91 octane on 93 octane program

[lbjailer]

For the last couple of weeks I have been running the 93 tune on 91 gas. I'm not experiencing any problems how the truck runs, but have noticed it runs hotter. My normal running temp is 196 on average, and previously have never seen over 200 on the ECT. (Its gone as high as 208) I plan on taking back to level 1 tune today, but was wondering if the higher octane is causing the temp increase or the tune? If I am still running hot after going back to level 1, I will take the truck in to be checked out. When I originally ordered the Gryphon I asked for level 2 to be for towing, and level 3 performance, but here is southern Calif I can't find any 93 octane. Do I need to have a program for 91 instead of 93?

[shotgun]

When ever I've seen an ECT issue in the past, it's been related to AFR (too lean).

But from page 17 of the Gryphon manual:

Lowering this value will not harm the engine but may reduce performance and economy. A good general rule is to increase timing 0.5 degrees for every octane count you go up. For example, if you are running 93 octane fuel in level three, you could safely increase the timing 1.0 degrees.

I'm definitely no expert, but if you suspect the octane difference is the culprit, you could try reducing the timing by 1 degree (93 to 91 = 2 counts) and check your ECT. If it's good, increase it .5 (1/2) degree (you will now be at 1/2 degree retarded) and check again. If it's good, you could leave it there and you probably won't need new tunes.

If the ECT is still high, then you probably have another issue.

Hopefully Jack, 88, Longshot, or Cody will be by to verify my troubleshooting process.

[lbjailer]

I returned the truck to stock, the ECT never went above 196. The outside temp was 85. Funny thing is, I first went to level 1 and when I did the RPM and Speed had no display, so I went to stock and it works now. I guess its better to return to stock when changing the tunes from one tune to another tune.

[88Racing]

Monitoring the CHT is more accurate since the ECT is an inferred value derived from the CHT.

[88Racing]

Originally Posted by lbjailer

I returned the truck to stock, the ECT never went above 196. The outside temp was 85. Funny thing is, I first went to level 1 and when I did the RPM and Speed had no display, so I went to stock and it works now. I guess its better to return to stock when changing the tunes from one tune to another tune.

When the Gryphon does funny little quirky things its indicating that there may be a voltage issue.

So check your battery, have it load tested.

[lbjailer]

I noticed too that the time it took to program from one level to the next seems to be taking longer. I will plug it in to get updates.
My truck only has 14K miles, so I can't think the battery would be going already, also the dealer during the last oil change inspected and found it to be good. Maybe because the engine was hot and it was hot outside the CCAs are affected.

[cleatus12r]

Originally Posted by lbjailer

I noticed too that the time it took to program from one level to the next seems to be taking longer. I will plug it in to get updates.

Please don't.

The only reason to "update" would be if you have custom files on the server or if you are directed to update any firmware issues.

[Jackpine]

And I'm going to weigh in here on temperatures. I don't think 208 degrees is "excessive" by any measure. However, as shotgun suggested, you COULD try reducing the timing, since you're using 91 octane gas in a 93 octane tune. Reducing the timing will probably cause the engine to run a bit cooler, but you don't want to reduce it too much, or you're going to feel a definite loss of power.

And, as 88Racing suggested, I'd monitor the CHT instead of the ECT for the reasons he stated. I have always monitored CHT and normally see around 210 on warm summer days when the engine is not operating under high loads. This is a very normal, and desired temperature for modern engines. Your thermostat is not designed to open until 195 degrees, and then it opens "gradually" to stabilize the coolant temperature in the low 200s region. The CHT and the ECT will actually be quite close when things stabilize.

I'm actually surprised you used to see only 196 before. Personally, I think that's too "cold" for efficient engine operation. The PCM doesn't trigger "fail safe" operation until the CHT reaches 258 degrees, which gives you an idea of what "normal" is.

- Jack