More ?'s

***907DAVE*** · #1 Fri, November 27th, 2009, 08:32 PM

Alright got a couple more for ya:

What is the reason for the reflash when installing a LL injector in #8?

What happens when a regular injector is installed in #8 with the reflash?

What are the effects of the blue CMP sensor?
I have read that timing will be retarded when using it but cannot understand why.

Let me explain, I have been chasing a random miss on the # 8 cyl. The miss is only noticeable @ idle and comes and goes with a rhythm to it. I was thinking/ reading about IPR duty cycle being to high(dual hpop's). Also read about people experiencing this with the "new" gray cps which I currently have. I purchased the blue on from international remembering the fad from a couple years ago, only to discover that there were alleged issues with them. Then started thinking about the reflash for the LL, and curious what changes were needed. WOW... a little jumbled but hope it makes sense.

***Power Hungry*** · #2 Sat, November 28th, 2009, 02:16 AM

There is almost zero change between the LL8 and non-LL8 programs. In fact, the reflash can be (and often is) used whether or not you had the LL8 injector installed.

The reason for the blue CPS timing shift may be related to how the sensors are manufactured, with some folks speculating that the output signal from the sensor is not quite as strong as the black CPS while other think it might just be that the inductor is shifted a little bit in the sensor housing. I don't think anyone really has an answer on that.

Not sure what the cause for your miss is. Can you isolate it to a specific cylinder?

***907DAVE*** · #3 Sat, November 28th, 2009, 02:28 AM

It is consistently #8 cyl. Strange because it only happens when warm, I have changed injectors thinking it was a worn poppet, but there was no noticeable change. Whats even stranger is how it "rolls through" the miss. Like it runs smooth than will miss for a few seconds than run smooth again. But sometimes it will be a steady miss. I have a couple programs with reduced ICP duty cycle than I will try and see if I can get a change. But all this talk of the grey CPS causing a miss on #8 got me wondering if this could be my issue.

***907DAVE*** · #4 Sat, November 28th, 2009, 09:46 PM

Well here's a video. This is the best I can get it with dropping ICP duty cycle. Kinda hard to tell from the vid but listen closely.

***907DAVE*** · #5 Sat, November 28th, 2009, 09:59 PM

Sweet.... got it working now, thanks Bill!

After many attempts I have been able to get the idle pretty smooth by dropping ICP + duty cycle+ PW just a tad at idle.

Why is this?

***cleatus12r*** · #6 Sun, December 6th, 2009, 03:45 PM

My guess is that the maps you listed are just a bit too "much" for a desired idle speed of whatever is programmed. When the maps ask for too much of something but the idle speed is commanded to be lower than what is able to be maintained with the higher PW in the map the PCM constantly tries to correct itself. There's a reason the "lope" tune works the way it does......

By the way, have you adjusted any parameters that I listed above?

***907DAVE*** · #7 Sun, December 6th, 2009, 05:12 PM

Quote:

Originally Posted by cleatus12r

By the way, have you adjusted any parameters that I listed above?

No.. have not yet. I put the scanner on the other day and all I had left was 2 codes for the AIH. Finally got rid of the #8 cct code( damn cps). So those two are next on the list.

What is PW at idle for stock single shot trucks?

Had one in the shop the other day and put the scanner on it to take a peek and it showed around 1.1-1.3 and 650 ICP at idle. Mine shows way more.

hayjayhorses · #8 Fri, March 12th, 2010, 07:47 AM

I am pretty sure my '99 F450 and '00 F550 do the same thing I always just thought it was some kind of load surge on the engine like A/C cycling on and off or somthing like that.