Finished with the 383 build, now getting to some tuning...

Flows 280 on the intakes, 3" all the way back, 30#SVOs feeding 383 with 165 controlling, 4-bbl progressive linkage 1000cfm TB.

MAF is cut up, so at ca. 40# FP @ idle, FI const came in to 28# for generally 128-135 across the board.

TPS only goes to ca. 80% at WOT, not enough travel on linkage I suppose, but the blades are open. Wish I could redefine in the binary. Secondary opens up around 35% or so.

Anyways, when going to WOT (enables around 40-45%) O2 values drop to the floor (like less than 100mV), and not around 800-900 where they should be. Yes, WB needed. Gotta weld in another bung at the Y. No I'm not going to run it like this.

Stock TPI fuel pump, probably original, MAF readings getting up to 230+...

I'll route the FP gauge to make sure this is what I'm seeing, but I'm assuming that there's a Fuel delivery limit here. What are those stock units good for? Suppose I could disconnect the return and measure it. It didn't look like it was exactly blowing through there when I had it disconnected.

So what is a decent replacement pump? Aeromotive A1000? Just put a tube down in plac of the stock pump? Any workaround to avoid an entire fuel tank pull?

Maybe a little off topic, but I was chasing it down by trying to pump up (no pun intended) the PE to like 60% and this is just not right. It helped some at the lower RPMs but it still falls off lean higher up (like 3500+).


Thanks...

 

try settin the tps to enable pe table at 50% across the boards.If it fixes the problem the you can fine tune the f/a% table with a w/b.there is also the "pump shot" tables.I'm sure you are aware of all this though?

 

Look for K3 in the hac.
It's the TPS Scaler.
Try increasing it about 15%.

Can you get the butterflies to be linear?.
Gonna be fun getting the delta AE LV8 for LV8 right with progresives. There's a hint in there.....

Did you catch my other resent post of mine about TPS and Load AEs?.

 

I definitely agree with swapping the fuel pump. When my buddy installed a fuel pressure guage on his 383, he found that in WOT his fuel pressure was dropping ridiculously low (under 30#s IIRC). Definitely not the 45# he had set it to.

I have no feedback on the Aeromotive A1000. About the only fuel pump I've heard bad things about is the Holley's.

 

Time to replace the pump with a walbro.

 

I didn't find any TPS scalar in the 6E or 32 code, but I did find some space for the following right after the LDAA / A/D on the TPS:

16 TAB (transfer acc A to acc B)
54 LSR (logical shift right, makes bit7=0, bit6=bit7, etc)
54 LSR (same, repeated)
1B ABA Add B to A

This should effectively multiply the TPS input by 1.25 at the input, so a value of 3v will be seen as 4.5v that should cure the span issue. Gotta displace some more code to do this, looks convenient to overwrite the EGR error check subroutine, it's right there. The A/D is done in two places though, so gotta look there too.

Linearity's another matter. Maybe as first pass see what butterflies are doing at a given TPS and set the AE & PE up to correspond with the secondaries getting cracked.

What happens when you do an arithmetic add (ABA) on two 8-bit values and the result is >255? Hoping it will just max out, if not (like rollover) further treatment is needed. Could just check to see if the result is less than the original. If so, drop in a 255, that'd be easy enough I guess.

 

Okay, the patch worked great! Problem is that TunerCat seems to want to mess with some of the area that I patched over. Gotta get that straightened out. As it stands, the patch would have to be applied post-tune to keep. Either that or I could edit the TDF to see what is 'meddling' with the patch! Gotta be careful patching over 'useless' code if an editor comes in behind you and rewrites that area!

Update... Don't know what I did before, but TC doesn't botch it now. Checksum reenabled. Need to investigate further.

I went ahead and set max TPS interpreted to 4.53v, occurs at an actual TPS voltage of 3.6v...

Here's the code:

81 B9 - CMPA Compare TPS integer to 185.
23 9E - BLS skip next step if less or equal.
86 B9 - Force acc to integer of 185 (3.6v)
16 - TAB Copy AccA to AccB
54 - LSR
54 - LSR Move bits over, ca. divide by 2 essentially, twice, by 4.
1B - ABA Add Acc A & B together. Gives integer in Acc A as sum.

Net effect is a multiplier of 1.25 on the input voltage with a 3.6v software clamp on the actual voltage input.

This goes in after the A/D call for channel 5 (TPS) and before it is written to RAM (memloc 0082). Lots of variations of this could be used for other stuff...

Now I've gotta rezero the TPS, but not through software. Or...??? Hmm...:rockon:

 

In $6E the TPS% scalar is at $C3A3 and in $32 at $C39A. After the add use the carry flag via a branch to handle overflow (BCS, BCC).

RBob.

 

Cheapest place on the net for a Walbro INTANK pump.

http://www.autoperformanceengineering.com/

I would never run an in-line pump again after going through two of them.

 

Installing the pump is much fun! Lucky for me I was having my 10-bolt rebuilt and hanging a new exhaust when I did my pump, otherwise I would have been very pissed to have gone through all that work of dropping everything in the rear of the car just for just the pump.

I bought from APE. Best wishes.

