Longranger1 wrote:Well, I have been thinking about the MN limp mode problem when the EGR is blanked. One solution involves a little electrical jiggery-pokery which has the EGR servo operating a very small relay (preferably a solid state relay to prevent inductive spikes) which keeps it electrically separated from the absolute manifold pressure sensor (AMPS).
The EGR when operating will close the relay contacts which are series wired with a resistor to slightly change the voltage output of the AMPS so that when the EGR operates the sensor output to a corresponding value of say 105 kPa (instead of 99-100 kPa).
The beauty of this is that when the vehicle is operating in a non EGR enabling parameter, the AMPS is completely normal so no limp modes are created.
The second idea I had was to relocate the absolute manifold pressure sensor line upstream of the throttle flap valve. This negates the P0299 turbo underboost fault due to the low manifold pressure because the EGR is blanked and the throttle flap is restricting the intake so as to draw in exhaust gases. The logical place for the line pick up would be the black steel bend which goes through the radiator support panel. I am stuffed if I know why I didn't think of this earlier - is this a cure that is too simple? Am I missing something here? The former idea has merit but how hard would the second be? Piece of piss I reckon .
Any ideas Uber Techs
Tex wrote:5 year/130,000km
Longranger1 wrote:UPDATE (For egr blanked MN vehicles only):
Early days yet, but over about 400km of combined highway/city driving over Easter the fuel consumption has dropped from around 10L/100km average to 9.3L/100km. Much, much less lag and a big improvement in throttle response (almost "SprintBooster" like ) .
Even better, low down torque is improved (especially noticeable off-idle on hill starts).
Not a fault code to be had and no Limpies! . This is despite setting up conditions which would normally throw a P0299 code.
Love that car!
Longranger1 wrote:Still no issues with mine as yet, but crikey, does it pull now. Over the weekend I took it up about a 15% climb and whereas before it would have been working hard(ish) in third, it now accelerates in 4th easily.
Since mine is stock, I think it changes the fuelling response fairly dramatically. It'll now break traction easily on bitumen just off idle in first - didn't do that before . The idea of what I have done was to cancel out annoying CEL and limp modes. I kind of predicted that engine response would improve - I just didn't realise that it would be this good.
As bizarre as as it sounds, the BOV might have some merit in your case Tony. Not sure how it would work though as the throttle flap valve doesn't operate the same as a petrol engine does.
I am getting useful boost pressure figures down low now - about 80 odd kPa (about 12lbs) at 1100-1200rpm.
Longranger1 wrote:Still no issues with mine as yet, but crikey, does it pull now. Over the weekend I took it up about a 15% climb and whereas before it would have been working hard(ish) in third, it now accelerates in 4th easily.
Since mine is stock, I think it changes the fuelling response fairly dramatically. It'll now break traction easily on bitumen just off idle in first - didn't do that before . The idea of what I have done was to cancel out annoying CEL and limp modes. I kind of predicted that engine response would improve - I just didn't realise that it would be this good.
As bizarre as as it sounds, the BOV might have some merit in your case Tony. Not sure how it would work though as the throttle flap valve doesn't operate the same as a petrol engine does.
I am getting useful boost pressure figures down low now - about 80 odd kPa (about 12lbs) at 1100-1200rpm.
finky_spoof wrote:Any pics Longranger? I just can't visualise what you did (in the descriptions you gave earlier in this thread) for the life of me
John 1 wrote:Guys I just want use blanking plate to block EGR I called chip it and they said drill a 3mm hole I see you guys say 6mm, so I know little difference what do you suggest. I'm not running a chip yet as the motor's only done 500km
RHKTriton wrote:After all my hunting around, I have come across an EGR soot filter from a German company (not yet checked on price and what sort of heat might be involved). It should be possible to filter the EGR without stopping the inert gas through - hence should meet all ADR requirements.
I'm thinking something along the line of the catch cans with an element you can either replace or clean every so often would be the go.
Putting a hold in the throttle flap is not good, as you might one day need it to be able to choke the engine if you ever have a self fueling situation. However, having a flap bypass that you can control and have the EGR blanked looks feasible.
helicoptercow wrote:
could imagine thought whatever the filter element, would be getting cleaned a fair bit or performance would be taking a hit...
Tony wrote:RHKTriton wrote:
Putting a hold in the throttle flap is not good, as you might one day need it to be able to choke the engine if you ever have a self fueling situation. However, having a flap bypass that you can control and have the EGR blanked looks feasible.
Nice in theory. Only problem with that is. Have you ever noticed what position it goes to when the engine is turned off? Fully open!:o
A small hole still prevents overrun anyway.
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