A/T 4speed fails, car wont move until hot.

[zukitrek]

...and arms and legs!!

[zukitrek]

So far so good señor Fix. She's running like new. Remember that you suggested that maybe I had a weak engine or maybe I had fuelling issues. My question, and I believe you have mentioned this in many posts: if a FPreg will not last the life of a car (or 21 years) it is not better yo get a new one instead of diagnosing if its bad? Remember that my fuel damper already failed (and about the same age of my FPreg) cause I have never replaced them under my ownership. Second, with A/T now overhauled, if I had a weak engine could the bad tranny before mask a weak condition or fueling?

I ask this now because it feels like when engine is cold, it lacks a bit of power in the first run of the morning. I still have that low idle which I don't know if it has to do with all this. FYI; Tbelt, pump, and idler new, as well as o2 sensor, and whole ignition system (plugs, wire, cap, rotor) timed following FSM steps and timing checked with timing gun. Also compression test was done getting 190 with hot engine at WOT.

Hope Im making sense,

Cheers!!

[fixkick]

ah ,yes the damper what an odd failure.. that was...
i have no hope for FPRs that old, most times they start leaking at the vacuum nipple, when checked.

yes, sure the tranny can mask a weak engine,
after all if it can not transfer all torque to the rear wheels,. then the engine can not be tested (be that tranny slip or in the wrong gear for load)

low idle , how low? rpm cold is what?

buena noches,, amigo

and Salud'

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btw it should have plenty of power cold.
in fact has more.... in PR.
the ecu does rich fuel cold and makes more power cold but is mostly equalized to the tight engine friction , nets about same power
12;1 air to fuel ratio is cold mix, (after some minutes) and is max power point on gas engines.
one way to have reduced power, cold
might be, low fuel pressure.
or a partially clogged injectors (spray pattern bad)
not only that the idle is faster cold than hot so , more HP there, even at idle.

[zukitrek]

Oh I see. Thewn points to a fuelling issue or looks like that. The RPM cold is 700ish. Is the line right below 1k rpm 900 or 800? I rarely or seldom get her to that line even on a super warmed up engine.

[fixkick]

your IAC is dead. no longer opens below 150F. this causes rich idle, (lack of air)
the dash tacho gauge is not too accurate, (it's pure analog meter , takes spark pulses and turns that to meter volts, crudely.)
the first tach notch below 1 (1000) is 800. )200 per mark) (i use shop tachometers. that are dead accurate. to see what is really going on, )"measurement errors make a genius tech go down wrong path...."

when you start any 16v the iac is open, before the start, even at 70F, (70 is way below 150f) so is open a lot. cold and lets in air and idle races.... on all 16v.
a bad IAC is common failure , on 1990 cars. very common.. mine was stuck open. (screamed hot, unstoppable! till fixed.)

the 8v engine , the IAC can be seen with naked eye,,, not yours sadly but wait... we have that now. kinda(below).
but shows how it works , (same is yours) see this photo see that wax pellet activated cone valve.? and those gaps.. (i took reading with number drills to do that trick and is very revealing)
http://www.fixkick.com/fresh-air/Slide_S...age_9.html

40F is temperature of milk in the Refrigerator. (measured using accurate tools...) this gap sets cold idle speed on all G16s...

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the 16v looks like next photo linked, and can only be tested in a pan of water, then blown into hole slots with lips. (open cold , closed hot, is all i can do)
the ECU when engine is cold,. assumes this valve works. if not?, engine EFI goes rich. (02 is not active cold so...)



the screws can be near impossible to remove (i had to do tricks to get them off.)

here is the last posters valve cut up.



to get a IAC< i had to buy used TBs ,one i found with whole intake manifold and TB and a working IAC, eureka !

[zukitrek]

So what you mean is when wax pellet warms up it closes this valve?

