Understanding timing with DataMaster
Thread Starter
Racer
Joined: Mar 1999
Posts: 292
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From: Vienna VA
Understanding timing with DataMaster
Just started playing with my new DataMaster software. I suspect that the ECM is not fully advancing the timing to where it should. Timing is being advanced to no more than 29 degrees with the TPS % near 100, above 3600 RPM, and no retard. Not sure how the PROM was set up, but I would expect it be around 36 degrees of advance.
Is the total advance = reading for the datamaster advance field or
= initial advance at the distributer + the reading from the DataMaster advance field?
When the engine is at WOT, should the DataMaster report "Open Loop" operation, instead of the "Closed Loop" operation that I am seeing? I read that at WOT, the ECM is supposed to go "Open Loop".
Carl
90' 6 spd
3.45 rear
350 with hooker SC, random cat, Power Effect cat back, mini-ram, K&N, high output coil, underdrive pulleys, Accel 219 cam, AFR 190 heads (milled to 58cc), full rollers 1.5, 30# injectors, Taylor wires, Dynamod HEI module, Custom PROM by Shalin, BFG KD/TA tires (awesome).
Safety Car
Joined: May 1999
Posts: 3,588
Likes: 1
From: Volcano, HI
Re: Understanding timing with DataMaster (Carl90)
Carl,
First off, check your knock counts. That can keep your timing back a bit. Also, if you're using a stock ECM, do you know what bin you're using? If you do, I can load it up in TunerCat and see what the maximum advance is at that MAP, RPM, with PE taken into consideration. As far as the open loop thing, I've heard (I'm not too sure on this one) that when PE kicks in, it's kind of a psuedo-open loop. It basically ignores the O2 readings and goes straight from the tables. I've noticed the same thing in PE mode when logging with DataMaster.
First off, check your knock counts. That can keep your timing back a bit. Also, if you're using a stock ECM, do you know what bin you're using? If you do, I can load it up in TunerCat and see what the maximum advance is at that MAP, RPM, with PE taken into consideration. As far as the open loop thing, I've heard (I'm not too sure on this one) that when PE kicks in, it's kind of a psuedo-open loop. It basically ignores the O2 readings and goes straight from the tables. I've noticed the same thing in PE mode when logging with DataMaster.
Thread Starter
Racer
Joined: Mar 1999
Posts: 292
Likes: 0
From: Vienna VA
Re: Understanding timing with DataMaster (Mojo)
Mojo,
Shalin set up a PROM to work with my 30# injectors. He did WOT tuning on a dyno for me. I believe that the retard table entries were set to zero, which effectively disables the knock sensor from retarding advance. My knock counts are not going up at WOT, accordingly DataMaster does not indicate any advance retard. How much advance are you run at WOT above 3600 RPM?
Carl
Shalin set up a PROM to work with my 30# injectors. He did WOT tuning on a dyno for me. I believe that the retard table entries were set to zero, which effectively disables the knock sensor from retarding advance. My knock counts are not going up at WOT, accordingly DataMaster does not indicate any advance retard. How much advance are you run at WOT above 3600 RPM?
Carl
