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Scope Questions

17K views 135 replies 33 participants last post by  bbbxcursion 
#1 ·
What all is involved in scoping a truck? No bitching and arguing, just what is involved.
 
#3 ·
Yup, seems Luke is willing to toss out his scope and with Jody's permission I'll do it and video it (as usual) as long as it doesn't call for cutting or splicing wires or something like that.
 
#4 ·
An oscilloscope for starters...


no, but seriously :hehe:

you need to know WHAT you are going to scope...the approximate voltages which will be scoped...the approximate frequency of what you are going to scoped (ie, how "fast" does the signal repeat)...

other than that... a probe (or multiple probes) and a ground connection to the scope.

then a few years to figure it all out... :D
 
#5 ·
you need to know WHAT you are going to scope...the approximate voltages which will be scoped...the approximate frequency of what you are going to scoped (ie, how "fast" does the signal repeat)...

other than that... a probe (or multiple probes) and a ground connection to the scope.

then a few years to figure it all out... :D


I was informed today of an easier way. Information came from a guy that I pay money to weekly and he drives a truck that has alot of toys in it! Granted it's only a 2 channel but it will work for what I need at the moment.


Maintain....do you have a scope? Know some one that knows how to use one? If not don't bother....seriously.


Thanks Golfer for the other info....what kind of 4 channel scope are you using?
 
#6 ·
Been playing with mine for little bit tonight. (scope that is!)
Tektronics digitilizing four channel. TDS 420a. Has a floppy disk drivs and printer to store waveforms. ewwwww ahhhhhh. lol
Not on the truck yet, but maybe it wont be long.
 
#7 ·
Well Luke offered one up, can't imagine that I wouldn't be able to do what you all want with your instructions!
 
#8 ·
I hope you understand, referring to Jonathan's post...

that in order to show what Jody/Kevin are purporting, is that you will have to show o-v-e-r-l-a-p-p-i-n-g FDCS signals...right?

it's not possible...ooommm-freaking-possible.

I think that is pretty clear.

CID (high or low) is the "window" for 4 injections (FDCS commands)

as rpm goes up...the window (length of the CID) gets shorter.

The shorter that CID window gets, the shorter the FDCS commands must be....unequivocally MUST be shorter.....otherwise...

the combined DURATION of the 4 FDCS signals will exceed the CID (high or low)...it just doesn't fit. can't fit...not enough rooooooom before CID goes low again, and the next 4 FDCS commands have to come

well...WHY doesn't it fit????????

because rpm's DICTATE THE LENGTH OF CID...it's really that simple.

but, if Jody & Kevin have only ever looked at what the PCM is doing...then the data they are reporting as being ACTUAL injector "on time" is false.

not even debatable.

take care~

Dave
 
#9 ·
So lets just say we take the whole "it's not even possible" out of it as far as what the trucks idm, pcm etc is capable of and just think about the scope itself. Is it possible for it to read up to the units suggested that the motor is supposedly running to?

I figure I could help the cause so Kevin doesn't have to drive halfway across the us to get scoped when I can do my own motor and probably John's motor who has the same tuning as Kevin.
 
#12 ·
So lets just say we take the whole "it's not even possible" out of it as far as what the trucks idm, pcm etc is capable of....
this is not a "let's just take it out" type of scenario...I don't care if Einstein & Nicola Tesla are holding the scope lead wires for Jody....

This is like trying to argue there are 80 minutes in one hour....and you say...well..but...uh....

sorry.

No matter what Jody/Kevin/Horatio Sanz THINK or HOPE they saw through the OBD port (which is hysterical, btw) does not matter.

if Jody thinks he DID squeeze more PW...then...the rpm is not there..period.

the two are LOCKED together, and no amount of "scoping" for it will change that.

My point is that if he learns how to use a scope over the next week or two, and scopes a truck with this time-warp tuning...he will see one of two things.

a) either the rpm's are not what he thinks he saw...

b) the PW is not what he saw

what Jody & Kevin are reporting is par for the course with what tuners have been working with over the last 8 years...OBD port data...


go unplug your ICP sensor, and see if Jody can figure out your HPOP pressure...might be easier for y'all to start by hooking up an oil line to a cylinder head, rather than coming on here arguing about what pressure you saw on the scantool...:hehe:

take care~

Dave
 
#13 ·
At this point it doesn't seem to me that they (Jody & Kevin) are arguing the point anymore, but looking to find out what the actual pw reading from a scope is, with Jody's tune, then relate that info to what Jody is seeing with his new tuning software/stuff.
And then learn more about tuning.

At least I think that's what they have come to...
 
#19 ·
...so now we are wanting to compare completely different trucks (different injectors, different turbo's, different tuning, drivers, transmissions, gearing)...rather than simply working with the only FIXED constant between ANY of these trucks...

the IDM-PCM & the fixed relationship between FDCS & CID.

Why don't we compare how many trucks have grenaded sub 400hp?

It's pointless to bring tons of other variables to this discussion...

take care~

Dave
 
#20 ·
I don't care if it says one thing or another. I just want someone to tell me how to do it and then I'll go from there. I know this isn't very simple but then again I wouldn't say I'm a "novice" by any means. I've tackled everything in my past, why not keep going?

