Timing Reading Wrong Since Update

[123456789]

I did the latest update V7.5.7 (Build 206). Have a 2007 5.9 Cummins. My timing (stock or otherwise), was always in the 15 to 25 degree range. Now the main injection timing is in the -3 to 7 range. One of my computers has an older version on it, so I pulled the file up on the older version it reads 15 to 25 degrees, then I copied that file to my other computerwith the latest version and the timing on that file is in the -3 to 7 range. So I bumped the timing to 19 degrees straight across as a test, and the truck was obviously WAY overtimed. I then took the truck to the dealer had it re-flashed. Then re-read the file, and sure enough, timing still shows in the -3 to 7 range. Is there a parameter that I'm missing? I'm extremely comfused and can't find anything on this. All of my files have the timing reduced by a serious amount.

[comnrailpwr]

The older dinosaur version you had before did not have the 20* timing ofset factored in. The timing numbers you are pulling out now are the actual timing with the ofset calculated. This is most likely your problem. Its not really a problem you just have to build a new timing map.

[DoghouseDiesel]

You DO NOT have to build a new timing map, the old one you were using is just displaying the 20* degree timing offset that the ECM reports.

DO NOT adjust the timing in the CURRENT version of the software to reflect those old timing values or, like you found out, you'll be WAY over timed.

This was discussed as it was developed and released in the software updates. Just update all your software, look at your current tunes (without changing them) and you'll see that the timing now looks like it should and not 20* higher than a diesel should be running.

[123456789]

You DO NOT have to build a new timing map, the old one you were using is just displaying the 20* degree timing offset that the ECM reports.

DO NOT adjust the timing in the CURRENT version of the software to reflect those old timing values or, like you found out, you'll be WAY over timed.

This was discussed as it was developed and released in the software updates. Just update all your software, look at your current tunes (without changing them) and you'll see that the timing now looks like it should and not 20* higher than a diesel should be running.

Thanks a ton for the answers. I couldn't find this anywhere I looked. Just so I'm clear, this is actual timing, now displayed? So when people are saying they have the 15 to 25 degree timing, or on a 12V, when they set their timing at 15-21 degrees, that's not the actual timing, BTDC? Sorry to sound like such an idiot, but I just want to understand.

[comnrailpwr]

BTDC are negative timing numbers. P pump guys are timing their injection pumps because thats what fires the injectors. The numbers you are seeing now are whats actually happening inside your motor. I wouldn't get into the habit of comparing to a p pump motor. Totally different style of tuning and needs to be approached differently.

[DoghouseDiesel]

Yes, the numbers you now see are the ACTUAL timing values. Anything with a negative value is after TDC.

THe thing with a 12V is it's timing is static. Doesn't matter if it's 1200 RPM's or 4000 RPM's. If you try to run a 12V at 0*, that MF'r won't play.

Now, what really dictates the amount of timing you can run on a common rail is the RPM range you are going for and how well built the motor is. Remember, timing is cylinder pressure and too much is the fastest way to damage the motor. On an otherwise stock truck, running stock RPM's and stock head bolts, I won't go higher than 20*'s of timing. But on something like mine, I have no issues running as much as 30 - 32*'s in the high RPM ranges.

The most important thing to do is TUNE IT ON A DYNO if you want to push those values. I nomally try to find the limits on the dyno and then back off 3 degrees to keep it safe for that particular motor. And remember, the timing you can run at 4200 - 4500 RPM's is NOT what you can run at 2000 RPM's. Timing is THE single biggest factor in power production and turbo response when it comes to all of the tuning parameters.

[123456789]

So just to clarify, when you're talking about 20 to 30 degrees of timing, you're talking about using the same table that on my stock timing ranges from -3* to 7*, right? So if I had my timing set from 0* say at 800 rpm, and ended at 20* at 3500 rpm, that is kind of a example of what the range would be with the latest update of EFI, correct?

