L31 Extreme Budget Build

[454cid]

It did not change the sound outside much but all the difference in the world in interior cabin noise. Never have been a fan of axle dumped exhaust even under the bed of a truck. I just put those on to keep from baking the rear axle and this is now the way I wanted it. I ended up doing the 45* angle vs straight out the sides, it was easier and I do like the look as it is a bit different than how it would have come. Less interior noise at highway speeds too.

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Lol, where did that stick come from???

 

[Scooterwrench]

Lol, where did that stick come from???

...and he ran through the places where the rabbits couldn't go.

 

[L31MaxExpress]

Sounds like my ElCamino minus the lopey idle. What was that you blew out from under the truck?

A piece of brake lathe silencer that had apparantly fallen in the tail pipe while it sat around for years.

 

[L31MaxExpress]

I am going to try a different base fuel map later and play with the idle throttle opening screw. The PF4 ECU has me ready to order a DBC LS swap harness, yank the PF4 ECU and harness and throw it all up on ebay along with the single plane intake that is already not being used. It is giving me the same issues it has had all along. The acceleration fuel is absolutely maxed out and it still has an extremely lean tip-in. The base fuel map has atleast 20-30% too much fuel in it during deceleration and at some cruising areas and 10% too rich globally resulting in large adaption numbers that are outside of the systems desired range. The map for a stock cam with ~18-20 in/hg vacuum had fuel trims of -50% in places, like really is a very mildly cammed 350 that hard for Edelbrock to dial in correctly??? The cam is so mild in this basic L31 350 it is pulling nearly 20 in/hg vacuum at 750 rpm. Cold engine, shift to reverse, stalls out. If the engine is hot, sits until it cools down to 100-140F, go to start it no throttle, it either floods out entirely or starts at an extremely rich, low idle then the IAC flares the idle up. The AC compressor also peeves off the IAC logic everytime the compressor cycles. Then add in the fact that the way Edelbrock setup the vacuum advance is absolutely horrible and identical to using the smog junk era ported vacuum emissions bandaid. Not enough idle timing and the vacuum advance setup can only provide ~10* more timing at 20 in/hg during cruising. ECU needs to be thrown back through the front door at the Edelbrock group, with a detailed spreadsheet of fuel trims vs map vs rpm and the a timing map detailed out in the same manner with note that says fix and return me.

I doubt the fuel map I am going to try changes much, but I am going to lie to the POS to try to get the base map leaner. It has a map calibrated for the same displacement and cam vacuum profile, except for use with a 58 psi regulator instead of the 43.5 psi unit I am running. They also have a map for 35# injectors rather than the 29# with the same displacement and cam profile. I am going to first try using the 58 psi map which should make the ECU believe it is controlling 33# worth of injector when it is actually controlling 29# worth. On paper should lean the whole calibration out 12.9%. My fear though is that it will make the already 16:1 tip-in lean spike even at slight throttle openings even leaner. If that fails to lean it out enough to even out the fuel adaption the 35# map should be 18.75% leaner on paper. There is also a 35# map for 58 psi that would be even leaner in theory. My hope is that the acceleration fuel is just some pulsewidth thrown into the calibration and not altered much in any of them, if I can get it leaned out a bit in the base map and not make the tip-in lean spot worse, it might actually help correct the lean tip-ins with the ECU not having to pull so much fuel in the overly rich spots.

This harness, L31 distributor housing for a cam sensor, some LS coils, the 24x reluctor already behind the timing cover and a P59 PCM on a speed density tune is looking like a great option at the moment.

DRIVE BY CABLE DBC 1997-2006 STANDALONE WIRING HARNESS W/ 4L80E 4.8 5.

This harness is a 5 wire MAF and a 1 wire alternator. FREE ADAPTER Connectors TO CONVERT Harness TO DELPHI MULTI 4.8 5.3 or 6.0) Injectors. All other sellers will give you 3 wire that you have to convert to 5 wire and ev1 injector connectors that u have to convert to delphi. Lots of extra costs...

highperformanceinjectors.com

 

[Scooterwrench]

Well,that sucks! Might explain why it was in the bargain basement bin. Are you going to try to run the PF4 TB?

 

[L31MaxExpress]

Well,that sucks! Might explain why it was in the bargain basement bin. Are you going to try to run the PF4 TB?

I think it was a display model. It had never been bolted up to anything.

I will run the PF4 throttle body, it is a really nice piece. It has a GM TPS and what looks like a GM IAC. Will need to investigate the MAP voltage readings and calibrate the map values for the GM PCM and find a matching connector or just swap it out to something different if I do.

 

[Erik the Awful]

Rough math with premium fuel allegidly ~6.27 lbs per gallon, it is knocking down 22ish MPG at 8% duty cycle.

Nice! I did quick math with fuzzy numbers the other day and I think WCJr's getting about 12 mpg. It'd be better if I could keep my foot off the happy pedal.

 

[L31MaxExpress]

Nice! I did quick math with fuzzy numbers the other day and I think WCJr's getting about 12 mpg. It'd be better if I could keep my foot off the happy pedal.

That is my problem right now, that happy pedal feels darn good and sounds even better.

 

[L31MaxExpress]

I swapped to the 5009 map this morning as planned, the 58 psi map. Fueling is closer but still too rich during cranking and warmup. I have as much fuel as can physically be pulled out of both the cranking fuel and after statup enrichment but it is still too much fuel. I am throwing a 195F thermostat into this. I usually like cooler, but I am wanting to see if maybe it is messing with the system as it learns although Edelbrock does state 180F minimum. It does run pretty darn well though aside from my complaints and is completely drivable. I cranked up the throttle body screw so that the IAC was hitting its target in Reverse standing on the brakes. Seemed to help the transition a lot between in-gear and out of gear. The engine definitely runs better all around on the 5009 map. I will put some more miles on it and see what happens. I may move to the 35# injector map if it continues to ovefuel during startup and see if it is better than the one I am running now.

 

[Supercharged111]

It's a shame they dummyproofed it to the point an experienced tuner has to struggle to this extent.