Problem to start when the engine is hot

[fixkick]

Hi, well I have some news to tell you that I discovered in these days..

Yes, I never saw your slide photo about IAC valve, you said is an expensive parts but because I don't see it was sealed on factory without paint or silicone I move it, but I squeezed two rounds and I signed with marker the exact place where it was when came from Factory. But because I never saw r.pm to 2000 before and this's not very good to the cylinder without any oil to lubricate them, and because we are in autumn time, I did that.. But I can put the ring on the same place again and I don't wanted to lie to ECU, of course, was not my intention but my ignorance..
you need to be clear, what rpm worries you, the 3 to 30 second, Dash POT RPM or the cold start AFTER< (IAC thermal RPM)
this is no CARB engine, you need to work with the rules of the ECU, in all cases (if you make the computer confused, then,...... all bets off)



So you said me about head lights, well, if when idle is normalized to 800 r.p.m and I turn on the switch lights the idle come down to 700 r.p.m only for half second, then go again to 800 r.p.m, and if I turn off go up to 900 r.pm for half second too, go again to 800 r.p.m, so according to your information this's normal ?.. GREAT THE ISC is alive, and TPS switch is closed GREAT>!

Then I have to say you sorry, because the TV is not separate from the lower screw sealed from Factory, I was wrong, I believed that, because the perspective view from that area is difficult to see and is so dark too..


But trying to test it I used a mirror and my photo camera and take some pictures and I saw very well that TV is doing full contact (photo in Gallery)
(under "acutator" please say where. or use a link to it)'
omg, i love your IAC photos, brilliant work that.....
nice new TB and ISC, do not mess with the hex screw or that too fools the ECU, we do tweak the junk yard ISC to get the worns seat to seals.
but never on any new ISC. ever. bad that.


with the lower screw, then you was right about is difficult that was happening..
Although you know also in old carburetor the throttle valve in the axle extreme sometimes and because long time using would have like "steps" or recess, but this not the case, so this point is forget.. very good, yes, carbs can do that. but never on TB, if the stop screw is left un touched.

Maybe and because you advice me to see coolant temperature and I knew about was possible too, I have bought a new thermostat but I'm waiting before repalce it to ask you some question.. (the new stat will warm faster, i run the hotter 192 or 195F stats so the warm up way faster and is a blessing on any 8v engine. TBI, this gets the IAC closed the most quickly)

1ª The radiator water is full until neck, has a new radiator cap, as you know, but the plastic tank is always two centimeters under the low mark, doesn't matter if the engine is hot after 500 kilometers or if the engine is cold, if I refill water just between the full and low marker in the plastic tank, and after three days more or less, will be two centimeter under the low mark again, like this is working about one month and a half ago, but I think is working like this during many years, perhaps, the thermostat don't close as in a correct way ? But this is only my opinion, of course, what do you think about ?.. (the side bottle, sucks as engine cools and fills as the hot water expands, the trick is , how much it refills cold , is how cold it got?)
see"? as side tank level will be higher on hot days, and less on cold, (pure physics of 50% antifreeze and water)
what really matters, is the bottle dont drop each day, or week, that be engine leaks.

2ª And the next is very curious, and is about to pinch ISC air hose, so when I start in hot and the idle speed is in 1000 r.p.m (why is this?) and I press or pinch with my fingers the air hose automatically idle speed come down to 800 r.p.m (no should go to 400rpm), and if I stopped pressing the air hose idle speed go to 1000 r.p.m again, but if I move TV to accelerate a little by my hand or pedal, the idle speed come down to 800 r.pm. and if in that moment I press again that air hose then nothing normal happen, the idle speed continue in 800 r.p.m all the time, then the idle working correctly driving through the streets, traffic light, stop.. Yes, is a curious event....
1000 rpm....
this is all very odd, on a hot engine, the TV is 100% closed, is it?
the IAC is closed, but did you modify that new IAC in base of TB, but it is closed hot. if hot, hot means over 150F and for sure 180F minimum, no guessing real instrument measurements....
The dash pot is retracted, is it?
the TPS idle switch is closed and new. and factory set. from SPain factory. (id calibrate it per my table on TPS, its factory data)
so where is that air coming from, seems it is the ISC. so that means the ECU sees reasons to activate the 1000 RPM rule.
but way, well only 4 ways,
1 (tps idle switch is set wrong and sometimes fails, on the cusp. so calibrate it . )
2 P/s overload switch wire grounding out.
3 fast idle pin on ecu set, (ecu see A/c on, and is not)
4: old cars with old tps have gunk under TV valve, or one of 3 throttle cables sticking... 3speed, cruise or main throttle)




I think, only my opinion, that when start in hot and idle speed is in 1000 r.p.m, the ISC is open as is normal working in a correct way, then the air is entering through ISC to the engine, but maybe there is some air extra coming from from anywhere so the engine is working at 1000 r.p.m, and when I accelerate the engine something happen about engine depression or vacuum into the engine and then the idle is right.. You have a new clue and important proof now, I think..
at 1000 rpm does the regulation test pass, HL on, and blower fan on, and holds 1000 rpm??? this proves ECU did the 1000RPM. if holds.


