Usually with a dirty IAC, you'll have very low idle or stalling soon after starting. Never heard of the IAC causing the car to idle fine for 2-3minutes THEN stalling the car. Also usually with a sticking IAC, the car may stall, but restart fine but still idle funky.

When this first happened, were you driving the car when it cut out or just idling in park? I would think it's something else than a IAC causing this to happen. How about keeping your foot on the gas to hold maybe a 2-3K idle? Will the car still stall? If that it happening, I would think it's something else. Maybe Fuel related?

 

How about keeping your foot on the gas to hold maybe a 2-3K idle? Will the car still stall? If that it happening, I would think it's something else.

Yes to that ^^. Even just hold pedal to keep low idle, this will bypass IAC.

Does this car have an EGR?

 

Does this car have an EGR?

Yep, it does.

Easy way to eliminate that as a possibility is to disconnect the vacuum line going to the EGR and plug it; a golf tee is perfect.

The EGR should not open when the engine is cold. After it warms up, it should only open under partial throttle, proportional to the amount of throttle. If the EGR vacuum modulator is bad, it could be fully opening as soon as the engine is warmed up.

 

The first time it happened, the accelerator pedal was slightly depressed (going around 35MPH). I pulled to the side and started the car, it started right up (no hesitation at all). went probably 1 minute and it stalled, this time, no foot on gas. Started right back, and I push the accelerator half way to get home back (prob 2 miles). If I give a good amount of gas, then I can see the rpm drops (to 300-400 range) for a split second. If I continue give gas, the car will not stall.

Car stalls whether I am driving it or in park all the time (I mean stalls without foot o the pedal). Fuel > always from the same pump for the last 4-5 years and never had a problem with this car or the other.
Brand new toyota fuel filter.

I will try the egr plug trick and report back today.

John

 

does anyone else think the OP should look at replacing the ignition control module and then the ecu if that doesn't fix it or does the I4 not have one?
tony

 

Does the engine stall while your driving or braking? Do you lose power steering?

 

There is a possibility the ignition switch is not holding the run position. This happened to me on a Honda and I had to replace the switch.

Just another possibility, especially if no drivability issues. I'm not sure how you'd test this (without some wiring mods) other than maybe wiggling the switch when engine running or when stalls. I know that I could put the car in neutral and coast while I restarted.

 

Would this happen randomly or occur more on a consistent basis (i.e. every X amount of time or every X bumps? ) Never thought they could go bad...

 

'still', would jiggling the switch while the car's running be a good test for a bad/faulty ignition?
tony

 

would jiggling the switch while the car's running be a good test for a bad/faulty ignition?

I'm not sure, but it's probably the only choice. These switches are detent'd so you'd have to get it to slip off the detent without actually turning it.

 

Sorry, it took me couple of days to try BMR's suggestion on bypassing EGR. With EGR bypassed (I plugged the vacuum line on the value, the line coming from airbox) and the car has been running for 2-3 days, ~100 miles and no stalls. I do have a check engine light because of the vacuum line, but no drivability issues.

I will put the line back and see if the car is going to stall. It used to stall (it almost always happens somewhere within 1.5 to 2 miles, ~5min from cold start, and within 20-30 sec on hot start), so other than plugging the line, I didn't do anything on the car.

Thanks BMR and others helping me troubleshoot this issue, hopefully I will be able to pinpoint a bit more soon.

John

 

I will put the line back and see if the car is going to stall.

I'd pull the EGR and give it a through cleaning. I suspect the EGR was opening as it should but gunk kept it from closing - which will cause idle stalls as well as drivability issues at low rpm due to vac leak.

 

+1 on still ^...while you got the egr separated from the throttle body, go ahead and separate the tb from the intake and the IAC from the tb and clean all 3 with seafoam and a toothbrush. don't forget to look for loose fitting vacuum hoses while you're doing the taking apart and putting back together and also check the creases in the accordian like rubber snorkle as cracks like to hid in there. lastly, put a can of seafoam in the tank and drive it.
Note that the egr has 4 pieces to test. there's a modulator, a valve, a vsv and the down tube. make sure to clean all of 'em. also, you can verify the valve closes with a vacuum pump and the vsv can be tested using a vacuum pump and a 9v battery.
let us know how you make out.
tony

 

you can verify the valve closes with a vacuum pump and the vsv can be tested using a vacuum pump and a 9v battery.
let us know how you make out.
tony

I used a mightyvac to test the valve. While the car is running, applied vacuum and the car stalled immediately. So looks like a good valve from this test, right?

I am planning to clean the EGR (which is not cleaned ever) this weekend.
How do you test the modulator?
VSV is a pain to get to, so want to test modulator first and then valve.

