Double Whammy

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del320

MB Enthusiast
SUPPORTER
Joined
Mar 4, 2005
Messages
2,435
Location
Near Melrose, Scottish Borders
Car
1996 E320 Coupe
Last month, at the Dirleton GTG, I mentioned to Trapperjohn and Druk that fifth gear had become ever more reluctant to engage. (722.5) Druk confirmed the fluid was clean and at the correct level. It had been changed 30k miles previously in 11/2007. After monitoring the situation for another week or so, the problem was getting worse although just as randomly intermittent.

Derek advised me to take the car to Merparts at Port Glasgow (also recommended by Pontoneer, and many others).

Paul and Stef Mazzoni certainly know their stuff – but, unfortunately rather too well.

To use technical jargon, the loom is knackered. Whilst not in total disintegration, sufficient damage has been done to the ECU and is the most likely cause of the loss of fifth gear and surging at idle. Needless to say the car appeared to perform faultlessly on the run through to Port Glasgow, but after being put on the ramp and running diagnoses on a hot engine, readings confirmed the worst.

View attachment 42815



  • New loom £762 plus vat
  • Air Mass meter £263 plus vat
  • O2 Sensor £195 plus vat
  • HFM ECU £1183 plus vat
  • Spark plugs £18 plus vat
Labour over and above brings total damage to just under£4k.
Worst of all is no car for three weeks.

124s and 129s are now in the ‘classic’ category and parts have rocketed in price and can take weeks if not months to be delivered. (4 – 6 months for 129 exhaust, £1000 for 107 headlamp)

On and ever upward... :doh:
 
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Surely your best bet would be with secondhand parts - certainly with respect to the ECU, or a repaired/re-manufactured unit.

I couldn't imagine spending £1183+vat on a standard E320 ECU.
 
Careful now.

There is a discrepancy in that page you posted up.

It only shows two faults:

1. MAF air sensor

2. O2 sensor (oxygen sensor)

So why list all the items including the ECU ?

Also the O2 sensor is NOT listed - why.

It shows the heater circuit of sensor to be too low.

The O2 sensors do go out of spec on our series of cars, so it will be a good change and will likely give increased economy, with it's restored faster and more accurate switching.

MAF on our 320 cars hardly ever give problems.

Did one of the brothers do the tests or did a minion do them ?

What system did they use on your older generation car ?

If your car drove and starts OK then the ECU is perfectly good.

ECU will only go bad if the ignition wires short together under engine top cover, and you will know about that, because it will blow a coil first and you will be on 4 cylinders. Then next time you start car it MAY blow one of the output transistors within one the ECU 3 output circuits to three coils.

Now your gearbox problem.

So far everything said in your post is unrelated to your gearbox problem on your generation car.

The 5 speed gearbox is a normal mechanical/fluid system like the 4 speed autos.

The 5th gear is an electrical operated system and has its own ECU.

It is highly likely that ECU is the problem (or the connections).

There is pin 13 socket at the diagnostic plug in engine bay on our cars for the 5speed gearbox diagnostics.

Pin 8 is the engine diagnostics for ignition etc.

All codes can be read out via a simple flashing LED and deciphered with a list of codes.

You seem to have had disappointing service from the company, which I always thought had a good reputation.

Has anything changed there recently ?

You need to focus on the ONE issue ie your gearbox fault and go back and ask if they know how to diagnose that alone.

Other stuff can be dealt with later if required.

Let us know how you get on and perhaps we can help further.
 
I've been told that HFM units with a part number beginning with 16 (& lower) are not coded.

Dunno if it's true or not. In any event if you can fin a breaker with that part number you'll be able to buy the ECU & all tied components for a fraction of the new price.

d W124 posted on here today he was having a W124 loom made for about £300.
http://www.mbclub.co.uk/forums/1899968-post201.html
 
Careful now.

Let us know how you get on and perhaps we can help further.

This is way beyond my abilities and understanding. Paul and Stef were very generous of their time explaining all this and my post is simply a resume of the bits I grasped!

I also had a long chat with Druk today and the consensus is that my options are limited to say the least.

I've been told that HFM units with a part number beginning with 16 (& lower) are not coded.

Dunno if it's true or not. In any event if you can fin a breaker with that part number you'll be able to buy the ECU & all tied components for a fraction of the new price.

d W124 posted on here today he was having a W124 loom made for about £300.
http://www.mbclub.co.uk/forums/1899968-post201.html

I simply don't have the experience, knowledge, time or energy to go scratching around so just have to go with the advice given.

