IAC/ EGR SES Codes

[moboman]

Hi everybody. My SES light has come on twice now with these 2 codes, both times.
The 2 codes it gave me are, (the descriptions I got off the web):
P1406(EGR Pintle Position Fault)
P1509 (IAC not responding)

I had the EGR off and cleaned it with electrical components cleaner. It was really bad before I cleaned it, could this be what is causing the P1406?

With P1509, do I just need to replace the IAC?


Thanks in advance, David

[91AWDAstro]

IAC (idle air control). Does the motor idle high? To really check it out you need to see the acutal counts with a scanner. It's common to get that fault if you have a vaccum leak too. The ECM can't reduce the idle where it should be and assumes there is a problem with the IAC. Spray around the intake with some carb cleaner while it's idle and see if the idle changes.

[moboman]

I'm sorry hate to sound stupid and ask but, when you say spray around the intake, where exactly should I spray? Maybe a picture?

My scangauge showed the van was idling a little high. It was idling really high until after I cleaned out the egr.



Thanks for the help.

[91AWDAstro]

I'm going by memory here, but if the IAC counts are below 10 then you are definately getting air from some where else. Since it started after you cleaned the EGR, it sounds like the EGR could have the leak. Try spraying around the EGR. It could be the seal between the EGR and intake or the EGR has a ruptured diaphram.

If the EGR seems ok, spray around the permiter of the intake manifold and also around the seal of the upper and lower plenums. Those manifolds are notorious for leaks, but it sounds more like your EGR is the problem.

[kings-x59]

One other suggestion: Pull the IAC and see what kind of condition the port that receives the pintle is in.
Mine gets gummed up from time to time and a bit of cleaning settles the idle down.

[moboman]

I replaced the IAC today and the PCV valve.
The Van has a real rough idle, and acceleration.

I get an error code of P0306(cylinder 6 misfire?).

Thanks again.

[moboman]

When I hold my finger over the hole that the pcv hose connects to (instead of the hose being connected) the van idles fine.

Thanks in advance.

[kings-x59]

which end of the hose are you writing about? the intake end or the pcv valve end ?

[moboman]

which end of the hose are you writing about? the intake end or the pcv valve end ?

The intake side.

Thanks.

[sfeaver]

Do that test again with your finger on the pcv valve, and put your finger over the grommet on the valve cover? Do you feel vacuum there?

That P1509 code means your idle is high and the system cannot correct it. The IAC valve was probably fine thogh, something else causing the high idle. How high is it idling? Do you know what your IAC counts are at idle?

Scott

[sfeaver]

I've been thinking about this one, you might have an EGR valve that is sticking open. I had this on a 92 Sunbird 3.1V6, and a chunk of carbon was stuck in one of the pintles so it was slightly open. That gives you exhaust gas into the intake, just like a leak. I'd try cleaning it again, but make sure the gasket is good first.

If you feel vacuum inside the valve cover then your intake gasket is gone. Hopefully its not that! Did all this start after taking off the EGR the first time?

Scott

[moboman]

I've been thinking about this one, you might have an EGR valve that is sticking open. I had this on a 92 Sunbird 3.1V6, and a chunk of carbon was stuck in one of the pintles so it was slightly open. That gives you exhaust gas into the intake, just like a leak. I'd try cleaning it again, but make sure the gasket is good first.

If you feel vacuum inside the valve cover then your intake gasket is gone. Hopefully its not that! Did all this start after taking off the EGR the first time?

Scott

I did not feel vacuum when I pulled the PCV off and held my thump there. I plugged the intake hole when I did this.
When both holes were plugged, the van idled perfect.

[sfeaver]

So when you had toe PCV valve plugged itself with your thumb, but the hole in the valve cover open, it did not idle right??

[moboman]

So when you had toe PCV valve plugged itself with your thumb, but the hole in the valve cover open, it did not idle right??

I pulled the pcv valve, plugged the hole in the intake, and left the valve cover open and the van idled fine.

It seems almost as if the engine is not holding a vacuum.

Thanks for your help.

[sfeaver]

The engine isnt supposed to hold a vacuum, as on the other valve cover it has the hose going to the intake. That is so it sucks the fumes inside the motor in through the pcv valve and burns it off. How new is that PCV valve? When you remove your thumb from the bottom of it with the engine running, does the spring still snap the valve back?

I've had this problem before, I'm just trying to remember what I did to fix it Did this start after the EGR service?

Scott