Help with INT-X Idle
 

Hey guys,

Just wondering if I could ask you a few questions and get your insight on something.

I just finished installing a turbo on my 8, using a GT35R, and a Microtech (INT-X).

I am having some issues getting it idling. I got the INT-X from Kane, and he had a preloaded map on it. It basically idles perfect for about 3 seconds, at -20Hg, then spikes to about -5HG and stalls for no apparent reason. Im leaning towards a vacuum leak, but I cant seem to find anywhere it would be leaking. I am thinking of taking my UIM back off to see if I missed any hoses anywhere...

I have tried playing with the fuel and timing at idle, getting marginal improvements (it will idle for maybe twice as long before it dies) but nothing to celebrate about.

Also, when I try to hold the revs at 3k for example, it will hold there for about a second, then although i don't move my foot, it just drops to almost stalling, catches, then the revs fly back up to 3+.

My injectors are 290cc P1's 650cc P2's and 650cc S's


I have screen shots of my maps, and two logs. One of the logs I was lucky enough to catch it go through a series of idling, almost stalling, recovering, idling, almost stalling, recovering, etc..

I am at a buddies house now, but I can post them up when I get home.

Let me know what you guys think.

Thanks!

-Bryan

My major complaint with the int-x and why I went with the AP eventually was because the idle was never perfect. The best I could do was to have it running around 13.5 afr and put up with the cycling.

The microtech unit does not have the ability to run negative split and that is, my my weak understanding, the reason you have to run so rich. The cycling may be another issue, but be exaserbated by the pig richness.

Whats the A/F it's trying to idle at? It should idle with a vac leak...so it's likely the Microtech settings that need adjusting. If it's the stock map it was likely running with 650 primaries..so you likely need a lot more fuel

Its pretty rich, around the 12.5 mark.

And i'm still running stock primary ones

Post up a screen shot of the idle/Aux screen...

So the "perfect idle" is at startup? (first 20 sec or so)?

My be a rehash but I'll offer it anyway.

INTx will add a customizable amount of fuel for the first 20 sec of startup to aid in the starting process. After that it will drop the additional fuel and revert back to table operation.

Intx loves to run rich and is pretty much the only way to get a stable idle out of it.

I suggest adding a good amount of fuel all across your idle map and seeing if you can just get it to not stall. From there you can work on triming it back to be a little leaner

Are you in Matrix Mode?

The only way I could get a good idel - was to zero out the Air and Water Map - do the idle and first load map since the Int-X will toggle between them at idle - and get to 12.4-12.6 with everything off - then when the fans or ac cycled it would not stall.

Then go back and try to adjust your Air and Water maps to get the best you can - overall it sucks; and I never liked the idle I could get.

Im not in matrix mode. The idle lasts maybe 2 seconds. I will post up a pic of the Idle screen, and I will add fuel across the board to see how she runs.

I would recommend you go to matrix mode.

Either way set your air and water temps up across the board to 0 - go to your idle map add some fuel. Also look at the bottom righthand window where it tells you what map your on and see if it says IDLE or RPM Cruise, Load or TPS Cal etc... when it dies.

finally have some time today to work on the car, I will post up my ignition maps shortly. Under positive load it runs well, rich, but runs ok.

Still wont idle well, I will post up what I have thus far. I got the idle working once, but it was idling at 10.5:1 which was crazy rich.

So give me 10 min and I will post a whole bunch of info up. Again, thanks for the help guys

good to see you are up and running . When is the dyno ?:)

Are you having stalling just during the first 30 sec or so of the idle?

Or will it idle fine for like a minute then stall?

One problem I was having was it would want to stall for the first minute or so, but then if I kept it going and drove around for a bit then the idle was fine.

If this is happening to you you need to go to the auxillary options screen and change the startup fuel amount to something like 30% or 35%.

It will idle insanely rich (10.5-11) for the first minute or so but if you let it running it will calm down.

Another thing I found worked was to make the idle progressively rich.

So at 15mmHg it would idle at 12.5ish, but in the vacuum table I had it get richer and richer as it approached 0, so if it tried stall and got into 10 or 5mmHg it would dump a ton of fuel in and keep it from stalling.

In essence, if it tried to stall the INTx would give it an extra squirt of fuel to right it.

OK guys here is my maps. Let me know what you think in terms of getting this idle sorted. Once that is done I can drive it around and lean the rest out so its not so rich everywhere.

thanks alot guys!

http://i46.photobucket.com/albums/f1...don/table1.jpg
http://i46.photobucket.com/albums/f1...don/curve1.jpg

hmm,

Seems like no matter what fuel setting I use in idle it always does the same thing. I can load the NA map, and then load the one I posted, and then load one with fuel numbers in the 5's, and it still starts, runs for about 3 secs, then just dies.

Is there something else I could be missing?

Crank MAP?

Here's something to at least think about. I've never used Interceptor-X but I've used systems like Hondata (adjustable chip in Honda ECUs) and MAP ECU (Interceptor-X or E-manage style piggyback).

The long term driveability and reliability on those systems heavily depended on your ability to get the factory PCM's short term fuel trim to +/- 5% and long term fuel trim to maybe +/- 1-2%. If your trims are out of that range, the PCM is trying to "out learn" your tune over the long run. That's why people get so frustrated with these types of piggybacks (and switch to reflashed ECUs like AccessPort), at least on any modern PCM that relies on fuel trims. When your trims get close to "0" the PCM thinks that the emissions controls are functioning properly and doesn't try to "fight" you so much by changing the long term trim all the time.

What I would like to suggest is that you start reading your trims first. I'm not sure if the Interceptor can do that directly. Probably the most economical option is to invest in a hand-held OBD II scantool that can read engine sensors/PIDs. http://qualitytoolsforless.com/Produ...?ProductID=572 I have this one, but you can get one used, and any scanner that can read PIDs will work (besides scanning/erasing codes). You can then use that scanner on any other car you have at home if something is wrong, rather than just buying some Rx-8 specific software that is useless on your minivan or whatever.

What I do on Hondas is I reset the fuel trims (usually by disconnecting the battery). Then I start the car up and try to get it to idle. On a universal OBD II scanner you only want to log 1 or 2 PIDs at a time to keep your sample rate up (SAE specifies 5 total samples per second as the standard logging speed). So I log long term and short term trim and read them live. If the short term fuel trim is above about 5% I richen it up. If it is below -5% I lean it out. If the trims are in this range, the ECU usually doesn't build much long term trim and doesn't "fight" you.

Then you have to drive around under low load constantly logging only short term fuel trim. You adjust your fuel map under the various load points so that STFT never leaves the acceptable range. Then you have to do a series of cold starts and verify that your water temperature correction is correct and trims don't drift while the motor is cold. The final result should be that you can start the car up cold and drive it around under low load without ever seeing your trims leave the acceptable range.

At this point the PCM is much more likely to be 'happy' , so that when you do WOT tuning the ECU won't "fight" you and randomly start richening or leaning out the engine. This is the tuning strategy I have used successfully on a turbo Honda engine.

The Intx isn't piggybacking the ignition and injector signals....the stock PCM is not able to affect the stand alone functions of the Interceptor.......

My guess is the vacuum source for the Int-X is compromised.

I will have to check the vacuum signal. If I had a vacuum leak, wouldn't there also be a boost leak under load? I am getting pretty rock solid boost at least.

I will also play with the crank map

I'm going to take this intake manifold off now and see whats what, maybe I missed something, or pinched a gasket!

If it won't idle correctly, why are you going into boost?

had to drive it home from storage, didnt have a choice. Plus, its running fine outside of the idle.