Engine Stumbles
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AmadeusSenior Member
- 166
Engine Stumbles
Hey everybody looking for some help. Today I pulled off the intake plenum so I could replace a broken pintle cap on one of my injectors and also replace the injector seals, also put in new spark plugs. But after putting it all back together I developed a problem with keeping it running. It'll start up and thenit begins to stumble really hard and I'll hear a hissing noise from around the throttle body area, and when I give it some gas I'll begin to hear a popping noise coming from I think the Intake manifold. I've looked under the hood and don't see any vacumm lines off nor do I see/smell and gas leaking. The only thing I can think about is that I have a leaky gasket between the plenum and the lower manifold.
Any ideas?Bah-chicka-wow-wow -
perna00Senior Member
- 314
If it is hissing that badly, take some starting fluid and spray it around the seal between the upper and lower plenum and see if the idle changes. If so, leaking gasket. Take a screwdriver to each injector to feel if they are all pulsing since you worked on them. -
CarelessSenior Member
- 13279
I've been hearing a slight hiss in that region near my throttle body too… I'm not sure if I used a paper or a metal gasket for the plenum gasket…
which did you use? -
AmadeusSenior Member
- 166
I reused my metal one. Cause everything that I had read said that you could reuse metal ones as long as they wheren't damaged.Bah-chicka-wow-wow -
CarelessSenior Member
- 13279
Did you ever sand or scuff the mating surface of the plenum or the lower intake manifold?
I resurfaced mine with a surfacing disc… but at this point I'm not sure if it was done well enough. It may be rounded out a bit at the edges, but it looked smooth… I'll have to re-torque the bolts to see if they're OK..
Have you tried checking the bolt torque? -
AmadeusSenior Member
- 166
Yep cleaned off the matting surfaces and tightened the bolts with a torque wrench like the FSM says.Bah-chicka-wow-wow -
CarelessSenior Member
- 13279
same. I used a paint stripping sponge that I used on everything else, so I don't know if it's leaking from there.
Does the throttle body seal leak under boost? I got a Stanza TB and It was one of the only things that I actually changed, mechanically, during my vg30 repair that also developed the whistle.... -
AmadeusSenior Member
- 166
No the TB seal doesn't leak. I'm just going to replace the plenum gasket cause it's a $5 repair and I'm almost 100% sure that that's where the leak is from.Bah-chicka-wow-wow -
AmadeusSenior Member
- 166
Well it turned out to be the plenum gasket. Replaced it with a new gasket for a 2000 Xterra and it runs like a top now, just need to tighten up a couple of the intake clamps.Bah-chicka-wow-wow -
michaelpSenior Member
- 9384
intake manifold gaskets these days..pff. LOL- VG30DET (HE341) 86 300ZX - 1982 280ZX Turbo - Headered NA 1986 300ZX 2+2 - 2000 Xterra - -
Matt89Senior Member
- 2380
No, it is not ok to reuse the metal gaskets. The sealing ring compresses when you torque the plenum down.Bolt on, fast, z31. You can only pick two.
Old weaksauce numbers: 391hp/433tq