VonOettinger '91 Multivan Syncro 3.2 WBX6

[VonZu]

Should be quite perky if re-timed for 95 RON

Well, as we have no 91 here in Norway, mine is adjusted to 95 Hmm... I wonder if that plays a role in my idling issue?

Hunting - two types:-

1) Rhythmic (Brmmm, Brmm, Brmm ), rich -tends to get the better of you in low gears jerking the vehicle about when off the gas... neutral throttle

2) Erratic, longer period, splashy, weak - tends to no real power or torque and tendency to cutting out, whereas above tendency towards pulling well and staying running.

I'm absolutely in the rythmic section with mine. And as said earlier, it can be dead stable while warm.

I find that I have little contribution to this discussion, as I'm fairly new to these wonderful vehicles. But I really appreciate all this info you learned men are providing.

[Aidan]

Incidentally we can no longer get the Syncro NTC2 temp sender anymore in SA. Only normal 2.1 which was clip in, ours for Syncro are screw in. be inerested to know if anyone else can get them?

http://www.brickwerks.co.uk/shop?page=s ... ord=sensor

[VonZu]

Some time ago, I discovered a petrol smell surrounding the car. I had a quick look, and immediately found the culprit. Yesterday came with good weather conditions, and it was used for a little work under the Oettinger. I don't fancy rolling around on my back under the car when working with the fuel system.

This leak is quite unique to me. I've never seen anything like it on a car before. It reminds me of hydrates found in gas pipes offshore.

Somewhere in my head, there is something about the freezing point of water when mixed with petrol, but I can't remember what it is.

This is how it looked after scraping it with a screw driver.


Two more taps with the screw driver, and the whole thing came off. The pump for the Eber was just hung up with tie-wraps, as the rubber connection thing had broken of.


I cut of the rubber, and put it between two washers(?) on a bolt. Not exactly like the original version, but not that far from it either.


The old hose was completely rotten. It was installed new in 2005 along with the Eber.


New hardware installed. I wouldn't recommend this routing for off-road use. But I'm not going there with this car, and I'm quite comfortable with the new routing.

[32wbx6]

I haven't seen anything like it before either, but then we don't get snow so couldn't have seen that! Amazing. I can't imagine why the fuel lines taken so low and exposed on Syncro either but there you go .

Some feedback on the idle thing and wiring. The imported Oettinger motor has identical wiring and loom to Bentley manuals Digijet loom and set up. Our SA made 2.1i's are the same. The only difference is that the German motor is wired for an oxygen sensor and the SA wiring does not include that. Disconnecting the O2 sensor plugs seemed to make no difference to the German Oettinger. Still absolutely perfect at start up and idle rock steady at all times! I have measured all readings at terminals on ECU 32 pins plug and found bad earth, Corrected that. All other readings now absolutely perfect. Idle is certainly way stabler. Still iffy at cold start for about 30 seconds then pretty steady. She still smells very rich at start up though. Still to check hall sender unit and TCI unit then will have completed all checks against Bentley manual in terms of wiring and injection system. Still can’t find any obvious difference to cause kangarooing!

A question to any 6 owners...can you tell me how your injectors are wired up? Usually easy to see. Mine has the 2 extra injectors wired on in parallel to 2 of the original 4. Remember this was originally a 4 pot loom. So usually you have each of the 4 injectors wired separately and Bentley’s manual shows to check at the ECU plug that specific resistance is found on each injector between terminal 7 and each injectors own terminal. With the WBX6, I now find correct resistance across two of original 4 but on the next 4 because they are joined to each other in parallel the resistance across these terminals is now halved in each case. My question is shouldn't this makes a difference then to operating of the injector impulses? In other words 2 injectors have correct resistance and 4 have half values. (I hope that makes sense)

[VonZu]

I haven't got much input to your measuring and fault searching. I'm learning while I'm reading your posts. Thanks for that

But I can tell you how my injectors are connected. And it's just as you say, with the two added injectors just hooked up in parallel. I do find it odd that they are connected in this way. It seems kind of like a hasty approach.
I wonder whats the "cure" for wrong resistance on a 4-pot?

Anyway, some unqualified pondering follows:
Did you measure 8ohm across the 4 parallel injectors? I see that the injectors on the digijet system has been increased from 3ohm to 16ohm "to eliminate the need for the separate resistor pack" used in the digifant system.
As the ECU gives out the actuation signal for the injectors, that means higher than normal current goes through the system every time it actuates the four injectors in parallel. Or one would think.
But then, what difference would that make? It's only an actuation signal, and shouldn't necessarily be that sensitive to such changes. Or maybe it damages the ECU in the long run?

