Rough idle after 411 swap

[Ben C]

When a cylinder doesn't fire the O2 sensors will read lean. Kind of the opposite to what would expect, but makes sense when you consider it is measuring oxygen content.

[Tparkhill]

Cool bud,....consider going to gmtruckcentral.com for the dizzy install procedure from Aloicious. His procedure works perfectly,.....you'll see many people have done it this way and congratulated him on the thread/write up. It sets it perfect the first time.

I had planed on following this, thanks for the info

[Fast4.7]

Check the distributor gear on the cam.It is also worn.
Check all the plugs.
Replace the plugs that are fouled.2,8?
Fouled plugs screw up the fuel trims due to unburnt fuel.
See if the oil smells like gas,change it if needed.
You should use a real spark tester.
This type will simulate the electrical load that the plug needs.

http://i926.photobucket.com/albums/a...tos/kd2756.jpg

I highly doubt the drive gear on the cam is worn. The OEM distributor gear is a much softer metal than the matching gear on the cam.

[Earwax]

Good point, why waste the two minutes it takes to look at the cam gear with a light?

[Tparkhill]

Good point, why waste the two minutes it takes to look at the cam gear with a light?

Earwax. I plan on inspecting it just to be sure, and i do appreciate the advice to do so.

And My new dizzy came in the day after I ordered it! (crazy!) alas, I wont have time to put it in until this weekend. I work long hours outside and we are in the middle of some nasty fires.... The air index has us at 356 for the past 3 days now Bleh!

[Fast4.7]

Good point, why waste the two minutes it takes to look at the cam gear with a light?

Honestly what you posted suggested it would be worn and I hate to disagree. I don't disagree with taking a second to look at it, but I have done literally dozens of these gears and I have literally only ever seen ONE worn cam gear and that was a result of the wrong gear type on a cheap chinese distributor. I have never seen the factory Vortec gear eat the factory cam.

[Tparkhill]

Update Y'all! Burb is back and running well...... as well as it can 20* out of time lol. This distributor doesn't allow you to move it so Im guessing ill need to follow Aloicious's instructions on how to set everything.

Fuel trims are back to normal and I dont smell any gas.

[Fast4.7]

Update Y'all! Burb is back and running well...... as well as it can 20* out of time lol. This distributor doesn't allow you to move it so Im guessing ill need to follow Aloicious's instructions on how to set everything.

Fuel trims are back to normal and I dont smell any gas.

I take it the distributor drive gear was in good shape on the cam?

[Tparkhill]

Oh yeah, no problems there at all.

Overall the engine seems incredibly tight.... I ponder if its been replaced/rebuilt at a point in its life.

has 236k

[Fast4.7]

Oh yeah, no problems there at all.

Overall the engine seems incredibly tight.... I ponder if its been replaced/rebuilt at a point in its life.

has 236k

Based on 2 different ones I have pulled apart, I doubt it. I think my Express would still be on #1 if it had not had an intake gasket leak that hydraulic locked #2 piston and shattered #2 connecting rod at 57K.

I pulled apart a 280K 1999 suburban engine that was factory untouched a few years ago. It had been overheated to the point it cracked a head after intake gasket failure. Hit the cylinders with a bottle brush hone and put rings and bearings in it on a standard crank and stock bore. The bore was still round and within factory tolerance for both out of round and taper. In fact it still had noticeable factory cross hatch. Shockingly the crank was also still round and had very serviceable journals.

I also pulled apart a 250K mile 305 out of a 1996 Express that had spent 200K in the van and 50K in my buddies 1998 K1500 solid axle swapped mud truck. He beat on that engine relentlessly. When I pulled it apart found the same basic story as the suburban. I only found 3 potential iminate problems. The oil pump drive plastic coupler was in two pieces in the bottem of the oil pan, the timing chain was super stretched and finally it had 2 different roller lifters that were locking up and had put wear on both the lifter rollers and the cam. I ended up putting rings and bearings and a Lunati high efficiency 268 flat tappet cam/lifter set into it. That 305 was going in an Astro I never built but ended up in my a 1999 Tahoe for my brother.

[Fast4.7]

The 350 got a pair of 810 casting TBI heads, the 395' GM 300 HP Marine cam (cheapest new roller cam you can buy with a fuel pump lobe), an edelbrock performer intake manifold and went into a carbureted square body Suburban Last I heard it was still pulling the Suburban and a heavy trailer around town just fine thanks to the granny 4spd it is hooked to.

2 years later the 305 is still pulling my brothers 1999 Tahoe around just fine as well.

[Tparkhill]

The 350 got a pair of 810 casting TBI heads, the 395' GM 300 HP Marine cam (cheapest new roller cam you can buy with a fuel pump lobe), an edelbrock performer intake manifold and went into a carbureted square body Suburban Last I heard it was still pulling the Suburban and a heavy trailer around town just fine thanks to the granny 4spd it is hooked to.

