Author Topic: Whats this? (Read 15319 times)

Ned337 · « **on:** June 10, 2004, 08:08:50 pm »

I recently swapped out my old injection pump on my Ecodiesel for a new injection pump. I have seen quite a few pictures of the members on this forum and my pump seems to be a little different. I have taken a picture of the pump, and was wondering what this sort of microswitch on my pump is? Here is the link for the picture:

http://www.photodump.com/viewer/Ned337/Picture068.html

type53b_gtd · « **Reply #1 on:** June 10, 2004, 09:10:40 pm »

Normally this switch has a small metal cover over it - perhaps your replacement pump did not include this cover.

It's the throttle input for the cruise control module on the AAZ engine.

Drew

MK3 GTD · « **Reply #2 on:** June 10, 2004, 10:45:06 pm »

im not sure if it is used for the cruise control or not but it is used to open the wastegate on mk3 TDs when your foot is off the pedal

QuickTD · « **Reply #3 on:** June 11, 2004, 12:45:43 am »

Quote

...it is used to open the wastegate on mk3 TDs when your foot is off the pedal...

If you look at a 94-95 passat you'll see what this switch really does. These cars have the AAZ engine with a full EGR system. The switch opens both the wastegate and the EGR valve via the vacuum solenoid valve on the strut tower under light throttle conditions. I presume the wastegate is opened to provide stable manifold pressure conditions while the EGR is functioning. On an AAZ engine without EGR the switch and solenoid valve serve no purpose that I can see. All they do is delay boost response.

Edit - I just looked at the picture a little closer. We're not looking at an AAZ engine, and it appears this switch is not set up like it is on the AAZ. It is triggered at or near WOT. It could be an AC cutoff switch?

Ned337 · « **Reply #4 on:** June 11, 2004, 01:25:14 am »

I am not sure what the AAZ engine means so I can't tell you yes or no. The car is a 91 Ecodiesel, I was told the pump came out of an 85 turbo diesel.I am not sure if this helps or not but one thing I did notice since I have had the pump in is how much quicker the turbo spools up. The minute I put my foot on the pedal, full throttle or not you hear the turbo almost immediatley. Any other suggestions?

type53b_gtd · « **Reply #5 on:** June 11, 2004, 07:08:23 am »

Quote from: "QuickTD"

Quote
...it is used to open the wastegate on mk3 TDs when your foot is off the pedal...

If you look at a 94-95 passat you'll see what this switch really does. These cars have the AAZ engine with a full EGR system. The switch opens both the wastegate and the EGR valve via the vacuum solenoid valve on the strut tower under light throttle conditions. I presume the wastegate is opened to provide stable manifold pressure conditions while the EGR is functioning. On an AAZ engine without EGR the switch and solenoid valve serve no purpose that I can see. All they do is delay boost response.

I reviewd an AAZ pump and the cruise mechanism is actually above this switch. My suspicion is that on the AAZ it may be related to the load-dependent timing cut (which is the electrically controlled solonoid on the the lower left side of the pump.) It is not related to EGR as none of the AAZ engines I have are EGR equipped (Golf/Jetta - EGR was a Passat thing) the Load dependent timing cut device retards timing at low speed and part load to improve economy and emissions.

However, I was asleep last night when I posted - this is indeed a 1.6 motor. If it is a 91 ECO, then the Turbo Diesel pump swap will improve performance, as the 1.6 ECO did not have a boost aneroid, so did not deliver extra fuel under boost. Interetsingly enough I note that there is a line from the intake to the boost aneroid - that should not have been stock on a 1.6 ECO.

The pump looks recently rebuilt - perhaps the switch is something that's a holdover from a previous (non-vw?) application. It's hard to tell in the photo - there's nothing plugged in to it? On a 1.6 there should be no switches on the pump (other than the older models which have idle and 2/3rd throttle switches for the upshift light circuit, and this is not one of those.)

QuickTD · « **Reply #6 on:** June 11, 2004, 08:38:49 am »

Quote

It is not related to EGR as none of the AAZ engines I have are EGR equipped

Exactly, very few are EGR equipped but they all come with the EGR switch and the wastegate "opener" solenoid and hoses. On the passat the EGR valve was simply teed into the wastegate "opener" hose. I have a complete jetta engine and a complete passat engine sitting side by side at the shop. The only thing missing from the EGR system on the golf/jetta is the EGR valve and the little plastic "t".