I really don't get this. Because if the ECU gives of an actuation signal to a specific injector, it should mess everything up if two new injectors were connected in parallel to two existing ones. Or at least, an existing injector would always open at the same time as a new one, but not firing because of no spark. Maybe that explains the fuel use... The ECU actuation signal is triggered by the distributor, I assume. But I cannot understand how it could be able to open only one of the injectors in parallel.

Suddenly I feel a strange need for MegaSquirt, or something similar.

[Aidan]

All the injectors sqirt at the same time on our system, not sequentially, it does seem a poor way of wiring them if they are just linked in onto existing harness, they are all wired in parallel normally, 16 ohm resistance each works out at 4 ohm total, so test the total load as seen by the ecu should be 4ohms, ECU just flashes them to earth to make them squirt

[VonZu]

So, if the ECU actuates all injectors at the same time anyway, there should be little difference in putting in two more. Except for the resistance, which drops to 2.67ohm. And wiring them separately to the ECU would look nice, but not necessarily make a big difference. I'm such a novice when it comes to injection...

I can't really see that this should affect idling in any major way. As I understand it, the injectors just squirt away when they are told to, not providing any direct form of feedback. The culprit should be somewhere further up in the chain of events.

[silverbullet]

If the combined injector impedance is too low, that's when the amplifier stage that drives the injectors will burn out. Lower resistance = bigger currents.

V = I x R

Slightly higher resistance is safer, or at least that's how it was explained to me once.

[VonZu]

It's tempting to connect the output from the ecu to a 1,33ohm resistor, and from there to all the injectors.

[HarryMann]

You might be onto something, but if that's how Oettinger did it, one could presume they knew the amp could supply that sort of current reliably...

Is it possible that the WBX-6 is just very sensitive to 'drippy' injectors ?

[VonZu]

You might be onto something, but if that's how Oettinger did it, one could presume they knew the amp could supply that sort of current reliably...

I like to think so.

Is it possible that the WBX-6 is just very sensitive to 'drippy' injectors ?

Meaning leaky needle valves? I have no idea. And I don't know if the injectors have been changed on mine. If not, I guess it's about time.

[VonZu]

The only difference is that the German motor is wired for an oxygen sensor and the SA wiring does not include that. Disconnecting the O2 sensor plugs seemed to make no difference to the German Oettinger.

I'm just looking in the ProTraining document for DigiJet. "The oxygen sensor is deactivated during engine warm-up, full throttle enrichment, and fuel cut-off on deceleration". Was the engine cold when you unplugged the sensor?

[32wbx6]

Thanks for all the input. Glad to know yours are added on too in parallel.

The frustrating thing about this motor is that I can get no input from Oettinger themselves! I also believe that Oettinger wouldn't have botched things up or done a hasty design when originally putting these motors together. But, how come so many of them have either the idle hunting and/or the kangarooing To the point that the fellow here who is Oettinger trained and used to be with VW says "oh they all do that!" Doesn't make sense to me, I have tried to order a complete loom and ECU from Oettinger Germany, we'll see what the response is. I believe they have lots of these motors still stuck away in a workshop somewhere (probably just a rumour).

With repect to the injectors in parallel , I have since spoken to an electrical engineer who also feels that it really wouldn't make any diffrerence to the operability of the injectors to have varying resistance across them.

With regard to Harry's comments about "drippy"injectors...I think after very careful observation and many miles of driving this motor that the kangarooing effect appears to come from the system "refueling" itself too much after passing through the overun cutoff stage. Its as if the injectors stop fueling as it throttles down, no fuel in fact injected at about 1500 revs. Then the fuel pump or injectors must now start up again at about 1200 revs to supply fuel for idle purposes. I get the impression that too much fuel gets pumped back in and it jerks/fires and revs increase, which now shut off again as ECU knows its at idle or low revs and so the cycle continues. The question is, what causes this re-injection of fuel into the cylinders? I did check for dripping injectors way back but will check carefully again, because as Harry suggests, that may be what causes the refueling to occur. I dont know what other reasons could cause this to happen? (Assuming my "re-fueling" hypothesis is correct)

I am going to wire my fuel pump dirctly to battery so that its is not "switched off" by ECU to stop injection flow at 15oo revs and then see what happens as an experiment. Assumption here being that the instruction or mechanism of fuel shut off is the fuel pump switching off and then on again? I believe its also a safety mechanism to stop fuel flow in case of accident? Please stop me now if someone knows that that definately isn't the case

I also am coming to the conclusion that the unstable idleing is a different issue to the kangarooing. The idle seems to be very sensitive to the mixture. The kangarooing is there regardless of anything else and i can only get rid of it if I overide the throttle overun cut off switch.

