The Stupid Engine Questions Thread

[JalopiedAllOver]

Where do these plug into? I feel stupid, can't figure it out!

97 k1500 suburban

I removed the air filter housing for this- but I did it about 2 weeks ago and just got back to replacing it and I don't remember what I did to unplug these. Don't see where these vacuum hoses go. Don't tell me they plug into each other!

 

[Orpedcrow]

97 k1500 suburban

I removed the air filter housing for this- but I did it about 2 weeks ago and just got back to replacing it and I don't remember what I did to unplug these. Don't see where these vacuum hoses go. Don't tell me they plug into each other!

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Rear heater hoses maybe? I don’t know how they’re routed on a suburban/Tahoe. But I don’t see anything else on that side in my Silverado.

 

[MMcc]

Wrapping up a regear from 3.73 to 4.55.
Does the PCM need to be reprogrammed right away? Or does it just throw off the speedometer?
33s, K1500, 4L60E
Mondays are tough at a desk when you rather be wrenching...

 

[IcicleDBR]

I have yet to find any mention of this on the exhaust thread, but why are nearly all aftermarket headers circular port when the tbi and vortec heads have rounded square port? I see people linking circular port headers to thr exhaust thread too. Are they aftermarket circular ones just so big that it doesn't matter on the head?

 

[Erik the Awful]

I know that circular port headers exist, but I don't know where to find them. Most headers have round tubing that's squared off where it goes into the flange. The headers on WCJr are that way, as well as all the other headers I've ever bought or made.

 

[baddawg]

Question, I've read it somewhere, I think it caused a problem between a few members, but I can't find it again.
I went from a coil and stock distributor, to a HEI with the coil built in. As ya'll know the plugs are completely different.
I changed over the POWER and TACH wire, and have them in the proper place, the HEI has its own wire from distributor to built in coil.
That leaves me with the 4 prong plug that went to the old distributor.
Does someone know the wire on the 4 prong that I have to put power to?????
I have an external fuel pump, so that is not an issue.
I rebuilt my 454 last winter to about 500HP, and I could not get the timing up enough with the old ignition, so I went with a MECHANICAL and VACUUM advance HEI.
Thanks

 

[FighterOfTheFoo]

Seeing if anyone in the Midwest has any input on the THERMAC valve/ thermostatic valve in the air filter housing intake on a TBI. I noticed mine does not open at all, even after half an hour on the interstate. Some people say in states where it gets cold you do need the heat from the exhaust to help on startup and to stop throttle icing. I do not see anyway to replace it and I'd rather not have all the air being drawn through that tiny hole. Has anyone had any negative effects in winter from removing or tack welding that flap open?

 

[EJ_74]

Which way does the PCM KS module cover go? Does the little pin (circled) press down on the module or go in the opposite corner, not touching anything?

 

[ralmo94]

Wrapping up a regear from 3.73 to 4.55.
Does the PCM need to be reprogrammed right away? Or does it just throw off the speedometer?
33s, K1500, 4L60E
Mondays are tough at a desk when you rather be wrenching...

Should be fine, shift schedule might seem off, but the truck will just think it's going the speed your speedometer says.
Shift schedule is based on throttle position and Mph, so it should shift the same rpm as it has been. Once you calibrate it, it might be different.

What means of calibration do you have?

 

[fancyTBI]

Are the ‘93 and ‘94 PCMs the same? I found a ‘93 K2500 454/4l80e donor truck. I was going to swap over the harness and PCM to my ‘94 K2500 350/4l80e if the process isn’t too involved.