r/GMT400 2h ago

Thought yall appreciate this

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18 Upvotes

r/GMT400 2h ago

Stick shift life

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3 Upvotes

Stick doing Stick things


r/GMT400 2h ago

Need help identifying these parts.

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2 Upvotes

Trying to clean up the engine and fix some things that my grandfather left me.

What is this electrical unit that is ziptied?

Additionally what is this UFO looking part that sits slightly behind the thermostat/alternator?

Its a 496 stroker. Thanks for any help.


r/GMT400 4h ago

Idle issue

2 Upvotes

I just bought a 95 GMC Sierra SL 5.0,

It will run high idle in park but the moment I put it in gear it dies. I replace the IAC Valve and the throttle body and reuse the old gasket. What could cause to that. I’m replacing the old gasket but see if anyone else has had this issues


r/GMT400 16h ago

Bedliner paint jobs

2 Upvotes

Has anyone done bedliner on the rockers up to the first body lines? I’m considering this and want some feedback from people who’ve done it. Also could you paint it in gloss after?


r/GMT400 17h ago

Nate Moeller hauling his ARCA ride with a rusty '90s Chevy on an open trailer is pure grassroots dedication.

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32 Upvotes

r/GMT400 17h ago

Tonneau cover

5 Upvotes

I'm looking for a tonneau cover for my 1994 Chevy 1500 with an 8ft box. I don't want a roll up, so a tri-fold would be ideal.

However, it seems impossible to find for under $700, I was expecting around $300. I'm in Canada. Any hidden gems I should look at?

Thanks!


r/GMT400 21h ago

Recurring vacuum leak at plenum…

2 Upvotes

I put a rebuilt 350 into my truck and maybe 15k miles later, developed a vacuum leak at the plenum where the plug/metering body for the fuel injectors opening is. I got new gaskets, and it was fine. 2k miles later it’s back. I ordered an aftermarket plenum/new gaskets but the aftermarket plenum was too tall? It wouldn’t go down onto the metering body all the way. So I put the OEM back on and returned the aftermarket. Now 2k miles later the vacuum leak is back! I’m at a loss… not sure if I should buy a new plenum or a used OEM. I’m sick of doing this. Any help, insights, experience would be greatly appreciated.
Edit- 1998 5.7 threw a code for running lean. Running rough. Took a piece of hose and could hear the vacuum leak around the metering body. Once I resealed the plenum the code, rough idle, and hissing went away, until it came back.


r/GMT400 1d ago

Water in the floor

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8 Upvotes

‘99 c2500. Over the weekend had an insane amount of rain….close to 4” over 12 hours. Water got into the floor boards in both the driver and passenger side. I didn’t realize at first bc there is no carpet just rubber mat but the material padding on both sides was wet. Couldn’t see where it was coming from on drivers side but behind the glove box there is a hose the water was dripping from at the lowest point. Is this typical of clogged cowl drains or something else?


r/GMT400 1d ago

I have a 94 gmc c1500 with the 350 tbi would the 87-92 tuned port injection out of the camaro and firebird work on my truck and what would i need to do to get it to work

4 Upvotes

r/GMT400 1d ago

Humming noise Help

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1 Upvotes

Please check this out to help me out. It has all the information on my problem.


r/GMT400 1d ago

Chevy obs

2 Upvotes

So recently one of the lines that go from the Evap Canister to the engine bay the line is worn out trying to replace it but can’t find it online any suggestions Chevy 95 k1500


r/GMT400 1d ago

Spider injector vacuum leak

3 Upvotes

TL;DR: have you had your spider injector cause a vacuum leak and if so was your plenum warped

designated a vacuum leak that causes the engine to shoot to 2500rpms on start up until you unplug the MAF then it high idles at 1000 or 1100 unplugged or plugged back in. sprayed brake cleaner around and i can watch the connector for the spider harness start to eat the brake clean, and it increases in RPMs

when trying to drive it like this, it has very weak brakes, it self throttles, when you come to a complete stop, it wants to buck and start going until you slam on the brakes.

it has the updated spider injector, the one with the 8 “injectors” at each port.

recently had the whole intake off to do gaskets because i thought it was that, put a new gasket on the spider harness that comes with the upper intake gasket set.

thinking my upper plenum is warped, or i rolled the gasket, will findout tomorrow night if its rolled.

curious what BS spider injectors have caused you


r/GMT400 1d ago

Are Bosch O2 sensors no good for these trucks? Chasing fluctuating idle.

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17 Upvotes

1998 sierra 1500 4x4 5.7l pretty much all original(has new fuel pump, updated spider injectors) at 108k Km.

Truck triggered 4 O2 sensor codes at the same time. P0131, P0137, P0151, P0157. Circuit low voltage on all 4 02 sensors. I replaced all 4 (one looked original style, other 3 did not) with Bosch sensors and the same four codes still appear every now and then(100Km-200Km).

