Diacom Question...
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
Diacom Question...
Ok, sometime this week, I'm going to hook my car up to a Diacom (a friend of mine is going to let me use his) I'm gonna hook it up to my Notebook and drive around with it connected. Now, my question is..What does diacom show? Will it show timing? Fuel Pressure? I'm wondering, because if it shows timing, then I can actually bump the timing up and check and see it it's still ok. Any help is appreciated.
Burning Brakes
Joined: Sep 2000
Posts: 1,199
Likes: 1
From: NewCastle IN. USA
Re: Diacom Question... (TIMSPEED)
first off, make sure to read the instructions for hook up and disconnecting the cable, there is a sequence that needs to be followed
[short version: connect or disconnect cable ONLY with the ignition OFF and with diacom running on the laptop (but not linked to vehicle).
Link to vehicle ONLY when the ignition is ON, also do NOT turn off the ignition while linked (press ESC to unlink then you can turn off the car).]
diacom will tell you what the ECM is doing and seeing, including timing BUT it can't see you change the base timing on the distributor. there should be 2 timing advance fields a total adv (with the stock base of 6degs added) and a field for just what the ECM is adding (minus the base).
there is also a knock retard area (how much timing is being pulled out when knock is sensed) and a knock count area (number of times knock has been sensed since the car has been started).
there is lots of useful info.
when I first used it, I saved some data to disk and printed out all the graphs so I could study them all side by side (it only lets you graph 3 fields at a time on the computer). this helped me understand what was going on.
oh, it won't show fuel pressure, what it will show is the O2 sensor voltage (this jumps around alot most of the time, the ECM uses an averge of this to know if its running rich or lean. during closed loop that is).
it will take a little time to figure out but you'll get there.
RJ
[short version: connect or disconnect cable ONLY with the ignition OFF and with diacom running on the laptop (but not linked to vehicle).
Link to vehicle ONLY when the ignition is ON, also do NOT turn off the ignition while linked (press ESC to unlink then you can turn off the car).]
diacom will tell you what the ECM is doing and seeing, including timing BUT it can't see you change the base timing on the distributor. there should be 2 timing advance fields a total adv (with the stock base of 6degs added) and a field for just what the ECM is adding (minus the base).
there is also a knock retard area (how much timing is being pulled out when knock is sensed) and a knock count area (number of times knock has been sensed since the car has been started).
there is lots of useful info.
when I first used it, I saved some data to disk and printed out all the graphs so I could study them all side by side (it only lets you graph 3 fields at a time on the computer). this helped me understand what was going on.
oh, it won't show fuel pressure, what it will show is the O2 sensor voltage (this jumps around alot most of the time, the ECM uses an averge of this to know if its running rich or lean. during closed loop that is).
it will take a little time to figure out but you'll get there.
RJ
Thread Starter
Le Mans Master
Joined: Mar 2001
Posts: 9,464
Likes: 1
From: Modesto CA
Re: (scorp508)
Thanks Scorp. That's exactly what I was looking for. Something that would VISUALLY show me what it shows. :cheers: I'll post my results as soon as I get them. See what's going on. (Since I know nothing about that stuff yet)
Drifting
Joined: Dec 1999
Posts: 1,319
Likes: 2
From: Douglasville GA
Re: (scorp508)
I hope it works better on your 87 than on my 86. When it links, it is VERY screwy. It shows the PROM ID as one value, then some other value, and the rest of the values are just a mess.
I am very displeased with DIACOM. Anybody want to buy it? I understand it works well on other years.
Tom Melton
82 CE
86 Z51 Coupe
I am very displeased with DIACOM. Anybody want to buy it? I understand it works well on other years.
Tom Melton
82 CE
86 Z51 Coupe
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Team Owner
Joined: Mar 2000
Posts: 83,383
Likes: 87
From: Boston, MA
Re: (tommelton)
I hope it works better on your 87 than on my 86. When it links, it is VERY screwy. It shows the PROM ID as one value, then some other value, and the rest of the values are just a mess.
Drifting
Joined: Dec 1999
Posts: 1,319
Likes: 2
From: Douglasville GA
Re: (tommelton)
Executable Rinda sent via email either got corrupted in the email, or was bad to start with. Get "Program to big to fit in memory". Have sent email back to Rinda again...
Anyone have the upgraded Diacom plus gmecm.exe (diacom-p.exe) file they could email me at tmelton@emory.edu ? I would like to try this tonight...
-Tom
Anyone have the upgraded Diacom plus gmecm.exe (diacom-p.exe) file they could email me at tmelton@emory.edu ? I would like to try this tonight...
-Tom
Drifting
Joined: Dec 1999
Posts: 1,319
Likes: 2
From: Douglasville GA
Re: (tommelton)
Well, it appears to be a laptop PC issue vs Diacom. I pulled out an old IBM desktop machine, 486, and Diacom links fine to my 86 Vette, when used with the TPI adapter and the /F option.
Anyone have a laptop that is compatible with Diacom they want to unload *cheap*???
-Tom
[Modified by tommelton, 5:28 AM 8/9/2002]
Anyone have a laptop that is compatible with Diacom they want to unload *cheap*???
-Tom
[Modified by tommelton, 5:28 AM 8/9/2002]
Drifting
Joined: Dec 1999
Posts: 1,319
Likes: 2
From: Douglasville GA
Re: (scorp508)
Scorp, Diacom documents a /F flag for the diacom and diacom plus executable. The /F command line flag alters how the diacom code works, specifically for machines that exhibit problems due to some chipsets that control the parallel port. IE, some chipsets for the parallel port do not match the "IBM standard" and thus caused Rinda some problems. These non-standard chipsets can even be found on IBM machines...
-Tom
-Tom