SiDeWaYS Z28

Recently I was driving in extremely heavy christmas traffic at the mall for over 30 mins. My left fan motor is out so the car was running hot, somewhere around 226 being cooled by the passenger side fan only. I got on the street and there was more traffic and I noticed smoke from under my hood so I pulled into the gas station as soon as I could. When I popped my hood there was a fire on the drivers side of the engine compartment. A hose that connects to the black vaccum box on the other side of the motor and to a metal valve of sorts on the drivers side, along with the hose from the intake runners to the master cylinder and two spark plug wires were on fire. I put it out with an extinguisher and had it towed home cuz it burned through the wires and the engine was misfiring. I have no idea how this fire could have started? I'm guessing since there is no other surrounding electrical wires that if possible? the spark plug wires were setting against the the side of the valve cover and burned through the rubber to the core of the wire causing a spark, I have an MSD ignition system so there is a lot of juice in the wires. Wondering if not this then what could possibly cause a fire on the drivers side of the engine component? Also there are four metal lines that run from the exhaust manifold to the metal valve or whatever it is connected to the hose, does that control engine vaccum? I'm replacing the tubes and wires but want to find a cause so I can prevent it from happening again. I would greatly appreciate your thoughts or suggestions.

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1991 Chevy Camaro Z28
350ci, 5.7L TPI
too many mods to list

Vader

Side,

Welcome aboard! It's too bad that you had to make your first post under such circumstances, but you've come to the right place.

The device you are describing sounds like the Air Injection/Reaction diverter valve. It has a inlet and outlet hose of about 1¼" in diameter (30mm) and the outlet hose breaks out through a check valve into four individual stainless steel lines routed to each cylinders' exhaust port.

The fire is not so mysterious. If the check valve fails and sticks open, hot exhaust gasses will flow back through the lines and toward the diverter valve. The plastic and rubber will first melt, then catch fire. You're lucky it didn't burn on both sides of the engine.

Your are fortunate to have been so alert. You are also very wise to have been carrying a portable extinguisher. Many of us overlook the extinguisher as part of a normal automotive "survival" kit.

I would suspect that if you remove the check valve, you will find that it flows air in both directions (it shouldn't). This would confirm the theory described above. Even though the MSD system creates a higher spark energy than the stock system, it was not likely the cause of the fire unless you have raw gasoline leaking out somewhere.

Replace all the damaged hoses and wires, and BOTH A.I.R. check valves (on each side of the engine). Hose, accordian tubing conduit, spark plug wires, and wiring are not terribly expensive, so you might consider yourself lucky that you were able to contain the fire to a small space.

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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

Vader

SWays,

Oh, yeah. I'm thinking this is what you're talking about:



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Later,
Vader
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"No matter how hard you try you can't stop us now"
Adobe Acrobat Reader 4.0

SiDeWaYS Z28

Vader, thanks big time for your help, I didnt know what the valve did, I'll check it, and see how much they run, so that would have probally happened again too, good to know. This is my first post but I've been a long time third gener. I submitted my ride with 10 pictures but thats when they remodeled it and it still isnt up yet. Thanks big time for the help.
ps, that valve in the pic is the one i'm talking about, thanks again

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1991 Chevy Camaro Z28
350ci, 5.7L TPI
too many mods to list

ViciousZ

iTrader: (1)

Hey Sideways, you know you could always leave that air injection stuff off. It'll clean up your engine bay, and maybe free up a few hp. Except it's not quite emissions legal, and you'd never pass emissions inspection there in California if they looked under the hood (I'm assuming they will.) But it'd probably be cheaper, all you'd need is a new belt and some brass plugs. There's a tech article on how to remove your airpump on this board somewhere.

SiDeWaYS Z28

vicious, yea i heard about that, but thats true that california is hella strict bogging down hp, i'll know more when i check it out tomorrow, i'll check out that tech article too, thanks

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1991 Chevy Camaro Z28
350ci, 5.7L TPI
too many mods to list