OLSD tune for a jet boat.

[blazeracer]

Hello all, I've been working all winter on 79 jet boat with a Gen III 5.3 running EFI. The guy that modded my harness gave me a MAF tune that needs O2's but I can't run O2's because the exhaust is wet and runs under an engine cover. If I kill water to the exhaust even for a couple of minutes stuff will melt. Also, the exhaust is iron manifold with no provision for O2's.

So I got everything in the other day and fired it up. It idles perfect but stumbles off throttle, cracks and pops to get going, then runs mediocre at best. Well, lets just say other than idle it runs like crap.

I'm going to buy HP tuners tomorrow morning. I found a dealer two towns over that has it in stock. I could post up a copy of the tune that's in it now, but it's totally useless as I'm going to have to ditch the MAF and use the MAP for speed density and keep it in open loop. I have no idea what I'll be looking at on my laptop tomorrow morning, but what can I do to get an initial tune that will work? Gonna have to fine tune by GPS and "seat of the pants" acceleration. Weather shouldn't be too much of an issue here in Texas and jet boats don't really use part throttle much so that part only needs to be close. If I can get a good idle set up, then a good WOT set up, averaging everything in between should be good.

The motor is a 5.3 with a freshened but stock rotating assembly. The heads have been milled to yield a 10:1 compression ratio and correct the smaller base circle on the cam. The heads are also ported. The cam specs are 226/229 .575/.578 on a 112 lsa. Everything, motor, harness, ECM, TAC module and DBW throttle body all came out of a 2002 Tahoe if it matters.

Does anyone have an OLSD tune I can load into this thing, or can I just delete the O2's and MAF and roll with the VE tables that are in it?

EDIT: I can look into this tomorrow. I have the stock truck exhaust manifolds at work. I could mount them upside down and run the exhaust over the transom with O2's to tune....... MAYBE. But it will really screw up the plumbing. This thing has water lines running everywhere. Once the tune is set put the water cooled exhaust back on.

[DrLoch]

Are the manifolds water cooled as well or are the tailpipes the only part of the exhaust water cooled? Is there a flange between the manifold and the tailpipe riser?

[blazeracer]

The manifolds are iron and fully water jacketed. They are double walled. The only way to get an O2 in them would be to drill thru BOTH walls of iron then weld in a bung to the inside and the outside. At the end of the manifolds the water mixed with the exhaust gasses. They cost $850 and I really don't want to chance ruining them. Not a whole lot of exhaust options for Gen III boats.

Here's a pic of them tucked in there when the motor was test fitted.

[DrLoch]

Not unless you want to pay the big bucks and go with a custom set of stellings.... the only way you are probably going to be able to get a tune that will even be close is to put the motor on a dyno and run it with a WB sorry to say.
I am a tech inspector for an offshore association. Was a crewchief on an open class and super cat boats.

Where are you located? Might be able to get you hooked up with some one who can help.

[blazeracer]

Option B is to turn the truck manifolds upside down and add extensions to them and run them over the transom. They have O2 bungs in them. Once I have a tune I then put the water exhaust back on.

Anyway, got my HP Tuners today. Gonna load it on the laptop and get started.

[Sam88gta1]

You have a very long road ahead of you.

Good luck!

[DrLoch]

You have a very long road ahead of you.

Good luck!

Roger that

[blazeracer]

Well, time to get it started. The guy that made my harness gave me and initial tune based on my engine specs that should be close in the VE table. To run it OLSD I just go into the Engine Diag, select DTC's and turn off everything for the O2's and MAF? Is there something else that must be done?

[blazeracer]

Well, just turning off the MAF and O2 codes didn't work. That would be too easy. It would rev out OK but once I lifted the gas pedal the DBW wouldn't open the throttle blade again. Putting the MAF back on and all was the same as before. Good idle, crackin and poppin.

I ran a scan but apparently didn't save it right, but here's the tune and config. I'll have back on the water this evening and try another scan.

I have another possible option for temporary O2's also using a spacer between the manifold and riser, but I have to make it.

[blazeracer]

You have a very long road ahead of you.

Good luck!

Can't be nearly as long as the road behind me, taking a 70's jet boat with a carburated big block Ford and converting to an EFI small block Chevy and having it actually run.

[HO4THSS]

http://ls1tuningguide.com/tuningmanuals/

i realize your engine is not an ls1, but this guide will definitely get you started on that long road.... lol, it explains exactly how to go into and tune in sd mode. you wont need narrowband o2 sensors though, my thought is if you have a way of using the truck manifolds going into a y-pipe and a single wideband mounted at the elbow? but even then when you switch back to your water exhaust it will surely mess with your tune again.... good luck man! would love to see more pics!

