300Tdi Fueling and EGTs

[RBBailey]

I recently tweaked the timing on my pump to get rid of the white smoke on cold starts. Pretty happy with the results after 500 miles or so, that fraction of a millimeter of rotation fixed the white smoke, and seems to have had no other appreciable effects. Now I'm almost certain I'm underfueled.

All through the 5000 miles I've owned it, I've only barely been able to produce a dusting of black smoke, and my EGTs have never been over 1200. The other thing I noticed about my EGTs is that they are very slow to respond. I drove a 300Tdi in a RRC and noticed that his EGT gauge was essentially reacting to what I was doing with the pedal. Nothing near as fast as the tach, but I could give it the beans and actually expect the EGT to roll up to 650 or so on in-town, spirited acceleration. Mine only slowly crawls up to temp, about a minute or two at 50-60 mph, then it takes about 4 minutes at idle to cool back down to 450.

BUT! The simple job of turning the fueling screw is sort of vexing me. When I release the nut (blue arrow) the collar (red) and the screw (yellow) turn all together with the nut. I tried holding the screw with a driver while turning the nut, but it seems to be already at its limit to go clockwise, so it will always rotate counterclockwise with the nut.

Unsure how to proceed. Once again, I was looking to do a tiny 1/8 turn, try it, turn it again, try it, etc... but with the lock nut loosened, the screw seems already at its clockwise limit, and the act of loosening it actually retards the fueling.

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[Red90]

It looks like it has the anti-tamper cover on the screw. Personally, I would leave the main fueling. Remove the boost compensation pin and see where it is at. Remove the nylon spacer and then add an "hour" of fueling to it. Keep going until you are happy. Don't touch the main fueling unless you max out the boost pin.

If your EGT gauge reacts slowly, it may not be installed in the best location.

 

[SARTech]

I agree with Red90. From what I have seen the reaction of an EGT indicator is often a result of the thermocouple location. I have also noticed that analog gauges are slower to indicate than digital.

 

[RBBailey]

OK, so skip the screw and just try the boost pin mod instead.


The gauge I was referring to in the RRC is the same VDO Vision I have. Are you saying that the probe might be at a bad angle? It's in the EGR port on the side of the turbo.

 

[Napalm00]

Post pics of your probe placement !

Also probably best if you check the timing with a gauge to verify the lift of 1.54 for stock or 1.6 for performance.

Then set all pump settings to the stockish locations and begin tuning from baseline.

That collar is the anti tamper collar

 

[Red90]

You need to make sure the tip of the probe is in the venter of the gas flow.

 

[Red90]

center....

 

[RBBailey]

Here?s the pics of the probe location.

 

[javelinadave]

Ben,
Your location is perfect but the probe may not be long enough. The tip needs to be mid stream. This is what I install in 300Tdi motors and is 100% compatible with VDO gauges.
https://www.auberins.com/index.php?main_page=product_info&cPath=5_22&products_id=145

 

[RBBailey]

Interesting! I’ll have to take a look when I get home. I wonder if I can see where the main stream is hitting the probe if I pull it out and look for discoloration.

 

[javelinadave]

If you are using the VDO probe it isn't even in the exhaust stream. That would definitely give you a delayed and possibly inaccurate reading. Credit to board member Viton who turned me onto using the Auberin probe.

 

[Napalm00]

If you are using the VDO probe it isn't even in the exhaust stream. That would definitely give you a delayed and possibly inaccurate reading. Credit to board member Viton who turned me onto using the Auberin probe.

What do you mean ? My vdo is directly in the path

 

[Red90]

With the fittings that he shows in that photo.

 

[RBBailey]

Would be much easier to change fitting than to reopen my dashboard. That is, I assume you are referring to it being too far out of the pipe.

 

[javelinadave]

What do you mean ? My vdo is directly in the path

Do the probes come in different lengths?

 

[RBBailey]

I looked at the pic I took and decided to see if I could get the threaded socket to go in deeper to allow the probe to reach further. Not sure why it won’t thread any further, working on it. However, I didn’t remember that the probe was this short, and now that I’m looking into the port, I can see that the VDO stock probe must be only half of the needed length.... wish I’d known that earlier. It took me three days of careful work to get the instruments in place, and buttoned up behind the dash. This is not going to be fun.

This info should be added to the VDO gauge thread: you MUST skip getting the EGT kit. Just get the gauge, then order the longer probe.

#$*%#!!

 

[RBBailey]

This is why I hate working on this vehicle.

I pulled the threaded blanking plate out to see why it was not allowing the socket to thread down to it's limit, to allow the probe just a 1/2 inch more reach. I figured if I'm going to have to undo the biggest part of my refurbish project, I might as well at least see if I can get the probe closer to the exhaust stream to see if I notice a difference.

I guess when I undid the probe I must have cross-threaded it on the way out. The thing is now so badly buggered up that I cannot get the probe to thread at all. So I now have a broke down Rover.

Important:
This info should be added to the VDO gauge thread: you MUST skip getting the EGT kit. Just get the gauge, then order the longer probe. Don't be like me. That's many hours of my life I'll never get back.

 

[Napalm00]

Dudes my apologies, on a 200 TDI this isn't an issue . No idea you were using the blanking plate.

Is the plate aboe to be retapped just for the time being ?

 

[RBBailey]

Well, it's no one's fault but mine.

I made the order for my gauges over a year and a half ago, maybe there's a longer probe that I could have bought right then, I simply clicked on the wrong one, and this wouldn't be an issue. I have no idea how the threads could have got so wrecked, it merely seemed a bit stuck. Maybe the thing was bad from the start and I just got lucky getting it threaded as far as I did when I replaced the turbo last spring.

One way or another, I'll just get a new one and focus on pulling the dash apart since the engine can't be run anyway. The thing that worries me is that this is one of the NAS/Saudi style ducted dash boards, and I always knew as soon as I closed it up, I'd have something break, and I'd have to pull it apart again, risking damage to the uberunicorn-hard-to-find-in-good-condition parts.

I'm also worried that I've put 5000 miles on the truck not realizing that I was getting bad EGT readings. (I'd always wondered why mine seemed to act differently than others, and I asked around a bit, but never got an answer.) Maybe this contributed to my previous turbo going belly up right after I got the project on the road? Maybe I've done some high temp damage without knowing it, even though I watch the EGTs very carefully.

 

[RBBailey]

OK, now some people are telling me that I should just splice into the wires to the probe, but the VDO gauge instructions are pretty clear -- DO NOT CUT THE WIRE! It would make life much, much simpler if I could just use the existing wire, but it makes me wonder if the length is calibrated for the gauge? How else can we tell if the gauge is reading correctly?

One way or another, I need to use a longer probe. And I need to get a new blanking plate. Is there anything else I need to know about this to set things right?