Engine: D5: A puzzle for the EGR valve expert/masochists out there...

[4candles]

Originally Posted by Jetmech

Ok a little knowledge is dangerous and I have little knowledge of things electrical! But I think this is the correct wiring diagram item 8/120 is the egr valve. It looks as if 4candles is correct,(highly unlikely) the ecm does the controlling. Anyway I hope this helps.
Attachment 86533

The screen shot isn't very clear, from the top. The yellow wire goes to pin A66 of the ECM plug, green/white pin A71, green/grey doesn't go to the ecm, brown/black pin A28.

Thanks, my eyes are baaad !

Off course the earths will be switched depending on info computed regarding operating parameters, ie. lambda, engine speed, temp, etc etc, but no other codes showing so all must be ok, right?

I always presumed EGR was a start up system which cleaned emissions until engine was at operating temp, but maybe its passive and continually active?

Anyway, KBB from Dubai Auto Academy is the man to de-mystify and correct any fumblings i or others dare to offer, as i say repeatedly, go to the man with the best onions, (striped jumper, beret and bicyle optional) What time does Dubai open? Does KBB have French connections? Is he called Johnnie?LOL

[SkintKnuckles]

Hi 4c,

yup, I have no problem admitting this is doing my head in!! Without going into details, this whole situation has happened right off the back of some terrible personal circumstances, and the one thing I didn't need is this, especially as my family and I are landlocked without the car.

I'd more or less made my mind up to have the EGR remapped and deleted from the ECM etc, and blanked off at the EGR assembly. This would fix all my woes. However, if the ECM thinks the throttle ain't moving (even though it manifestly is), I'm worried that if I pay for this work, and the revised map needs the throttle info, then it won't work. Then, at that stage, I'll have a reflashed ECM, no EGR/cooler etc, and Volvo likely won't touch it What is so annoying is that the work I've done, and various wee jobs along the way, have resulted in the car never having run better (except when its in low power mode).

Yup, I went as far up the loom as I could see the 4 wires from the EGR position sensor and 'holed' them to do exactly the check you suggest. On all 4 wires, the voltages were the same as at the block connector to the EGR sensor, so the problem seems to lie further up. Sigh !

Thanks for the suggestion.

cheers
Neil

[SkintKnuckles]

Hi Simon,

thanks mate. Well, if a little knowledge is a bad thing, then I'm downright dangerous to be around, lol!

Thanks for this. I'm currently having a quick chill (to let my grump subside) before hving another bash. As if to prove my point (regarding my having a little knowledge), how do I identify the pins at the ECM. Obviously, I can look for the different coloured wires, but do you have a scheme or a map for how do distinguish A66 say, from, A34 (if such exists).

Sorry, if this is dumb, but I've had to accomodate so much new information in so many new areas in the last 3 weeks, that I've gone snowblind and gradually getting thicker by the minute, lol

cheers
Neil

[SkintKnuckles]

Hi 4C,

this is good to know. I'm definitely hitting off the limiter on my current capabilities. Mechanical stuff I'll have bash at, electrical issues give me the heebie jeebies !

If I can't make any headway with this, I think I'll invite both KBB and Clan to this thread, as they have good reps on this board and maybe they can see a pattern to this.

I thought I'd nailed it, until I remembered the whole 'throttle position = 91.3%' on VIDA. I just don't get why this is the case, especially as all aspects of the throttle response (speed, rpm, idle etc) exactly map to what you request at the accelerator pedal. As I said, I'm up for the EGR deletion/remap, jusst for a quiet life, but maybe this parameter will screw it up.

just to clarify, the only codes I have are 44B0 (faulty signal from EGR position sensor) and 4430 (EGR valve signal missing). These codes make perfect sense from the multimeter readings I'd done, where little/no voltage is making it to the EGR position sensor (when in limp mode) and yet normal voltage when the car is in full power mode. To date, I've opted to interpret this as the EGR valve, EGR sensor (brand new) etc being functional, but unable to speak to each other due to dodgy wiring. Now I'm paranpid that this is just a downstream consequencce of the throttle position apparently being locked (even though its not)..

