Back after trading to the dark side (MY JEEP)..2G MAF question

[RHDgalantVR4]

Need to know what it's gonna take to hook up the 2G MAF and INJEN 2G intake I just purchased for my JDM? Is there any differance between the USDM and JDM VR4's wiring? Also what is it gonna take to vent to atmosphere without running into problems? Thanks in advance as it has been 2 years since I have even given my VR4 the time of day. /ubbthreads/images/graemlins/bawling.gif

 

[belize1334]

AFAIK the JDM Galants have the same MAF as the USDM so "hooking it up" is gonna be the same. You'll need the 2G MAF, a pipe that fits it, a filter, and a 1G-2G/3G/Evo adapter harness. But, getting your ECU chipped and compensating for the bigger MAF might be a different story.

 

[RHDgalantVR4]

I have it all ready to go. Not sure what to do about the ecu issue you speak of? What happens if I hook it up with out the ecu being chipped? Whats the difference between USDM and JDM ecu's? Been a while for me really rusty. Jeeps are easy VR4's not so much /ubbthreads/images/graemlins/smile.gif

 

[belize1334]

Same thing that happens with the USDM ecu if you don't have it chipped for a 2G maf. You'll run DANGEROUSLY lean. The 2G mas has a different calibration so you must compensate for it in the ecu or it won't run right.

 

[RHDgalantVR4]

So what do I have to do to make this work? My car has the YELLOW top injectors which I believe are 550's? and I spent a lot of money on the intake MAF and filter.

 

[AnotherNewb]

Here is a diagram on how to wire a 2g mas in a 1g car. Keep in mind that the 1g plug is the stock harness, if you are making an adapter harness. Or you can just buy a premade adapter harness from the sticky in the FS: section

Supposedly 550cc injectors make up for the lower reading from the 2g mas, but from experiance you need to have your ECU chipped. It makes a world of difference. Keydiver can socket your ECU and install a compensated chip.

Since you have a bunch of money tied up in the Injen intake and 2g mas you CAN'T vent to air. If you really want to VTA than you need to change to a GM mas with MAFT and set it up in a blow-through set up. Or you can switch to speed density.

There is/was an older MAFT in the FS: section for cheap.

 

[RHDgalantVR4]

"GM mas with MAFT and set it up in a blow-through set up. Or you can switch to speed density."

 

[belize1334]

The problem is that, while your 550cc injectors are ~20% bigger than what the ECU expects, the 2G MAS isn't 20% bigger than the 1G. It's "about" 20% in alot of places but it's not linear. That means that while the two effects may cancel to give you good AFRs in some regions, there will be other regions where your AFR is off. Also, these two effects end up putting your in the wrong load-row on the ECU which means that the timing is more aggressive than it should be. The point is, this was a common mod back in the pre-y2k era, but now there are better ways.

To do it RIGHT you need to have your chip adjusted to compensate for your injectors and your MAS. You'll have to do some research to determine whether this is possible on your ECU (I assume JDM ECU since you mentioned JDM in the original post). Contact Jeff (keydiver) Oberholtzer who runs DSMChips.com and inquire about a chip for your ECU / octane / etc.

 

I bought and run this setup currently in 1947, and also thought if I bought some 550cc injectors this would fix all. Wrong! I had all the hesitation and stalling you spoke of. So, I contact Jeff(who's a hell of a good guy), and get the 411 on sending my EcU to him for some Keydiver magic. Get my ECU back with the quickness( great turn around time), plug it in, and viola. 1947 runs better and smoother than ever. Worth every penny. You definitely need to recirculated your BOV though, or problems will persist. Good luck

 

JDM cars with yellow injectors are 510 cc not 550.

 

[steve]

Quoting Dbossman:
Get my ECU back with the quickness( great turn around time), plug it in, and viola.

 

^^ /ubbthreads/images/graemlins/rofl.gif Viola indeed! /ubbthreads/images/graemlins/rofl.gif

 

[belize1334]

[Cartman] I

 

[RHDgalantVR4]

Hooked up rec and car runs like it has never before. Waiting to see what its gonna take for jeff to fix my ECU so it runs even better /ubbthreads/images/graemlins/smile.gif

 

[AnotherNewb]

Yeeeaaaa You. Just wait till you get the ECU done. /ubbthreads/images/graemlins/devil.gif