hpx maf blow thru wont start or idle?

[meet07]

I swapped out my maxed out ford lightning maf for this hpx maf so I can hopefully drive my car and it will not start or idle?? what is suggested?

[Matt]

Adjust injection multiplier on auto until you can get it started using about 1/4 throttle. The estimated HP may not be close enough for it to be correct to start with

Make sure you are using 0.10.14 or later with the updated HPX VQ maps

[meet07]

What about the 10.19? I downloaded the 10.13r so ill update to the latest version. This morning I was able to get it started once or twice but I noticed the afm was reading low. Somewhere like 0.550 or something. Right before I swaped out my lightning maf I had it running like a dream. Afm for the lightning maf was reading like 1.2 or so. With this hpx maf the "K" was originally at 161 and I had to bring it up to like 1000 for it to even idle...and the idle was all over the place...like 15 to low 13's. It wouldnt start unless the injectors was seeing 50.00+ Not sure if thats normal but im just throwing out as much info since only a few has messed around with this maf

[Matt]

Have you got it plumbed in for suck through or blow through

I was going to do blow through on my R34 but the piping is only 2 1/4" which is too small for the sensor so going to make a sandwich plate perhaps. But now might just do suck through and see how that goes

[meet07]

Im doing blow through in a 3 inch pipe. The car starts and idle now after downloaded the most recent application but afr's still fluctuate quite a bit and there seem to be some sort of hicup or blip with the injectors as well. First time starts acts kinda funny to. For example at 80° 17 will get it started and anouther time 50 is what it takes to start. I hate to take it to a tuner and they pretty much tell me that they cant sort out the flaws and force me to dicth out anouther $1500 for aem or haltech....Im running low impedence 1000cc's injectors with a buikt rb25 bottom end. Ill go down the street at moderate throttle one way and the afrs are supper lean and coming back up there all of a sudden 14-13?

[meet07]

Matt...I got it to start and idle but I noticed when it gets around 78 degrees celsius the car starts to act a little more eratic. When I make a correction with the engine cold (10-70 C) the engine reacts great but after like 70 it keeps blipping from like 14.7-10.0. The injectors ms shown on the Consult View jumps from a 1.70/1.80 to a like 4.0+ and trys to stall. Sometimes it does stall...

any input?

[skylinegtrhr]

Im running low impedence 1000cc's injectors with a buikt rb25 bottom end.

Hi can You please post log and that base bin? And injectors are from which manufacturer?

I'm now in process of ordering HPX for 3 cars so would like to see if there is any issue with these AFM's

[Matt]

Let me wire it up Sunday on the R34 (suck through however) and see how it goes here

[skylinegtrhr]

Let me wire it up Sunday on the R34 (suck through however) and see how it goes here

Hi Matt, did You wire HPX?

[meet07]

Ill post it up later. This software program seems so mathematical. I adjusted my k constant for a decent idle(14-13 sometimes 12) and it was running really lean cruising around the highlighted cells. Then had to go back and lower the maf voltage at the idling voltage and lower since the k was raised. Ill post the log later today but it seems like tbr maf volateg needs some tweaking

Im running msd/ delphi injectors. I looked for a latency spec but couldnt find it. Plus I don't know the convert it to ms

[Matt]

Pouring down with rain all Sunday that the wiring never happened. Right going to try it now!

[meet07]

It at least gets my car started but like I stated before...This maf sucks with nistune in my opinion thus far. When I had my ford lightning maf, I dicked around with the program and pretty much street tuned it..

The bin I posted has:

-modified maf voltage(lowered all cells from 560 mV and under)
-pretty much tripled the k constant
-left the latency alone
-had to raise the min ttp at 1400 rpms + b/c when I held the rpm at idle it was showing like 19.0 AFRS
-started to lower the max ttp around boost(5,000rpms +) since the 1000cc injectors where pumping out 10.0 afr's. Not sure if this is the right approach but...
-zeroed out the warm up table from like 60 degrees and up so I could make sure the k would act right
-load scale was maxing out around 67-70 or so, s I pretty much raised it to like 80 since I was hitting around 17psi and expect to raise it....

All in all it works but this maf and program is a royal pain and my car idles like crap....whole engine shakes and it didnt do that with the ford lightning maf. I had to cancel my oppointment with the tuner b/c I was on call at work over the weekend but im definetly getting it tuned this coming saturday. We will see how it goes...

[bachig24u]

I tend to disagree, HPX, works with Nistune flawlessly.

idle can be a little challenging at times but it really varies on the mechanical setup.
I can take a few good batterries to get idle sorted though!!

As the HPX has such huge scope, no one VQ table will suit two cars alike.
just varying the position in the housing by as little as 0.25mm (gasket or sealant), even rotating the housing a 1/8 turn can cause a different idle characteristic.

if K was trippled, consider changing the VQ as I think your injector/MAF combo is just about close to stock.

[meet07]

I changed the vq. Look at the attachment. The afrs are all over the place at idle and there is a blip at idle. If you would like I could make a video. Like I said...before this hpx I had the frod lightning maf and it was fairly easy to tune. I even tuned the lightning maf with my old turbo setup with no issues. It shouldnt take that much work to get this thing to idle. If you can give me some more info that can help I would appreciate it but im not seeing it. I won't. Be messing with the tune anymore this week. Im just gonna let the tuner figure it out. Im not sure about your setup or setups you have ran with the hpx but I havnt seen anyone using nistune yet with a somewhat ballzy setup trying to make big power. Every ones setup pretty much looks the same....

[bachig24u]

If the idle isn't stable by fixing areas around idle in the VQ table then other compensations are taking affect or the motor is just really loose until warm (large cams can do this also). What are the clearances on the top piston rings? Cam profile? alot of overlap can play havoc on a Large MAF in Blow through in a pissy small tube.


If you seem to get varying results maybe the MAF is dodgy or warmup compensations are affecting the injection pulse or flow through the MAF housing is not smooth, laminar screens may help.
Compare Inj Pulse (old MAF to new MAF) and you'll have a good idea of whats needs adjusting.

not sure why balzy/power has any relevance here, but since you brought it up, I have only installed the hpx MAF if the engine will use the CFM it can measure.

This issue requires logs before and after the changes made. try and supply your logs/address/bin files from both setups and we may see something thats been overlooked.