Strange engine judder between 2000-1700 RPM

Give input on tuning as well as any tips and tricks you may have. Also feel free to share base mapping files for various engine types.
Dayle
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Re: Strange engine judder between 2000-1700 RPM

Post by Dayle »

No idle valve mate just the butter fly slightly open and uses ignition advance to control the idle.
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86sixsix
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Re: Strange engine judder between 2000-1700 RPM

Post by 86sixsix »

Dayle wrote:am I correct in thinking a large up and down in revs is lean running?
yes...it's got the air (as it *can* rev higher than you want) - so it's that or you're too aggressive with your ignition-idle-loop deely.

if when you cold start - you have to 'blip' the throttle but then it will hold itself without you 'feathering' it to keep it going - then 100% you want more go-go-juice.
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
Dayle
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Re: Strange engine judder between 2000-1700 RPM

Post by Dayle »

If she holds the throttle lightly at about 1800 rpm cars doesn't rev up and down,and revs stay constant but with a slight misfire for the first minute but if you fully lay of the throttle to idle again the revs up and down by as much as 800 revs.

Any idea how much to richen up by.

Water temp compensation is currently 30% for 0-29 degrees and the start up fueling is DTA standard setting
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86sixsix
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Re: Strange engine judder between 2000-1700 RPM

Post by 86sixsix »

Dayle wrote:If she holds the throttle lightly at about 1800 rpm cars doesn't rev up and down,and revs stay constant but with a slight misfire for the first minute but if you fully lay of the throttle to idle again the revs up and down by as much as 800 revs.

tells nobody anything new except the miss.
Dayle wrote:Any idea how much to richen up by.
i wrote some rough figures earlier on for starting you could try but no, every engine requires different amounts of go-go when it's cold
Dayle wrote:Water temp compensation is currently 30% for 0-29 degrees and the start up fueling is DTA standard setting
start fuelling starts the car, water temp is for when it *has* started - you'll end up in world of nastiness if you attack both at the same time. i'd be amazed if your engine needs *the same* amount of fuel at 0 as it does at 29. didn't know there was a 'standard' startup map :|

split the difference between my startup figures and your current ones.
make 0deg water temp 50% scaling to your 30% at 29.
slow the ignition-idle-loop down a bit by increasing the loop delay number or lowering the prop factor as vr6turbo suggested.
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
Dayle
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Re: Strange engine judder between 2000-1700 RPM

Post by Dayle »

As I said earlier, sorry about all the questions I am still learning all of this.

The start up map that is in the ecu now is the one in the DTA Manual.

Image

Attached pic of the current set up the mapper left it.

I will mod the map now and load it into the car tonight for a cold start tomorrow and let you know how we get on. Thanks :)
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86sixsix
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Re: Strange engine judder between 2000-1700 RPM

Post by 86sixsix »

why did you change from your previous maps? have you had a exhaust probe up it's bum to measure stuff?

these then:
split the difference between my startup figures and your current 'dta official' ones.
make 0deg water temp 50% scaling to 0% at 50. 50, 40, 30, 20, 10, 0 etc
slow the ignition-idle-loop down a bit by increasing the loop delay number or lowering the prop factor as vr6turbo suggested
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
Dayle
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Re: Strange engine judder between 2000-1700 RPM

Post by Dayle »

We had the mapped on the rolling road, to run in then at 1000 miles took it back to finish the map off as the engine was really tight and overheating.

Both times when we left the rolling road the car had a judder when decelerating (the seccond time the worse) like when you are learning to drive and the car kangaroo's but obviously not accelerating when you let off the throttle between 2000-1700 rpm it was very aggressive. I spoke to the rolling road bloke over the phone and he gave me a few things to change but they didn't really help.

Jon_rally of here offered to help as he runs the same engine and changed a few things on the map which seemed to work (didn't cure the judder but was cope able as it was no where near as bad a judder) but living in the Canary Islands they are lucky enough to not see below 20 degree's so we have been running around on that map and it had been excellent but now the weather is going cold, the cold start isn't great thus I took the warm up and start fueling from the original rolling road map and put it into Jon's map. I hope this makes sense.
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86sixsix
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Re: Strange engine judder between 2000-1700 RPM

Post by 86sixsix »

that wasn't quite what i meant heheh. tps only cold start = 58 bajillion gallons of fuel for the first few (10-15) turns - it's as simple as that. don't go making crazy huge changes like you have done on a whim in case it breaks something else like hot restart after filling up with go go juice. you end up looking a womble trust me :oops: :lol: (yep, i *know* haha)

we only learn by prodding buttons - but only prod a few at a time, yeah? :D (and always save your maps with new names just in case you aren't)

if you want to eliminate overrun judder simply fire after top dead or turn the fuel off :lol:

edit: you have important PM!!!
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
Dayle
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Re: Strange engine judder between 2000-1700 RPM

Post by Dayle »

Image

Is this the kind of thing that we are talking about now then??

Replied to your PM mate.
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86sixsix
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Re: Strange engine judder between 2000-1700 RPM

Post by 86sixsix »

now that looks a *way* more sensible table for tps!

if she starts to 'catch' better tomorrow - i'd leave that alone for a bit and look at the water temp table deely. (what *may* happen is that she'll catch and run for a few seconds and then fall flat and stall after 60 turns or so...that'd be ideal to progress)

even the scary looking 200s may not be enough...but we shall see...what's your firing-tooth-at-startup set at now?
Renault 1.6 K7M, '92 Clio 16v shell, Rotrex C30-74, S40, Faceache, Sh***er, YouTube Blue Shed Channel
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