The Stupid Engine Questions Thread

[Zabo]

Really don't feel like TLDRing the thread but here's my dilemma.

Picked up a '95 Tahoe Blazer LT for next to nothing. Aside from a dying 10 bolt rear and a finicky 241C case, it's also got the TBI Chug-a-lug at idle. It's sat for the past year and prior to coming into my possession the gas was purged, a new fuel filter installed, injectors cleaned (twice by myself), Dizzy replaced, new wires, plugs, shocks were newer Rancho. For an LT Trim it was in damn good shape for 235K miles.

I've replaced the O2 sensor (first idea) and also had a local hotrod wiring shop take a look at it (they own several T-400s so it's not foreign territory). Wiring came back good, no codes either. The O2 sensor solved a cold surging idle and stalling issue but for some odd reason the engine still chugs (won't stall) when idling in gear through a parking lot. Blip the gas (pedal is stiff) and 15mph+ the truck runs totally normal. I'm also getting oil pressure dips into the 20-15psi range but the truck has plenty of oil and there's no knocking or pinging.

I've narrowed it down to sensors now but I'm at a loss still.

Here's some photos of the dash. Engine is warmed up and it stutters on takeoff but above 30 it's fine.

http://i.imgur.com/nrKYxbf.jpg

http://i.imgur.com/OrdDkDB.jpg

http://i.imgur.com/zj0z9eY.jpg

 

[brhaacke]

I have a small oil leak with my rear main seal. Anybody have experience with this? I was going to try something called "blue devil rear main seal leak" just cause why not.

Vortec 350 with 150 on it. I would love this motor to last me 5 years until I can afford to rebuild it. Poor college kid.

 

[senja]

Before you get your hands dirty, do one quick check. Check the dipstick to see if there is any water in the oil. Is there oil pressure first thing when you fire it up in the morning, but then the oil pressure drops to 0-5 after a minute or two? Drain the oil and put 4 quarts of fresh in. Is the oil pressure consistent? If it is, you got out cheap, and your oil is water contaminated. Now...where's that water coming from? The other suggestions are all good, too. Especially the oil filter check for tiny metallic flakes.

 

[House003]

Where is the fuel pressure supposed to be at? 5.7

 

[Neb15]

I was changing the air filter and started cleaning the tb and parts around it. as soon as i started messing with the metal spacer under the air cleaner (above t.b.) and the old gaskets started to fall apart. I went to a couple local part shops and the one said it is a part that comes with the throttle body so they dont stock gaskets for it (the other thought it was aftermarket). He said I could replace it with a straight spacer that had built in gaskets, but I would have to add the breathers to the valve covers and block the egr. I might go down that road in the future when I want to spend some cash and get an open element air cleaner.
Any way my question is what do I do in the mean time to seal this up better? I was thinking using some silicone gasket maker on both sides of it, letting it dry for a bit then putting it on. Any other suggestions or anyone have similar problems with the stock set up. I might add a catch can to keep a bit more oil out the intake too, off the line on the back of it.
Here is a potato quality photo of what im talking about

You must be registered for see images attach

 

[Neb15]

Anyone know off hand if an s10 radiator is big enough for our trucks? I know they have all the same trans and oil coolers built in, I might measure it up this weekend and see if its possible.

 

[frito-bandito]

I have a 98 c1500 with the Vortec 305, why would it idle high and have a slight miss at above 2k rpm? All ignition parts are new....

 

[96C1500]

I'm not the most experienced in this, but the high idle might be the idle air control valve, miss might be the distributor. Like I said, I've never had an issue with one of these trucks like that (knock on wood lol) but that might give you somewhere to start.

Sent from my Vortec powered HTC One M8

 

[Ruger_556]

I was changing the air filter and started cleaning the tb and parts around it. as soon as i started messing with the metal spacer under the air cleaner (above t.b.) and the old gaskets started to fall apart. I went to a couple local part shops and the one said it is a part that comes with the throttle body so they dont stock gaskets for it (the other thought it was aftermarket). He said I could replace it with a straight spacer that had built in gaskets, but I would have to add the breathers to the valve covers and block the egr. I might go down that road in the future when I want to spend some cash and get an open element air cleaner.
Any way my question is what do I do in the mean time to seal this up better? I was thinking using some silicone gasket maker on both sides of it, letting it dry for a bit then putting it on. Any other suggestions or anyone have similar problems with the stock set up. I might add a catch can to keep a bit more oil out the intake too, off the line on the back of it.
Here is a potato quality photo of what im talking about

You must be registered for see images attach

You can buy that spacer from GM with the gaskets, it wasn't very much when I bought mine... You don't have to modify anything to make it work either.

 

[frito-bandito]

The PCV line was broke, so that fixed the high idle, still chasing down the miss, which is strange cause the truck has amazing power for a 305, that's what's throwing me for a loop.