High idle help.

[kidd666]

Ok so I replaced my intake manifold gasket yesterday and the truck won't idle right. The idle stays around 1000 to 1200 rpms. I need some help idk what to do or where so start. It's a 94 k1500 5.7l

sent from your moms house

 

[1998K1500]

Around 1,000 to MAYBE 1,100 is normal for a cold start in winter but it should go back down obviously

Check for vacuum leaks or maybe an issue with idle air control valve. Just a few ideas to check out

 

[kidd666]

Checked for leaks with starter fluid and didn't get any. will check the valve tho

sent from your moms house

 

[skylark]

The timing being set too high can cause this also. Make sure that you disconnect the wire behind the glove box to set the timing. If my memory serves me correctly it is a tan wire with a black stripe.

 

[kidd666]

Looks like it is possibly a bad intake gasket. I'm getting vacuum off of my valve cover. Pull the oil cap off while it's running and flip cap over and you can tell it's pulling air in instead of pushing it out. And also the truck won't time right. Set it back to 0 degrees and when you plug the timing wire back in it will advance it's own timing

sent from your moms house

 

[vic_v8]

yup, sounds like a bad intake gasket set. Been there. Also, I check for a leak with one of those little blue torch bottles.

 

[someotherguy]

OK, you're getting vacuum at the valve cover but you need to be sure first - disconnect and plug the PCV, disconnect its breather tube from the valve cover, plug those holes with something that won't get sucked in. Corks, strong tape, rubber plugs, whatever. Then run the engine and check for vacuum at the dipstick tube. If any, yeah, you got gasket problems. They might have shifted while you set the intake down. I use some RTV on them to hold them in place. A ring around each coolant passage and then a very thin skin of it over the rest of the gasket just to be safe...then thread some bolts in a little bit as a guide to hold them in place while the RTV tacks up a moment.

You must be registered for see images attach

Richard

 

[skylark]

OK, you're getting vacuum at the valve cover but you need to be sure first - disconnect and plug the PCV, disconnect its breather tube from the valve cover, plug those holes with something that won't get sucked in. Corks, strong tape, rubber plugs, whatever. Then run the engine and check for vacuum at the dipstick tube. If any, yeah, you got gasket problems. Richard

Genius! I always knew there had to be a better way to check for an intake gasket leak under the manifold.

 

[kidd666]

I ended up replacing gasket again. Didn't have vacuum problem after that. But my tps went out too. So that's now fixed and all is well now. Thank you all for the tips and advice. It is very much appreciated

sent from your moms house