Running waaay rich at idle. Backfiring.
 

So. I replaced my spark plugs in the TII a few days ago and ever since then, my car has been running way too freaking rich at idle. It's been backfiring a little bit at idle too. It sounds like a little intermittent burp every so often. If you look into the muffler, you can see a little blue flame that halfway pops out.

The exhaust reeks of raw fuel....

Icemark mentioned that the o2 sensor could be fragged or my spark plug wires are bad. Karack said the same thing about the plug wires. Any other causes for this problem?

are all the plugs firing?

all the plugs are firing. It almost seems like I'm not getting the timing split at idle. I'm not quite sure what to make of this problem.

Check the FPR vac hose.
If that hose come off the UIM nipple on a turbo, you go rich at idle & lean at boost.
Been there, done that.

Thanks sure shot. I'll check it out.

I'm thinking that my O2 sensor has something to do with it. I unplugged it completely and ran the car without it earlier today but it did nothing. That tells me that the O2 sensor is probably toast and contributing to the problem...

The FSM (S4 N/A) says to set 2 things to control idle mixture: TPS and variable resistor.

There a few main things that control injection amounts. These aren't only at idle.

Intake air temperature sensor (on AFM)
Atmospheric pressure sensor
Water thermo sensor
Throttle sensor
Boost sensor (Australia only)
Crank angle sensor
Ignition Coil
Variable resistor
AFM
O2 sensor

^ yeah....i'm running through all of those too.

Spark is controlled by the AFM, CAS, water thermo sensor, throttle sensor, and boost sensor.

Those sensors feed the control unit which tells the coils what to do.

Check those things to verify proper spark.

Yeah, but it is looking like that this is not just an idle issue, as from his description to me yesterday on the phone, it sounds like it is running rich all the time, not just at idle.

Ah, ok.

Then I'd go with the list of stuff that control injection amount listed earlier.

After speaking with Icemark over the phone, i've decided to just run withthe basics. first, the O2 sensor, then the TPS, and if those don't work, then i'm going to swap the injectors and check for vaccum leaks....

plug wires?

I'm getting spark.

While you're looking at the basics, when was the last time you replaced/cleaned the air filter?

I just replaced the element...it's a cheapo cone filter...

Do you have the spark plug wires going to the right place? :)

nah....I just toss em where ever... ;)

J/K

All the wires are in the right place. I made sure to check that first...

Damn, there's goes my brilliant inspiration idea for the day. THANKS FOR MAKING ME WASTE IT! :)

ya i had backfiring to after i had changed my sparks, then i looked at o2 sensor and it looked pretty :S so i changed it and no more flames! :) mine was just shooting them whenever i let off gas though.

Tony

did you
 

take of emmisions recycle system and stock exuast?

Yeah...it's an 87 TII with all emissions and rats nest removed open 2.5 inch single exhaust. It usually only backfired when I let off the throttle while it was under load.


OK...UPDATE

I replaced the freakin O2 sensor. The old one was totally fragged. The metal sheath around the sender was all exploded and shit, lol...

took about an hour to get the old sensor out. a bit of a tight fit in there if you're using a 22mm box-end...lol

So, all said and done, the problem mostly cleared up but the car still sounds the same. I'm going to run through some more shit when the temp cools down outside and see if I can readjust the TPS and check for vaccum leaks again.

Thanks guys!

Are you telling me it is possible to change that O2 sensor from under the car? My broken ABS pump blocks me from up top and I didn't even try to get to it from the bottom. It looked like an impossibility.

if you have an o2 sensor socket and a swivel extension you should be able to get to it from up top. I have nothing above my DP so I attacked the POS sensor with a 22mm box end...

damn, im having the opposite problem...fine one day, then the very next morning it just went so lean it wouldnt idle...had to turn up my SAFC...
the next day it got a little better, then did it again...
my SAFC is now at +20% at idle...
gots to have a massive VAC leak, so i do!

Could it be that one of the injectors is stuck open?