I'll be as mad as a hatter by the end of this one, I tell you....

cheers
Neil

[4candles]

Drum roll for KBB..... he's in the building !

[4candles]

oo my arms are tired now and i've got several noise abatement orders pending...

[KBB]

Neil,

Thanks for the PM and happy to offer some assistance. This is a 4 wire EGR set up Iv just finished for the week end so if some one could kindly look up on VIDA the ECM pin descriptor's for pins A66, A71 and A28 we should be able to take a step forward.

EGR activity only takes place at part and high engine load conditions. It is these conditions that create the high in cylinder temperatures that are responsible for the creation NOX2 (Nitrates of Oxide). The should be no EGR activity at engine idle.

The EGR pipe work will come from the exhaust through the EGR valve to a delivery point on the inlet manifold on the engine side of the throttle plate. When activated EGR inert (non combustible) gas will take up some of the volume of the inlet manifold and will allow less air in through the MAF. This reduction in air through the MAF dilutes the air entering the engine and lowers the combustion temperatures to threshold's no longer able to create NOX2.

Problems are common in and excess build up of carbon deposits on the EGR pintle and in the EGR passage ways. A very useful first test to get a feel of thing is with a scan tool with bidirectional control is to run the engine at idle speed and activate the EGR valve. If the valve functions and the passage ways are clear allowing EGR to flow at idle will cause the engine to stumble and in most cases stall proving valve function and clear flow. If the is no reaction during this test then we investigate the control side of things and wiring and after that excess fouling.

If some one can provide the ECU pin info we can formulate a test plan.

On a cautionary note I have dealt with a fare share of EGR codes that have actually been down to a MAF sensor issue.

[ShadeTek]

Originally Posted by KBB

Neil,


On a cautionary note I have dealt with a fare share of EGR codes that have actually been down to a MAF sensor issue.

On that note, is it worth disconnecting the MAF and running the engine to see if this cures the issue?

[SkintKnuckles]

Hi KBB,

many thanks for the offer of help and the overview of correct functioning of the EGR valve.

I've kind of done this in reverse. As per the above posts, I can confirm that the EGR valve/housing/cooler/ETM/pipes to manifold etc are now spotless and free from fouling. Similarly, the EGR position sensor currently fitted to the car is brand new. The EGR valve is clear and can be moved by hand. The only impediment to movement is the spring that keeps the EGR shut.

I do not have a copy of VIDA, so am hopeful that someone on the board can help with information re: pins etc.

I do have access locally to VIDA, to try the EGR valve move test, but do not want to wear out my welcome with this helpful guy (Kenny37), as he's already given up a lot of time this week. Thus, I'll wait and see if someone does/doesn't come up with the pin information and, if they don't, I'll then ask Kenny for help with the pin information.

What we did do the other day with VIDA is send a command to drive the EGR valve. We did this with the engine off, but ignition at position II (this was so we could hear the motor for the EGR valve). When we did this, there was a very clear noise from the motor that lasted for 2 - 2.5 seconds (subsequently to sending the command via VIDA).

I felt that this proved that the EGR valve motor was working and/or responding to instructions to move. However, it is not as clean a test as the engine falter/stall when the engine is running. What do you think KBB? Is a live test of the EGR valve still advised, or does the above test suffice (I guess not).

Kenny - do you think we can meet sometime to do this test quickly? PM me and I'll work around you.

Many thanks KBB. Something elusive is going on, but its pretty complex. I will be pro-active with the pin information if someone else doesn't have it. Ditto any test plan you come up with.

cheers
Neil

[SkintKnuckles]

Hi Shade

off to do just that...... This is the kind of test I like. Quick and at the top of the engine. If the skin on my knuckles gets any thinner, I'll look like I've been flayed

cheers
Neil