HCSKnight

1988 with about 65k on the engine. Never had any issues up til now & cant figure this one out.

Engine starts, but takes a bit of gas to get running; idles high, RPM about 3-4000.

As soon as you give it gas it coughs & almost stalls out. If you give it more gas it pushes through the stalling and runs & you can drive it; but moving off the stop requires giving it an almost full pedal and pushing it through the cough/RPM drop.

After about 5min/warmed up she idles & runs normally.

First time this occured I took a look around the engine and noticed the air filter rubber had melted. Litterally there was a semi-liquid puddle of rubber in the airfilter compartment.

Also, I had put a fuel injector cleaner & an octane booster in prior to this occuring; however there were no problems after doing so & I doubt doing so created this latest issue.

Hoping someone would have ideas of what is going on &/or how to fix.

Thanks,

Joe

Ice_Wolf

Are you positive that it's the air filter rubber that's melted? That's really odd that something like that would happen. For it to melt, you'd need some pretty damn hot temperatures there. The only thing I can think of right now is that since it was so hot in that area that it could have melted one of the wires on the AFM and maybe that's what is making the car run so goofy. Also, why the hell did you put octane booster in your car?

HCSKnight

First off thanks for throwing out your thoughts.

I am 100% certain it was the airfilter rubber; it was litterally melting off the edges with strands of melted rubber sticking to the airfilter compartment when I pulled out the filter. Believe me I was surprised.

As for the booster, I dont know what I was thinking. In the short, the basic "hey it's a high RPM engine" that needs the RPM to really move the car. This might give it a bit more strength & kick on the lower end...? Really didnt think it would work, but didnt think it would hurt to throw it in & see if it did change the perfomance.

What's the AFM? Also, all the melting took place inside the airfilter compartment; no melted wires or anything was seen anywhere in the engine.

Tx again.

JD

Ice_Wolf

Yea, that is very very odd that the air filter would do that. I seriously can't imagine that would make it that hot inside the air box that the rubber would melt. Even pulling hot air in through the intake won't do that, seems like you'd need some sort of fire. I know it sounds funny, but that's a really crazy issue.

The octane booster will raise the octane rating of the fuel. There's absolutely no reason to do this on a N/A, and especially if you're running pre-mix. Running a higher octane fuel on a car that doesn't need it is pointless. Most of the time, it is used on higher compression engines. If you had a TII with some mods, you could get away with using 91 I'm sure, but on a N/A, 87 will do perfectly well. I run 87 + premix in my N/A with some mods, and it works perfectly well.

The AFM works the the same way as a MAF in the fact that it tells the ECU how dense, the temperature, etc. of the air that's coming into the engine. If this sensor is reading incorrectly, the ECU may overcorrect and add too much or too little fuel, which would obviously cause the engine to run incorrectly. You can find the AFM plugged into the right side of the airbox. I'd get a multimeter and check the AFM just to make sure that it's not malfunctioning. If something was hot enough to melt the air filter rubber, it could have possibly messed with the AFM too.

Rickyw

guys its true. I posted that i needed some help last night. I just finished taking apart my whole intake set up and doing pics I will post them up later tonight. The rubber litterally melted and went through the AFM and was causing it to have alot of resistance when closing back up and causing the engine to flood some times. Like i said i will post pics. RIGHT NOW i need to get some quick help from everyone:-D

texFCturboII

iTrader: (17)

AFM is the air flow meter, it tells the ECU how much air is coming in; it is located just behind the air filter. It looks like a simple connector piece, if you didn't know what it was you would probably just mistake it for plumbing, except for the tell tale sensor wires coming off of it. So ricky, the AFM was messed up from that huh? This would be the third time then that I've heard of this before.

jgonzales

The rubber melted around the air filter on mine too, still not really sure what caused it because I haven't had time to mess with it... I searched a week or two ago and found about 5 more posts that mentioned something about the air filter rubber melting. Nobody knew what caused it though.

Rickyw

ya it was tex you wouldnt happn to have a wiring diagram for the connector would you? as far as on the inside?

Chief

just curious, but are you fellas sure it was heat that melted the rubber and not chemicals?

texFCturboII

iTrader: (17)

I don't know what chemical you would put on your air filter. Rick, go here: http://www.rotaryheads.com/PDF/2nd_gen/ there ya go! When you are done there you can go to rx7city.com and get yourself a FSM for your car, it's a great thing to have! BTW, is your seven a s4 or s5 (1986-88 or 89-91)?

Rickyw

s4 pictures are uploading and i will be posting them on my thread and on here so everyone can see what im talking about ITS BAD atleast on my car....

trainwreck517

iTrader: (1)

Well back to the issue, sounds like maybe a bad coolant temp sensor.. so runs like **** till the car warms up. Which is what your experiencing.

Try checking the engine codes, to see what you come up with.

Rickyw

for the none belivers

Rickyw

if you look at the filter in the first picture see something missing???!!!!

kontakt

IMHO that has a very chemically melted appearance.

Is it still gooier than it should be, or has the rubber fully re-hardened. It looks shiny.

Edit: Also... why is your lampshade still wrapped in plastic?

Rickyw

Now if someone can show me a pciture of a properly hooked up AFM

this is what it looks like under the black Cap




I need one from someone else so i can compare

ya it does i wonder what happened i dont really know what happened alli know is it did....

Stanis

iTrader: (2)

When I got my FC back in 2000, it had that very same goo all over the filter box and on the inside of the compartment under the filter box. No idea what from though. Perhaps a cheap air filter was used and the material just got hot enough to ooze.

cptpain

iTrader: (1)

i had the same problem in my 85 GSL-SE. i highly doubt its rubber, as when i touched the stuff it has the very same characteristics with a low-temp silicone paste that was aparently used to seal the filter.
it feels sticky, gooey, and very hard to clean, if not next to impossible.

the car runs like crap because the goo is not letting the flapper door not move freely, and only WOT will make it run normally.

the only way i fixed that problem was got a new intake assembly and ran like a champ.

i wouldnt even bother trying to clean the AFM, but if you find some kind of cleaner that makes the gooey stuff come off easy and the AFM still works then you should make a separate thread and tell a mod to sticky it cause this is the 5th time someone other than me has had this problem

Rickyw

its actually kinda simple for the most part on the AFM i just need to go head and make sure my wires are done correctly on the actual sensor SOO if anyone can pop off there little black lid and make sure i got it right i would be happy to do a write up thread to the best of my ability

HCSKnight

Speaking for what happened to my air filter, it melted - not at all a chemical situation. The rubber was hot to the touch. And the pics posted by "Rickyw" looked exactly like what I found when I opened my air filter box. My airfilter did have considerably more rubber left around the edges though.

I have not taken my AFM apart, and quite frankly didnt know it was there so thanks for the education; regardless, from Rickyw's pics, the discussion in this thread & what I experienced it sounds very likely that the problem is the valve being gunked up by the melted rubber. It would explain why the problem goes away once the engine runs for a while; the engine gets warm and the rubber that melted & found it's way into the AFM gets warm again & as a result has less adhesion capability. Therefore the AFM valve moves more easily.....

Guess I have a project comming....

Rickyw, did you get your AFM cleaned out & did it get rid of the problem?

Tx to all for your posts & discussion; and especially Rickyw for the pics. Those things are worth far more than a thousand words. Great info & thanks again.

HCSKnight

Cptain - what is "WOT"? Tx

RETed

It has nothing to do with the air filter.
It looks like Mazda used some kinda sealant on the air filters.
I've seen this on many other FC's including mine.


-Ted