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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 06:30
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The Altezza 3SGE in my Sprinter has had a constant rough-running problem at part throttle ever since it's gone into the car, and the last thing we were going to try was to make a mesh to straight the airflow going over the hot-wire AFM in the inlet pipe, as we suspected there was turbulence affecting the signal it was sending tot he ECU.
So!
Cheap-arse mesh made - From $0.94 of drinking straws. 
I also got the cheapest superglue I could find, hoping that I could get it to 'wick' its way through the bundle of straws. Fortunately, it seemed to quite well.
So, armed with a 70mm diameter glued-up bundle of drinking straws, I shoved the mesh up the inlet of the Sprinter and went for a drive.
And it works perfectly now!!!
Yee-friggen-ha!!!
So I've cut the bundle in half to make it fit into the pod air filter and added some flyscreen mesh over the upper end to stop any loose straws from getting sucked into the engine.
Here's the Bill-Tech mesh, just before fitting ->
And here it is just before putting the air filter back on, taking from under the car.
So at least the damned thing drives nicely now, I can get out & about in it some more - Once I get it re-registered. 
FWIW here's the engine in the car ->
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Location:
Brisbane
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 07:00
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Ghetto engineering, Billzilla style - I'm loving it!
BTW, your car is an AE86, and thus has a 4A engine in it, so this may have been the source of your initial confusion. Hope that helps.
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Location:
NSW, Sydney
Registered:
April 2004
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 07:41
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that is bad ass.
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I supported Toymods
Location:
melbourne
Registered:
June 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 08:31
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get some alluminium stuff bill, do it properly 
and put the battery in the boot for goodness sakes.
looking good, is it faster than it was with the monster 4AGE yet?
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Location:
Perth
Registered:
July 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 12:17
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Huge opportunity there!!
Call it a mega Ueo-Dori drift mod, paint them pink, flog the straws for $300 and you'll be able to retire....
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 12:45
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Bill, this may be a couple of stupid questions but....
how far away from the sensor can this be and still be effective??
did you ever try just a plain restrictor in the inlet path?
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 14:17
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| shinybluesteel wrote on Thu, 10 November 2005 19:31 |
get some alluminium stuff bill, do it properly
and put the battery in the boot for goodness sakes.
looking good, is it faster than it was with the monster 4AGE yet?
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Yes, I'll be fitting some alloy mesh when I can find the right stuff for it.
Why would I want to put the battery in the boot? It's fine where it is.
No, it's not as fast as the 4AGE I had in the car. Certainly doesn't sound as good either.
| oldcorollas wrote on Thu, 10 November 2005 23:45 |
Bill, this may be a couple of stupid questions but....
how far away from the sensor can this be and still be effective??
did you ever try just a plain restrictor in the inlet path?
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Don't know how far away but as long as the sensor is in the lnlet I don't think they're too fussy. No I haven't tried a restrictor, what would that do?
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 21:44
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restrictor might introduce new turbulence after the tubing widens to the sensor
maybe use the honeycomb from a karmann vortex type afm 7mgte 1uzfe
but hey straws work
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Location:
Lost in the K hole
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 10 November 2005 21:50
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the guts of an old cat converter perhaps??
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Registered:
October 2005
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 01:11
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That takes dodgy to a new level - you ought to be ashamed of yourself!
Just out of intrest, what exactly makes this sort of thing work?
Is it the restriction? Is it the increase in wind velocity like a venturi?
Surely a proper tune would be the most effective?
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 03:36
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As far as I can tell there's very little restriction with the straws as such. But they're only temporary and I'll come up with something permanent later on.
But for the moment I'm just happy to drive the thing around like normal car for a while.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 06:00
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| gianttomato wrote on Fri, 11 November 2005 13:10 |
than turbulent if the airflow across the hotwire is turbulent this will wreak havoc with the ecus abiltiy to determine afr rough running is the result
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Bill, i guess i was wondering, how long the airflow stays liner befor it begins tumbling again... it looks like you have a 90 deg turn between the straws and the hotwire, which made me wonder if it will still be laminar flow...
or if the issue was more of a problem of having unequal flow between top and bottom of pipe (and subsequent slight difference in hotwire reading) from air favouring the top of the pipe after turning 90deg (but only at part throttle.. idle is less flow, WOT is much more, so the distribution of flow in those cases becomes more even?) and also wondering if the slight restriction was enough to affect this, moreso than the straightening?
but maybe i am barking up wrong tree  feel like doing a smoke test??