[123456789]

Does anyone have a rate of how fast the fuel burns, or how fast the pressure rises in the cylinder, to give a good baseline of how fast to bring the timing up with RPM's. I'm sure many factors like injector size, etc. effects this, but there has to be some sort of "rule of thumb". Also, how far in advance does the pre-injection need to be for best power results. Stock it's all emmissions based I'm sure, but is there a "rule of thumb" for the pre-injection also?

[comnrailpwr]

Rich is correct, negative values ate atdc, not btdc. I had a brain fart

[DoghouseDiesel]

Does anyone have a rate of how fast the fuel burns, or how fast the pressure rises in the cylinder, to give a good baseline of how fast to bring the timing up with RPM's. I'm sure many factors like injector size, etc. effects this, but there has to be some sort of "rule of thumb". Also, how far in advance does the pre-injection need to be for best power results. Stock it's all emmissions based I'm sure, but is there a "rule of thumb" for the pre-injection also?

It's not really as easy as "rule of thumb". There are tons of factors, both mechanical and environmental that play into all of the parameters that you use.

The best thing to do is tune the truck on the dyno when you're really going to push it. The dyno chart tells the story when it comes to fuel delivery.

There are specific things I look at with the truck on the dyno, that you simply DO NOT see in the data logs. This is one of the reasons I WILL NOT do mail order tunes, I'll only do them here at the shop or another place that has dyno access. Getting the timing right for a specific application has a 3* - 5* window between safe and boom when you start playing in the upper RPM ranges.

Down on the low end, it's pretty safe to adjust timing by seat of the pants and listening to the motor. If it's overtimed, you'll here the characteristic diesel rattle and the turbo(s) will be lazy. Undertimed, you lose some performance, but the turbo(s) light FAST.

The only "rule of thumb" I use is absolutely no more than 25* of timing advance on a truck running stock RPM's, stock rods, or stock head bolts. It's just too much cylinder pressure if you run any higher and it's also a LOT of heat put on top of the pistons. Now, running higher RPM's, coated or aftermarket pistons, god head studs, good rods, etc., and you can run the timing up a bit more.

[DoghouseDiesel]

So just to clarify, when you're talking about 20 to 30 degrees of timing, you're talking about using the same table that on my stock timing ranges from -3* to 7*, right? So if I had my timing set from 0* say at 800 rpm, and ended at 20* at 3500 rpm, that is kind of a example of what the range would be with the latest update of EFI, correct?

Correct. An OEM timing table with the current software will show approx -3* to 8* of timing.

Same exact table, redone to make the truck run correctly is anywhere from -2* to 20*.

[123456789]

Again Thanks Doghouse Diesel for he help. Now I see the timing calculator built into the system. Is there an explanation of it somewhere that I can read up on it? I see that pulse width tables are included in the calculation, but why the pressure tables?

[FUBAR]

I see that pulse width tables are included in the calculation, but why the pressure tables?

You mean mm3 isn't the only fuel quantity needed variable???? Lol...I had to go there Rich!! Pressure is incorporated because it has a direct effect how much fuel flows. Take a 5 gallon bucket of water and knock a 2" hole in it with an attached 2" hose and let it drain by gravity. Now, go out to Lowes and buy a handy dandy sump pump. Submerge that into the same bucket with a 2" hose attached to it, plug it in, and tell me which one is able to flow more fuel through the same 2" hose..or drain faster.

[DoghouseDiesel]

You mean mm3 isn't the only fuel quantity needed variable???? Lol...I had to go there Rich!!

Don't make me hurt you!

:chair:

:anitoof:

[Tobin]

Is the actual start of the combustion the main injection table value minus the pilot injection value to give the start of the combustion in relation to crank angle? The pilot table is off the main injection timing table to altering the main table changes the start of the pilot, correct? I am just trying to understand when exactly the first injection of fuel start in relationship to crank angle.

I was fooling around to remove pilot, I zeroed the pilot base table quantity and all other pilot tables, then I copied the base timing and pilot timing to excel, added the pilot value to the main timing value and pasted those values back into the main injection table. It seemed to run fine, only ran it for a minute or two though.

Tobin