1992 toyota pickup 4x4 v6 engine

I am really hoping you guys can help me out. I am new to posting but read up on many of threads. I just moved down from Alaska to California and have been trying to pass smog. I replaced the coil and o2 in hopes of passing but I failed the NO2 so I am now replacing the cat.

A couple of days after failing, I was driving when all of a sudden I lost all power. The engine bogs down now under load and when it bogs down I can hear a whistle or what almost sounds like a loose belt. I checked the belts but they're nice and snug. After beating my head against the wall all night all while reading the chiltons manual, I got a revelation. I believe its a vacuum leak? I am beginning to think that during the smog check they didn't replace a vacuum hose properly and it came loose. I just went out and visually inspected the vacuum hoses but can't see anything.

Here are the symptoms. When I first start the engine all is good, idles fine revs up fine. Then going around the block the sound appears and the engine will bog down and acceleration is difficult to say the least. It will also at times buck.

What do you guys think? Do you know which hose the smog techs would have messed with and am I on the right track? I did read similar problems with the bogging down under load but nobody has the added whistle or screeching sound. Please help! All advise is greatly appreciated.

 

I'm not an expert or anything, but it sounds to me like something is going on with the airflow meter, which is located on top of your air cleaner. Sounds like it is closing down and shutting off air to your motor, which would give ya that whistling sound, just my 2 cents hope it helps.

 

I was driving in extremely wet conditions when this first occurred. So you may be on to something. Could it be that the afm got wet and is shutting down? Thanks for the reply.

 

Were you driving though high water, Where it could have taken some into the air intake?

 

Well, when it first occurred I was passing a semi which was hosing my truck pretty good to where I needed the highest level wiper speed to see anything. My best guess that water may have been able to get into the intake. Do I just wait and let it dry or do I need to get in there?

 

Not sure how to test that thing, it has some electronics in it which are sealed, I would bet your problem is there. Might want to see if ya could locate one at a salvage yard, sure it's a high dollar part new. I wouldn't bust open anything that is sealed, but couldn't hurt to take a peek at it.

 

Hey, check the forum for AFM, think there is something out there about checking this thing , values with a multimeter.

Good Luck, hope ya get it

 

Hey thanks for your help. I will check that out. My initial feeling when this first occurred was that this was some sort of sensor issue, but I was thinking about the o2 sensor and not the afm. The whistle sound though was really puzzling. I will check out the afm and hope for the best. Thanks again for your help.

 

You can ohm out the afm your chiltons manual should have all the info you need. If you hav a haynes manual is in chapter 4 section 14. good luck

 

Well I just went out and checked the air filter and it was dry as a bone. I will check the chiltons manual and test this out as soon as the weather clears.

 

[YOUTUBE]http://www.youtube.com/watch?v=SMcw_pEg9E8[/YOUTUBE]

plug your ears because the sound is very high pitched and annoying!

ok so I drove to the store to pick up a new multi meter to test the afm and noticed the sound was getting worse. That turned out to be a good thing because now it happens with high revs and not only under load. I am now able to hear that it is in fact a vacuum leak coming from one of the hoses. I thought it was the u shaped hose but I put a clamp on it and still the sound. I guess Im going out there with soapy water!

Thanks for all the help any other advice would also be appreciated.

 

ok, now that I'm deaf, I am now thinking the sound is coming from the EGR valve. Would that make such a sound if failing?

 

Yeah, that sounds like it's coming from your EGR valve, make sure all your vacuum lines are ok that are related with it, test it as stated in the manual and I believe you'll find the answer. Most likely not opening like it should, but this could also be lack of vacuum going to it, good luck, sorry for being wrong on the afm.

 

So I finally got a new egr valve and replaced the old one. However, the sound is still there. It sounds like its coming from the as reed valve now. Its definitely coming from the passenger side but its such a high pitched noise that I cant pin the exact location down. Does anyone know if the reed valve would make that sound? I really need help with this.

 

Did you remove the tube going into the plenium that the EGR is connected to, I know they can clog up and cause trouble. When I did the head gaskets on mine I removed it and there was alot of build-up, did you test your EGR before replacing and check the vacuum going to it? Sorry you're having so much trouble, wish I could be there to help ya.

 

No I didn't check vacuum before replacing but wish I had. I did find a post here on this site that is very similar to my problem. The only thing is the thread doesn't explain the solution to this puzzle. So, i emailed the person even though the post is from 2007.

Now the idle is low and the sound is almost constant. So whatever it is its getting worse. It no longer sounds like its coming from the egr. I didnt replace the hose only because the store didnt have the parts needed. Now the sound seems to be coming from further back on the engine. Close to where the as reed valve is, but again its very difficult to pinpoint the exact location.

I really appreciate your responses! Not sure if I should post another thread to get more help or not. I am stumped.

 

Wonder if an intake or plenium gasket leak could produce such a sound, I was kind of ruling that out, but now with the low idle and all who knows. Hope he emails ya back, take care.

 

Your going down the right path. i cant see the videos, but your egr is what helps to control the NOX emissions. Ill bet you fix this and you will be able pass your emissions test.

 

Ya, I did see that and wasnt aware that the egr controls the no2. Now I know and thats why I was so sure that the egr was the problem. Now that it is new, I still have the same problem and its only getting worse.

Ticain you might have the solution. Everything I have read previously pointed to the gasket on the intake manifold. I just ruled that out because I wasnt showing all the other symptoms and now its acting like a vacuum leak. But I have never heard a noise like this created by a vacuum leak.

I wonder if everyone is having problems with the video. I may not have put it up correctly. I know there are two copies of the video and I only tried to put up one. Let me know if there is a problem with viewing the video and Ill try to repost it.

Thanks again.

 

Not trying to get ya to do a bunch of unneeded stuff, but I'd pull that tube out of plenium and clean it,not hard to do, but you'll most likely need a new flange gasket.