service exchange reconditioned injectors: whats your opinion?

[mebobster]

after spending a small fortune to trace & eliminate the minor cold start problem on my W210 E300TD Auto, only 3 possibilities remain:
1. injectors
2. diesel pump
3. something else!

i had already got my injectors reconditioned on the cheap, but i have been now advised by an honest local engineering firm that it is about time i actually replaced them with new injectors or service exchange ones. apparently there comes a point whereby it is useless to recondition an injector unless a full overhaul is done?

to replace 6 injectors with new ones will cost me around £800-£1000. however i can get service exchange reconditioned injectors with a 12 month warranty (and free loan of the socket!) for a fraction of the new cost...

just wanted an opinion from anyone who has tried & tested service exchange reconditioned injectors.

thankyou.

 

[Aussie Nick]

If you are going to keep it I would suggest you get the new ones

 

[Parrot of Doom]

Or you could change the nozzles and springs on your existing injectors and have them set up properly.

 

[roadhog]

Which is what I had done with mine. £16 each and next day turn around at a local diesel place.
I used to read a lot of discussions (mainly on the yank forums) about different injector tips and their virtues, no idea which ones went in mine but they seem to work just fine.

 

[wireman]

The only difference between a full recon (nozzle, needle and spring) and a new one is the injector body's age.
If the nozzles were done by somebody with the knowledge, clean area and test set required there should be no difference in anything except the price.

The fuel pump has a cold starting mode which offers a combination of an increased max delivery and a small timing change (normaly 1-2deg advance).

In the older all mechanical pumps this was all driven by a manual "choke" knob or automated with a thermostat bulb on or inside the pump, later pumps use a thermal device which warms up from the vehicles battery at startup to provide cold start help, and those very modern things have boxes of transistors to make a simple thing harder but more reliable (and expensive in the event of unreliability).

Take it to a real diesel bloke with a good reputation and ask what can be done.

 

[Bolide]

How can you spend a small fortune on a cold-start problem on a simple diesel engine and not cure it? If all that is left are the injectors and the IP what did you spend the money on?

Most starting problems with the late W124 diesels and the early W210 diesels are caused by air leaks. Replacing about £10-worth of O-rings cures this problem

Sounds like you need a new diesel specialist

Nick Froome
www.w124.co.uk

 

[sigman]

Have you tried FORTE fed striaght into the pump @ £10 worth a shot ,fed direct blasts all the crap away ,but of course if spray pattern is no good injector replacement

 

[mebobster]

Thanks for your opinions/advice gents.

Just a quick note for NICK FROOME-BOLIDE because you want to know what I have spent my money on:

1. The original problem was covered in my following thread: "E Class 300TD misfire on cold start". Fancy a read?
2. My money has been spent on (in no particular order): 6 Glowplugs, Head removed due to glowplug stuck in therefore replacing head gasket with original and also temperature switch, leading to oil & filter change, 6 injectors reconditioned, pre-fuel filter, fuel filter, O rings, all this work done by myself and help from an Uncle with over 40years in the trade, problem still there so taken to an Engineering Firm: Diagnostic testing and maintenance by them- NOT CHEAP- they diagnosed minor fuel leak to seal/gasket/fuel valve and minor air leak to inlet manifold. They replaced Fuel Shut Off Valve, cleaned out inlet manifold and EGR valve, replaced seal rings and some gaskets, tested for further air leaks and confirmed NONE now, they advise replacing the 6 injectors and replacing the fuel pump. Hope this has been interest to you Nick...

For the record, I actually went ahead and replaced all 6 injectors yesterday with the service exchage ones for my piece of mine and to eliminate THAT as the potential cause of the problem. But the problem is still there, slight misfire on a cold start, where the whole engine just shakes and splutters, but after about 20 seconds, it runs like new.

Interesting what WIREMAN has said though about the fuel pump. What I have noticed is when I start the car, something is taking/draining power from the battery causing the fan belt to squeek. Fan belt was replaced during head gasket change and my W210 is self adjusting, so I just cant figure out why it squeeks and then goes quiet after about a minute or so. It does sond like the battery is being used/getting drained on a cold start just for a minute or so, but I have everything inside the car switched off...?