I'm happy to have further views but I'm certainly not in any position to pass comment on the Mazzoni brothers.

In passing, I mentioned to Derek that I've spent 3x the amount on my teeth over the past five years - just had to rely on and trust the experts. :D
 
As far as I can make out the HTTWIN is a Chinese clone version of the Mercedes Star system. They have their own [ invite only] forum e.g. Mercedes EPC & WIS [Discussions/Problems]
This may well function OK and there may be good fiscal reasons for going down this route to keep costs down for the business but it ain't Star.
While I can see a sort of justification for most items on that list the ECU is a " biggy" at £1400 inc VAT if its not strictly necessary so I hope they made a convincing case for its replacement.:dk:
 
If the loom is rotten (and i thought a '96 car should be from after MB relealised what a bad idea the biodegradable looms were?) i don't get how anyone can confidently condemn a bunch of sensors and the main ecu from a list of fault codes!
Perfectly good or brand new sensors and ECUs ain't gonna work properly if the wiring to them is shot
 
Based on hotrodder's comment above , a sensible approach might be to replace the loom first then , having cleared fault codes , run the diagnostics again .

I would doubt that ECU faults would damage the new loom , but the existing damaged loom could be throwing up strange readings .

Once the new loom is fitted , any faults still existing could then be dealt with .

This might run up a little more labour , but might also save on parts .
 
Someone posted a while ago they enquired as to the cost of an A service with Merparts and the quote was no cheaper than any Mercedes dealer would ask.

I'm not doubting they know their stuff, but maybe a saving could be made on labour costs at a good Indi with lower costs. Also surprised at how many parts you need, with that many faulty parts I would be surprised if the car ran at all.

Russ
 
I've spent 3x the amount on my teeth over the past five years - just had to rely on and trust the experts. :D

Jaws.jpg
 
Del:As ^ I would change the loom only and go from there as the loom itself can cause a lot of problems such as the maff which might be nothing wrong with it
Also I would get the part number for the wiring loom and run it through inchape as the price I got there was nearly £400 less than the dealer quote
 
124s and 129s are now in the ‘classic’ category and parts have rocketed in price and can take weeks if not months to be delivered. (4 – 6 months for 129 exhaust, £1000 for 107 headlamp)

I know this one well...you have my sympathies!

3 week wait for a lambda sensor from Germany, £1700 for an OEM catalytic converter. :wallbash:
 
I have been through a similar sort of process over the last 4 years with our 280. Previous owner replaced the loom. Done at main dealer in France which saved a bit compared to the UK. Few months after I got it intermittent misfire put down to faulty coil packs. After replacing three of these in quick succession they twigged there was more to it. ECU was fried probably by the dodgy loom. New ECU was fitted and all fine since. It was not quite plug and play. I was told it did need some coding. This year new MAF and Lambda sensors to get through the emissions test. Both easily available from Germany in a couple of days. I have replaced so much on the car there can't be much left to do - heres hoping anyway. I would tend to agree with doing the loom first and see where you are after that though it may have already killed the ECU.
 
As far as I can make out the HTTWIN is a Chinese clone version of the Mercedes Star system.
This may well function OK and there may be good fiscal reasons for going down this route to keep costs down for the business but it ain't Star.
[/QUOTE]

You are wrong! and let me correct you. The latest system is actually called Xentry Connect, the Star Diagnosis name has been dropped. There are three versions inside Xentry Connect they are: HHT WIN (Hand Held Tester: Windows Variant), DAS (Diagnostic Assistance System) and XENTRY (Latest platform Interconnected).
There are very few independents in the UK who actually have purchased the official Xentry Connect/Xentry Tab. This equipment allows SCN (Software calibration number) coding and CVN (Calibration Verification Number) coding. Please in future do not insinuate that we have a cloned machine.

Happy and safe motoring,
 
Double post
 
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You are wrong! and let me correct you. The latest system is actually called Xentry Connect, the Star Diagnosis name has been dropped. There are three versions inside Xentry Connect they are: HHT WIN (Hand Held Tester: Windows Variant), DAS (Diagnostic Assistance System) and XENTRY (Latest platform Interconnected).
There are very few independents in the UK who actually have purchased the official Xentry Connect/Xentry Tab. This equipment allows SCN (Software calibration number) coding and CVN (Calibration Verification Number) coding. Please in future do not insinuate that we have a cloned machine.

Happy and safe motoring,

Thanks for clarifying the situation. I was just trying to help out a fellow forum member. I should have checked your website which makes clear the considerable investment you have made in the latest equipment. Merparts Ltd Independent Mercedes Benz Specialist
 

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