Mis Fire and Back Fire
 

I took my car out on Sunday, it was quite hot, got stuck behind a parade when I got past it the motor started to misfire took the car home. Started it up a few hours later everything was fine. Started it tonight, it back fired slight smell like catylictic convertor check engine light came on, rough idle , drove it a mile or two seemed ok, then occasional misfire and rough idle check engine light still on. Injectors, O2 sensor?

Re: Mis Fire and Back Fire
 

Howdy Neighbor!!

First thing to check is the MAP sensor hose.
It's behind the plenum on the drivers side.
A backfire will nearly always cause it to pop off.
Usually the car will run rough and smoke a lot with the MAP sensor hose off.
Check it first before we try to diagnose the misfire.

I'm only an hour or so away on the other side of Sacratomato. I'd be glad to lend a hand if you need it.

Tom
'Crabs

Re: Mis Fire and Back Fire
 

Hello Tom, couldnt find the map sensor hose, what diameter is it? Would appreciate some help, thx for the offer, Im just off of Hwy 12 between Santa Rosa Sebastopol.

Thx Richard

Re: Mis Fire and Back Fire
 

The MAP sensor hose is attached to the bottom of the sensor. It's hard to see it. You will have to remove the whole MAP sensor bracket with the MAP sensor attached to really see it and re-attach it if the hose has come off. Here is a picture:

http://i13.photobucket.com/albums/a2...oprearview.jpg

Re: Mis Fire and Back Fire
 

You can get to the hose by reaching from the passenger side, but its really tight. It probably has years of oil accumulation in it, I know mine did. I would take it off and clean it well before reinstalling it. Not to hijack this thread, but does anyone know where can you buy these replacement hoses?

Jason

Re: Mis Fire and Back Fire
 

remember you can build s new one fpr about 10 a the local parts store . they sell the plastic tubing in pkgs you get a wound up abot a ft long you can by one pkg of ends that will work with both ends for 4.99 .use a hairdryer to bend the tubing .very lightly or you burn it up .i just set the dryer over the end of my workbench turn it on low and behold the tubing will bend . alot of guys also use rubber tubing .i just like using the plastic and ends for a line that spends its life in an oven.:mrgreen:

Re: Mis Fire and Back Fire
 

Thx guys I'll take a look tonight!
Richard

Re: Mis Fire and Back Fire
 

FWIW here is another view. I used these spring clamps. They've never come off since.
But then I'm not convinced this is your car's problem. Yet, it is the place to start as was said.
http://home.comcast.net/%7Escottfab/...s/MVC-217S.JPG

Re: Mis Fire and Back Fire
 

I agree, it does sound like he's got other problems, injectors most likely.
But since it had backfired, the MAP sensor needs to be addressed first.
I figured we'd start with the basics and work from there.

Richard, tell us more about your car, year, mods, mileage, the usual stuff.
If it's a '90 or '91 and still has original injectors, it's more than likely time to replace them.
If they've been replaced, the likely suspects are coils, spark plugs, spark plug wires, O2 sensors and on and on and on.
I'm not available this weekend (Mothers Day and all), but next weekend is open (for now, but gotta check with "She Who Is To Be Obeyed").
After that, my next free weekend doesn't happen until June.

TomC
'Crabs

Re: Mis Fire and Back Fire
 

Like I said "Yet it is the place to start like someone said".

My gut says following a parade got the coils hot enough for failure.
Not based on data, just hunch and description. Hope not for his sake.