Simple ISC question

[zukitrek]

I'm in the process of fine tuning my 94 kick and I thought about testing ISC according to the steps outlined in the fix kick page.

My question: When I pinched ISC hose engine did not stall but rather died. The same as when I disconnected the wires. Is this OK or RPMs should have only dropped and engine not die? My engine according to the tachometer in dash, idles up to 1k maybe 11 hundred and then drops to 700 or so. No stumbling no surging, real smooth when accelerated. Is there anything else to check or all this is OK?

PS: I still need to change rotor, wires and plugs. Has a new rotor cap, air filter. TB, manifold and EGR all fully cleaned and tested.

[fixkick]

edited.
that's good, the isc closed (by hand) on a hot engine, there is no more air supply at all now. only the bleed screw, so it stalls.
some cars run at 600rpm, and that is wrong.

there are only like 5 checks ( 5 with A/T) HOT engine, 180F or more, 4 with 5sp
1: above
2: turn on all electric loads. no drop. (can blip) holds 800...
at all times, all alternator loads, A/C off , P/S over load, not active. (the P/s overload switch if stuck closed, idle is 1000 rpm for ever , hot)
P/S is the power steering pump overload switch, if bad or shorted to ground forces the rpm rise by 200, to 1000. and duty cycle change
the calibration must not have any of those loads or fail modes, nor in limphome or a bad tps idle switch, all are bad for the calibrate.

3: check duty cycle is at 50% if not adjust duty to land here.
4: shift from park to drive, 800 rpm , bumps down, 1sec and returns to 800.
5: hot idle is 800 plus 50 or minus 50 RPM. that is the ECU job to do that, we do only duty cycle.

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sure all that is good,
good fluids, brakes, tires.
good timing
good idle.
if have scan tool?, holds closed loop at idle and hot fast light flat cruise, foot steady.

[zukitrek]

2:...P/S over load, not actibe.
3: check duty cycle is at 50% if not adjust duty to land here.

How do you achieve this?

[fixkick]

#3?

this is the hard part. 5 ways. ?
A: FSM WAY WITH SUZUKI DUTY METER, Nobody on earth has one, so we can skip this, seen on last page of fsm for idle speed sections
B; some cheap DMM have a duty meter selection, some work others not,. if the meter can handle 200HZ input at 12vdc, it works, if not, not.
C: SCOPE. all scopes work and all since 1930 can do 200HZ, all.
D: shade tree? way? hummmmmmmm...... ok, pinch the hose to ISC, (air) and try to get the engine to idle as low as possible, by unscrewing the bleed. then pray it lands at 50. later.
E: using the DMM meter to on DC range 20v. and then setting duty to 1/2 battery volts, 14 div by 2 is 7v . if the meter hates 200 hz (0ld meters) it will read wrong.
this is DC averaging method. turn bleed to 7v on meter. bam 50% you are there, (i pray)

the purpose of 50 is to get the ISC (half open ,at 800 hot) so it can drop RPM or Raise RPM the same amount.

[zukitrek]

Got it. Many thanks.

Ill post my results.

[fixkick]

you are very welcome. if you find a way that is cheap to do ,please do share it ...! thanks.

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page 25 , manual hz/duty
this might work, if not?, take it back.

http://www.harborfreight.com/5-in-1-digi...98674.html

put it in volts, see 7v?
good
then push duty/hz, see 50%

luck happens here. this might work, as some meters have lowpass filters on DC and will not even see the average. (blind)
others do.
but this pdf on this meter implies, it has no such filter, and allows , the duty button to wake and read the duty rate.
be cool if it did.

[zukitrek]

Also #2 in the first methods. Don't know of an electrical connection in P/S system? You mention a page 25 of what manual?

Let me know.

[fixkick]

sorry the P/S means power steering, when turn the steering to the stops, it overloads the pump then the engine, then the ECU sees this (o/l switch close) and raises idle 200 rpm from 800 to 1000
or the switch fails, or its wire shorts to ground and same.
an the harborfright link, is a tool with PDF manual and page 25 tells how to use duty cycle.
http://manuals.harborfreight.com/manuals.../98674.pdf

page 25 here.

[zukitrek]

Thanks for going thru the hassle of finding the page. My DMM is relatively new. Is Craftman but I don't remember seeing duty? I'll check.

J

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Found a PDF on my DMM specs. Here is the link. Don't thing it has the hz/duty range?

http://c.shld.net/assets/own/03482141e.pdf

Check it out if you can.

[fixkick]

no hassle buddy, i see lots of dmm with duty , mode. but some ive tried, do not work at all. they get upset with the 200HZ signal.
im told the very expensive fluke meter , does work. it is not slow, and can do the average correct.

if the meter flash rate (conversions cycles ) are slow, it can not average it.

i may try this meter soon, and run it through some paces with my function generator.