Monsterbox

iTrader: (6)

my car is completely stock aside from m2 downpipe...everything runs great except when the throttle is blipped upon idle it tends to drop way down and try to recover while spitting black smoke

- problem

when i am driving the car seems normal and people following me say they car sounds and drives great. However, when i get on the throttle and hit full boost 10-11(due to dp) people driving behind me say the car smells like a tractor or gas pump..ive had plenty of friends inluding knowledgable car gurus say that the smell of fuel is very overwhelming from behind when i am boosting

- are 13b's supposed to run really rich underboost? Is my ecu dumping fuel ( i know in the mr2 if u pass through the boost cut it will just plain dump tons of fuel) Do i hav an emissions problem with my airpump, o2 sensor, or main-cat...would hooking up an AFR gauge to the stock o2 sensor yeild anything..i hav one i just havent set it up

Thankyou

Mahjik

iTrader: (1)

Here's where I would start:

1. Check the operation of the airpump to make sure it's working

2. Check the vacuum routing for the ACV to make sure it's correct

other things to consider:

1. TPS adjustment (make sure it's withing range)

2. Check spark plugs (replace if needed)

3. Check O2 sensor (replace if needed)

As for hooking an AFR gauge to the stock O2, that's not going to help.

Monsterbox

iTrader: (6)

wow..ok well ive had the car for 3 weeks so im very new to these complex twins...

first of all to tell u the truth i dont give a **** about emissions if the car just smells rich because of an emissions part gone bad i dont care all i care about is gas milage and performance...i want to find out if the engine is actually running richer or does it jjust smell rich due to worn emissions system?

- how do i check that the airpump is working? check to see that it hums with airfilter off? (how will this effect richness of the engine, i thought that it only effected emissions)

- ACV..is this the valve right near the stock bov that runs down to the twins?

- TPS (throttle position sensor im guessing?) where is this located what are the ranges?

- plugs have been replaced 250 miles ago

- how on earth do i know if the o2 sensor needs to be replaced?

- if the AFR gauge is hooked up it will at least show if the o2 sensor it working by picking up different ratios? if it stays static then it probably means the o2 sens. is bad or the engine isnt running right?

dgeesaman

iTrader: (7)

The stock O2 sensor is going to be extremely crude for measuring AFRs. The ACV is the valve tucked inside the LIM right alongside the injectors, with air hoses leading from the air pump, around the LIM, and into it.

There is a link to TPS adjustment in the FAQ. The TPS is on the rear of the throttle body.

Do you have a main cat? Do you have an airpump injecting air to it? If you do have both, then perhaps you have a secondary injector dumping fuel. These injectors do have issues more than most, and a testing/cleaning is a good thing to do. If you can borrow a wideband O2 setup that would be ideal.

Dave

Mahjik

iTrader: (1)

First off, download the FSM (Factory Service Manual):

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/94-fsms-available-download-449950/

You can find about 90% of anything you'll ever need in there.

The airpump injects air to the ACV. The stock ECU is already tuned for the little extra air that the airpump is supplying. If the airpump isn't working, the A/F mixture will be off causing an unstable idle (as well as less than ideal emissions control).

It's located on the inside of the LIM (lower intake manifold). You have to remove the UIM to get to it (and it's associated vacuum lines).

https://www.rx7club.com/3rd-generation-specific-1993-2002-16/fixed-my-idle-problems-backfiring-bucking-more-170731/

If you don't know when it was replaced, it's a good idea to go ahead and replace it (so you can start tracking your car's maintenance history). Bosch(sp?) has a $40 replacement you can get from AutoZone.

The stock O2 is a narrow band O2 sensor, it won't be able to give you enough information. Besides, you are on the stock ECU so it's not like you can just "program out some fuel" if that was the problem.

Mahjik

iTrader: (1)

Also you may check for an exhaust leak or failing cat. You are just going to have to break out the tools and start getting dirty.