Intake Manifold caught fire!!!
 

My car is an 87 RX-7 fuel Injection. I had a cooling leak a few days ago from the thermostat filler & it's cap. Fixed it with water pump & thernostat housing RTV silicone. Fixed the leak. Could some of it fallen onto wiring and caught fire?

I asked for the high temp silicone and that was what they sold me.

I was test driving it today and my final test was only for one mile to my house. As I pulled in the drive way something did not smell right. I lifted the hood and a wire from the Intake manifold was on fire!!!!!!!!! I had to blow it out.

Car starts - haha - but don't think it's going anywhere.

Help from anyone? Please. I'm unemployed or I wouldn't have tried to fix it myself in the first place.
Any guesses what went wrong? Any advice? I really love my car a lot. I'm really not that stupid - including about cars - but I'm feeling it right now.

Carolyn

A wire??? Sounds like something shorted out and burnt a wire??
Which wire was it? Try turning the car on and feeling the wire to see if it gets hot.

One thing to make sure of- is there gas around there? Does it smell like fuel at all? 7's of those model are notorious for having the fuel rail pulsation damper blow out and spray fuel on the engine- can be very dangerous.

Betcha it is the PD. They should be replaced every 10 years or 120K miles.

No fuel smell. I disconnected the wire. Yes it was hot. It is the uppermost forward wire on the intake manifold. Car still starts without it. (With fire extinguisher in my hand.)

What is the PD please?

Carolyn

Carolyn

The Pulsation Damper Is located on the front of the main Fuel Rail, below the Intake Manifold. You have a s4 so look for a plastic cap at the front of It. It's primary concern Is to smooth out the Incoming fuel prior to distribution to the Injectors.

Mazda noted the Infamous PD's with the s5's by loosing the screw thats used to keep the diaphram In place. However, I hear that s5's fail occasionally too. When the PD starts leaking, chances are the screw Is working It's way out or gone all together.

When my PD failed, I simply put the screw back In and gave It a touch of Silicone RTV. It's been fine for the last 3yrs...

An S-5 is a what?
 

What is an S-5 please?

S5 is an rx-7 from the years 89-91
s4 86-88

Thanks
 

Then I have an S4 as mine is or was an 87. Going to look at in the daylight today. That and increase my insurance on it before it's too late.

If you can, pop off the cap to see the state of the screw. ie. If It's backed off or not.

If you don't smell gas, the PD is Ok. If it leaks, you WILL smell it.

Few wires to the intake carry enough current to get hot.
Bad or just corroded grounds can cause the remaining grounds (usually black wires) to carry the extra load.

I would start by cleaning & resecuring the main battery ground to the starter and the accessory ground from the bellhousing to the firewall.

BTW - I took my own advice about grounding last week and it fixed an intermittant idle problem.

Looks like it's time to get dirty and start studing diagrams. No gasoline smell. Wire is black. Only see two wires coming off intake manifold. One side, one front (burnt one), both black. What does the hose in the front of the intake manifold connect to? Water pump or alternator? Water pump doesn't make sense. Off to the books.

Is there a good site for a manual for the 87? I have the Haynes book.

so it sounds like it wasn't the intake manifold on fire, but just a couple of wires that shorted out???

can you take a picture of where that fire was? that would help

I have a mirror FTP site with the complete Factory Shop Manuals. The link is in my sig below.

Don't have a picture yet but the manual calls the part, the air control valve. It's the front electrical connector of the air control valve (split air solenoid valve appears to be the name of the connector) that was on fire.

I'm checking with the dealer to see if there was a recall for this car. Waiting to hear back.

Something is screwy.
Those solenoids run on low current directly from the ECU (computer).
Even a direct short should in the solinoid not burn the wire.
You would just get a "check engine" light.
I assume you have looked around that area for any other signs of bare or shorted wiring

That was kinda funny.. "yes it was hot".. it was just on fire.

Okay. You got me. But they asked if the wire got hot.

Thanks. I needed to laugh too!

There have been no recalls on the S4 (86-88) RX-7s

Okay. I think I'm getting somewhere here. The wire has it's covering off from the fire. There is a black wire and a white wire inside. And one of them is bare and frayed, if not broken.

My assumption is to disconnect the battery. See if the wire can be spliced? Cover bare wire with electrical tape. Or replace air contol valve for $386.50.