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Location:
Adelaide
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 06:12
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Stu isn't that the afm right after the straws (the plug in the second pic down) or am I looking at the wrong thing?
How long did it take you to to figure out that it was turbulence in the inlet affecting the sensor bill? I think I would have been scratching my head for quite a while!
Oh, and does that radiator flow left-right rather than up-down?
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I supported Toymods
Location:
Adelaide
Registered:
July 2004
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 07:16
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hahaha its so ghetto-tastic I love it!
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Location:
Brisbane / Gold Coast
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 07:25
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Yes the AFM is down near the bottom of the steel tube (you can see the wires coming out of it in the second photo)so the straws are very close to it.
It took a while to guess what it was. Initially we had three suspects -
1. Fuel pressure. Manged to find out what it should be and set it to 62psi, no changes.
2. Oxygen sensors. There's two of them and for a while we thought that maybe they'd gone back in their holes in the wrong spot. (one probe does cyls 1 & 4, the other cyls 2 & 3) I disconnected them to see if it'd make any difference and it didn't. After digging through some old build photos I found that we did indeed put them back into the wrong holes and after a bit of cursing and swearing found that it was bloody nearly impossible to swap them back over without pulling half the the bits & pieces off the engine on that side. So we ended up just swapping over the plugs, as they only go in one way.
3. The last one was turbulence in the inlet, and a few days ago I took the pod filter off to see if it'd make any difference as to how the car drove. It did; It was barely driveable so I thought I might be onto something there.
A bunch of straws, superglue, rubber bands, and tape later and I knew we'd fixed it.
Fug it feels good.
Now to get the speedo working, the big rear brakes (pick up the new discs tomorrow) and a few other things and the car will be in bloody good condition again.
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Location:
Kita-Ku, Sapporo, Japan
Registered:
January 2003
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 07:44
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| Bill Sherwood wrote on Fri, 11 November 2005 18:25 |
Yes the AFM is down near the bottom of the steel tube (you can see the wires coming out of it in the second photo)so the straws are very close to it.
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ahh, my apologies.. now that i've managed to find 4 hrs sleep in last two days, i can actually see the wires
heh heh, nothing like solving abstract problems
can't wait to see it.. in a couple of years
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I supported Toymods
Location:
Epping, Sydney
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Fri, 11 November 2005 09:30
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love your use of punctuation gt
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Location:
Newcastle
Registered:
August 2003
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Re: Rough-running problem fixed on the SE-86
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Wed, 16 November 2005 22:19
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Interesting..........
So a non ghetto-tastic job if one had the money and time to fix this. How would one go about it, instead of the straws.
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Wed, 16 November 2005 22:24
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| gianttomato wrote on Fri, 11 November 2005 08:44 |
maybe use the honeycomb from a karmann vortex type afm 7mgte 1uzfe
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read the thread
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Location:
Newcastle
Registered:
August 2003
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Re: Rough-running problem fixed on the SE-86
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Thu, 17 November 2005 05:19
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missed that bit. sheesh sorry.
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I supported Toymods
Location:
I renounced punctuation
Registered:
May 2002
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Re: Rough-running problem fixed on the SE-86
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Thu, 17 November 2005 05:39
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haha
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Location:
Canberra
Registered:
July 2005
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Re: Rough-running problem fixed on the SE-86
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Thu, 17 November 2005 05:58
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| oldcorollas wrote on Fri, 11 November 2005 17:00 |
Bill, i guess i was wondering, how long the airflow stays liner befor it begins tumbling again... it looks like you have a 90 deg turn between the straws and the hotwire, which made me wonder if it will still be laminar flow...
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won't ever be laminar oldcorollas. The straws remove some of the vortex/swirls, but strictly speaking, the flow regime will remain turbulent.
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