Stalling, Low RPM

[blumonster]

Hello,

Our 2003 Sienna had been stalling right after starting from time to time. We start the van, RPM is very low (200-300) and when put into gear it used to stall right away. But if we acted fast and put into gear and moved the van, it would not die.

This was back in July. I used Redline fuel treatment. It might have something to do with it.Who knows.

It did not do this for a while till late August. When I started the van I saw the low RPM and turned the engine off and re-started. It started just fine then. I experienced this a few times.

But today after I got out of work I was not able to start the van. When it started it stalled after showing very low RPM (around 200) and shaking a little. I checked to see if anything was visibly broken under the hood, I could nto see anything out of the ordinary. After 50 minutes of trying I was able to keep it running for a few hundred feet to Autozone. I got Chevron's fuel treatment and a MAF sensor cleaner (to use later). I added the fuel treatment to the tank. I had trhe battery checked. It was at 99% capacity. Scanner did not show any codes present. No check engine light was on.

Then I opened the air cleaner box to check the air filter, it was clean both sides. There was a hole in the upper right corner from which a sensor cable was extending. I tapped on that hole from within the air filter box. I closed the box/air hose. I started the van. It started and the RPM stayed normal. That is how I was able to drive the van home (after an hour or so), thank God.

It looks like this is something intermittent. But the today's last episode was a first for me.

What do you think is the problem/culprit here?

I use 100% pure gasoline (ethanol free), I used Redline fuel treatment a few months ago, I changed oil a month ago with Pennzoil Platinum 5W-30. The oil filter is Toyota (Denso) 90915-20004. The previous oil was Pennzoil Ultra 5W-30 and the previous filter was NPN 90915-20002.

Today it rained and stormed in the morning before I experienced this episode. It was humid and warm. Back in July when I first noticed low RPM and stalling right after starting, it was very hot and humid in the morning also.

If it is relevant, the PCV is 3-4 months old.

[wiswind]

If it is stalling with your foot off the accellerator, but OK when you press the accellerator, then it would most likely be the Air Intake Control (IAC) valve.
This is mounted on the bottom of the throttle body.
On my 2003 Sienna, the IAC is on the bottom of the throttle body closest to the firewall. The hole in the bottom of the right-most throttle body in the picture is the opening into it.
I cleaned mine by spraying some Berryman's B12 Chemtool (spray version) into the hole......does not take much to clean it up.
It could be sticking....with cleaning solving the problem, or if the cleaning does not clear it up, it may need to be replaced.



If the problem is not solved by pressing on the accellerator, then the problem is most likely NOT the IAC.

[blumonster]

Originally Posted by wiswind

If it is stalling with your foot off the accellerator, but OK when you press the accellerator, then it would most likely be the Air Intake Control (IAC) valve.
This is mounted on the bottom of the throttle body.
On my 2003 Sienna, the IAC is on the bottom of the throttle body closest to the firewall. The hole in the bottom of the right-most throttle body in the picture is the opening into it.
I cleaned mine by spraying some Berryman's B12 Chemtool (spray version) into the hole......does not take much to clean it up.
It could be sticking....with cleaning solving the problem, or if the cleaning does not clear it up, it may need to be replaced.



If the problem is not solved by pressing on the accellerator, then the problem is most likely NOT the IAC.

If I keep my foot on the accelerator it does not stall. When I let my foot off, it does. I kept the rpm at 1-1500 by pressing the pedal for a few minutes, then it stayed running -although at 200 RPM- for a minute or so and stalled later.

I have CRG (something similar to that?) air intake cleaner and maf sensor cleaner. Would these do the cleaning without harming anything? Or should I get the Chemtool? I will try cleaning. Hopefully it works.

Thanks for your reply, Wiswind.

[clanofwolves]

I agree with the diagnosis, the Air Intake Control (IAC) valve caused a similar issue on my 2002. Although I cleaned it while on the intake, that fix only lasted a year or so. I later removed it and really gave it a cleaning which has fixed the problem with no recurrences for the last 80k, so I recommend removing it to really get it sparkling. Good luck!!

[blumonster]

Originally Posted by clanofwolves

I agree with the diagnosis, the Air Intake Control (IAC) valve caused a similar issue on my 2002. Although I cleaned it while on the intake, that fix only lasted a year or so. I later removed it and really gave it a cleaning which has fixed the problem with no recurrences for the last 80k, so I recommend removing it to really get it sparkling. Good luck!!

Thank you for your reply, clanofwolves.

I cleaned the area with CRC air intake cleaner on Sunday. It is a difficult part to reach.I was not able to see inside the throttle plate. Since then I have not experienced stalling problem yet. Hopefully not for a long time. I did not take it apart, hopefully there won't be any need for that.

I have another question related to A/C clutch relay. What is the amperage of this relay? I found Denso 157-0004 relay to be cheaper than Toyota brand relay. If the amp ratings are the same I am thinking of buying this Denso relay.

[wiswind]

To clean the IAC, hopefully all that is needed is to get some spray into the intake hole that is visible in front of the throttle body plate.
Letting it soak, but not dry up, and then running the motor should flush the fluid and junk that it cleaned out.
MUCH easier than taking things apart.

As for Redline Fuel System cleaner, I use that on a regular basis (in a maintenance dose) so I know that it does not cause problems.....full strength once in a while or in a maintenance dose of 1/3 to 1/2 of a bottle per 20 gallon tank of fuel.

I am not up on the A/C compressor clutch, so I have nothing to add there.

[clanofwolves]

I am always looking to save $$$ if the same item can be bought another way. I have found Denso parts and have used them in the past on Toyota's. I havent replaced a compressor relay, but if the ratings and contacts are the same, I certainly would. I'll wager Denso makes quite a few parts for Toyota's -we all know they do with their own markings- and probably the original relay is actually built by another subcontractor... Denso perhaps? I'd wager that. Let us know what and how you fared.

[wiswind]

latest number for Magnet-clutch relay is 90084-98031 which replaces 90987-02012
There may be a "85934" on the front of that number, not sure.
Those are TOYOTA numbers, list price is $66.52, Toyotapartszone lists it for $48.87
They list it as being made by DENSO of Japan.