2.0l 16v Starting Problem

[bigtunes 0]

Having a problem with my valver, I've tried the search but can't seem to find anything!

 

When trying to start, first turn of the key she will fire but then conk out without running.

After that cranking it over for ages (2-3 mins) will eventually get her running, and runs fine once she is going.

 

So went into the garage, they've checked the fuel pressure, cleaned the metering head and checked all the supply voltages to no avail. His suggested solution is replacing the whole metering unit - basically everything on top of the airbox. Which seems a bit extreme and costly!

 

He's also found a sort of work around. Cracking open the union for the 5th injector, turning it over until fuel gushes out and tightening it up again seems to work. Not ideal, spraying petrol all over the place doesn't appeal long term, and it stinks for a couple of miles afterwards!

 

Anyone else experienced this? There is a metering head in the for sale on here, but it's only the metal block that the fuel pipes run from, would it be worth fitting this part just to see if it sorts it?

[Kempy 0]

could be one of your pumps..still quite costly. Ive had similar symptoms with my old valver. you can test the fuel pressure after the pumps to see if its normal?

[bigtunes 0]

Sorry forgot to put that! Fuel pressure is there, garage checked that as well. Had the main pump & filter changed about 4 months ago, along with the immobiliser unit and ECU. So pretty sure that all should be ok there.

 

From cranking it with the union cracked it does seem to take a while for the fuel to get to the metering unit, must admit my first thought was the in tank pump packing up.

 

Fault came on really quickly as well, parked up one night running fine, next morning buggered.

 

Anyone know how the metering head works or point me in the right direction for some info? I'm thinking that if the metal block on the airbox that feeds the injectors has valves inside it it may be sticking or something?

 

 

ETA: Found this K-Jet quite an interesting read if you're into that type of thing....

[Jim 2]

Have you tried disconnecting the cold start injector all together (the blue plug connected into the 5th injector) and then starting it?

 

I find that mine is a little more reluctant to start in a morning if I have the 5th injector connected. Vince @ Stealth reckons it's because the injectors are old and tired and probably leaking a little. Add to that the additional fuel that the cold-start sprays in when starting on a morning, then you're ending up with too much fuel in there.

 

It might be in your case you have really leaky injectors and the 5th injector is spraying in too much fuel and it's flooding the engine or something?

[easypops 8]

The blue plug on my car has never been plugged in.......i did plug it in when it was going into the garage to get a new fuel pump......the guy there told me to keep it unplugged as they always seem to over fuel the engine???.......that was a good couple of years ago and it has done no harm......so it stays tied up :D

[Jim 2]

That could be down to the thermotime switch which (I think) governs how long the cold-start injector runs. Problem is it costs something ridiculous like £70 from VW.. and seeing as our country never really gets that cold, just disconnecting the coldstart injector is a good workaround.

 

That said, I'm sure Vince mentioned something about the coldstart injector being used when the engine is warmed up to help smooth out fuelling occasionally at high revs..?

[bigtunes 0]

Cheers, I'll try the blue plug in the morning and report back then!

[davidwort 0]

I'm not knocking your garage, but the more I read and learn myself about the K and KE jet systems, the more I realise very few garages know how to test and diagnose problems properly, and then set them up properly.

There's a number of methodical steps to ensure all parts of the system are working properly, inlcuding testing injectors, the delivery from the metering head and the system pressures. In particular it's not just a single reading of fuel pressure that can give the OK for the pump,pickup pump, pressure accumulator etc. but a range of tests including how long the system retains pressure, if this drops, fuel vapourisation can occur and that can cause all sorts of starting issues.

Once the factory calibration of the metering head on the KE jet 9A are tampered with, usually after some other component causes running issues but is not correctly identified, it can be very difficult to get things right again.

It's worth taking the metering head apart and cleaning any gauze filters that are fitted, some units have more than others, and inspecting the plunger and metering comppnents, but you really need a systematic test of all the senders, lambda, injectors, system pressures and a rolling road session should pick any lambda/metering head issues.

[bigtunes 0]

Well, totally refused to start this morning, tried with the blue plug on and off, union cracked and not.

 

Agree with what you're saying David, from the reading I did last night it seems that the K Jet can be a bit tempremental when things are not right. Do you have any info on injector pressures and spray patterns or pressures at the various points in the system?

 

First time I've used this garage, the one I used to use closed, but was recommended by a guy I work with, who's used him for several years. But he is more of a Mercedes specialist. He did check the pressure at the pump and going into the metering unit and all the supply voltages, so it seems that the fuel is getting to the metering unit but having trouble getting out the other side, so maybe a dodgy valve. If, as Jim suggested, the 5th injector is leaking would that cause a vacum lock in the pipe between it and the metering unit?

 

I've taken a punt on the new metering head so when that arrives I'll strip it all down and see what happens, you never know, always handy to have a few spares anyway. Problem is moved house last week so a bit skint at the mo!

 

Farnham's only down the road so I'll be giving The Phirm a call if I don't get any results :shrug:

[Kempy 0]

would any thing be recorded on vagcom? if you plugged it up to one.

[bigtunes 0]

dunno, but now you mention it I know a bloke who knows a bloke who will.

[Kempy 0]

I only just found where to plug them in :D dunno if I got one on my early valver but my 93 has, might be worth a try

[davidwort 0]

... Do you have any info on injector pressures and spray patterns or pressures at the various points in the system?

Yan's the man, I think he's got old dealership workshop manuals, you need the KE jet specific info to measure fuel delivery amounts from the pump at certain voltages, residual pressure in the system, injector flow balance (is the metering head giving more fuel to one injector etc) and then on the KE jet you have the complication of the lambda, differential pressure regulator (the ECU controlled unit on the side of the airbox that effectively replaces the Warm Up Regulator on plain K-jet) and then temperature senders, manifold pressure(vac line to ECU) and I think KE has a TPS sensor too.

Mercedes 'familiar' mechanics may have experience of similar K-jet setups, but they all vary and the 9A system seems pretty unique :(

Don't think VAG com helps a great deal on the simple 9A ECU, but there is a lot of testing and 'process of elimination' stuff you can do yourself, of course the ideal is to have a similar car to swap known good bits over from?

hope you get it sorted,

David.