[blazeracer]

http://ls1tuningguide.com/tuningmanuals/

i realize your engine is not an ls1, but this guide will definitely get you started on that long road.... lol, it explains exactly how to go into and tune in sd mode. you wont need narrowband o2 sensors though, my thought is if you have a way of using the truck manifolds going into a y-pipe and a single wideband mounted at the elbow? but even then when you switch back to your water exhaust it will surely mess with your tune again.... good luck man! would love to see more pics!

There are TONS of pics of the entire build on Texas Hot Boats.

http://www.texashotboats.com/forums/...?topic=11838.0

That includes paint, floor, interior, a big block Ford that blew up, another big block Ford that ate a cam, and now the Gen III motor. I have a set of spacer that may work in the exhaust. I welded up one tonight and will do the other tomorrow. Would I have to run two wide bands on it to get it right? Or can I run one wide band and one narrow band. I'm new to this EFI tuning stuff so bear with me here.

Oh, here's a condensed version of the boat that has mostly pics.

http://www.classicglastron.com/phpbb...hp?f=34&t=5852

BIG TIME thanks for that tuning info too!!

[blazeracer]

Does speed density and drive by wire work? I've tried two different SD tunes so far. They both will rev up real nice, especially the one following the guideline linked above. The problem is after the first rev, then lifting the gas pedal and letting it come back to idle there is no response from the pedal unless I turn it off for a few seconds and turn it back on.

Ever heard of that? Both SD tunes did it. Doesn't matter if the MAF is plugged in or not. In a MAF tune the DBW works just fine.

[acehaag]

I am running speed density with an electronic throttle in my s10 with a 6.0 so it does work. Here is my current tune, the transmission stuff is all screwed up but that shouldnt matter for you. the maf is failed and it it set to run open loop for wideband calibration. I hope this helps I'm still a newb at this though.

[planethax]

........The problem is after the first rev, then lifting the gas pedal and letting it come back to idle there is no response from the pedal unless I turn it off for a few seconds and turn it back on......

Just from reading another thread, have you tried disabling throttle tip in torque management in the engine section?

[blazeracer]

I am running speed density with an electronic throttle in my s10 with a 6.0 so it does work. Here is my current tune, the transmission stuff is all screwed up but that shouldnt matter for you. the maf is failed and it it set to run open loop for wideband calibration. I hope this helps I'm still a newb at this though.

Just from reading another thread, have you tried disabling throttle tip in torque management in the engine section?

Great ideas. I knew there has to be a way to make it work Ace. These boards are awesome for this stuff. Maybe we can all learn something. I'm gonna try out the throttle tip when I get home Planet. I didn't bring the laptop to work so I can't do it till then. I'll post up what happens.

I think I have an answer for the O2's. Got steel bungs welded into the iron spacers but they seep water. I think I can surround the inside of them with JB weld and they wont leak. The inside is not under pressure, only water flow on it's way out the exhaust.

[blazeracer]

Tip in torque is set for 640 across the board. What disables it? I also zeroed out the traction control spark retard since I don't have a tranny.

[blazeracer]

Tip in torque is set for 640 across the board. What disables it? I also zeroed out the traction control spark retard since I don't have a tranny.

Ok, making zero out of the tip in torque and traction control caused the fuel pump to shut off after about 50 seconds It did run really good in those 50 seconds with the throttle working perfectly. Reflashing turned it back on. Haven't ran it again.

[blazeracer]

Looking my tune compared to some other that are close, but not a 2002 Tahoe with a 5.3 and DBW. I have a 2000 Silverado stock tune I'm referencing and there a few differences. One is the tip in torque. Possibly because it's not a DBW vehicle so it's not needed.

Another is the secondary VE table. I though they were all supposed to have a secondary VE table? The Silverado has it, the Tahoe doesn't.

Also, the VE table for the Silverado is quite a bit lower than the tune I have. I've read the for a nice cam all the values should be bumped up by 5. Is that true? I don't have a 2002 stock tune, the 2000 is the closest I have.

Here's a screen shot of both VE tables next to each other. Mine's on top, the 2000 Silverado on the bottom.

EDIT: Found a 2003 Tahoe stock tune. The VE table is identical to mine and there is no secondary VE table.

[blazeracer]

Don't worry about this thread. Got O2's on it now. Had to make them myself, but it's got em. Not a whole lot of boats with these on them.