

 

[mersum1es]

The title is of the 163, 270 5 pot.
Pretty sure that's why he installed the lift pump.

One issue is that there isn't going to be the lift pump shut down by the ECU after (is it) 15 seconds?
But if it shuts down on a dead head that should serve purpose.

Good call, didn't read title any more

 

[Hargy78]

Perhaps you have wired the lift pump to an unsuitable 12V source.

Has it’s own battery

 

[Hargy78]

Your tweakpump may now actually block fuel delivery so that pressure in rail drops immediately. Do you have a diagnostic device which could log rail pressure? It also could pinpoint is it fuel based issue or something else.

Another culprit could be that you injector connector pins has no proper contact (since you have played with them - pin withdraw/black death damage etc). Some engine models shut down engine if they found open injector solenoid circuit, can't remember if yours is one of them.

Thanks, I only removed injector 2. Will check the connection.
Looking at diagnostic devises. Leaning towards xentry; aparently it will provide diagnostic guidance as well as fault codes.

 

[Hargy78]

Appreciate links to discussions on diagnostic tools - then w164 ml320 i need one

 

[Hargy78]

No, pressure rises due to load (in this case pressure control valve), and function of in/out flow vs. rail volume. Increasing inlet pressure has very minor effect if system is at normal operating point. Another thing is that if there still is air bubbles in intake lines. that can cause fluctuation in pressure.

Now writing this, it occurred to me that is OP talking about W164 seen in signature? That car has OM642 engine, which already has tank primer pump. That engine does not suffer air leaks either. So if there now has some extra pump, it can be fully possible that tweak is actually causing lower primer pressure than original pump, and thus car dies at fuel starvation.

Sorry for slow replies (working and looking after kids). Driving a w164, gifted a w163 ml270 cdi that apparently wasnt running. But when I got it home it started and drove off the trailer.
I cleaned up black death and unplugged #2 injector (straight 5). Injector wouldnt come out so recommected in and was going to get the engine hot before trying again. But it now it would start instantly but stop immediately.
Read about the air bubble saga that many have had and filled the tank all the way - no change.
Checked for bubbles - cant see any.
Added “tweakpump” and no different; starts instantly and stops immediately. Barely lifts needle to 1000rpm. But, with ignition on the tweakpump is pumping freely, after trying to start, the tweak pump is deadhead so shut off valve is closing for some reason which points to electrical.
Tacho moves so probably not crankshaft. Replaced cam pos sensor as it was easy and its not that.
So I need to gef a diagnostic tool to see what’s going on. One that will do w163 and w164 ml cdi.
Thankyou all for your help - still reading through

 

[M80]

I'm assuming that the 163 has been stood for a while. You might consider diesel bug.
This pest thrives in part empty tanks. It will block, or partially block fuel filters.
The evidence would be a black gunge in the bottom of the fuel tank, or within the filter.

It may be that you exhausted the cleaner fuel while moving the car, and pulled through enough gunge to then block the filter.

The gunge is what the creature cr*ps, as it digests diesel in the top layer of the fuel where there is some oxygen.

 

[mersum1es]

oh this has shut down valve? Check that wires too, common place to fail,

 

[Hargy78]

I'm assuming that the 163 has been stood for a while. You might consider diesel bug.
This pest thrives in part empty tanks. It will block, or partially block fuel filters.
The evidence would be a black gunge in the bottom of the fuel tank, or within the filter.

It may be that you exhausted the cleaner fuel while moving the car, and pulled through enough gunge to then block the filter.

The gunge is what the creature cr*ps, as it digests diesel in the top layer of the fuel where there is some oxygen.

Good point, algae will grow in the water that builds in diesel. I dont think this is the issue as diesel pumps freely with ignition on, but cant after it shuts down. And this is consistently the case. If the filter was blocked enough to not let the engine even idle, it wouldnt pump freely with the tweak pump when switching the ignition off an on again.

 

[Hargy78]

oh this has shut down valve? Check that wires too, common place to fail,

Thanks, i’ll have a look this weekend.
If I dont find anything then I’ll have to wait till I get an SDS/xentry/star onto it.

 

[Hargy78]

Thanks, i’ll have a look this weekend.
If I dont find anything then I’ll have to wait till I get an SDS/xentry/star onto it.

oh this has shut down valve? Check that wires too, common place to fail,

Ok so it started.
I put the battery on the smart charger all week.
Got my cheap Bosch obd reader - no codes. And deleted (no codes) to be sure.
And started it. The tweak pump is in situ but mot powered and it runs fine.

Sooo, maybe emarrased again by a battery?
****** thing started before, surely that entitles it to keep running?

Anyway thanks for everyones help.
If keeps running, I’ll repky to my original post to save any future trouble shooters the read.
And post links to similar trouble shootings

 

[Hargy78]

Ok, so it’s not a low battery. Drove it to service station, pumped up the tyres and drove back.
Sprayed the car with water, gave it a quick wipe over with a sponge and rinsed it off with the hose. A very light wash, and the problem returned.
Starts easilly but shuts down straight away.
Took out battery, fully charged it but problem still persists. Must be electrical - water getting into a connector?

I’m going to need to get a Xentry….

 

[M80]

Cut off relay,
engine components relay.

Replacing those seems reasonable.

The starting then stopping is a bit confusing though. A bad relay and I would expect some failed starts.