88-93 chevy truck owners

[dr_of_lovephd]

Greeting everyone,

I wanted to let everyone know about a problem I found with my 89 pickup that was robbing me of a lot of horsepower. This is for people running the stock air intake assembly.

On the stock air intake there is a valve that controls whether the air comes from the outside or from that little pipe that runs down to the exhaust manifold. The valve is to give the engine some warm air for cold starting. When it gets hot it should open. Well, mine got to where it never opened. My motor was getting all of its air from that little 2 inch pipe. I perminatly opened it with some screws and it probably gave me 25+ extra horses. I think they changed the intake style in 94.

Later, my uncle asked me to check his 93 chevy truck because it was not running well, and it had the same problem.

I don't know if anyone else has noticed this problem, but if your truck seems to have lost some power, it is worth the time to check it out.

[TaNK_Em]

I have a 93 i will have to look into it.

- Kevin

[broughy84]

Yep...already tore that little puppy outta there and plugged that hole!

[chevytrucks92]

I got an AIRAID intake on my truck now, but never really noticed any loss in power with the factory set up.

Now this new AIRAID intake makes the truck like night and day power wise.

[tirefryer93]

Flip the stock lid upside down.

[LT1 Kayker]

I used an acetylene torch and cut the whole thing out a few months ago and welded a plate on the bottom where the valve was. It doesn't seem to do much different than before though.

[rjrhoades]

The pupose of the door is to help the engine run better while warming up (and help on emissions). A better solution would be to fix the problem, probably pretty inexpensively.

Your rememdy can cause drivability problems when cold, unless you always let it warm up for 15 minutes before driving.

[tirefryer93]

I guess I wouldn't worry about cold starts, because engines are much happier with cold air anyway. If you are in search for power, it is worth a few minutes of warm up time.

[roadrunner_70]

I've just bought a '93 cheyenne and it came with no hose for that valve. I also don't think the valve works, but given that the prevailing temperature here is below zero celsius(-20), I installed a new stovepipe. When it's this cold you want all the warm air into the intake that you can get. I also installed a winter cover for the front to lessen the effects of windchill. I drive about 15 miles to work so it doesn't really get a chance to warm up fully. This can mean alot when it comes to preventing fuel saturation in your oil. It actually might burn off some of those contaminants. The replacement valve has to be screwed in, whereas the original is rivetted, which you must drill out. It's a good investment to maintain it.

[J-Ri]

It's definately better to keep the valve working. Mine doesn't work. Even after the engine is up to temp, a big gulp of cold air will make the engine stumble a bit. Also, it takes at least 5 minutes of revving to get it to accelerate quick enough to get on the highway without getting hit. If you live in the south, it may be worth removing it... but if it gets cold where you are, it's probably best to leave it on there.

[J-Ri]

Oh, and I forgot... the trucks that have the heat riser go back well before 88, I know 86's have it, and I think it goes back to the earliest models.

[v10_viper]

Yeah that damn thing got stuck shut on me one time for awhile and i couldn't figure out what the fuck it was until i took the hose off because i thought something was clogging it and it was that. It actually took some force to loosen it so i dont' know what happened but I just left it, it opens now so that's good enough for me. I really dont think that valve or w/e needs to be there because with the warm air coming from that hose it should take it in, open or closed.

[big_blue_chevy2006]

i dont have a stock air intake nemore but i did notice that i have a k&n air intake assembly. well about that adding 25 horses i REALLY HIGHLY doubt that, my k&n air intake dont even add that, when air intakes say they add up to 15 horses or so that normally means with very big mods otherwise it might add like 3 or 4 horses.

[Xrrider280]

how does the motor know when to change that little valve anyway, there are no wires or anything just that tube going to the heat sheild.

[rjrhoades]

Originally Posted by Xrrider280

how does the motor know when to change that little valve anyway, there are no wires or anything just that tube going to the heat sheild.

That tube is a vacuum tube. The "motor" is powered by vacuum (instead of electric) produced by the motor. In the older vehicles, the vacuum was controlled by a mechanical thermal switch (sort of like a temperature sensor) mounted in the engine block. I haven't followed the evolution, but the switch could now be an electrical vacuum switch controlled by the vehicle computer. If an aftermarket air cleaner is used, the whole assembly was probably thrown away.....