 

Ditto to above...walbro 340 with direct batt. power using original power for relay-no lack of fuel now!

 

Thanks for the info. Ordered Walbro high pressure 255 in-tank, cut the panel above the tank for the install, never looked back. Getting the fuel it needs now! No more WOT lean conditions...

 

Craig

Do you have pics and the steps involved for cutting in for the pump? Would love to know in case mine croaks in the future for some reason.

 

Don't cut up your car just for a pump, they aren't that hard to do the swap properly. There are multi 100's of posts length threads on the tech & general board about this very subject.

RBob.

 

Ditto on the no need to cut. It really isn't hard to drop the tank.
How I did it (to replace the pump);
Loosen the lugnuts on the rear wheels while car is still on the ground. Chuck the front wheels!!!!
Jack up the car and support the frame where the LCAs go into the unibody. Get the car up as high as possible without the nose hitting the ground. Remove rear wheels.
Unbolt the rear brake line bracket so that the hardline and flex line can flex from the fuel filter. You might even find it helpful to unbolt the fuel filter bracket, I didn't.
Unbolt your shocks from the rear axle brackets. Unbolt the panhard bar from the body mount and remove that other bar that goes from the mount to the body, not sure what that bar is called. Support the rear diff housing with the jack. Make certain the brackets are all unbolted for the brake lines and the shocks are out of the mounting holes else the rear will not go down far enough. Lower the rear as low as possible.
Now you'll want to remove the exhaust. Since the rear locating suspension components are out of the way (no you don't need to remove the passengers side LCA) you can unbolt the exhaust intermediate pipe from the cat flange, remove the exhaust from the hangers and slide the exhaust out of the way.
Now you're ready to get a little messy. Find the return and supply lines going to the tank. The supply line is easy to find since it's hooked to the fuel filter . Now have a big bucket ready. Hopefully you don't have a lot of gas in the tank, if you do, get it down LOW. The lower the better. Anyways, remove the lines and put them into the bucket. Pop the hood, look at your fuel pump relay and use a paperclip to hotwire it on. Fuel should be in bucket and tank should be nearly empty, don't worry about running the pump dry.... it's getting replaced remember
Now it's time to finish removing all the hose connections going to the tank. One of them is a vent, other is for the canister. Okay, remove the filler neck plastic cover and remove the gas cap. This way you can have somebody tell you if the filler neck is getting caught up. Undo the straps (they hinge so it's only 2 bolts) and bend them out of the way. Bench press the tank (it's light with no fuel) and pull it over to the passengers side a little ways. Now rotate the tanks front (thick side) down towards the rear and while you're doing this pull the tank over to the passengers side rear brake. The tank should come out relatively easily so long as you've dropped the tank low enough. Replace the pump, reinstall everything.
It might sound like a lot but it really isn't hard. It's definatly going to take one person an evening to get it done but it shouldn't take any longer. I did it myself without any help and no instructions. I had a friend come by the next day to help me get the tank back in. It helps having an extra hand hold the tank up while you get the strap bolts started.
If I had to do it again I'm sure I could do it in less time. Practice makes perfect.
Cutting into the car is another option but definatly more dangerous. It could save time if you've got the tools but I figured the pump is a one, maybe 2 time replacement part so why cut.

 

Wow, I swapped my fuel pump out in about the time it took you to type the instructions on the 'correct' method. And if there's an issue, it's easily accessible again. I just double-clamped the high pressure line, should be good enough.

If my car was 'pristine' then yes I would have thought twice. As it stands, I've done much worse to it in the past. I was weighing the options, like swapping in a different rear end and some LCAs/PH bar. but I didn't have that stuff on hand. Just finished getting the exhaust like I wanted it too, so nahh.

Even though a new fuel pump install in this case was prompted by a lean condition that was discovered and compensated for via ALDL communication and PROM burning, I know we're getting off topic here. But I took a couple pics of the butchery via cutoff wheel. I'll close it back up with sealant and a couple of screws. The clearances are close so watch it. In fact don't do it unless you're lazy like me...

1) Make sure there's no gas around, and then cut square out with cutoff wheel. Cut all 4 lines with hack saw, and clean up ends with die grinder.
2) Pull pump assembly out, replace the pump, and clean out the lines from the cuttings. Might want to blow it out from the front, but not too critical. Replace filter after you get the new pump running.
4) Put the pump assembly/tank back together, and use high-pressure EFI rubber hose to make up the places you cut the lines earlier. The high pressure one is the only one that counts, so you might want to double-clamp or flare it some.
5) If you want to make it pretty again, put the plate back in with some windshield sealant / 'Gorilla Snot'. Call it a day. If you wanna get fancy, fab up some trim & a door panel or something.

 

Another closer up:

 

Craig, make sure you "seal it up" really good if you get a fair amount of rain where you live. Water has a funny way of finding any holes and openings to leak inside.

I personally shudder at the thought of cutting my GTA, but it's an effective way to get at the pump. It is your car afterall.

 

personally id cut a bigger piece of 16guage sheet metal. bead roll it and fold the edge them make a gasket and use #2 sheet metal screw with a machinew head to cover it back up. then paint it body color.

 

Good lookin piece of work! Thanks for the pics.