Rx7TyreBurna

iTrader: (1)

Well, when i rev up, sitting in my car, and then let go of the accelerator, while the RPM's drop, it sounds like my car wants to die. It makes a slight pop pop sound out the exhaust.

Any other information I can provide?

Just weird while the car is dropping RPM. Wondering if it is anything familar.

Thanks.

vaughnc

Is it bucking? These cars have a de-celeartion system where the engine compresses air to help slow down the car when you let off the gas. As the car ages, sometimes the "anti-afterburn diaphram" on the ACV valve may start leaking leading to a slightly rougher transition from acceleration to deceleration. This is especially true with a high-flow exhaust, headers, and racing catalytic converter.

The car should decelerate smoothly from 8000rpms to 0800rpms. Popping in the exhaust is normal when shifting at higher RPMs or transitions from deceleration to acceleration.

Rx7TyreBurna

iTrader: (1)

Anti-afterburn diaphram? Hmmm, I will look into it.

ACV huh? Can I just replace the diaphram or do I need to replace the ACV all together?

Thanks! There is a good chance that might be what it is.

Wankel7

Search for Dashpot.

ViperDude152

Dashpot is only used to keep the plates from snapping shut and make a easier shut. It wont effect how the engine comes down from high rpms to idle.

if your engine is making a lot of poping noises while decelerating, check your TPS. If its to high in volts such as, set to over 1v while the plates are closed, the ECU wont shut the injectors off on decel like its supposed to. The TPS can become out of adjustment if you reset the idle in anyway.

You have an 88 so try making sure the TPS is set to "1K Ohm" at 750-800rpm while the engine is at operating temps. This seems to work better on Series 4 engines. Having the TPS set to 1v seems to work better for S5 engines or atleast engines with S5 TBs. Why? I dunno. This is just what I have oberserved.

Rx7TyreBurna

iTrader: (1)

Hey, thanks ViperDude. I will take a look at my TPS.

Thanks to everyone for all input.

JCurry

iTrader: (6)

how are u guys with tmic's setting your tps while the car is running?

My5ABaby

iTrader: (7)

Doesn't need to be running, just warm.

SpAm@FC

iTrader: (4)

make the right tool

i've took a big screwdriver, cuted it into 2 pices, took a nail and welded it between the 2 srewdriverpieces

long enough to geh under the IC to the screw...
to check the TPS setting i use the 2-led-method

works fine and takes 1minute to adjust that sing perfectly

SpAm@FC

iTrader: (4)

make the right tool

i've took a big screwdriver, cuted it into 2 pices, took a nail and welded it between the 2 srewdriverpieces

long enough to geh under the IC to the screw...
to check the TPS setting i use the 2-led-method

works fine and takes 1minute to adjust that thing perfectly

lupin

iTrader: (3)

If you need new aircheckvalves I have a set I will sell for $40 shipped

ViperDude152

Your welcome. Give that a try and see if it works. If not. You have just crossed one item off a very large list