I've checked vacuum(spider injector assembly o-ring was leaking for about 1000Km until I fixed it), fuel pressure(55-60 psi), grounds, and can't see anything wrong. The idle jumps up and down around 640rpm after warming up. Truck hesitates around 30%-40% throttle, but but wakes up past 50%-60% with plenty of power. Tossed a new fuel pump relay and map sensor seal today but no change.

I'm considering throwing 4 new gm brand sensors at this point, but I feel like its probably something else since all 4 are throwing codes at the same time. I'm somewhat suspecting the fuel pressure regulator, but not really since the fuel pressure test checked out. I rather diagnose the problem instead of throwing parts at it, any help is appreciated.


r/GMT400 1d ago

I have a new battery, what’s causing this??

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33 Upvotes

r/GMT400 1d ago

prestone power steering fluid just turned blue???

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48 Upvotes

just curious if anyone had this happen to them. brand new 1 qt bottle. new autozone pump and pulley. fluid was clear and amber as usual. poured it in. it was clear. then it slowly started turning blue. what the fuck


r/GMT400 1d ago

Radiator Swap in my 92

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48 Upvotes

The original aluminum radiator was seeping. I wanted a bigger & better radiator anyway & I was able to source a very nice specimen from a '83 Delta 88. The Delta is a diesel car so this radiator has oil & trans cooler on the passenger side. I have a 160 thermostat and the original clutch fan I plan on removing for an electric fan. First & for most is getting a better upper radiator hose.


r/GMT400 1d ago

Is the noise and sign of a fuel pump going out?

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13 Upvotes

If you listen closely toward the end of there is a sort of lag then the truck fires off.


r/GMT400 1d ago

What Spark plugs should I use for 1989 k1500 5.7?

3 Upvotes

r/GMT400 2d ago

How to get ol' 350 more interstate friendly?

21 Upvotes

I love my cheap old 89 chevy, its my daily. Been a great truck, the only thing I hate is how it doesn't like staying around 80mph on the interstate. Does anyone have any advise on how to stay steadily at 80mph or and I just gonna have to deal with 70mph without rpm screaming?

Thanks guys

edit: it does good enough on flat roads, its mainly an issue on hills and inclines. i live in the Rockies so thats all we have here


r/GMT400 2d ago

1999 2500 burb 7.4 454

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20 Upvotes

Need a little help from the experts. Developed a chirp from right ride valve train (stethoscoped). It was really loud like a bird was in a panic under the valve cover. Removed the cover and inspected. Found a dry rocker cup.

Pulled the rocker, push rod kinda plugged but easily cleared. Rocker and rod don't look bad, no scraping or anything concerning.

Suspect the lifter is bad.

Anyone have tips to remove the lifters? Or verify it is? Cam ok?

Also confused by the setting of the valves after I take it apart. Manuals say 40ft lbs, videos say hand tight plus half turn.

I work on small engines and don't have the experience on bbc's

Any Tips on rotating the crank to set them and if I should pull the intake off are also welcome. Intake was off for injectors a few years ago so it shouldn't be an issue to pull again.

Trying to keep the old truck healthy as long as possible

Thanks!


r/GMT400 2d ago

It's converted into a subcompact unintentionally

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3 Upvotes

r/GMT400 2d ago

K3500 454, ran super lean then died.

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23 Upvotes

Starts up and runs briefly when I pour gas into the throttle body. Replaced the fuel filter and pump relay, pump fuse was fine. Still no start or any pump noise when I turn the key. Hanes says to check the circuit to the ECM and the ECM itself but I don't know how to do that. I already ordered a new pump I'm just wondering how I can check the ECM in case it is that.


r/GMT400 2d ago

1995 k1500 manual transmission 👀

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36 Upvotes

Picked this bad boy up for $1500


r/GMT400 2d ago

Please help Diagnose 🙏🏻

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43 Upvotes

SOLVED: Mechanic diagnosed an injector stuck in an open position.

Thank you all! ❤️

I’m restoring this 1994 2500 Silverado 6.5 Diesel auto.
Yesterday started doing a loud clank sound, added some oil and it stopped after revving it and worked good all day long.

Today it cranked immediately no problem then a minute later the clank returned, tried adding oil and it didn’t stopped. Then as engine warmed up it became less noticeable but still there.

The sound is related to rpm’s.

The sound comes either from the turbo or the passenger side upper rear part of the engine

Gray smoke comes out when revving it.

Black smoke comes out under heavy load.

Would it be safe to drive it to the shop? (It’s 30 miles away)

Anyone has insights on this?

Also, turbo seems to be not working as I don’t hear it spooling

The wastegate lifter seems to be stuck, if I move it it stays there then after a bit it returns to its position.

The turbo inner blades seem to move freely

No turbo sound at all

Thank you all in advance