[fixkick]

a great question.....
take a old cooling thermostat apart, (cut it up) what is there. like the other posted did to his IAC and what i did to my ISC.
body
spring
valve.
wax pellet, in the olden days, my old old 50s car has a bellows, ether bellows chamber.(rare today, )

wax is a substance, (nice and non toxic too) that expands like crazy hot, and is predictable (math equations)
the wax expands and the valve closes on the IAC. (cold its wide open, sucking huge air volumes at 20 " vacuum)
the cooling thermostat works opposite to that.

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the ISC is not therma acting at all the ISC is pure electric. (modulated too)
posted to see both photos if IAC and ISC all cut up , on one post. above and here.

[zukitrek]

But if my idle is not crazy high, where does the bad IAC fit in my problem if lets say is not closing, therefore causing a high idle or I got it wrong, causing low idle?
My 16v indeeds first start does idle at around 1k-11 hundred like for a minute or so then drops to 700ish (my bad when I told you cold idle was 700ish, i got confused).
So again if IAC is bad then huge amounts of air would get in, and give a low idle or other way around?

BTW Fix, would you like to move this part to a new thread in order for other users looking for this kind of problem?

Javier

[fixkick]

no opposite low cold with a dead IAC.... i answered from low idle..cold.. so forget my post.
the iAC can fail in many ways, like all things can, (as they say, good./bad or ugly) ugly has many forms....damage has no limits on earth.
1: sticks closed.
2: sticks open
3: go out of calibration or go non linear (psychotic, like thermostats love to do.. "unpredictable")

lets review some basics here, this 16v engine, adds fuel to air, (by calculation, EFI magic does that. and varies by mode, "crank, cold idle, warm and hot modes")
facts as i know them.... (helps diagnosis, knowing this)
when you crank the engine cold, fuel is added by using tables, the ECU has IAC tables, in perm,, memory. it uses those tables to add fuel, to match the iAC air flowing. (maf mostly useless and dead cranking so cant us that. ) These fuel tables, even calculate fuel evaporation rates, in super cold weather, like at -40C (or F). when fuel refuses to evaporate, (like in Alsaka) now you know why it richer, do to this one fact.
if the iac is not open the engine wants to flood. see why? (NO AIR supply!)
now pretend the engine starts, now it's in cold run mode, dead cold, the MAF is not very accurate at low idle speeds (read near useless) so the ECU will use tables for the IAC
to help the maf gross errors, and the 02 is dead cold so that is of zero help here. the IAC is key device. In fact most maf cars, ignore the maf in this mode. newer cars run dual meters, MAP/MAF to cure issues here.
now the engine warms up, not in 1minute.. ? not ever with a cold block. (use a real thermometer or scan tool reading ECT for this data)
you need to learn this. by using a temp gauge on your engine, and see when 150F temp is hit in time. it's like 10mins. right? (im sure your not burning NITRO) LOL

so in those 10 minutes (70f to start) the IAC slowly closes and idle drops. to 800. (most ISC run at 1500 rpm cold and wind down to 800 (the 800 is ECU's ISC servo taking command and the closed loop 02 activating.)
and regulates now at 800, the ISC goes ONLINE and regulates at 800 rpm, i prove that by turning on the headlights and heater fan to high. and RPM does not drop.
it can blip down but bounces back to 800 this is sure sign that the ISC is work, some what. (the ISC is an regulating RPM servo system it too , is a closed loop system hot, idle , just like the 02 servo system)

all my words here are using real tools, not dash tools.
real tacho , real temp gauges. (so i can never chase my tail)

