I see where people with " problem tuning "are running in open loop only.
As I am primarily looking for all out performance and WOT operation with no Cats this would appear to be the quick fix .
Am I correct that with setup the ECM only commands the fuel / spark off the tables and does no "self correcting?

How do you setup to run open loop with 165 ?

 

Only thing required is to set the closed loop enable temperature at a high value. However, it is also best to disable (un-check) the DTC's for 13, 44, & 45 (O2 failures), and reset the ECM by disconnecting the power for a moment. That will clear any learned BLM cells.

RBob.

 

I ran OL for a summer. Performance mods. I "thought" the car ran better in OL but it was just masking other issues that I have improved upon since. My gas mileage sufferred by about 20% and I run premium fuel. Considering the car is driven 120 miles on average per week there is no way I would run OL.

 

Thanks for replies.
I am currently overwhelmed with tuning info from this forum and just want to get a base tune on my new setup.
Ultimately hope to run CL once I have mastered Tuning 101.
Engine I am trying to tune is my detuned race engine I just want to setup for the strip.
Backup is the Vic jnr and 750 DP.

 

RBob, I'm curious about doing this also- I have one EBL I'll be using on my daily driver, but now that the EFI bug has bit me I'm considering putting one on my bracket strip car also. It seems like the main limitation would be living with the 6400 RPM limit, is that correct? Also getting enough air and fuel to the engine, but it looks to me that with a bored out 454 TB and higher fuel pressures this may be possible.

When running in a strip only car with no cats (or muffs), it would seem to me that open loop is the only thing that makes any sense, there's no point or advantage to aiming at 14.7 that I can see.

When always in open loop with a strip only car, there also isn't any point to the PE mode is there? It looks like you would just always stay in open loop non-PE mode and tune your VE tables for best power and AE settings for best launch, would that be the best way to go?

Paul T.

 

The 6400 RPM isn't a real limitation. It is just after that RPM the fueling & SA can't be changed. If the engine is shifted at 6800 RPM, how much change in fueling and SA is required in that 400 RPM? If shifted at 7000 RPM, then the last 600 RPM?

To me getting enough injector is the issue. As the engine RPM increases the injector DC% becomes critical. Going to async injection mode helps in this regard.

On the EBL PE mode can be helpful on a stick car. The PE SA adder is based on the current transmission gear in use. This allows for less timing as the load increases with each next gear. Gives a better top end pull. Otherwise PE mode isn't needed. The one car is a stick so I kept PE mode, however, I also set up the OL AFR table to match the PE mode commanded AFR.

Then by adjusting the rate of advance for PE SA, there is a smooth transition into power. Not the sudden increase typically felt. If this car was an auto I probably wouldn't be using PE mode.

The Flash version also has better open loop AFR tables then the Classic version. This was done to enhance open loop mode. As you say, set it for open loop, adjust the VE tables to match the commanded AFR. And adjust the AFR table(s) for best power & driveability.

RBob.

 

I'm interested in running full time OL on a Formula I recently purchased. There's absolutely no comparision in WOT performance from OL to CL. What's the simplest and what's the most effective way to full time OL? Thanks

 

Post #2 in this thread has the answer to your question.

There's absolutely no comparision in WOT performance from OL to CL

No comparison or no difference? There is no difference at WOT unless your BLM's are abnormally high. Otherwise the SA & fueling is the same at WOT, which is OL anyway.

RBob.

 

The car runs way way better in OL. For about the 1st five minutes (until the car reaches temp to go into CL), you can roll along about 15 or 20 MPH in first gear, stomp it, completely annialate the tires, granny shift into second, stomp it again, blow the tires off again. It just runs 100% better in OL. Once in CL, it will chirp the tires between 1st and 2nd, but won't break them loose at 15 MPH. I have heavily modified a 1988 IROC which relies on DFI for tuning, but I don't recall there being any difference in CL and OL back when that car was stock. The Formula is 1991 305 TPI 5 SPD with factory dual cats. Only mods that I know of are a performance chip, K&N Filter, and an air foil. I will be putting an SLP CAI and SLP catback next week.

 

OK.

The engine is cold which raises the VE and the ECM is usually running a richer then stoich AFR.

The is a difference in breaking tires loose and accelerating the vehicle.

OK, so no difference between OL & CL when the vehicle was stock? Maybe the current tune needs some work.

A different vehicle (?), if it has cat's and you want to keep them. Then CL is the only way to go. Two cat's cost twice as much to replace as a single cat.

RBob.

 

The vehicle in question is the Formula. It certainly has way more power in OL. Being able to blow the tires off in two gears while in OL tells me it has more power. You can really tell the difference in third gear and up between OL and CL once the car hooks up. Feels like two different cars. As far as how much difference between OL and CL when the car was 100% stock, I can't answer that. I just picked the car up a few months back. We're talking a K&N, airfoil, chip and catback that it already had. In my opinion, thats still pretty much stock. The previous owner also stated that the "car runs alot better for a few minutes after it's been sitting awhile" (when I bought it, the car had been sitting five years with a fuel delivery problem that turned out to be the FPR). Would an AFPR and raising the pressure help the performance in CL? Or are there any chips made that will automatically go into OL at a pre-determined load, say 3/4 throttle? The DFI on my IROC reverts back to the OL tables at 75% throttle. Sorry for any confusion with my previous post.

 

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