Sounds like I need some luck as well Nick...

 

[ernieh]

Start up Miss-fire?

Hi,
I'm sure you did a thorough check before changing everything that has been changed, but your problem sounds to me as if one or more of the glow plugs are not operating properly, possibly due to a poor electrical connection.

Noting that these have already been changed, I wonder if you have checked for voltage at each of them when they are switched on? I would also check for an electrical open circuit in the new glow plugs.

Sorry if this re-invents the wheel.

Ernie

 

[sigman]

if problem clears within 10 seconds theres a good likelyhood of gumming in the injector pump
http://www.forteuk.co.uk/Diesel_fuel.htm

worth a look ,works like magic for us example mot fail 7.06 after forte fed direct into Inj pump1.92 should be able to coax a local garage to buy you a bottle .

 

[wireman]

Your fan belt squeak is most likely as you guess a heavy electrical load on startup, this may be not only the massive short term drop in the batteries charging impedance after its done lots of work heating the plugs ~70A and the starter ~200-400A, but also the fact that some glow plug systems use after start heating to help improve cold starting emmisions.

In the after glow type systems (common on older indirect injetion engines) the period of post start heating varies from 0 to as much as 30 secs depending on the ambient temperature, during this period the alternator tries to provide all the power for the heaters, about 750watts (~1HP) as well as charge the battery. This puts a very heavy mechanical load on the drive belt and tends to make it squeak or worse still slip if anything is amiss.

With standard claw pole car alternators efficiency being quite poor I would expect the belt to be transmitting some 3HP or more under this condition, that's quite a lot of power and just for the alternator alone, add in a whole bucket full more for the PAS pump, water pump and air con (even when its off) loads plus belt and pulley losses to get an even more realistic idea of the peak workload your auxiliary drive is expected to cope with.

Oil contamination of the belt could be the simple answer but here are a few suggestions of where to else look:-

Check the condition of the auxilary belt, replace it if you have any doubts as to its fitness for continued service since the loss of this essential component when you are using the car is most inconvenient. Examine the pulley side of the belt for degradation and loss of its ribbed "tread", the back side will almost always have some wear marks due to the inside out running on the tensioner pulley, these will soon reappear on the new belt.

Whilst the belt is off check that the tensioner and its associated pulley and damper are also very servicable since these bits are even more of a sod to repair by the roadside.
It may be an automatic tensioner but that does not mean it can mend itself, a poor damper will cause the squeak.

Wipe the pulleys with white spirit to clear off any oil contamination allow it to dry off and ensure that there are no oil leaks from any of the shafts associated with any pulley.

If you car has the sometimes troublesome freewheeling roller clutch in its alternator pulley check this for integrity while you are at it.

Carrying a spare new fan belt just in case is a bit foolish, the new one should be on the engine, you can keep the old one with the spare wheel just in case.

 

[mebobster]

a warm thanks to everyone with their advice, especially to wireman for providing a lot of info & food for thought. looks like im going to be spending a bit more time on my merc. i am aware that the FORTE treatment is very good, but was feeling a bit hesitant on using it to clean the diesel pump because the injectors are quite new, but ill probably give it a go. as suggested earlier, i got the glow plugs re-tested today by a specialist and they are working 100% fine, so at least thats out of the way. it does appear to be the diesel pump. i met a man today who drives a P reg E300 TD Estate. He had a similar start up problem to mine. He had everything replaced connected to the fuel line, and still had the problem. He then fitted an additional manual pump to his engine, and on a morning he just pumps it for a few seconds, and the car starts perfect. He said fitting a new diesel pump is too expensive and too much of a big job for him. He also said its a pretty common fault??? anyhow, if the FORTE doesn't work, looks like a new or RE-CON diesel pump for my merc, not too chuffed about that mind! is there a way to test the diesel pump? ill do some research... once again, thanks to everyone. i might just get in touch with that chap and ask about his manual version pump!