Exhaust sputter

[xLeGeNDx]

on Idle I get a sputtering sound thats fairly constant on my LQ1 at idle but clears up starting at the 1500ish RPM range, is that a normal thing?

i remember before i did the swap the engine ran perfectly with no exhaust sputter so what could the likely things be that would cause this?

94' LQ1 with 121k miles
new spark plugs and wires (properly gapped plugs)
New EGR Gasket
New Intake gaskets

[pocket-rocket]

When was the last time the timing belt was changed? The cams changing time from belt stretch can cause a sputter, but only to around 1k, which kinda throws me on yours...

[TGP37]

Sputtering? As in misfiring or popping in the exhaust?

Maybe you over looked something and oxygen is entering the hot exhaust allowing unburnt fuel to combust. Or you have a minor vacuum leak which is enough to disturb idle but is too minor to cause slight at throttle. Sometimes vac hoses get brittle at the ends and crack. And while working on the engine the brittle piece cracks open. Seems plausible since you just did a swap.

Check the goofy areas like the vacuum plenum for the blower.

[xLeGeNDx]

The timing belt was did about 35k ish miles ago i checked the belt on it before the swap and it still looked brand new but with these engines that really doesnt mean to much. Theres not even a single code being thrown either.

Maybe a small vid would help to hear whats going on, it kinda seems like a slight miss fire but its still pretty perky through out the entire RPM range.

See what you guys think of it, Video is here

[xLeGeNDx]

Well tore into a bit and removed my EGR and found unburnt fuel still inside of the EGR, which is starting to sound more like timing. opinions?

[pocket-rocket]

Wow, that's an odd missfire. It doesn't quite sound ignition related, so I would at least pull the plenum and valve covers and check to see how the cam flats are setting.

At least your EGR should be nice and cleaned now thanks to the fuel

[xLeGeNDx]

LMAO i was thinking that too but its still soot covered haha

I got the plenum and cam covers pulled and the cam flats all match in correlation to each other and are in the correct spots, so maybe it might be a DIS/coil slightly dropping maybe?

[pocket-rocket]

You could pull plug wires on the front one at a time to see which cylinder pair it is, then move that coil to a different location and see if the miss follows it. If it does it's the coil.

[TGP37]

Well tore into a bit and removed my EGR and found unburnt fuel still inside of the EGR, which is starting to sound more like timing. opinions?

Maybe, but a simple misfire, for what ever reason, can dump lots of raw fuel into the exhaust. Just the misfire alone does a lot but then the oxygen sensor detects extra O2 and thinks the car is running lean. That makes it even worse now the car isn't running at optimal AFR and more fuel is dumped.

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IDK Pocket, seems a failing coil would get worse at higher loads?

It almost sounds like something is loose. Like a worn valve spring not closing fast enough and allowing the valve to smack the piston.

I would check the DOHV system with a fine comb mentality.

It sounds like it is not rotating, up/down motion. It also sounds like it is loose and is being struck without force behind the object making the noise. Did you loose a small socket in the engine somewhere?

edit: Noticed the fuel in the EGR mentioned. Well, it is causing enough misfire for sure. I would think a valve problem resulting in a loss of pressure.

bad valve, valve seat, spring, etc......my guess

Are you noticing more torque in the low rpm range? Camshaft timing?

[xLeGeNDx]

Sorry for the extremely late reply on this, I have been extremely busy at the house here lately to actually get anything constructive finished to this car, had a little time today to check things out, started off by doing the carb cleaner test just to double check the gaskets and everything. turns out the upper intake was leaking and maybe the lower one is a bit as well, sprayed around the upper intake and saw a huge difference in RPM, so took the intake off and sure enough the gasket had a split right down one of the ports, would that be enough to cause the sputter that im hearing? i checked out everything else and it all checks out, even my timing is still intact.

EDIT 1: was looking around in the trunk of the car and found the FEL-PRO box in the trunk it had the 2 LIM gaskets and some other grey/red gasket in there, so im guessing at the time i replaced the upper i did the upper ONLY, upon doing some other research a leaking lower attributes to the "putt putt putt" sound im hearing like 75% of the time. opinions?

[Schurkey]

sprayed around the upper intake and saw a huge difference in RPM, so took the intake off and sure enough the gasket had a split right down one of the ports

It'll never run right that way.

[xLeGeNDx]

yeah, i tore it down and actually did the lower intake gaskets and that valley gasket here today.

that valley gasket was the worst part of doing the gaskets, the one that was on there looked so old and brittle, and was stuck down to the engine and was extremely hard to chip away.

Hopefully once i order a new upper intake gasket and 2 EGR gaskets it should be alright and if that annoying "putt putt" sound is back i guess imma have to do some back tracking to find it.

[velasaa2522]

I'm having the same exhaust sputter issues in my LQ1. My lower and upper intake manifold gaskets are still new. I'm thinking it might be an EGR or MAP sensor problem. It's throwing a code "EGR Error". I cleaned it up and put some silicone around the gasket but it's still throwing a code. Also it does smell like its burning rich. Could my MAP sensor cause it to misfire?

[Schurkey]

It's throwing a code "EGR Error". I cleaned it up and put some silicone around the gasket but it's still throwing a code.

Did you clean the carbon out of all the EGR passages?

[velasaa2522]

I just bought a brand new MAP sensor & cleaned inside the manifold the best i could. Unfortunately that did not do the trick. Back when I cleaned the EGR I just sprayed brake kleen on a rag & cleaned what I could with my finger. Put some gasket silicone on but that's about all I did.