Thanks
John

 

hi im haveing kinda the same issue with my 94 camry. it runs beautiful then stalls out usually when coming to a stop, its got a check engine light on with codes 12, 13 coming up which is no rpm signal but the car runs! this is what ive done so far distributor has been replaced (3 times) latest one replaced last night, new plugs and wires, pcv, ect sensor (2 wire), cleaned throttle body egr removed and cleaned and tested for operation checked egr control valve and vsv and all vacuum lines, ignitor module, and checked all engine grounds and battery cables. and still throwing both codes no stalling as of yet knock on wood!!! anything i may have missed? i cant understand how car runs with out rpm signal and run great

 

"runs beautiful then stalls out"
"no stalling as of yet"
kinda confused.
checked crank and camshaft sensors if applicable?
tony

 

I take it back i was on my way to work this morning and it died as i was getting ready to pull in to my job it would just crank no start, pushed it into parking lot and waited about 3 mins(not trying to start it and it started up and ran) i think its the main wiring harness. Does anyone know if i can jump the wires from the crank sensor to the ecu or is it not a direct connection?

 

john, that pain in the butt vsv goes bad pretty often. i'd check it. or bypass it with a new one and some rubber tubing so you can mount it wherever you want it. it's electrical and mechanical so 2 chances for it to fail. the modulator can be checked also with a vacuum pump. the air flow directions/specs are in the haynes, which for me anyways, is a great source of info on my car. it's not perfect but much cheaper than the fsm and with it and a vom to check resistance values of things like the vsv and other sensors/electromagnetic valves, plus alot of help from this forum, and I usually get the job done.

tony

 

Well update i talked to a 30yr toyota tech and he said that it sounded like my egr was sticking or not seating properly even though icleaned it and it tested ok with a vacuum pump so I disconnected the vacuum line and pluged it, it stalled in my driveway right after but ive been driving the hell out of it trying different driving styles and sofar no stalling its been 3 days and about 50 miles knock on wood!!! To check the vsv with 9v is there a certain way to do this? I know my erg pipe is clean the fitting to erg is alittle rusted but airtight and the modulator worked properly so i have 2yrs till next emissions inspection so i have time to investigate all avenues! And thanks for all the help in advance

 

it's been a while but they haynes shows which connection is + and which is - . just put the 9v cross the terminals and you'll be able to blow/suck with it connected and no air flow when it's removed if i remember correctly.
if yours is the i4, from what i understand, it's easier to remote it than try to locate and check the old one. especially since you've narrowed it down to an egr problem.
tony

 

Yeah it is a i4 its down the back side of block idk y toyota decided to put it there i understand its the only engine/ platform all other platforms its mounted on the firewall. I will try that

 

Update on 6/12::

I finally removed the EGR valve and the elbo tube.
They both are pretty clean. Blew some air through the hole that connect to the modulator, air is going smoothly to through the tube.
Manually raised the diaphragm and the air is going through the valve, no blockage at all.
The valve is holding vacuum (I closed the top pipe with my finger and the diaphragm stayed. I also tried with a mightyvac and it is holding the vacuum.
So from this, it looks like the valve and pipe are all good.

Now on to the modulator: I will test that sucker soon and then move on to the VSV.
I have been running the car with EGR bypassed (~750 miles), so far no stalls, no issues with the car.

Any additional pointers on testing the modulator would be greatly appreciated.

Thanks
John

 

Scroll down a ways in this thread for some tips on diagnosing the EGR modulator...

http://www.toyotanation.com/forum/1...-1992-1996-1997-2001/357502-diy-1mz-egr-code-p0401-p0402-diagnostic-repair.html

 

Cur0$ityKuttikal
science4kiddos


6/19 update:

Finally got some time to do further test on EGR modulator. I am a bit confused after these tests.

1. Put a mighty vac on EDG valve rubber hose (the line on top of EGR Valve). When I rev the engine, I see vacuum in this line but It is NOT cutting out after say I reach 3500 rpm. It just sits between 20-30Hg no matter how much I rev the engine or how long I rev the engine. Vacuum comes only after I rev the engine, when the engine is idle, no vacuum at all.

2. put vacuum at Q port, there is vacuum when reving and keep it 20-30Hg no matter how much or how long I rev
3. Removed modulator, blow through P, air is coming out on Q and the tiny hole on top of the modulator (under the filter)
4. blow through R and Q, air is going through, no blockage
5. put a vacuum on the bottom port on modulator, i can sense a diaphragm moving and closing

Looking at some you tube videos, some suggesting bad modulator, some suggesting VSV.

Based on these, what do you guys think? VSV or modulator or BOTH?

Any other test to do other than this to nail down the issue?

Appreciate your help on this.


John

 

did i miss where you tested the egr vsv with a 9v battery for air flow as I laid out a few posts back?
tony

 

I didn't test the VSV yet as it is a pain to get to and remove. I thought with this test results, we may be able to mail down the culprit. If my above test is inconclusive, vsv is my next troubleshooting stop.

 

if not done yet, i'd check the cts and clean the intake/tb/iac and check for vacuum leaks.
tony