FLOWS OF AIR:
now to answer 16v air flows and RPM as you asked
the 16v when cold is rich, running. (by design an fuel tables inside ECU) MPI needs less RPM that TBI because port injector is 10x better.
when rich , all air leaks, from any sources cause and illegal excess RPM, (metered)
if the IAC leaks , this is leaking metered air, not fresh outdoor unmetered air. (called illegal air leaks, vacuum leaks or for example the PCV hose cracked sucking in fresh air.)
the IAC metered air , will cause rpm to rise. not lower.
in fact, at this same moment , pressing the throttle does exactly the same thing, it lets in metered air. (ecu matches all this new air with new exactly mixed fuel)
in fact, if you look more closely, see the IAC is just a TV bypass device,
seen in my slide show,.. page 3,frame 40

see that here, the IAC is just holding open the TV (virtually) for you, so engine will not stall and engine don't flood the CAT with loads of raw HC (gas) (lacking proper air to run RIGHT)

http://www.fixkick.com/fresh-air/Slide_S...ge_40.html

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the down shot to a bad IAC is what? (stuck closed)
1: wasted fuel. (and more for folks that warm cars up parked)
2: cylinder ring wear, excessive. (too rich washes off protective oil film)
3: CAT damage. (progressive)
4: slower warm up's. unless you drive it cold. (best is to do just that,gently)
5: spark plugs foul faster.

that first thing i watch on all G16, is the thermostat, how long it takes to get closed. and hit 180f, old stats, are slow,and waste fuel, and wear engine out faster.
then i watch RPM to see when the IAC closes, i want it to work correctly, at 150f end point., so I watch it like a hawk.

cheers, and happy trails.

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seen many old sidekicks now with a tacho that read totally wrong. they can do that.
i never believe gauges on cars, and for sure this old, i do what is called, validation.
like here. (using real tools)
here is me doing just that.

see this, the meter has no numbers. so it just a toy, so here is a new sender, and my IR gun proof that it really is 195 f
now on just this car, i know where normal is.... see how i did that?

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now a tacho.
i have 2, one is optical , can see pulley slip and check idle for timing , while never leaving confines of hood. (lazy) $12 on fleabay

or electric.

the hand held tachometer electric must be told, 4cycle, and 4 cylinder to work
or get a timing light that has this built in.

or clamp on tacho (HV wire)
or DMM with a tacho.

http://www.ebay.com/itm/Digital-Tachomet...xyzHxRO7bC


this link on fee bay, you connect to coil minus (can very hard to do that,)
or to the noise suppressor brown wire , called Tacho line.


there vast ways today to get good tacho readings, not one on the dash.

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if you drive off cold, and keep moving
you dont need the IAC.
see why?

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i have DMM that does tach.
timing light,
and the opto tach.

the opto wins, most easy , no wires. way, no contact. safer , faster, and dead accurate.
the thermal couple probe in my meters do great for thermal accuracy, with due care used.... (technique)

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as a tech, you learn fast to use tools that dont lie to you,.
measurement errors the top way to make me go WRONG, wastes the whole day.. zero productive. so the tools are free, see why?

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no move, that it too pain ful. must fix wifes car. now.

idle issues are the most complex.
Due to ECU modes .
and that nature hates a vacuum,,,, cept in outer space,
watch the movie, the martian. (i read the book too, its 10x better)
watch that man fight vacuum. every moment of his life.

see how nature does hate at VACUUM but in this case, it hates, you for not being in a vacuum. (same reason, seals.)
the other big fight for man kind is Entropy.
all things want to turn in to something else. (like steel to iron oxide) and the whole universe. ,mans toys are all short lived.

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all we do.
is slow the entropy (called service)
or erase it and start anew.

[zukitrek]

Wow. I read some of this real quick, but will have read better later. As for more info on my idle, yes my hot hot idle is 500. Way too low by my engine specs. But no violent misfires or stumbles or anything. revs good and gradually.

BTW you mention that is best to run car on first start like right away better than letting it sit until it really warms up? Oh ideal warm would mean 180F, what I meant by warmed up is that idle goes down to my number (500) after 1 minute or so. What ECT i have at that moment? I will find out.

Now, after tranny rebuilt, gas pedal seems kind of heavy going from 0-15mph. Afterwards the respond feels normal. My wife drove her for the first time today, after tranny rebuilt and noticed same thing. Don't know if throttle cable was fiddled with or what.

Thanks!!!