OE Quality Parts - Really !!!

Ask for and share advice on using the PicoScope kit to fix vehicles here.

OE Quality Parts - Really !!!

Postby STC » Tue Jul 05, 2016 11:49 pm

I looked at a Vectra C today, Running rough with several codes including one for "System Lean" - I think P0171, I went for that first.

Garage has already replaced the Maf, had the ECU tested, replaced pistons & Rings, Head has been rebuilt.

Smoke test proved no air leaks, forced O2 rich and lean - all good. Fuel Pressure and Flow to spec, Injector durations at 5ms so it's begging for more fuel. No EGR to add to the confusion.

In data streams I noticed MAF voltage at 0.6v at idle and didn't like that. specifications state that anything fro 0.5v to 1.2v is ok at idle, I still didn't like that and went after the maf. I replaced it with a Variable Potentiometer set at 1.0v and happy days it idles perfectly.

A new MaF in a VDO box - OE Quality - arrives from a Motor Factor and its worse, I now have IAT and MAF signal high faults, indeed I have 8v on both signal wires - Measured values show 5v on both, that's the most it is expecting ?? !!
So now I have to manipulate both IAT & MAF with 2 Variable pots and again it idles perfectly. That is my Wiring and ECU proved good and able to react to differing inputs.

Then we order another from GSF which came in a box with the seal broken and clearly not new, we tried it just in case and get the same 8v on both signal wires.

Tomorrow we have one coming from the Dealer - lets hope it is a fix.

So these VDO / Siemens OE Quality replacements ?? Are they just bad or am I buying cheap clones.

If so I want to be reporting this to Trading Standards, I spent a whole day on this and believe it should have been 2 hours max from start to guaranteed fix.
Last edited by STC on Mon Jul 25, 2016 9:12 pm, edited 1 time in total.
STC
Zen Master
Zen Master
 
Posts: 224
Joined: Sun Sep 13, 2015 2:10 am

Re: OE Quality Parts - Really !!!

Postby Fat Freddy » Thu Jul 07, 2016 6:43 am

Just food for thought but I may have misunderstood or overlooked something here. Not trying to muddy the waters here (although I probably am) but.

System Lean" - I think P0171


would explain:

Injector durations at 5ms


Bearing in mind I don't know the conditions (hot/cold etc.) but I would normally consider 5 ms too long a duration on a warm engine at idle. Though with a poorly running engine, warm with a stumbling idle, the ECU will dump a lot of fuel in to save it's self, multiple injection, long duration's etc. So saying that, could the 5 ms may be a result of the high load (running rough) and the P0171 because of poor combustion???
Or has the duration been opened up because it thinks it's lean??? I say thinks because I would consider, generally, 5 ms long enough to inject plenty of fuel.

Did you happen to see injection duration after you dialed in the Pot's?

Why was this rebuilt? Badly cooked? High Km's?

I would normally say you were on the money but something is not sitting right but I'm not there and as I've said I may of missed something (and often do).

HTH
FF
User avatar
Fat Freddy
Zen Master
Zen Master
 
Posts: 267
Joined: Fri May 04, 2012 4:52 am

Re: OE Quality Parts - Really !!!

Postby STC » Fri Jul 08, 2016 11:21 pm

Freddy

First, a genuine new MAF and it is fixed. I didn't fit it and the car has gone so no Post Mortem info is available.

Or has the duration been opened up because it thinks it's lean??? I say thinks because I would consider, generally, 5 ms long enough to inject plenty of fuel.


That does not sit right with me either.
For sure the first Air Mass was under reporting the air entering the system hence a good reason for it to throw less fuel then required accounting for the Lean Condition and Rough Idle. To be precise the injector durations were flickering around 4.5 - 4.7 ms, not often hitting 5ms, O2S1 was constantly lean and I could force it rich. At those durations I would have expected it to run rich. Cant quite get my head around that right now.

Did you happen to see injection duration after you dialled in the Pot's?

Yes the dropped back to 2.3ms, that I was happy with

Why was this rebuilt? Badly cooked? High Km's?

In an attempt to cure the this fault, the replaced rings and re seated valves. - Who knows for sure ? Most of what I hear turns out to be Botox from some of the establishments that I get called to.

In the same place, under the care of the same technician a 1991 Escort RS Turbo Non Start. He has spent 2 days stripping the fuel metering unit and anything else fuel related that he can get his hands on.

The job was passed to me with Spark and fuel at injectors confirmed !!!

I probed the Fuel pump from the relay under the dash and could hear it running, pulled the pipe between tank and pump to reveal no fuel in the tank. Put fuel in it and the pump has died, it now trips out my probe (8 amp circuit breaker) Fit a new pump and it is now pissing out fuel from the return pipe above the tank - Yes they have just fitted a new tank to it.

Its all wrong and they have been in business for 30 odd years.
STC
Zen Master
Zen Master
 
Posts: 224
Joined: Sun Sep 13, 2015 2:10 am

Re: OE Quality Parts - Really !!!

Postby STC » Sun Jul 17, 2016 7:46 pm

FF

I have been analysing this a day two and have come to the conclusion that the new MAF sensors had never seen the insides of a VDO factory, the closest they got would have been flying over said factory on route from China :D :D :D
STC
Zen Master
Zen Master
 
Posts: 224
Joined: Sun Sep 13, 2015 2:10 am

Re: OE Quality Parts - Really !!!

Postby EAAD » Sun Jul 17, 2016 11:14 pm

STC wrote:FF

I have been analysing this a day two and have come to the conclusion that the new MAF sensors had never seen the insides of a VDO factory, the closest they got would have been flying over said factory on route from China :D :D :D


Hmmmmm.....nice one STC
EAAD
User
User
 
Posts: 31
Joined: Mon Apr 04, 2016 12:15 pm


Return to Diagnostic discussion

Who is online

Users browsing this forum: No registered users and 2 guests