Load dependent timing is controlled by a speed switch located in the glow time control module. It energizes the load dependent timing solenoid at speeds above 2800rpm. Performance generally improves quite a bit when the load dependant timing circuit is disabled by connecting the solenoid to 12v. This prevents the timing from retarding at low RPM, vastly improving cold starting, fuel economy and low end power. Load dependent timing is primarily a NOX reduction strategy.

I'm gonna stick with my guess that it's an AC cutoff switch. Most AC equipped models have this switch.

type53b_gtd · « **Reply #7 on:** June 11, 2004, 09:37:34 am »

Quote from: "QuickTD"

Exactly, very few are EGR equipped but they all come with the EGR switch and the wastegate "opener" solenoid and hoses. On the passat the EGR valve was simply teed into the wastegate "opener" hose. I have a complete jetta engine and a complete passat engine sitting side by side at the shop. The only thing missing from the EGR system on the golf/jetta is the EGR valve and the little plastic "t".

Well that certainly explains the presence of this silly changeover valve that doesn't appear to do much of anything then, doesn't it?

Quote from: "QuickTD"

I'm gonna stick with my guess that it's an AC cutoff switch. Most AC equipped models have this switch.

Interesting - I've not seen it on the 3 A2's I have with A/C - a full throttle cut-out for A/C then? makes sense - when the bridge rings for all ahead full, the engine room needs all the power it can get...
Looks to me like it might make a good intercooler mister activation switch, if its adjustable.

Drew

Otis2 · « **Reply #8 on:** June 11, 2004, 09:27:33 pm »

Great thread!

As long as we're identifying odd, possibly EGR-related parts on our various injection pumps, I have a question, too. This is on an AAZ engine taken from a Canadian 1997 Golf.

There are two vaccuum hoses that run to the LDA on this thing. One is the usual one from the intake manifold to the top of the LDA. The second one appears to run from the wastegate diaphragm to a vaccuum actuator diaphragm that is attached to the LDA. [Photo 1 shows this indicated with RED arrows and question marks.]

There is a rod running from this odd vaccuum actuator, going down to a spring-loaded lever that sits where most of you have an idle speed control screw. It's shown by the PURPLE arrow in Photo 2. This spring loaded lever has the limits of its travel controlled by two stops, which are the machine screws with nuts shown in Photo 2 (I sprayed only one of them with penetrating oil in the photo).

So my question is, just what the heck is this second vaccuum hose (from wastegate) supposed to do, and what is this spring-loaded lever which is operated by it supposed to do?

I haven't started messing with the main fuel control screw, since this stuff baffles me as to how to turn my idle back down once I've done that.

QuickTD · « **Reply #9 on:** June 11, 2004, 10:34:43 pm »

The vacuum line connected to the wastegate is normally connected to the changeover valve, which is part of the partial EGR setup that we have been discussing here. The thing that it is connected to right now is the idle speed control dashpot. It is normally used in AC equipped AAZ engines to boost the idle speed during AC operation and at cold start. My guess is that someone just used a piece of hose to connect the two ports as a means of plugging them. I'm assuming this engine is not installed in its original application.

You don't need to worry about the extra hose on the wastegate actuator, just leave it unhooked, the wastegate will function normally. The idle speed control dashpot is normally connected to an electric solenoid valve that is actuated whenever the AC compressor is engaged or the engine temperature is below 70ºC. You could jury rig something to apply vacuum to it when the coolant temp is low or you could just leave it disconnected as well.

The spring loaded lever that the dashpot is connected to is the idle speed control lever. Some late model 1.6TD's and all 1.9TD's use a seperate external lever and internal governor spring to control idle speed. The two screws adjust the low and high (AC or cold start) idle speeds. To reduce the idle after messing with the main adjuster you will need to adjust these screws as well as back out the "residual" or main governor spring preload. The residual adjustment screw is located on the main throttle lever, it's the screw that the throttle lever rests against at idle.

Hope this sheds some light...

Otis2 · « **Reply #10 on:** June 12, 2004, 11:58:17 am »

Quote from: "QuickTD"

Hope this sheds some light...

Perfect. Thank you!