I got the go ahead from Diane this morning so if Luke is up for it and it doesn't mean any spliced wires or similar then I'm up for it.
 
#27 ·
Both in Georgia. Time for me to go searching deep on all the forums on how to use one.

Luke, have you used yours?
 
#30 ·
No one is trying to take away from your abilities, Maintain.



It's just that you have to know what you are scoping. Read that WIKI info you posted and reread it. You'll have to know how to setup the scope(voltage and Time) to get it to be readable.




Or you could step up and buy one that gives you all the info that you need on how to scope various vehicle signals. Understanding them is a different ball game which you have already stated "you don't care" what they read.:pointlaugh:


Here's the one I have ordered that will be here next week.
My O-scope choice.
 
#31 ·
OK... here's the exact procedure for connecting an oscilloscope to the truck, in order to monitor FDCS & CID...

FDCS is Pin95 on the PCM, it is circuit # 821, wire color is BN/OG (brown/Orange)

at the IDM, FDCS is Pin17

CID is Pin96 on the PCM, circuit 817, YE/LB (yellow lt. blue)

on the IDM, CID is Pin16

Rather than cutting or splicing any wires, we take a short section of MIG (welding) wire and a butt connector, and heat shrink the welding wire to the leads on the scope wires.

Now you can take the (~1.25") piece of welding wire and push it through the connector on whatever pin you are wanting to scope...might have to wiggle it around a bit to acquire a good signal/connection...

In order to validate the supposition that Jody has magically exceeded the time allotment for injection events...

The "proof" will need to be scope screen shots, of CID, with a known horizontal scale (to determine rpm)...as well as FDCS signals (which are simply the PCM commanded pulsewdiths)...

To verify the actual injector PW, you'll need to unhook the scope from CID, and hook it up to inj high side, bank 1 or 2, which is the middle wire on the valvecover harness.

This will show a difference from the commanded PW to the actual PW at the injector.

engine rpm can be determined by the "length" of CID (hi or low).

have fun~

Dave
 
#37 ·
OK... here's the exact procedure for connecting an oscilloscope to the truck, in order to monitor FDCS & CID...

FDCS is Pin95 on the PCM, it is circuit # 821, wire color is BN/OG (brown/Orange)

at the IDM, FDCS is Pin17

CID is Pin96 on the PCM, circuit 817, YE/LB (yellow lt. blue)

on the IDM, CID is Pin16

Rather than cutting or splicing any wires, we take a short section of MIG (welding) wire and a butt connector, and heat shrink the welding wire to the leads on the scope wires.

Now you can take the (~1.25") piece of welding wire and push it through the connector on whatever pin you are wanting to scope...might have to wiggle it around a bit to acquire a good signal/connection...

In order to validate the supposition that Jody has magically exceeded the time allotment for injection events...

The "proof" will need to be scope screen shots, of CID, with a known horizontal scale (to determine rpm)...as well as FDCS signals (which are simply the PCM commanded pulsewdiths)...

To verify the actual injector PW, you'll need to unhook the scope from CID, and hook it up to inj high side, bank 1 or 2, which is the middle wire on the valvecover harness.

This will show a difference from the commanded PW to the actual PW at the injector.

engine rpm can be determined by the "length" of CID (hi or low).

have fun~

Dave
Assuming you will have to also hook the lead to one of the four injector wires also? Asking cause I may hook mine up just to learn more after i get the tranny fixed. Sorry for the big font, I couldnt find the color change option .lol
 
#39 ·
Ok, I know where the PINS are ON the PCM. You take the PCM out and it's got little gold color pins there, and the plug has two tabs per hole that make the contact w/ the PINS. So am I pushing the mig wire into the PCM or squishing it between the contacts where the pin goes with the pin? I've had experience with the PINS in the PCM back when I bent some and pushed some through the PCM when installing a chip in the dark really quick.
 
#42 ·
I could have answered Scotts question since reading up.

I need someone to answer my question and I need verification that Luke can send the scope and software. I have a laptop, pming him now.
 
#43 ·
10-4. Thanks. Since Im having surgery in a week or so on my foot, Ill have plenty of time to goof off and mess with some stuff. Come on down here maintain, you can use my scope, and we can ride around terrorizing unknowing sports cars.:D. BTW I got two bottles we can empty in the process.:pullover:
 
#45 ·
If only you weren't like 8 hours away :doh: You, Brian, Myself, and my buddies John and Mike should all live closer. Lots o go fast junk would get done. ;)

you don't have to even pull the harness off the PCM or IDM...

just push the scope lead wire in through the harness side of the IDM or PCM...right down the length of the wire. into the connector..
Ok this is what has confused me so far. How do you do that when there's a 10mm bolt and a plastic cover over it? I figured you'd have to take it off to get to them. The less invasive the better (whole reason behind not wanting to splice ANY wires).
 
#46 ·
Ok this is what has confused me so far. How do you do that when there's a 10mm bolt and a plastic cover over it? I figured you'd have to take it off to get to them. The less invasive the better (whole reason behind not wanting to splice ANY wires).
the bolt passes through the plastic connector...you can release a couple of little plastic clips on the part of the engine side harness to the PCM...which releases that plastic cover...and then you'll see the big birds nest of wires.

nothing broken, clipped, or cut
 
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