hpx maf blow thru wont start or idle?

[meet07]

Its a rb25det bored. 040 over with a set of wiseco's. Ring gap is set for turbo street/strip. Stock valves with a 5 angle valve job. I dont think its the engine since all I did was removed the cold pipe, and have the welder remove and add in a 12 inch piece where the old map was located. I even did a compression test to verify. Read 150 on all 6 (8.8.1 pistons) when I 1st installed the sensor I made changes to that vq map and decided to start from scratch. When I get home tonight I can post up my old bin with the lightning maf. I can also take some pics of the piping but ive looked and the inside looks just like the last flange and sensor did...bead on the top and little penetration on the inside.

This is what I did with the map:
Transfered my Fuel and timing map after changing injectors from factory(370) to 999 or 1000's. Then changed the maf from stock to hpx 3.0 tube. It took like 6 minutes for it to recognize it but it accepted it. I double checked it frequently during the tuning process. Bump k up to like 1000 to start and lowered it immediately b/c afrs where at 9. Still burning through thanks to the gm truck coil packs. Doing this I knew the k needed to b lowered and that I needed to increase the 1st time enrichment table. Zeroed out the warm table so I wouldnt have any interference adjusting the idle. Once warm I took it up and down the street. Immediately recognized crazy low afrs. Holding steady speed and rpm increased the k until I saw 14 or so. Noticed that one minute the afr would be around 14-13 and then letting off the gas, slowing down and picking back up speed it would be running lean again. The junk would kinda have a mind of its own....played with alot of othere things but thats just the basics of what I did.

[skylinegtrhr]

So Matt did You try HPX finally?

[Matt]

Was going to and cant find the damn connector for it. Been looking all weekend

[bachig24u]

no excuses!!

. just use a pc mlb front panel or mlb usb board connector.. standard pin spacing.

[Matt]

Yeah I know... honestly was looking everywhere. I'll have another look tonight since I dont feel like doing any software work

[Matt]

Finally found it... fitting in the morning

[Matt]

Okay its fitted finally using the 3" HPX tube on my R34

So far K required quite a bit of adjustment (double in fact) to get it running about right. The start of the VQ map has been bumped up to about 230 for the first few cells since the current default values are too low

Its fluctuating around idle which is why I adjusted the VQ map and flattened it to keep the injection consistent, cuts out on deceleration. Having another shot at it tomorrow but reving at idle seems to keep AFRs but holding shows some fluctuation

I'm thinking of relocating post turbo to resolve some of those issues but need a sandwich plate for my 2.25" piping

[meet07]

Update: took my car to a reputable tuner that has been playing with nistune for 6 years now. He talks good about this program but just like me he didn't feel comfortable putting it on the dyno. He actually used my exact words "It was acting stupid," and Wasn't reacting like it was suppose to. He might poke around this forum to gather some information but like I told him the person that put this program together can't even figure it out. What im having a hard time understanding is that others say " this sensor is awsome or it works great for me," but no one can post any proof or information on what they did. This is very aggrivation to spend $1000+ usd on this setup(untuned) and my car is still having issues. Im considering trashing this unit and upgrading to standalone if my tuner can't sort this out. Is there any information on making this maf work????

[bachig24u]

which (pins) did you use for the HPX? I've grouded both sensor and vehicle to ECU gnd.

[Matt]

Understand with the HPX that the calibration curves originally came by doubling the existing tables values but were not accurate enough so I could never get it running on the R31

Now since the VMP calculations were hacked I am able to put the better calibration curves in now but testing takes time and I dont have much available so only spent about an hour yesterday trying it out. The R34 has it fitted now instead and is revving up good at the moment on that VQ map but I feel there is too much fluctuation of air with the current positioning on my vehicle. Will continue tomorrow since most of today has been spent on software updates

[meet07]

Understand with the HPX that the calibration curves originally came by doubling the existing tables values but were not accurate enough so I could never get it running on the R31

Now since the VMP calculations were hacked I am able to put the better calibration curves in now but testing takes time and I dont have much available so only spent about an hour yesterday trying it out. The R34 has it fitted now instead and is revving up good at the moment on that VQ map but I feel there is too much fluctuation of air with the current positioning on my vehicle. Will continue tomorrow since most of today has been spent on software updates

How long before you get all the calibrations right?

[Matt]

Calibrations I believe are correct as another customer has used them but reported some issues with idle like I am also seeing

Bad calibrations show the AFRs going out of range at certain load areas. I'm seeing good AFRs at standstill but the airflow on decel causes stalling during the tests on Thursday. Had 6 ECUs arrive on Friday so that consumed most of the day fitting those

However existing calibrations need adjustment for the vehicle. Lower end has needed increasing to improve idle stability. I'm going to try for a blow through scenario but need to adjust the piping to suit on the vehicle firstly so planning that tomorrow assuming I dont get swamped

[meet07]

Ok. Currently my car is sitting at the shop and Im debating what I can do with this sensor and program. I really don't want to fork out anouther 2 grand on an AEM or Haltech unit...thats last resort if I can use what I have.

[bachig24u]

use a diablo maf extended and new lightning MAF or bite the bullet and get a speed density system installed. You won't be disappointed, either way, just out of pocket.
If you still experience the same issues then the problem will be more obvious.

[meet07]

use a diablo maf extended and new lightning MAF or bite the bullet and get a speed density system installed. You won't be disappointed, either way, just out of pocket.
If you still experience the same issues then the problem will be more obvious.

Yeah I was looking into that. The prices seem to be somewhere around $2-$300 dollars and once again I'm not spending another dime on this software program. I more than likely will b forced to go back with the lightning maf. I read a little about guys adding like 2 resistors on the signal wire that leads back to the ecu. A 1 and 4 ohm resitor is suppose to limit the maximum 5 volts to like 4 volts. I'll also be setting. It up as draw through, hoping that one day soon this hpx maf will one day work as smooth as the all the other mafa this program supports....Don't really like being tbe guinea pig.....