Cheesetoast · « **Reply #11 on:** June 12, 2004, 10:57:37 pm »

i have that little switch too, it's one of the first mods u do for more power according to this page:

http://www.vwquebec.ca/forum/viewtopic.php?t=4344&start=0&postdays=0&postorder=asc&highlight=&sid=b0f4ae287f1179cf6bb986ef09995d76

i also have a/c, and i do still hear it cutting in/out depending on my speed/throttle position, which can sometimes be irritating, my vr6 never did that.

type53b_gtd · « **Reply #12 on:** June 13, 2004, 08:56:21 am »

Thanks for clearing things up QuickTD. It's been a number of years since I had a 1.9 ECO - we traded it on the TDI back in 99. Now that I have one again (picked up a '94 with a ventilated block cheap) I'm needing to familiarize myself with it. Regrettably my Bentley is a 97 edition, and is severely lacking in details on the wiring in and around the pump. Time for a new one - as this one doesn't cover my A3 TDI either.

Cheesetoast - thanks for posting that link! Great information. I have two comments/questions - #1 the author advises installing the control cone from a 1.6TD in place of the 1.9's cone, which appears to have a very flat profile. Has anyone done this, and is it a direct fitment as the author suggests? If so, this is definitely an effective method of giving the "ECO" some much-needed balls...

#2, the author discusses our mystery switch on the top of the pump:

Quote

1. Il faut dévisser les vis #1 et #2 et retirer la limit-switch. (vous avez probablement un couvert par dessus), Vous pouvez utiliser des tie-rap et fixer la switch ailleurs (mais elle doit rester ouverte) Cette modification permet au turbo de fonctionner à temps plein au lieu de compresser seulement quand vous demandez toute la puissance.

Roughly translated (my french is a little rusty too:)

Quote

1. You have to remove screws #1 and #2 and remove the limit switch (you'll probably have a cover over top of it.) You can use tie raps to mount the switch elsewhere (but it must remain open) This modification permits the turbo to operate all the time, instead of only when you need full power.

So, if this description is accurate, then how does this switch keep the wastegate OPEN? I have a KKK03 turbo, and integrate wastegate actuator has to ports on it - one on the boost side that is connected to the compressor housing, and one on the other side of the diaphragm that I can only assume is vacuum. On my turbo this port was capped with a rubber cap.

Keeping the wastegate valve in the open position would require the application of vacuum - from the vacuum pump - so is the changeover valve (mounted by the shock tower) responsible for switching the vacuum to the wastegate based on the setting of the switch on the pump?

I would think boost air is better - the more air, the less particulate exhaust emissions - but do NOX emissions increase at the same time or something?

If this is really the way these engines are set up, it's no wonder my 97 was such a dog.

I think I'm more confused now than ever.

Drew

QuickTD · « **Reply #13 on:** June 13, 2004, 10:09:29 am »

Quote

#1 the author advises installing the control cone from a 1.6TD in place of the 1.9's cone, which appears to have a very flat profile. Has anyone done this, and is it a direct fitment as the author suggests? If so, this is definitely an effective method of giving the "ECO" some much-needed balls...

I've done this mod but I used a bmw 524TD cone. Pretty much any cone from a bosch VE turbo pump will fit, there are hundreds of profiles available. Anything is better than the stock 1.9 part. VERY effective mod. This will get you at least a 10-15hp.

Quote

So, if this description is accurate, then how does this switch keep the wastegate OPEN? I have a KKK03 turbo, and integrate wastegate actuator has to ports on it - one on the boost side that is connected to the compressor housing, and one on the other side of the diaphragm that I can only assume is vacuum. On my turbo this port was capped with a rubber cap.

The wastegate is pulled open by vacuum applied to the "extra" port on the wastegate actuator by the changeover valve. The changeover valve is activated by the switch on the throttle linkage at anything below 1/4 throttle. Like I said before, it appears the system was designed to provide stable manifold pressure for EGR operation, but they just omitted the EGR valve on the golf/jetta. Strange indeed...

Otis2 · « **Reply #14 on:** June 13, 2004, 01:07:09 pm »

Quote from: "QuickTD"

Pretty much any cone from a bosch VE turbo pump will fit, there are hundreds of profiles available. Anything is better than the stock 1.9 part. VERY effective mod. This will get you at least a 10-15hp.

Is this something that I could do to my own "flat topped" LDA on the injection pump, or is mine just too different in design?

The photos I have seen of this "new cone mod" (like "Smog's" pump on his instruction pages) show a very different LDA cover to mine (see my photo above). They all seem to have a bolt in the center of the cover. I believe my LDA has no "star wheel" to adjust either, in addition to having the odd flat cover.

I have yet to excavate under that cover, but if I can add any other Bosch VE turbo cone to fit under there and give me 10 to 15 more HP, then that's got to be a way to go.

What happens when you remove the fasteners holding the LDA cover in place? Is the cone spring loaded? Something will try to escape or move into the wrong position if you're not careful?