Fun on a budget- My 96 Sierra 2500 454

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454C2500Longbed

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You got to be careful checking spark with a screwdriver, it's not like the old days, they kick like a mule now and can seriously hurt you.
Yeah, you're right, is a bit different now! I'll probably be more careful now, don't plan on doing it all the time, haha! Wasn't honestly too bad though, just let me know I'm awake LOL! It was pretty funny, got a chuckle out of my dad.
 

454C2500Longbed

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I got the cap and rotor replaced last night, of course it was not without stupidity. When I was taking off the cap I dropped my torx bit under the upper plenum and could not get it out. So the plenum had to come off again. Oh well, at least I'm getting good at it haha. It was much easier to get the rotor off with the plenum out of the way, so I didn't drop anything else. I really don't like hex or torx hardware, I never have. While working, a little parody of Edwin Starr's song War popped into my head. 'Torx! (What are they good for?) Absolutely nothin!'
Put it all back together and it fired right up! Thank God.
Here's some comparison pics if anyone is curious:
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someotherguy

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Getcha some actual torx screwdrivers. Way better than counting on the bit not falling out of your driver. Craftsman has a set of 5 that fit most of the smaller GM stuff - CMHT65051 includes T10, T15, T20, T25, T30 for $11 off amazon or even at Lowe's. Heck of a value for a decent set of drivers.

Richard
 

Road Trip

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I got the cap and rotor replaced last night, of course it was not without stupidity. When I was taking off the cap I dropped my torx bit under the upper plenum and could not get it out. So the plenum had to come off again. Oh well, at least I'm getting good at it haha. It was much easier to get the rotor off with the plenum out of the way, so I didn't drop anything else. I really don't like hex or torx hardware, I never have. While working, a little parody of Edwin Starr's song War popped into my head. 'Torx! (What are they good for?) Absolutely nothin!'
Put it all back together and it fired right up! Thank God.
Here's some comparison pics if anyone is curious:
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Q: What is the starting ratio post rotor & cap replacement? 1 for 1? 10 for 10?

And out of curiousity, how did the underneath of that rotor look? Any signs of
thermal stress or arc-through?

Just another big block owner rootin' for ya! :0)
 

454C2500Longbed

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Getcha some actual torx screwdrivers. Way better than counting on the bit not falling out of your driver. Craftsman has a set of 5 that fit most of the smaller GM stuff - CMHT65051 includes T10, T15, T20, T25, T30 for $11 off amazon or even at Lowe's. Heck of a value for a decent set of drivers.

Richard
Might have to grab those. Be great for the places my big ratcheting screwdriver won't fit.
 

454C2500Longbed

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Q: What is the starting ratio post rotor & cap replacement? 1 for 1? 10 for 10?

And out of curiousity, how did the underneath of that rotor look? Any signs of
thermal stress or arc-through?

Just another big block owner rootin' for ya! :0)
It was late by the time I finished, only ended up starting it twice. But it fired right up both times! Idle was a little high, even for warmup, so I'll check that out to see if I missed something. I've been holding off on replacing the plenum gaskets until I'm done taking it off and back on 5.875 million times, but I'll probably end up doing that soon.

It did look like it has arced through a few times, can grab a picture later if you want.

Thank you sir! And I gotta say, I really like your truck, man I wish mine was the same color.
 

Road Trip

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It did look like it has arced through a few times, can grab a picture later if you want.

Absolutely -- sharp failure photos are very helpful for others who are new to
the old school distributors and how they look when they are keeping us from
the big block purr.

Thanks in advance --
 

454C2500Longbed

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Absolutely -- sharp failure photos are very helpful for others who are new to
the old school distributors and how they look when they are keeping us from
the big block purr.

Thanks in advance --
Took a closer look at it, and all the dark spots are just dust that acts similar to brake dust in the way it sticks.
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The rotor does actually look salvageable, so I'll clean it up just to have on hand. Shouldn't need it with the new fancy stuff, but can't hurt to have. I believe most of the problem was with the cap, it's pretty trashed.

Fired it up a few times when I got home from school, and then a few more when I got home from work. Cranked up right away, no issues at all. It was idling suuuper high, 2 grand high, so I checked all the connectors on the throttle body, and sure enough, one was loose. Plugged it in properly, fired it back up and it ran perfectly.
 

454C2500Longbed

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Just got back from a drive. I had let it warm up a bit before we went, then shut it off. Went to start it up... and cranking. And cranking. Still cranking. Tried again, held the throttle wide open, then it stuttered and popped to life, had to feather the gas and open it way up to get it to come out of it. Once it came out of closed loop it ran and idled properly. Got it out on the road, drove alright. When I kept it at constant throttle it would start to stutter and buck a little bit, a heavy right foot would clear it up. It's getting way too much fuel, so I need to make the JET software communicate properly with my PC so I can learn how to tune it, as I can't get it to open any files. Turns out these injectors are not quite the same as stock. Got the truck out on the freeway, MAN, is it gutless at WOT. Wanders really bad on the freeway, really needs tie rods. Doesn't wander bad on the highway though.

Definitely needs a tune now, but at least I guess I have a baseline to improve over. Disappointing for a fuel injected big block. Lol.
 

Road Trip

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Just got back from a drive. I had let it warm up a bit before we went, then shut it off. Went to start it up... and cranking. And cranking. Still cranking. Tried again, held the throttle wide open, then it stuttered and popped to life, had to feather the gas and open it way up to get it to come out of it. Once it came out of closed loop it ran and idled properly. Got it out on the road, drove alright. When I kept it at constant throttle it would start to stutter and buck a little bit, a heavy right foot would clear it up. It's getting way too much fuel, so I need to make the JET software communicate properly with my PC so I can learn how to tune it, as I can't get it to open any files. Turns out these injectors are not quite the same as stock. Got the truck out on the freeway, MAN, is it gutless at WOT. Wanders really bad on the freeway, really needs tie rods. Doesn't wander bad on the highway though.

Definitely needs a tune now, but at least I guess I have a baseline to improve over. Disappointing for a fuel injected big block. Lol.

454C2500Longbed,

Thanks for the photos. I looked closely at the underneath of your distributor cap, and it looks
like it is just starting to show the discoloration that was evident in the cap below, which also
was causing a no-start situation:

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As for your new injectors, I want to be clear about the correct terminology.

When you engine is first started, and as long as your O2 sensors are below ~600°F, the
computer will be making all fueling and timing calculations based *only* on the stored
(default) tables in memory. This is referred to as Open Loop.

Once the O2 sensors are up to temp & the engine coolant is above a certain threshold, the
computer goes Closed Loop, and the fueling is now driven by feedback signals from the
operational O2 sensors.

In English, the tables in your VCM are tailored to the original injectors, so whatever net difference
there is between your new injectors versus the factory ones will be the error during Open Loop
operation. Once the system goes Closed Loop, then assuming the difference is within the limits
that the computer is allowed to deviate from the default, then your system will 'tune' around
this difference. Given this, I would expect that your truck won't drive quite right when cold,
but once it goes Closed Loop it may run just fine.

Definitely get your tuning setup operational, and once you figure this out, then all future tuning
down the road will actually be fun. Just that steep learning curve in the beginning.

Fingers crossed that you get this all sorted out sooner rather than later.

Best of luck --
 
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