Strange rev range issue

ihiryu · Post by **ihiryu** » Wed Jul 13, 2016 10:10 am

2016-06-28_15.32.07.msl

dakota.msq

Hey guys, I'm lost on this car.

3000GT VR4 running a MS3 + MSX

I installed it this way
http://www.3si.org/forum/f103/megasquir ... de-715938/

Internally stock motor, stock turbos,
RC 660cc
LS1 coils.

This car will NOT rev over 3700 regardless of what I do. I synced timing, and it's dead set on whatever I lock it to at idle.

It idles smooth, the moment I rev it up, it won't go past 3700. The car spits and sputters, and backfires like crazy.

No matter what I do to the ignition, or ve tables, it just doesn't do anything. I've tried turning all the ignition to 15 degrees, to 40 degrees, I've added, and removed fuel, and I cannot get this thing to work right!!!

Fuel pressure is good at 40 psi when I'm at this rev range.

I will pull of the MSQ in a bit, my laptop died, so it's currently on the charger.

billr · Post by **billr** » Wed Jul 13, 2016 11:49 am

That VE table is rather "lean". Is that one of the richer or leaner ones that you have tried? I'm thinking you are just too lean. I suggest setting "req_fuel" to the correctly calculate value and leaving it alone.

ihiryu · Post by **ihiryu** » Wed Jul 13, 2016 1:06 pm

This one is lean

Regardless of what I do to the 3700 portion of the table, I've tried as high as 180, and still get the same issue.

I've also dropped it as low as 60 (what I have in my idle tables) and same deal.

Every time a do a plug chop, the plugs come out looking black. I'm at the point, I'm going to send the injectors to RC and have them clean and flow test them. Since they are old.

billr · Post by **billr** » Wed Jul 13, 2016 2:51 pm

Have you checked timing on all the plugs (through whole rpm range)? Will it go over 3700 with no load? It may seem silly, but I gotta ask... what are compression readings like?

ihiryu · Post by **ihiryu** » Thu Jul 14, 2016 9:31 am

Compression is solid. And it will not rev over 3700 without load. I've checked for all the usual (Overrun fuel, launch etc), and they are all off.

What do you mean checking timing on all the plugs?

TheSilverBuick · Post by **TheSilverBuick** » Thu Jul 14, 2016 11:27 am

I'm at work so I cannot open the msq, but do you have any of the software noise filtering options turned on?

I once accidentally turned them on, when I didn't even have an issue, and from the arbitrary settings I had put in while on my couch and mistakenly uploaded to the car it would quit right at 4800rpm. Like clock work. The tooth logger showed a crystal clean pattern right up until there was zero teeth. I changed the sensor, adjusted my wiring, pulled my hair out, decided to "try" the software's noise filtering options and saw they were already turned on! Turned them off and VROOOM! So perhaps its something like this?

ihiryu · Post by **ihiryu** » Mon Jul 18, 2016 1:44 pm

The only thing I have on in Noise filtering (which is default) is Noise Filter Period which is set at 4. Then the Noise Curve Filter which is a 2D graph. These were all default when I got the unit.

Matt Cramer · Post by **Matt Cramer** » Tue Jul 19, 2016 6:06 am

What sort of O2 sensor are you using?

ihiryu · Post by **ihiryu** » Tue Jul 19, 2016 11:40 am

AEM wideband that currently isn't working right.

I just tried the whole MS on another 3000gt, and it won't even idle correctly. after changing everything. The main relay clicks like mad in this car.

I followed this guide in wiring it, and made adjustments for the LS coils (adding 3 channels and LS specific dwell etc)

http://www.3si.org/forum/f103/megasquir ... de-715938/

Matt Cramer · Post by **Matt Cramer** » Wed Jul 20, 2016 5:57 am

See if you can get a working wideband on there - O2 information will tell me more about the rev issue.

Also, is the timing consistent from idle to ~3000 RPM?

ihiryu · Post by **ihiryu** » Wed Jul 20, 2016 2:09 pm

There was a little timing drift as I rev'ed it up. Once I have the injectors back, I'll start working on the O2

93supercoupe · Post by **93supercoupe** » Thu Jul 21, 2016 5:10 am

ihiryu wrote:There was a little timing drift as I rev'ed it up. Once I have the injectors back, I'll start working on the O2

Get rid of the timing walk, you will end up chasing your tail with issues

But have checked to see if it's losing sync? Composite log?

DaveEFI · Post by **DaveEFI** » Thu Jul 21, 2016 6:07 am

ihiryu wrote:This one is lean

Regardless of what I do to the 3700 portion of the table, I've tried as high as 180, and still get the same issue.

I've also dropped it as low as 60 (what I have in my idle tables) and same deal.

Every time a do a plug chop, the plugs come out looking black. I'm at the point, I'm going to send the injectors to RC and have them clean and flow test them. Since they are old.

IMHO, you'd do best to start off with a TS generated VE table.

ihiryu · Post by **ihiryu** » Fri Jul 22, 2016 9:53 am

93supercoupe wrote:
ihiryu wrote:There was a little timing drift as I rev'ed it up. Once I have the injectors back, I'll start working on the O2
Get rid of the timing walk, you will end up chasing your tail with issues

But have checked to see if it's losing sync? Composite log?

Lost Sync Meter reads decently low most of the time. Maybe 1 at most. At times it has been really high randomly. I have replaced the CAS before and it didn't fix the problem.

How do I fix the timing walk? Is there a delay function?

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