1996 Geo Tracker 1.6 16v Stalling when Warm

[hatchetman]

the riddle is ,what was that sealer, sealing. not good answers to that.
felpro set is best, all parts in kit fit perfectly

[hatchetman]

oil in radiator juice? (AF contam?)

it might just be a head gasket.
the compression test usually finds that out. fast.

[Garemie]

Well, we're back in business.

New head gasket, it was running perfectly.

I swapped the motor into my Suzuki Samurai, and was running fine for about a week, but now the engine racing is back.

Super high idle followed by low and high RPM alternating. It runs and drives fine though, again.

I'm very confused. I will try to get a picture of the engine bay as well as a video of the engine racing.

Thanks!

[fixkick]

i assume hot engine fast idle an with surge., help.
well it only surges for 2 reasons. (and one can cause other , for 2 times surging.)
1: all lean engines surge. and if the iSC works it will try to correct the illegal RPM and make it go away or make it worse, (the leaner the worse)
2: ISC is out of control, either for above reason or there are air leaks.
3: lets say engine is rich for some reason (error 1 lets call it) and then error2 an illegal vacuum leak, the engine will scream. excess Fuel + air = scream.
no scan tool to connect this ECU?, all scan tools work here, and makes diagnosis 10x more easy.


Is the engine getting hot? 180F or more and holding. if not it will scream due to IAC open all the time.
ok, it's hot, does the IAC closes above 150F. it must or the engine wills scream .
if you pinch the ISC air line (2 are hot water (Felt) and 1 is air, pinch the cold one, 800 rpm hot engine, it drops to 400 and stalls.
if racing , say at 1200 rpm, pin and it hits,800. (1200-400)
is the throttle cable slack, it must never be tight.
the TV is closed 100%
so the only normal air , is ISC + bleed hot. so close the bleed. what is the RPM NOW hot. (turn CW, direction, do not force it in to seat. gently)

here is my new fast page. might work.
these checks put us on track. to true cause.

http://www.fixkick.com/IDLE-AIR/fastfix.html

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we can find it. its not too hard with some simple checks.
as long as manifolds are not cracked, or injector cushions leaking or 2 problems.
first lets get hot closed loop working, this is necessary, then set idle.

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when moving(swap) engines, and for sure MPI ,this engine uses a MAF sensor,
the MAF sat at the air cleaner box. and the long pipe from there to the induction(intake TB, and plenum) must not have any air leaks at all.
This is how mpi WORKS. It must measure all air sucked into the engine or all bets are off.
if you get leaks it goes lean. (all else working and 02 can not correcting , this massive air leak.)
if not in closed loop, at idle that means the 02 is not correcting for things like air leaks.(vacuum leaks) or is out of control. (both)
if the engine goes lean the rpm drops, then the ISC will open and if it cant get rpm up from lean, say 600, it then hunts. << not your case.
if how ever. there are 2 problems (and closed loop dead) if say the FPR is bad. and fuel pressure too high, it (AFR) goes rich, and any air leaks (problem 2) causes racing.
and the ISC then closes to correct rpm down to 800 (say from 1200), and if it cant,. it hunts. (really THE ISC is just a servo and hunting is its bag) It just tries hard.
under normal conditions the iSC is only correcting timing changes and does it so fast you dont notice it.
ISC is electric. (electric air valve is all it is)
IAC is thermal, it is closed 100% hot, so is not a factor if working.

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iac is open cold and idle races 1200 to 1500 rpm and the ecu does not try to set idle to 800 under cold conditions , using the ISC,
when the engine hits over 150 , the ISC wakes up. and runs the show., that is runs idle at 800 or goes nuts.
it's hard coded, 750 to 850 RPM is a hard coded software rule. and the iSC works hard to do that. (isc is software + hardware)
so 180F is important as is the water tube at the IAC, gets hot say near 170 by heat gun measured. for sure way over 150f pointing there. or the line is clogged, missing or bypassed during the swap? or connected wrong.

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in an early post you said fast idle ended with IAC port blocked, well that is only caused by 2 things.
it's bad,.
or is not hot.
easy peasy

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its only like 5 wires to get scan tool working. if the orig harness is missing this part.
12v(p16)
ground (p4/5)
2 comm lines.