2 years later the 305 is still pulling my brothers 1999 Tahoe around just fine as well.

Sounds like you been around the block a few times (no pun intended)

I feel like tahoe's could have had the option for the 305's and been just fine. At work we have an old C2500 with the 305 5spd and it gets around really well even with a dump trailer hooked to it. people complain about 305 but in reality its the same as a 350 just has a smaller stroke and bore.

People also dont realize that HP means nothing without the right gears......

[Fast4.7]

Sounds like you been around the block a few times (no pun intended)

I feel like tahoe's could have had the option for the 305's and been just fine. At work we have an old C2500 with the 305 5spd and it gets around really well even with a dump trailer hooked to it. people complain about 305 but in reality its the same as a 350 just has a smaller stroke and bore.

People also dont realize that HP means nothing without the right gears......

Considering the base powertrain in the 8600 gvw 8-lug 2500 Express was a 4.3 V6 backed to a 4L80E and 10.5" 4.10 14-bolt. The 305 moves well. I feel the Tahoe could have come with a 4.3 and been fine too, especially if that 4.3 had a supercharger.

305 has the same stroke, smaller bore than a 350. I personally like the 307 better than the 305 as far as Bore/Stroke and Rod Length/Stroke ratio. The 307 is basically a 283 block with a 327 crank.

[Tparkhill]

Considering the base powertrain in the 8600 gvw 8-lug 2500 Express was a 4.3 V6 backed to a 4L80E and 10.5" 4.10 14-bolt. The 305 moves well. I feel the Tahoe could have come with a 4.3 and been fine too, especially if that 4.3 had a supercharger.

305 has the same stroke, smaller bore than a 350. I personally like the 307 better than the 305 as far as Bore/Stroke and Rod Length/Stroke ratio. The 307 is basically a 283 block with a 327 crank.

The 4.3's had potential for sure. A tahoe with a factory supercharger? those would have flown off the lots like crazy and maybe I'd own one lol. But I dont like the wheel base and that the windows dont go all the way down.

You know another thing that I ponder about GM's thinking. My friend has a 98 1500 suburban that came factory with a 4L80E but they paired it with a 10 bolt rear end and 3.73 gear... And I own a 94 GMC pickup with a factory 4L60E but it has the 14 bolt S/F rear end (6 lug) because of the F44 package... kind of weird to think about. 1500 suburbans never came with a 14 bolt S/F (6 lug) rear end. And 2500 burbs that came with a 5.7 had the S/F 14 bolt (8 lug) and 2500 burbs with the 7.4 always had the F/F 14 bolt (8 lug)

sometimes you just gotta shake your head and wonder who was in charge of this stuff........

[Fast4.7]

The 4.3's had potential for sure. A tahoe with a factory supercharger? those would have flown off the lots like crazy and maybe I'd own one lol. But I dont like the wheel base and that the windows dont go all the way down.

You know another thing that I ponder about GM's thinking. My friend has a 98 1500 suburban that came factory with a 4L80E but they paired it with a 10 bolt rear end and 3.73 gear... And I own a 94 GMC pickup with a factory 4L60E but it has the 14 bolt S/F rear end (6 lug) because of the F44 package... kind of weird to think about. 1500 suburbans never came with a 14 bolt S/F (6 lug) rear end. And 2500 burbs that came with a 5.7 had the S/F 14 bolt (8 lug) and 2500 burbs with the 7.4 always had the F/F 14 bolt (8 lug)

sometimes you just gotta shake your head and wonder who was in charge of this stuff........

Ran across a 1995 G30 Van not long ago with a 4L60E behind the 350 despite the semi float 9.5 14-bolt.

I swapped a 4L85E and 3.73 G80 9.5" 14-bolt into my 1997 Express as the factory parts failed.

[Fast4.7]

I ran across something online that should give an idea as to just how long the Vortecs can keep running.

https://m.youtube.com/watch?v=zqzfWmWOROo

[Tparkhill]

That is literally insane! I think I'm going to switch over to Amsoil now lol

And no way a 4L60E got him to 1,000,000... its gotta have a 4L80E lmao

[Fast4.7]

That is literally insane! I think I'm going to switch over to Amsoil now lol

And no way a 4L60E got him to 1,000,000... its gotta have a 4L80E lmao

I am running Mobil One 0w40 and have forever in mine. From what I saw the last time I was in the engine I will not be changing to Amsoil.

[Tparkhill]

so the burb is running better but still has a pretty rough idle...... Its not registering any misfires or anything but the idle is still rough, especially in drive.

I hooked up my scanner and went through the engine data and saw the O2 sensor on B2S2 was showing a mV of 4 while every other sensor was floating around 400-700 at idle.

Dunno if that means anything............

[Tparkhill]

Bump