You say "On some engines, you can block the IAC with clay, or the top suction port or at the base and find that the engine still races fast... huge leaks,"
But I don't understand very well how to do it, I need to open IAC valve as in your photo and to put the clay covering all the gap ? But I suppose before start the engine.. And "the harder way to make a bottom gasket blocking the bleed/IAC PORT, as I read in your slide photo is the hole in the rigth side of the ring.. Please, explain me how to do it is difficult to me this system, I never did it..
this is all moot, your TB is new, the IAC is brand new, and works perfect if water temp is above, 179F (> 81.7 centigrade )
my comments are for old TB, or molested only.
The IAC is 100% closed on all hot engines, but I for sure do not know that yours is actually really hot. (20 year old thermostats are hopeless are are line clogs to isc or iac)
The clay test just proves the IAC is bad. you put the clay there, and idle goes NORMAL. bad IAC. (3 ways to block any IAC there are. but is moot here.)


Yes, I know some folks doing like you say, but that TBI came fron Suzuki Santana that is in Linares a town from Jaen province in Spain, and I had in my hand the box where this TBI came from Factory sealed whit Suzuki Company as new one..

I'll be waiting your information about, you can see the photos TV in full contact and pressing ISC hose..

actions.

1: new thermostat, and hotter is better if you dont like TBI , fast idles, (all TBI do that. for just cause) 82c or more , more is better.
2: TPS calibration, not set on the cusp of failure. use the 3 feeler gauges. use usa 91-95 rules
http://www.fixkick.com/sensors/tests/TPS...alibration
3: does 1000 rpm pass the regulation test?
4: is P/S switch wire line not grounding out.
5; is A/C line not 12vdc to the ECU idle up pin.
this ECU only has 2 idle up modes, unlike the 1990. ecu.... more... they have head light idle up.... ouch.
6: TV dont stick, cables dont jam
7: TV not blocked in junk (no its new)
8: ISC good, (its new)
9: IAC is new, and is closed so is not causing issues.
10: vacuum leaks are all suspect here, any leak at all can cause the ISC to loose control, even a cracked brake booster diaphram. or any hose or any diaphram on any vacuum servo on engine or leaking VSV valve.
11: Duty cycle set wrong, so that the ISC looses control , at either end of it's , command authority. (50% is correct , only)


oh wow, thanks for such nice photos !!!!!!!

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where is your bleed screw set (duty cycle set screw it really is) (count the turns from where it is now to Clock wise seated gently)???
the hot engine has only 2 air sources.
Bleed + ISC.
so when you pinched the ISC hose, and rpm was 800 (no the engine will stall, or nearly)
well there is no way in hell, the Bleed path can run your engine.
sorry cant.
my guess is you never set duty cycle, with new TB.
the bleed screw does that.
set it to 7vdc, on the ISC wire with a DC meter.
with a scope, set it to 50%
seen here. and wrong.

turn the bleed , not engine, (new thermostat) and set it to 7v .
my guess is the duty is set wrong, and the isc can not close more that 100% and then looses control and rpm rises..

as you can see there are lots of paths for vacuum leaks.
all leaks wreck duty cycle calibration.

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when the hot engine has no vacuum leaks, (cept bleed and ISC)
we then turn the bleed screw.
until that scope view is 1/2 up and 1/2 down, 5v/div on scope,, the signal is 200 times a second. (very fast PWM)
12v is open
0v is closed.
at 50% the command authority is set to dead center. allowing maybe +400 and -400 rpm (roughly) controls of idle, under all conditions.

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a DMM meter can work too.
if the dmm is fast enough? (not and old slow meter)
and has no band width filters on DC mode. (blind to AC)
it will digitize and average the reading, so that 7v = 50% , if lucky.....
many meters now can do this...
and some have duty cycle mode, on the dial....

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a/c DMM mode will fail due to RMS rules. root mean squared rules. due to it's a square wave and not SINE.