795 posts in this topic

Wow, that looks sweet, Duck! It will probably be worthwhile to plug the other end of the MB harness (now just a plug) into the EGR receiver to keep out dust & moisture, eh?

Edited by bilgladstone

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You had the same thought I did. :) It is a sealed plug so it will make sure nothing gets in there.-Iain

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I'd suggest the heat shrink with epoxy in it if you want it to be as water tight as possible. You should be able to get it at an electrical supply store (I know for sure Westburne Ruddy has it in Hamilton as I get it for work. It will come in a size that will cover the assembly, just leave it a little long and squeeze the open end together. Unfortunately my experience is that normal heat shrink won't really keep moisture etc. out for long (the equipment I repair is used in sewer inspections so I tend to see moisture problems, and that is not even at any pressure at all). Just a thought.Scott

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We buy stuff from Westburne as well - I'll ask our rep when he's next in (doing some servo sizing right now so I see them often). Thanks for the suggestion!-Iain

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Is the valve always open or always closed, now? (ie, which way is spring return?)

With no voltage going to the solenoid, the mixing valve will be always closed. No exhaust gas going through to mix with intake air.B :sun:

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Awesome, that's what we want!The way I plan to monitor if it's doing anything: My fuel consumption used to be 6.6 L/100 km on my MDC BordComputer, at high speed in 6th gear, floored. It would never exceed that, but would reach that at speeds above 100 km/h or so, when it was floored.As of late, that number will not exceed 6.2. :( So, that tells me there is some restriction or limiting going on somewhere, for reasons unknown to me. If I put this in and go for a long drive, and can hold 6.6 L/100 km - then I'll know that the EGR valve was what was causing the limitation.If it still peaks at 6.2, it doesn't mean the circuit doesn't work - it just means my problems lie elsewhere. I didn't post it last night because I was too tired to think straight but smartdriver - I owe you a beer, your circuit is the first one I've ever soldered together that I can remember that works. ;) As a kid I used to make these little "SolarRoller" robots and things like that and very rarely would anything work at all. Electronics frustrates me because if something doesn't work I have no idea how to troubleshoot it. Mechanical stuff it's obvious because you can see what's going wrong, but with circuits it's all invisible.So again, thanks for your work on this for us!! You are as far as I'm concerned a genius.-Iain

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Duck:Thanks for the compliment, but there are still some caveats that should be looked at before the circuit is deemed bulletproof.I'm hoping that you and Bil, will be able to resolve any potential difficulties with the circuit.By the way, I want to compliment you on your workmanship. Very pretty! Much neater than my version.

Edited by smartdriver

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I'd suggest the heat shrink with epoxy in it if you want it to be as water tight as possible.

In thinking about this more, I'm having a hard time imagining what this looks like... I emailed our Westburne rep to see if he has a chunk he can get me.-Iain

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If the ECU only monitors the EGR via the feedback pin why would the bypass circuit need to simulate the 100ohm solonoid with the resistor? I would think that as long as a proper feedback PWM signal can be emulated dynamically according to the Pin 1 PWM signal nobody cares for the 100ohm load. Can anybody enlighten me on this? In a 20 page thread it's easy to miss out on the tid bits.Anyways, here is a suggestion I would like to add to the table. Taking into account that the feedback signals all seem to be low level, a possible solution could be to use a programmable micro-controller. With this, Pulse width modulated feedback signals could be reproduced and varied to a tee according to the Pulse Width modulated signal sent by the ECU. I attached a schematic to better illustrate the idea. For those who don't know what a micro-controller is, think of it as a blank chip that you program (like a software application) to do whatever you want it to. Any kind of chip can be used, in my schematic I used that 12F683 because that is what I happened to have lying around on my desk. These things are really cheap. (under 3$).post-310-1222162095_thumb.gif-Thanks-pf :croak:

Edited by ProgFrog

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If the ECU only monitors the EGR via the feedback pin why would the bypass circuit need to simulate the 100ohm solonoid with the resistor? -Thanks

The computer likely has a FET driving the solenoid coil to ground on Pin 1.This is the PWM waveform that the circuit intercepts. The feedback on Pin 2 must match the PWM signal on Pin 1 or an error code will be generated.If there were no load resistor, the PWM waveform on Pin 1 would not exist.The feedback signal on Pin 2 is an analog Voltage, proportional to the duty cycle of the PWM signal on Pin 1.The load resistor representing the solenoid may not have to be as low as 100 Ohms ( the actual solenoid coil is 8 Ohms), but there is a possibility that the computer monitors the current in the solenoid and anything less than 100 Ohms would have required a larger Wattage resistor.As far as using a microcontroller, great idea, but you will still need a pullup resistor to simulate the solenoid and likely some signal conditioning or level conversion as the PWM signal is 12V peak.It might be possible to have the solenoid resistor connected to +5V instead of +12V. So much to do, so little time! Edited by smartdriver

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Thanks for the quick reply SmartDriver and also to all the work you put into this! I had forgot about the PWM being 12v Peak. -pf :croak:

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I think the idea of using a microcontroller is an excellent one. If the ECU does not monitor the solenoid current, it should be possible to use a pullup to +5V instead of +12V.Perhaps throw in a few resistors (or not) and you've got a working circuit.

