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Thread: Stock sr20 stalling during idle

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Posts: 1-10 of 10
2009-12-03 05:02:01
#1
Stock sr20 stalling during idle
I know this happens all the time to all kinds of people, but this is part of a problem that started over a month ago that i tried to find a solution to online.

im basically gonna copy and past the post i put on s-chassis.

a few months ago i was having problems starting my car (it wasnt turning over), so i came on the forums to try to figure it out.
after some reading i figured it was my MAF having problems, so i pulled the maf off then started the car, then put the maf back on. it seemed to be the end of it.

MORNING---
before i tell what happened this morning... the past month the car has acted strangely in other ways... its running alot richer than usual (esp. with a cold engine but thats a given), its hitting 10.5 on my afr between shifts, and its not really swinging back and forth during cruise, its sitting at a low 13 and sometimes high 12. im unsure why, but anyway..


this time around, the car started fine this morning, and i went in the house and let it idle and when i got back it had stalled. so i tried to start it again and the car turns over instantly. (it smells of gas even in my car so maybe was running too rich?) but it dies right away. i tried pulling the maf off but it wont start like that either, so it seems like a deeper issue.

NIGHT----------------------------------------

ok i went out to try to cold start it tonite, and it started easily.
as soon as i was sure it would stay idling, i ran to grab an ice scraper cause it frosted tonite...
when i went, it tried to stall for like 10 seconds, but kicked itself back in.
i went to sit in the car to rev it a bit, like up to 1800 and it was running rich like usual, between 10 and 13..... then as soon as it warmed up, it started leaning out FAST, and as soon as it held a solid 15+, i turned it off right away.


so im thinking when it warms up, its leaning out and stalling.
what could be the cause of this? timing issue?

any help would be great.
2009-12-03 05:28:04
#2
hmm....there's a bunch of possibilities that come to mind for me, but honestly without testing them individually I couldnt tell you which is more likely. I'm more of a hands-on troubleshooter than anything else.

What came to mind for me when reading this: Coolant Temp Sensor, Leaky Injector, Bad MAF, Spark-related Issue.

Timing would cause more problems than random stalling and running rich, so I don't think that's your issue.

Also, what are you using to detect your A/F ratio?
2009-12-03 05:42:31
#3
its an autometer wideband and its like 6 months old so the sensor should be good still hehe.
the bad maf is what im thinking too cause mainly because its been running crazy pig rich lately and all of a sudden leaning out, and it was showing signs of aging before with simmilar but different problems.

the coolant temp might be it but its hard to tell cause my engine is always running way below running temp.... running a koyo with stock thermostat in teh winter hehe..


as for the leaky injector, i dont really know anything about that with this engine
and the spark related part... what would that root back to? should i basically check my whole ignition system from the plugs to the ecu?


i knew there was gonna be a whole range of possibilities here which is why im asking for suggestions, cause im really no good at this, ive only been around engines for a year or so.
2009-12-03 06:18:11
#4
spark would likely be either coil, plug wires, or plugs. So far my main thought is MAF, so I would look into that, but the spark stuff is regular tune-up things so it's a good idea to do that anyway, along with filters and such that hasn't been changed in a while.

When it runs, can you rev it above 2k rpm? If not, it's going to be your maf. If you can, it means the maf is still working although it could be dirty or such.
2009-12-03 06:38:25
#5
ok thanks for the insight!!

if i can rev it higher than 2k, and the maf might be dirty, how would i go about cleaning it? water, or some rubbing alcohol or something?

as for filter, its one of those AEM "never wash it again untill you buy the AEM brand cleaning agent" ones so the air filter is good.

anyway, ill try this stuff asap. thanks for the help wingman
2009-12-03 07:18:49
#6
for cleaning, there's stuff made just for Mafs, called MAF Cleaner,

CRC Mass Air Flow Sensor Cleaner, 11 Wt Oz - CRC05110

Can be bought at most any auto part store, like NAPA, Autozone, O'Reilley's, etc.

As for the filter, I was thinking more on the fuel filter side of it, the air filters I rarely change or clean myself.
2009-12-03 12:22:07
#7
I'd check base idle (instructions available on this Forum) before looking for more complicated things. What happens is that over time, grunge collects in the throttle body and reduces the amount of air that gets past the throttle plate at idle. The engine compensates for this with the idle control valve, which is controlled by the ECU, to maintain the proper idle spped. But the idle control valve also has a physical adjusting screw intended to get the idle speed close to spec with no interference from the ECU. If the physical setting on the idle control valve gets too far off what the engine needs to maintain proper idle, then the ECU has a hard time compensating and idle can get erratic.

If this doesn't do it for you, then I would move on to other possible problems.

PS-> If it were warmer out, I'd recommend cleaning the throttle body and then setting the base idle.
2009-12-04 04:04:13
#8
oo my fuel filter was changed when i did my fuel pump shortly before the swap, so its fairly new.

as for base idle... well the throttle body was shining clean 6 months ago... so i dno how much grime could possibly get in there to change anything.. and that wouldnt really make me run lean enough to stall would it?
2009-12-05 00:54:35
#9
Originally Posted by BCJunglist
as for base idle... well the throttle body was shining clean 6 months ago... so i dno how much grime could possibly get in there to change anything.. and that wouldnt really make me run lean enough to stall would it?


It's easy to check your base idle speed, that's why I suggested it. Six months is long enough to collect some grime, depending on your driving habits. These are old cars with old parts, sometimes my idle just goes off, I adjust base idle, and I'm good for a few months.
2009-12-05 03:40:04
#10
Originally Posted by BCJunglist

the coolant temp might be it but its hard to tell cause my engine is always running way below running temp.... running a koyo with stock thermostat in teh winter hehe..

I'd replace the thermostat.
Doesn't matter what radiator you have - if the thermostat is functioning properly,
it will stay closed until the rated temp - 170 F (per 1994 SR20DE FSM).
Even if you have the biggest radiator and fans blowing all the time,it shouldn't run below
170 F - unless there are other tuning issues.

Also check the Engine Coolant Temp Sensor (ECTS) (and wiring).
From the FSM:
"When engine coolant temperature sensor output voltage is below
or above the specified value, water temperature is fixed at the preset
value as follows:
Just as ignition switch is turned ON or Start: 86 F
More than 6 minutes after Ignition ON or Start: 176 F
Except as shown above: 86 - 176 F"

I had one that was reading nearly 300 F on a cold start. Not good, lol.


From FSM - Engine Stalls when Engine is Cold:
Check IACV-Air Regulator & AAC valve
Perform power balance test (disconnect each injector connector one at a time
to see if any cylinder does NOT change engine speed)
Check injectors (should be 10-14 ohms resistance between terminals)
Check ignition spark
Check spark plugs
Check fuel pressure
Check ECM harness connector
Check ECM power supply and ground circuit
Try known good ECM

For stalling when hot:
Check fuel vapor
Power balance test
Check injectors
Check ignition spark
Check fuel pressure
Check ECM harness connector
Check ECM power supply and ground circuit
Try known good ECM
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