Stall hot, P0400, P0505

[fixkick]

Dear All,

Please help with my constant stalling issue...! (if only EGR stalled, it is sticking open ,as all old EGR mains do, that is what they do as you roll to a stop
i can clean them and 1/2 work for a year, then fail or fail next week, some that stick CAN NOT BE CURED< only replaced.

Car: USA spec, made in Canada, 1996, manual, 2 door, 4x4, geo tracker with 150,000 miles.

Tune up is up to date. The car still gets 24 mpg and feels peppy for what it is.

Some months ago it started stalling at stops with a p0400.
I checked the hoses, clean the #4 hole in the throttle, the SST tube, but there was no change in behavior.

Then I did the stall test. It passed. (GOOD that means the exhaust that is clean , mostly)

I then did the bark test. I thought the bark was too weak, so I cleaned all the passages toward the exhaust. No change.

By then I was sure it was the EGR main. I put a new one, no change. why the stall passes now?

Then, of course, it had to be the modulator. I put a new one. No change. (this is hard to test, and the CAT tests is first, not this)

Now the car was stalling hot every time I stop pushing the gas pedal. (parked and it is stalled? really) then pull the eGR main VAC hose, the stall must end or the VSV is bad.)
The idle switch must be closed at idle, but the ported vacuum also kills all vacuum at the TB ported vacuum port so at idle there is NO VACUUM possible
so the MOD is dead now, it can be MOD, as NOW there is no VACUUM see??????
you actually missed this very important test, pulling the VACUUM line, after all VSV can fail stuck open, all valves made by man can do that, (lots of fail modes in all Valves)

Since it is passing the first two tests, I did the live test. It passed.

I have not formally tested the VSV valves. But I did check that they are open when the car is off and they close when the car is on.

Then I noticed that the car is not idling properly at start up.
When I start it, it only goes to about 600-800 rpm and once it gets hot it stalls. (cold idle is about 1100 to 1500 rpm by virtue of thermal IAC valve)
and there is no cold EGR ever. period and if you push the EGR main diaphagm with index finger and it is closed, they the EGR is NOT IN THE LOOP, its OFF LINE NOW, end EGR worries NOW.
HOT idle the EGR is closed too, but now IAC is off line and ECU runs idle at 800 hot, via ISC, valve, if not 800 then there are problems , more.
ISC dirty, ever clean it and bench test it per my ISC pages>?

I got an ELM327 OBD2 Bluetooth transmitter and using the Torque application I can see that the car reaches closed loop in 15-20 seconds. The vacuum is about 20 in Hg and the car gets hot and stays hot.
Try to know that the EGR tests can fail if there are other, more basic engine/EFI failures,
The EGR tests all take a perfect running engine, good MPG, no misfire, no bad idles. no dead 02, no exhaust leaks hear 02, no cracks here.
The EGR tests both , look in test "A" for steady states, then fires off the test, if the conditions change (say misfires) the EGR test can be void, fails and is a lie.
Like watching a clown juggle, is perfect and fun to watch then some bad guy throws a tomato at his nose, bam he drops the ball, same with EGR monitors.
This is a slow, ECU, its not going to be fast and see fast changing errors. like the tomato. so can lie, this is a fact on all cars, now. 1996 to now. gets better but is fact.

For some reason everything worked perfect yesterday. It went to 1300 rpm at start up, went down to 800 and stay there at idle at every stop of my 15-20 min commute.
GOOD !

Coming back home, the same, no issue until this morning. Started at 900 rpm, first stop sign, it stalled. this has happened once before.
Every few months one good day.

I keep it alive by feathering the gas, and the car always start right back up. it responds easy and quick to feathering the gas pedal, just a tiny touch will raise the rpms.
BUT CAN YOU SAVE THE STALL EASY, if yes, the ISC may be stuck closed. all do this.

The only two modifications to the car are a less restrictive CAT back and replaced the transmission with a lower mileage one like 10,000 miles ago (the old one had a bad internal bearing).
Is the CAT honey comb in tact, seen with eyes, if yes, its ok, forget cat, the cat must be there to have a working MOD, and pass federal smog test.
if the cat is missing EGR fails and p0421, cat dead test fails. 2 fails, one cause.

