Questions on my new VX

[andy454]

I f you are getting that low of milage than you need to take it in and have the technician look at the fuel trims. This will tell you if the vehicle is running rich and trying to pull fuel from the cell. Here is how the block learn works. You have a 3d fuel map in the calibration that has values for ms injector pulse time. Based on feedback from the o2 sensors this value can be made positive or negative. Positive means it is adding fuel to that particular cell in the fuel map and the oppisite if the numbers are neg. It should be able to keep the fueling normal unless the trim values max out. You may also want to to take a look at the baro reading and coolant temp reaging. Not the one on your dash, but internal to the pcm. If the coolant temp is wacked it could be reading off of a coolant comp map that would be adding fuel for a really cold situation. Just a few things to try.

[Moncha]

VVVVVVVVRRRRRRRRROOOOOOOOOMMMMMMM!!!!!


That was the sound of that post going over my head!!
I'm not technically challenged but..... :winkg:

[andy454]

Sorry Scott
I sometimes get into fueling a little too much. There are two fuel corrections the pcm can make to the final fueling. One is short term and one is long term. The short term is correcting the fueling right now. The long term value is corrected form the short term value. So if short term is -15 this means that is is taking away 15ms of fuel from the base fuel for that particular cell in the fuel map. If this # stays at the -15 for a calibrated amount of time it will start to change the long term value to a -15. After this happens the short term will count back up and should get back to near 0. Now the long term is -15 and the short term is 0. This would tell you that the enine is running a little rich but was able to correct for it. I would like to see the long near 0.
+- 5. Hope this helps

[Moncha]

There you have it! Take this info to your local technician.. Of course, the tech will freak but at least you have some ammo..

Thanks Andy!

[Zu4two]

I've got a question for you Andy. I have a supercharger on my 3.5, and am worried about running too lean and blowing up the motor. Is there a way to see just how much "headroom" the injectors have by checking the long term trim value you mention above?

A while back, there was some talk about injector size for our engines. Is it true that they are only 200cc units? This seems a little small compared to the 400-550cc injectors they're running on Hondas.

A local tuning shop told me that they could "splice" an aftermarket AFC unit into my PCM and get me the adjustability to run higher boost (more fuel). Is there any way to hack the OEM fuel maps?

I wonder if Isuzu ever thought people would be hot rodding their motors!

Thanks for all your valuable knowledge.

Kirk

[Tone]

I’m running 5lbs of boost and still running rich. The 19lb stock injectors can handle boost up to about 10 PSI IF the ECU can be tweaked which is possible with a product called the UniChip that may be included on stage kits in the future from Alpine.

[valenki]

Thanks to everyone for your help, especially Moncha for helping me with the forum.

I use 87 octane gas and I buy it from the same people for over 6 years.
I drive like an old lady, cause I had my license suspended for 1 year and I just got it back feb 14. 1 more ticket and they ''ll have it again . I start off very slowly at the lights and use cruise all the time on the highway set on 64.

With the STP I went 340 miles on 18.7 gallons which means my MPG was ~18 , for me that was a significant gain. I am not sure if STP gas treatment did the job or some other variables are at hand, but there you go.

Also, I have a delema. My air filter looks very new. I am wondering if I should put in a K&N or Calmani?? What will give me better fuel economy?

And to those of you who have an air intake mod, where do you get them, S or calmini and how did it impact you MPG ??

What kind of spark plugs are you guys using?? After changing the factory ones, did you see any change in MPG? Any one tried ultra-sonic plugs on their VX's ???

Thanks for your time guys