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i need both rpm's low and high, hot.
and what parts are missing. (engine, sensors. harness, induction parts, sensors.etc)

[Garemie]

I have a working OBD2 scan tool.

I will begin testing tomorrow, and I will try to get a picture of the engine bay and a video of the engine surges.

[fixkick]

screw the air bleed screw, in , CW on the TB. (top of Throttle body , under black plastic cap)
see if the ISC wakes up. (it can) wake up means it gains control of idle. again. and drops to 800 steady.
if not ,you have air leaks. to the plenum.

at hot idle, the Closed Loop status must be true, that is , closed loop active.
(i tend work CL first. as that means getting the AIR fuel ratio correct first,so that idle can have a chance (isc controls working)

[Garemie]

I screwed the bleed screw all the way in and it dropped the idle a little, still way too high though.

I took a picture of the bay as well as a short video, however the video does not capture when the idle is a constant up down up down every second.

http://i.imgur.com/wNcCdwX.jpg Here is the engine bay

https://www.youtube.com/watch?v=DzX57wCB1KU Here is the video

I will try to get a video with the idle surging when it happens again.

Apparently my OBD2 reader died, as it doesn't work on any of my cars now.

I pinched the ISC hose and it lowered the idle, but it's still very high.

[fixkick]

i dont like the bouncing $1000 maf sensor. but. typical... for swaps sure. make a clamp for it, so it moves with engine, not flop.

the screamer wow.! the worse the scream the mor easy it is to fix, and find. yours IS.

cheap clolne ELM327 readers are like weak kittens, die easy. the regulator inside (clones, not the scantool.net ones) are no good in cars. ever. $9 tool are that.

ok so both air normal all correct air paths are closed, so that proves.
1: iac stuck open, Clay pack it. per my leaks page. if still races the plenum is leaking. (or some "bad guy" played with the the TV stop bolt, (takes hard effort to do that) the TV stop has a metal bracket with tab blocking all CARB guys from ATTACK.

wish all were this easy. it is.

if it still leaks? and screams., IAC blocked.
then:
plenum ingress time. TV closed 99.99%.

1: brake booster leaking.
2: injector cushions leaking
3: base gasket or any intake gaskets leaking, that can be found with, sprayed carb cleaner or propane gas (safer) rpm increases ,then gasket is bad.
4: all vacuum hose pinched yet,?
per my list of who and want not to pinch>? pinch all but PCV and FPR. (inspect those , its easy roll them with fingers , no cracks allowed..
i leaking FPR (vacuuum) should not suck too much air. but i do a real leak down test on everyone i see, zero leak down rates allowed by me. zero. for 30 seconds.
the booster hose, block it some way. pull hose and pack it with say a cork. what ever wont suck in. (suck side)
i think i hit them all but the IAC test is proof, i add the blocks, i keep block and blocking, just on the off changes 2 leaks.? see? add the up, assume they all leak, then prove other wise and win every time/
the engine can not run with zero air supply, YOURS IS.

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don't feel bad, this happens all the time, nature hates vacuums.
but one guy said?
if that is true, why does not earth suck in all of outer space..
or reverse? (depends on where you stand)
(funny huh>? but is gravity .
in your case, it's hoses , gaskets and valves.

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gosh what a nice RIG!!!!!!! super nice JOB !!!!!

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be happy you have G16b
and not this POS.

http://www.fixkick.com/look/1980vacuum-hell.jpg

i feel so sorry for any one owning this dog....

[Garemie]

Well you were right, the coolant lines were cold. I took one off and blew on it, and it cleared the blockage.

After that I took off the entire ISC and resealed everything on it, and now with hot coolant lines and no air leaks, the car idles perfectly.


Thanks FixKick, finally solved this one.

I'm going to do a basic walkthrough on swapping a G16B into a Samurai soon, so I'll be sure and post that here when I'm done as well.

Thanks again!

[fixkick]

my gosh, what a great find, and no horror removing those ISC bolts and they snap, ouch.
mine was jammed open inside, had to buy a used TB to get this working.


would love to have a Sammi swap.... wow !