bouncy idle

For discussing MicroSquirt (TM) configuration and tuning of fuel parameters (including idle valves, etc.).
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MegaScott
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Posts: 149
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Location: Seattle, Washington USA
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Post by MegaScott »

Thus the reason the OEM's have such a problem controlling idle, there's so many different combinations out there, different engine characteristics, different idle controls, and sticky valves, very difficult to make an idle algorithm to control every possible combination. This is amplified with Megasquirt, it's very hard to get a system that works perfect for everyone, it's almost always a compromise.

On one of my cars, with the OEM ECU it idles at 1200rpm, I put Megasquirt on it and it idles like a dream at 900rpm. Go figure.
tmbg
MegaSquirt Newbie
Posts: 26
Joined: Fri Jun 02, 2006 11:41 am

Post by tmbg »

it's idling a little smoother now, not quite as bouncy.

I've been trying to tune idle for minimum map, sometimes I can get it down around 38kpa, but it doesn't seem especially steady.

I adjusted my Accell Enrichment, it's very odd the way the TPS rate behaves. The default max rate was 154%/s, but I found I could only get about 20%/s by flooring it immediately. A more reasonable throttle 'goose' is like 2%/s. I cut all the rates down ten times, and I was able to actually get throttle gooses that raced the engine rather than stalling it.

I'm concerned for a couple reasons, for one, it sounds like it might be missing a cylinder sometimes, other times it sounds pretty smooth.

Another thing is that CLT is getting pretty high, this might be related to the fact that I don't have the fan blade attached to the fan clutch... Ishould probably put that back on, huh.


Here's a new datalog of me getting it started and idling halfway ok, then trying to get it to race in the 2500rpm range and smooth it out, with a small amount of success.
'88 300ZX turbo (SS)

MSII 2.36, v3 board, MT 2.25
tmbg
MegaSquirt Newbie
Posts: 26
Joined: Fri Jun 02, 2006 11:41 am

Post by tmbg »

Well hey, it's starting to get there, at least under no load!

have a lookseee... the first couple TPS spikes, you can see the Gve go through the floor, so I richened up the low-MAP bins above idle RPM, and was able to get it to smooth out in the 2k-3k range..

Is it ok that it's running so rich? I'll pick up an LC-1 from Jerry pretty soon hopefully :)

Anyway, I'll smooth out the table above no-load map bins, and tomorrow night try to drive it some.

Image
'88 300ZX turbo (SS)

MSII 2.36, v3 board, MT 2.25
MegaScott
MegaSquirt Guru
Posts: 149
Joined: Mon Jun 14, 2004 8:35 am
Location: Seattle, Washington USA
Contact:

Post by MegaScott »

It looks like you are getting around to figuring it out.

You have some spiking going on with your CLT mand IAT, you may want to check connections, and try to get them moved away from any plug wires that may be nearby any of the low voltage engine wiring.
Clifton
MegaSquirt Newbie
Posts: 33
Joined: Tue Aug 02, 2005 7:25 am

Post by Clifton »

tmbg wrote:they're high impedance injectors, 260cc on a 3000cc engine, REQ_FUEL is set to 12.9, idle VEs are around 25.

It seems like it's running very rich, but I'll try playing with the ASE and WUE.

I guess I need to go get that LC1 I've been wanting.
Stock S130/Z31T 260cc injectors are low imp. Are you sure yours are high imp?
tmbg
MegaSquirt Newbie
Posts: 26
Joined: Fri Jun 02, 2006 11:41 am

Post by tmbg »

88-89 have high impedance injectors. The 450cc DSM injectors I'm about to put in are low impedance.

Refer to http://www.redz31.com/pages/fuel.html for more info.
'88 300ZX turbo (SS)

MSII 2.36, v3 board, MT 2.25
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