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how does one remove the egr valve? what tools will i need? hoe long does it take? I saw the pics on page 3 of Broken intercooler scoop. but it doesnt describe how to do it. anything tricky I should worry about?

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Sorry - I'm not following, what's the connection between the EGR Valve (Mixing Housing) and the Intercooler Air Scoop?-Iain

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I was looking for instructions on how to remove and clean... someone suggested that there were good photos in that thread. Is there a thread on how to do it step by step?also I have oil all over the engine on the half of the engine that the egr valve sits and oil all over the dipstick area. thats not normal..

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... also I have oil all over the engine on the half of the engine that the egr valve sits and oil all over the dipstick area. thats not normal..

Check that your oil filler cap (the "710 cap"!) is properly seated and locked. Check that your oil is not over full. Start another thread on that oil subject and get lots of help!B :sun:

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So I ordered and installed that cable from mb you guys installed... hows it working for you? Now my car goes above 3000 rpm... how nice.

Edited by calgarysmart

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So..... next question.Once the EGR system has been made invisible electronically, what would be involved in doing an actual physical delete of the entire EGR assembly?Could it all be removed and a straight, smooth bit of pipe put in its place?Block the diversion tube from the exhaust.Crimp the liquid coolant tubes.EGR-ectomy of the whole mixing chamber and valve solenoid.Replace all of the above with a short length of suitable turbo tube or an entire new intercooler pipe from i/c to combustion intake head.Et voila! Smooth and clean new air channel!:scratch:Waddaya t'ink?

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So I ordered and installed that cable from mb you guys installed... hows it working for you? Now my car goes above 3000 rpm... how nice.

Hey sweet! :thumbup:That suggests that the MB harness is doing what we think it is supposed to do. Cleans up a noisy, errant signal that causes the ECU to toss a trouble code into "limp home mode". At some point you may get an actual full-on code but that will mean a true obstruction rather than just a fiddly valve opening or closure like you probably have now.Very nice!Time to hit it with some (e.g.) Prestone Diesel Treatment to help reduce further carbon deposits... and go for a sporty, high-EGT drive.Cheers,Bil :sun:

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Could it all be removed and a straight, smooth bit of pipe put in its place?

It might be harder than that. The tube which goes from the turbocharger up to the EGR housing has a blanket that is circulating coolant (from the engine, I guess?) to cool the exhaust gases further by the time they reach the mixing housing.I talked with my friend John about this on the weekend and he works for Cummins. He told me how their first shot at using EGR's on their big engines put the mixing housing and valve right next to the turbocharger... you can guess what happened! The heat from the super-hot exhaust gases cooked their valves very quickly. They then moved them closer to the intake side so the gases had time to cool.-Iain

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You should be able to just make up a flange and blank off the feed pipe at the manifold, and then just cap, or re-route the coolant hose. That way you could remove that jacketed tube altogether.

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Twice LOLIf you guys get that EGR-faker-circuit dialed, I'd buy one and I'd volunteer to be the first one to remove the EGR and figure out all that's required for an EGR-delete kit...

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EGR Pin#2 Dynamic Voltage Report

[*]Standard electrician’s multimeter, select dial to 12vDC

[*]Red lead is alligator clipped to green (Pin2) wire where short length of insulation has been scraped back to reveal bare wire. This was using the new harness for easy access and so we didn’t have to strip oem wires.

[*]Black lead is alligator clipped to the bare multi-strand ground wire in engine compartment

[*]Leads are long enough to just nicely reach through to the front seats, where the meter can sit on the passenger seat, easily visible to the driver.

[*]Testing was done on a 20km run at 80kph speed limit roadway, fairly level with a few light grades, then a few km in town stop/go at 60kph roads.

Results of measurements

[*]Sustained idle (cold or hot) 0.8v

[*]Gentle acceleration 1.2v

[*]Hard acceleration 0.8v

[*]Steady cruise @ 1800rpm 2.0v

[*]Steady cruise @ 2500rpm 2.4v

[*]Deceleration from cruise 3.5v

[*]Return to idle from cruise 2.2v

[*] > after 10sec idle, return to 0.8v

There you go, my friends.

Bil :sun:

Here is a small video capture I made of the EGR signals. I hope it can be useful. CLICK HERE.

0:00 - 1:00 I'm backing out and getting out of my parking lot,

1:00 - 1:20 I'm on a residential street

1:20 - 10:10 I'm on a 80km road, driving between 60km and 80km/hour, with a few soft and hard accelerations

10:10 - 11:37 I'm back on the residential road. Cruising very slowly (~35km/hour)

11:37 - 13:21 Back in the parking lot and idling for a few seconds at the end.

Ideally I would of liked to have an elmscan or similar OBD2 reader but unfortunatly I don't own one. I did have a webcam though :cheeky:

-pf :croak:

Edited by ProgFrog

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That is WILD! The sawtooth on top is the PWM that drives the solenoid, bottom is the feedback from the pot?-Iain

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