Touya

Ok, so today I noticed that for the past 7 months I have been driving my 91 N/A without a fuse in the Engine Fuse box for the ENg INJ. So I went and bought a 40 fuse just like in the FAQ picture for the 91. SO after letting it idle and some lihgt driving the car suddenly starts to backfire really loud, the exahust is louder and deeper as well, the car seems a little faster but I havn't wanted to push it. Should I take the 40 fuse out and run without it. I have a Bosal Brospeed dual exahust....some POS that was on the car when I bought it. Just wondering if i have just FUBAR'd my car by replacing the missing fuse. Does it just controle the secondary injectors, my 91 N/A has seemed since I got it slower than how people talk about them. At times not as fast as my ZX3 focus it feels like....any input?

Wizz

Odd. I would have thought the car wouldn't ever run with out that fuse installed.

Touya

thats what i thought, now i'm not sure exactly whats up, the Main fuse is also a 100 and not an 80....I need to have the whole ting looked at, any other reason it may be backfiring?

Touya

maybe its just me, but its sad when a post about if a car is worth 2k or not gets more input than a post about a serious tech problem.....oh well bump....i'm drunk and frustratred with the 7

RotaryEvolution

iTrader: (30)

91 didn't have 2 EGI fuses but i can't remember what that spot was for or if it even had a fuse there at all.

Bob_The_Normal

There is nothing in the EGI fuse spot... my fuse box cover has a / through a box for that spot's label...

You don't have the original fuse box cover?

--Gary

RotaryEvolution

iTrader: (30)

sounds like your catalytic converter went bye bye, your car should not be able to backfire with a still functioning cat which would explain why it has more power, backfires and is louder.

Bob_The_Normal

I dunno about that Karack, my cat was fine when I took a look at it and I get lots of backfiring/popping in my exhaust.

Not sure what is causing it right now... but I found the dashpot wasn't even TOUCHING the throttle today, so I adusted it... sure that wasn't helping. But it didn't fix the problem.

Anyway, back to this guy... it wouldn't matter if he put a fuse in the un-used EGI fuse spot... so it sounds like he put it somewhere that DID matter... but where?

What spot exactly did you put it in?

--Gary

Touya

when I looked at the 91 FAQ in the forum is shows a 30a EGI Comp 40a Eng Inj 30a head 80a main , a empty, 60a BTN and 30 a Retractor. I noticed I was missing the 40a Eng Inj and put a 40 a in the spot. there is a 100a in the main, the car ran without the fuse, I'll pull it tomarrow to see if that does anythinng, but then again, the car does seem slower without. Sorry i was bitchy, just drinking + problems again with the 7 when I get nothing fixed is piling up.


http://www.teamfc3s.org/forum/attach...&postid=190649

NZConvertible

The info and pic you posted in for an S4, not an S5. Go look at the fuse box diagrams on page T-13 of the Body Electrical chapter in the S5 FSM. You will see that you're not supposed to have a 40A EGI INJ fuse, and since there'll be nothing connected to the empty slot there's no point in putting a fuse in. You'll also see that you are supposed to have a 100A MAIN fuse, so do not put an 80A one in.

If the exhaust note is louder and deeper, then chances are something has happened in the exhaust, probably the cat. Exactly when does it backfire? At idle? Cruise? Trailing throttle? Decel? Full load?

Touya

backfires in Decel, i'll try to get under the car to check the exahust today. its still wet here.

NZConvertible

It just pops once or twice when you lift off? That's perfectly normal if the emission controls have been removed.

TiGeRC|aw

taken from mazdatrix.com

Air Control Valve
Large back-fire on deceleration and/or between shifts usually means this valve is "no good" especially on 79 & 80 RX7's.