[VonZu]

The frustrating thing about this motor is that I can get no input from Oettinger themselves!

I have the impression that they forgot mostly all about this engine... They've been pretty quick to respond, but fairly thin in their response.

To the point that the fellow here who is Oettinger trained and used to be with VW says "oh they all do that!"

I'm not mentally equipped to handle that kind of statement

I believe they have lots of these motors still stuck away in a workshop somewhere (probably just a rumour).

I believe a raid on their facilities are in order.

With repect to the injectors in parallel , I have since spoken to an electrical engineer who also feels that it really wouldn't make any diffrerence to the operability of the injectors to have varying resistance across them.

Fair to assume. I guess the only thing handling larger loads here is the ECU. And in my mind, just switching them to earth is not that delicate a matter. But still, they increased resistance across the injectors from AFC to DigiJet/Digifant, and I guess that was not just by chance.

With regard to Harry's comments about "drippy"injectors...I think after very careful observation and many miles of driving this motor that the kangarooing effect appears to come from the system "refueling" itself too much after passing through the overun cutoff stage. Its as if the injectors stop fueling as it throttles down, no fuel in fact injected at about 1500 revs. Then the fuel pump or injectors must now start up again at about 1200 revs to supply fuel for idle purposes. I get the impression that too much fuel gets pumped back in and it jerks/fires and revs increase, which now shut off again as ECU knows its at idle or low revs and so the cycle continues. The question is, what causes this re-injection of fuel into the cylinders? I did check for dripping injectors way back but will check carefully again, because as Harry suggests, that may be what causes the refueling to occur. I dont know what other reasons could cause this to happen? (Assuming my "re-fueling" hypothesis is correct)

Thinking out loud: What if the reduced impedance across the injector activation system takes it's toll on the system over time. Resulting in some kind of "uncalibrated" operation of the injectors. Put that in combination with old and possibly a bit leaky needle valves, and you get a system that is not responding properly to ECU input. That would render the ECU helpless to adjust properly according to feedback from the rest of the system, no matter how good that feedback was.

I am going to wire my fuel pump dirctly to battery so that its is not "switched off" by ECU to stop injection flow at 15oo revs and then see what happens as an experiment. Assumption here being that the instruction or mechanism of fuel shut off is the fuel pump switching off and then on again? I believe its also a safety mechanism to stop fuel flow in case of accident? Please stop me now if someone knows that that definately isn't the case

If you have a spare fuel pump, it's a fairly simple task to rig up an external system. Leaving the ECU to do whatever it want's with the now passive system on the car.

I also am coming to the conclusion that the unstable idleing is a different issue to the kangarooing. The idle seems to be very sensitive to the mixture. The kangarooing is there regardless of anything else and i can only get rid of it if I overide the throttle overun cut off switch.

I'm not quite sure that I have a full understanding of the "kangarooing" thing. I wonder if I may have the same issue, after all. In low revs, approaching junctions or parking spaces or whatever, mine can be a bit "jerky". Not speeding off in any uncontrollable way or anything, but more like "stuttering". Hmmm... Challenging to describe.

As a note, I recently had mine on what we call "EU controll". I believe it is called MOT here. My emissions are off the scale, and I only passed the emission because the mechanic is a T25 enthusiast, and of the belief that cars like the Oettinger should be excluded from the emission check But it left me wondering about potential relation to this idling-injection-kangaroo-thing.

[32wbx6]

I'm not quite sure that I have a full understanding of the "kangarooing" thing. I wonder if I may have the same issue, after all. In low revs, approaching junctions or parking spaces or whatever, mine can be a bit "jerky". Not speeding off in any uncontrollable way or anything, but more like "stuttering". Hmmm... Challenging to describe.

I think that is exactly what i refer to as the kangarooing. Easiest way to find it is to drive down a slope in first or second and let the revs drop off to below 1500 or therabouts. My vehicle will then start jeking or surging and if left will continue for a bit in a very exagerated jerking fashion, seemingly caught up in a viscious cycle of no fuel and now too much... I think you may have it too
Mine can be very exagerated which is why it has become an obsession to cure. Most if the time in normal driving not too bad but any slow or offroad work it can become unmanageable.