I do not have any code right now, but the car stalls immediately once it gets hot.

I was going to disassemble the ISC next...or try to do more tests on the VSV...any ideas?

Anything I can get from reading the OBD?

Thanks for any and all help,

Jorgi

what is MISSING here?
engine stalls!
get out of car, and see if EGR main is stuck open, do not get burned, it will be roasting hot.
this is not easy to do. i use gloves and try to finger it. (your finger may be too big or?)
if it's closed, EGR issues are a red herring hear, NOT IT.

now know this,
close the EGR cold (with finger is its suborn , new valve will not fail here, remove the egr hose, from it and put a golf tee in the hose EGR MAIN,
now the EGR is closed forever (a test only, ) and the hose can not suck air,
now drive, if car stalls THE EGR IS NOT IT.
we then WORK IT.

see>???? this is how all EGRs on G16s are best done. all. up to 1998, random stalling... this....way....

If the EGR is NOT IT what might it be?, well that is easy . but is a long list.

1: the 50 causes of misfire. omg, really 50, yes. huge. (case in point sticking intake valves or exhaust) but is what?,misfire.
so lets do stalls all the way, possible, and how to find it .
2:misfire. (misfire can stall and engine, infact if EGR is GOOD , this is why)
3: engine bad. sure. can be, and lots of parts to fail the larger list in the 50
4: fueling issues.
5: ECU see bad sensors.
6: leaking or clogging injectors. or low fuel pressure.
its and endless lists, but no fear....

the true list is MISFIRE> only MISFIRE CAUSES STALLS. (spark : fuel or engine caused) EGR not, as we just proved its NOT. see? leaving the not so NIFTY FIFTY.
if the right fast foot (feathering) trick saves stalls, it's not spark, I Bet if spark is bad, adding more air with fuel should not cure bad spark.
leaving 2 more mACRO reasons., engine and fueling.

if the engine is really strong, and valve lash set like the bible said (fsm bible) for 60k mile cam belt change it says, check valve lash if lash is good, then valves will not stick open
if oil is changed regularly valves do not stick.... but my vacuum gage in 5min work shows hard steady vaucuum 20inches and the NEEDLE DOES NOT TWITCH AT ALL !!!!
and compression is at spec. leaving us with just 1, fueling.

FUELING 101, (really a huge topic, once here, and need to fix FUELING : be it know fueling runs in MODES, many modes, cold engine, hot, idle , cruise and WOT, cranked all have own rules.
best way to learn this is think its like 6 different ECUs' up to 8 counting Limphome or BACKUP MODE (OMG)

when i say fueling I mean AIR AND FUEL, as that only matters now to end misfire. done not be confused, the ECU controls both and you with right foot.
Idle controls go off line as soon as your right foot gets into the TV, Throttle valve,idle switch opens and YOU ARE THE AIR SUPPLY see?


if adding throttle saves a stall super easy, (you never said what transmission and that matters, big time)
as the A/T loves to stall why, because the AT clutch dags full time and if the ISC sticks closed the engine stalls from lack of air.
if m'/t the driver slams clutch to floor and there is NO LOAD on this engine at all. (besides pumping losses, i will not digress to that) (AC off , accessories off then no load at stall right?)
the engine needs air to run, lots and lots of air, if air ends so does, combustion and stall fast.

ISC cleaned, and tested per my ISC page (type ISC in the search box on fixkick.com and see that) SURE !
leaving what, FUEL ONLY. if ISC works only fueling remains. (ECU inputs ,etc)

Does the Fuel pump pressure tests at RAIL? okay, and leak down test, if they fail, injectors are leaking there is also the injector balance test, to see if all 4 flow equally.
using oBD2 scans , and data log.
what are all the sensor readings hot. ? every one matter.s


MISFIRE IS a hUGE TOPIC as is COMBUSTION.
are the spark tips white or black or green. that too is a free test.

http://www.fixkick.com/misfiring.html