TOPIC: no mileage or performance gains from grooved car

I am from Lancaster, Pa. & have a 1997 Chrysler Cirrus with a 2.5l v6 with 204,000 miles. I had gadgetman Nick groove the throttle body I sent him.I installed the grooved t.b., I checked & repaired some vaccuum leaks, plugged & rerouted the pcv, reset the e.c.u.I even tried plugging all the emission lines. I tried with a cold air intake & with the stock air cleaner, with & without the volo chip & with and without hho.The only thing I noticed was a whistling noise at part throttle.The best mileage I seem to get is with the cold air intake & with hho.My o2 sensors were replaced about 75,000 miles ago.My vaccuum is 19" at idle.Does anyone have any other ideas?
Thanks,
Gordy

post your fuel trims long and short idle and 1700 rpms o2s could be slow o2s are the fuel controllers.

Hi Gordy,

Your engine has an Idle Air Control intake, from the part itself I cannot tell if
the air intake is routed through the TB or a seperate air intake line.

At some point, before or after that air flow has to be minimized to 1/8".

That should also kick your manifold vacuum up between 20" and 21".

Karl Fortner
Tacoma, Washington

Also, being that you're in Pa. and it does get really cold there, you'll want to be able to fit it in such a way that you can insert a "restrictor" with different hole size so you can adjust for the cold. Colder it gets, the more that IAC is going to want to work until the engine is warmed up. You do sound like your an experimenter so if you come up with some stats using different hole sizes at the differing temperatures it would be good info to post here on the forum.

Karl Fortner
Tacoma, Washington

Some background on the modification:

Gordy's Cirrus got the full mod including the intake air reduction and re-routing. If there is idle issues when it's cold out, Gordy has been instructed to increase the idle with the idle adjustment screw.

One question Gordy, how many tanks of gas did you run through the modified set up before you determined you had no gains? Sometimes it takes a few before the computer adjusts to the changes.

If you could get the before and after fuel trims, as Dan requested, that would also tell the story as to how the computer is responding.

There are a couple more stones to turn over.

Hi Karl,
Nick did do the idle air mod, so I am taking that it is in the t.b.How would you minimize it to 1/8"?

Gordy

How do you make this restrictor?It is starting to get a little colder here.What is the purpose of the IAC?

Gordy

Hi Gordy,

THe Idle Air Control takes care of the engine idle at warmup, th ecu will open the valve at startup and close it down as needed to maintain a proper idle. Once the engine is warmed up the ecu will either close the IAC valve completely or minimize the opening to maintain the idle rpm.

Pretty much a high-tech replacement for a choke on a carburetor.

Since Nick did the IAC mod so it would already be at the correct size and it sounds like it goes thru the TB.

Being that Nick did the mod for you it would be good to work with him on it so the information stays first hand.

Karl Fortner
Tacoma, Washington

I agree with Dan here, Gordy. We need to see fuel trims. With 75K on the O2's, they are likely slow, I would suspect 'em. Nick does first-class work definitely work w/ him!

TracyG Gadgetman Reno

Hi Dan,
I set 2 x gauges for short & long term fuel trims and checked them at idle and at 1700.Short at idle between -4 to 7, at 1700 between -4 to 7.Long term at idle 4 to 5, 1700 -4 to 12.How do you correctly check for these fuel trims?They seem to be all over the place.Do you check with the engine cold or warmed up?Do I need to set fuel trims for all banks or just 1?
Thanks,
Gordy

Hi Nick,
I ran through 2 tanks before switching back.I could always try 3 tanks.

Gordy

Gordy,it looks like ecu is learning,however reset ecu disconnect batt again this will restart things again but will learn much quicker.
The short teaches the long think of the long as a hard drive and shorts software teachers.
The way to tell if the ecu is learning is the longs will not change very swiftly but the shorts are in flashes.The minute you start up, the ecu will read longs neg when the ecu is conditioned.
Don`t give up you are close,remember you add the shorts and long to determine how much raw fuel is taken away. The max is 50% without a code. Another check is at 70 mph the ecu will shorten the time in milseconds the injectors are on.

Dan Gadgetman Mo.