Damaged ECU

Nickukay

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Hi All

Wonder if anyone would like to chip in and offer any advice? I have been without my car on and off for 2 months (2002 270 CDI Avangarde) and now been hit with a £1000 bill.

The Short Story - Car went in to garage with fume smell in cabin which was diagnosed as seal on injector required replacement

Car came back and after 10 miles driving big bang - injector shot through underside of bonnet: Fault diagnosed as failed injector bolt thread

Got car back - sluggish performance and miss firing: Back and forth a few times with garage: Fault diagnosed as damaged ECU, new one required....

Question i asked the garage:
As each injector is wired, is it not feasible this wire was stretched when lifting occurred due to the failed bolt causing a short, which potentially could cause damage to the ECU?


Their response:
No the wires are well insulated, there is slack within the loom to allow for movement and the ecu fault relates to no 2 and no 5 fueling circuit, this is why a fault of injector was diagnosed twice at no 2

Is this a fair response?
 

rpe2

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A Lazy response.

What does it matter that the wires are insulated? As you correctly suggest, what has this to do with the wires being damaged?

Best to start with the fault codes...
 
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Nickukay

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The whole story

Car came into garage with a complaint of a fuel smell; Vehicle assesed and fault found was the fuel injectors leaking at the point where they seat in the cylinder head. This causes compression, exhaust fumes and unburnt fuel to 'chuff' into space under bonnet. The rectification is to remove injectors, clean holes, replace sealing rings and refit injectors. This was done and car returned to yourself.

Were any replacement injectors fitted at this point? Were new fixing clamp bolts used when re-fitting or were the existing bolts re-fitted? If new injector/s were fitted were they / these coded to the ECU- If so how were these coded i.e. what equipment was used to re-code the ECU?

No replacement injectors fitted at this stage, it was only the sealing rings at fault.

Following day Nicky called to say smell of fuel was worse than before after driving a few miles. The vehicle was returned to workshop and assesed. Number 1 injector had been pushed up from its seat so asll the fuel and all the compression from this cylinder was leaking into engine compartment. This was due to when fitting the securing bolt that holds the injector tight to the cylinder head was tightened it stripped the thread so the injector could not hold down tight. This was missed on reassembly and come adrift after driving just a few miles.

COLOR="Blue"]Nikki called to say the car was running like a chug boat and totally un-driveable with steam coming from under the bonnet, with the car sounding like it’s going to explode[/COLOR]

Correct this was due to the explanation above.

We removed the injector, fitted a sleeve into cylinder head to give injector a good thread to tighten to. The cam cover, injector, bolt and pipe were replaced along with plastic covers over the engine that had been damaged, the dent to bonnet was caused when this injector came adrift and repairs are planned for this at a bodyshop at a later date as agreed with Nicky.

I assume that the injector that damage the bonnet was replaced at this point? If so, Once again were new fixing clamp bolts used when re-fitting and were the injectors coded to the ECU if so how?

Yes, injector, clamp and bolt were replaced at this point.

With this repair each individual fuel pipe from common rail to each injector to be replaced, was this done?

With the replacement injector a new pipe was fitted.

As each injector is wired, is it not feasible this wire was stretched when lifting occurred due to the failed bolt causing a short, which potentially could cause damage to the ECU??

No the wires are well insulated, there is slack within the loom to allow for movement and the ecu fault relates to no 2 and no 5 fueling circuit, this is why a fault of injector was diagnosed twice at no 2

Fault could also be in wiring harness where damaged occurred, was this checked?

All looms were tested by ourselves and by mercedes.

The car was returned to yourself. After driving into work you reported a lack of power. We again took the car back into workshop and spent many many man hours checking and testing to try to find cause of this lack of power.

We came up with no cureing solution so decided to take the car to the mercedes specialist in Cambridge to see if we were missing anything.
They advised a fault on another injector (number 2) this was replaces and the system all reset to the new injectors.

The car was returned to yourself. Nicky drove to stables and all seemed fine. On way home a warning light came on and lack of power followed.
I came to your home and carried out some diagnostic checks which revealed a fault with the air mass meter which measures the amount of air being drawn into engine and adjusts fuel quantity as required. The checks also revealed a faulty glow plug relay, ths controls the pre heating plugs in the engine which work when the orange coil light comes on pre starting to warm the air inside engine to aid starting, This fault would not cause any lack of power. We again took the car back to workshop and replaces both parts. These faults are not connected with the injector removal and replacement but I felt that I should replace for you free of charge. This put the warning light out but we still had a lack of power.

Lots more man hours followed to find a solution including help from our technical 'bods' It was agreed to remove the inlet manifold to check on the air flaps. These flaps inside the manifold are moved electronically to vary the air entering the cylinder at different engine loads.

We found that on number 2 cylinder this flap had a broken linkage and was jammed shut. Finally we thought we had found the problem. Two days labour and a new linkage later we still had a lack of power, again this fault with the flap is unrelated to the work carried out on the injectors.

More man hours crying over your engine were spent by grown men! We drew blanks so decided to get another opinion from Mercedes in Cambridge.

The car was sent into the dealer and after a couple of days they reported back with a faulty no 2 injector. Now this had been replaced already.

The following day they reported back to say replacing the injector did not cure the fault and they refitted the one they took out.

3 days later they reported back with suspected fault within the main brain of the car and a test unit had been requested from Germany.

The dealer requested authority to replace unit an a cost of about £1000.00 to cure the fault. Again this fault has no relation to injector work carried out during the first visit to Mitchell's

We have spent many many hours to try to resolve this, fitted failed parts on the way at no cost but cannot continue to pay for any more repairs that arrise on the car. All of our work carrys a warranty for faulty workmanship and all of the parts we fit have a 12 month warranty. This was put to the test and passed with the repairs carried out when injector bolt thread failed.

How can you be sure that the ECU was not damage at the point in time of the injector lifting?

I can be sure of this as the ecu fault relates to different cylinder circuits as explained above, as with the manifold flap, glow relay and air mass all these faults are coincidental to follow after repair of leaking injector seals.
 
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rf065

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There are companies who will test & repair ECU's, some are better than others though. Go for one who is recommended & it should be a lot less than £1000.

Russ
 
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Nickukay

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Thanks both, apparently my ECU is non repairable - Both Mercedes and the Garage said they have looked in to this :-(
 

jberks

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Sad tale but it sounds like the garage has been very reasonable. Unfortunatly sometimes you repair one thing and another goes almost immediately and you end up chasing. No idea why.
My E270 has run perfectly for 70,000 miles, 2 weeks ago, a front spring broke. The dealer replaced the springs and returned the car. The following day I set off to work, 50 miles up the motorway and by the time I got there, she was really sluggish, no kickdown and no power over 1/4 throttle. I had it diagnosed in Manchester as the Air Mass Sensor - totally unrelated to anything the dealer had touched. Ordered a new one for the following day and limped her back home that night and back to Mcr again the following morning. Half way back, she was starting to make a fluttering sound. By the time I got to the garage that lunch time, the sound had developed to a loud flutter. The garage replaced the sensor and reported that she'd blown a turbo hose - hence the flutter - again unrelated. New hose and she's 100% again. So, no costs for 3 1/2 years and then in a week, a heavily discounted £170 for 2 springs and £250 for the sensor and hose, all out of the blue and I have to say utterly unrelated and no one to blame.
Sadly, it happens.
 


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