My first ls

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Jan 25, 2018 | 09:38 PM

Squarebody1

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My first ls

I'm new to the group. I'm hoping for a little advice I have a 2000+ 5.3 truck engine and 4l60 transmission I'm putting in an 85 Chevrolet pickup. I had the engine running before I pulled it from the donor. I installed a btr stage 4 truck cam, valve springs, timing set, oil pump, and long tube headers. I'm running a flashed computer. I put a 3200 stall in trans. Dropping it all in this weekend. I have a set of 36# injectors but I'm not sure I'm going to need them. Anyone farmilliar with this setup? Am I going to need a tune immediately or will it run on stock tune? It will be open headers on initial start so I'm not planning to run it long. Thanks in advance

Jan 26, 2018 | 06:43 AM

Floader

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It will run on the stock tune if you dont change the injectors. It probably wont run real well, but it should fire up and idle as long as the VATS is deleted.

Jan 26, 2018 | 07:17 AM

Squarebody1

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Thank you floader. The vats is deleted. I pulled the setup out of another older truck and it ran in it. I'm not all up on the computer thing , that's why I'm here. Why will it run rough? Is it because of the cam and different air flow? If I buy a handheld tuner , can I tune it myself?

Jan 26, 2018 | 09:14 AM

LS1MCSS

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Quote:

Originally Posted by Squarebody1

Take it to a good tuner. Hand held tuners are usually a joke.

Jan 28, 2018 | 09:20 AM

Squarebody1

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So I've got the motor and trans in. I'm finishing up the wiring this morning and plan to start it in a few hours.

The donor truck had no 02 sensors. Exhaust was unhooked at manifolds. With a flashed computer I would still need them, correct? And again, why will it run rough with just a cam swap. I'm used to older sbc stuff. Thanks again

Jan 28, 2018 | 09:20 PM

Squarebody1

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Chirp chirp

Jan 28, 2018 | 09:57 PM

G Atsma

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Because a cam changes the way the engine pulls air in, which would change fueling and spark advance parameters. A different cam needs a different tune. A stock tune will not like a bigger cam, making for rough running.

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Jan 28, 2018 | 10:10 PM

G Atsma

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You can't delete the forward O2 sensors, as they are vital to running the engine.

Jan 28, 2018 | 10:23 PM

#10

Squarebody1

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It's running. No codes and no 02 sensors. Was told I didn't need them but will get some if I do

Jan 28, 2018 | 11:33 PM

#11

G Atsma

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It's running in open loop, speed density. About as accurate as a carburetor.

Jan 30, 2018 | 12:58 PM

#12

Lsxford

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Quote:

Originally Posted by Squarebody1

It's running. No codes and no 02 sensors. Was told I didn't need them but will get some if I do

You need to find a tuner and consult them on whether to use o2s or not. If its tuned properly it will run great in open loop, alot of turbo cars are this way. Are you running a MAF sensor?

G Atsma Will it not use the MAF sensor for fueling even without O2s? Should be open loop MAF or is that a custom OS only?

Jan 30, 2018 | 03:31 PM

#13

G Atsma

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The MAF tells it how much air is coming in. The O2's tell it how much of that air got used. Which of those two functions would you rather do without?

Jan 30, 2018 | 06:06 PM

#14

Lsxford

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Quote:

Originally Posted by G Atsma

The MAF tells it how much air is coming in. The O2's tell it how much of that air got used. Which of those two functions would you rather do without?

i understand what each sensor does. IMO for a daily i would want all 3, but for a performance type vehicle like a weekend toy you can get by with none of the 3 and it will perform fine. there are pros and cons to all of them, CLMAF, CLSD, OLMAF, OLSD. i believe it comes down to 2 things, the person that will be driving the vehicle and the person that will be tuning the vehicle. OLSD may not be as accurate as CLMAF, but it can run efficiently with great drivability.

my own vehicle runs OLSD btw

different strokes for different folks.