Rough Idle Solved!

ic3man5 · January 24, 2016

Posting my results in hopes it will help someone else down the road.

I've had a slight rough idle since around 500 miles driving the truck with it progressively getting worse over time. Had the BB Tune bump the idle up to 600 at 1000 miles and that seemed to eliminate it for the time being. I'm at 4.5K now and the idle was starting to get rough again. I decided to use seafoam spray (https://seafoamsales.com/sea-foam-spray/) into the intake, let it sit for about 8 minutes. Drive the piss out of the truck and now my idle is smooth as silk and looks like the instant MPG is better by about 4-8MPG. Before it would sit around 20-22MPG and barely stay in V4 mode going about 42-45MPH while now its sitting 28-32MPG at the same speed. Giving it enough gas to push it down to 20MPG while crusing at 42-45MPH will actually make it accelerate now instead of barely keeping it at the same speed.

Have a catch can on order and will be installing it within the next week or so, I'm convinced GM messed up big time with how dirty the intake valves get on these DI engines. I think my engine accelerated the problem due to a lot of multiple remote start warm ups and being below freezing temperatures.

Jordan18 · January 26, 2016

That's a pretty common fix that a few guys have tried here. I still spray sea foam every once in a while even with a catch can on mine to be sure. My question is, how much did you spray into the intake?

ic3man5 · January 26, 2016

I sprayed the whole can basically constantly for about 4-5 minutes. I had the hose around the throttle body just off enough to cause an air leak and enough to fit the plastic line in which cause the engine to rev to the point where I almost didn't need another person. Let it sit for about 8-10 minutes and then beat the shit out of it for about 10-15 miles. My 25 mile average is already up about 2-3 MPG since yesterday.

I'll probably do it one more time before I put the catch can on just to make its as clean as I can get it without actually taking the intake manifold off.

Stars_Fan · February 1, 2016

I sprayed the whole can basically constantly for about 4-5 minutes. I had the hose around the throttle body just off enough to cause an air leak and enough to fit the plastic line in which cause the engine to rev to the point where I almost didn't need another person. Let it sit for about 8-10 minutes and then beat the shit out of it for about 10-15 miles. My 25 mile average is already up about 2-3 MPG since yesterday.

I'll probably do it one more time before I put the catch can on just to make its as clean as I can get it without actually taking the intake manifold off.

Awesome news. I will seafoam mine next weekend when I'm free

ic3man5 · February 5, 2016

Quick update with the catch can installed, link to all the pictures of the install and how much came out after about 400 miles.

http://imgur.com/a/ZJx0b

FL335i · February 6, 2016

I can see the catchcan being expensive in terms of adding oil!

ic3man5 · February 6, 2016

I can see the catchcan being expensive in terms of adding oil!

The catchcan doesn't make the engine blow by extra oil, its just catching what would have gone into the intake.

FL335i · February 6, 2016

^ then why am I able to go 6,000-7,500 mi intervals stock, with no can and not be low on oil? I agree the catch can is only catching what is going through the system and I am looking at getting one. Let's say what you have in the pic above is 4oz in 400 miles. basically 1oz/100mi is what goes through the system. On a 7,500 mi OCI, using that math, I would use 75oz of oil or 2.3qts. That's an alarming rate of oil ingestion. Note I stated ingestion, not consumption. The motor is not burning it through the rings, valves etc. We are talking about how much is ingested via the PCV system. For all the amounts of oil I see on the catch can threads.... how were these people not adding 2qts of oil between oil changes? Something is not adding up here with the logic. I have 37,XXX on my truck. I drive a lot. I had 2 free oil changes when the truck was new. After that I started doing them. At no point have I ever needed to add oil between changes. I check my oil in the garage (level floor) after driving the truck a while and everything is hot. I let the truck sit about 15-20 minutes and then check the oil. Oil has never been low. I check my oil every 2-3 weeks. Note, I also only re-fill the engine with 8.0qts of oil, not 8.5 as the 8.5qts overfills it on the stick. I use AC PF63 filters or M1 filters, both the same size. Both made by Champ labs. I do not use the E-core AC's. So again, how were pre-catch can trucks not adding large amounts of oil. Were you adding oil prior?

ic3man5 · February 6, 2016

I would say 90% of that cup is water. Thats a 3oz cup and its half full. So maybe 0.15oz of oil per 400 miles. So catching 2.8oz of oil over 7500mi OCI that normally end up on my intake valves.

I'm not adding oil and I'm over the dipstick when cold with 8qts but its not foaming so I didn't remove any. Checked it one time after 2000 miles and doesn't look like I'm losing anything. Going to probably put 7 qt in next change and see where it sits on the dipstick; I think 8 quarts is too much IMO but I wouldn't be able to confirm it without dropping the pan and filling it up.

jagabom (Esquire) · February 7, 2016

I wonder if putting Seafoam in the gas tank would do the same thing? My gas lawn mower was running lousy so I put Seafoan in the gas. Fixed it right up.

Jim

1300c · February 7, 2016

I wonder if putting Seafoam in the gas tank would do the same thing? My gas lawn mower was running lousy so I put Seafoan in the gas. Fixed it right up.

Jim

It wouldn't work because our engines are direct injection. The Seafoam in the gas would be injected directly into the combustion chamber, and would miss the intake valves completely.

ic3man5 · February 7, 2016

It wouldn't work because our engines are direct injection. The Seafoam in the gas would be injected directly into the combustion chamber, and would miss the intake valves completely.

I still put some in the gas tank for the hell of it just for the combustion chamber even though I know its worthless it makes me feel better; Old habits die hard.

gmacecsko · February 10, 2016

I wonder if putting Seafoam in the gas tank would do the same thing? My gas lawn mower was running lousy so I put Seafoan in the gas. Fixed it right up.

Jim

I have about 18000 on my 2014 and it started running a little rough. Seafoam in a full tank cured the problem after running about 1/2 the tank. I also bought a can of the spray but have not used it yet. I have to add about a 1/2 quart of oil between the 1st and 2nd oil change at around 7k. But have not have to add since.

SierraMyst · May 26, 2016

Posting my results in hopes it will help someone else down the road.

I've had a slight rough idle since around 500 miles driving the truck with it progressively getting worse over time. Had the BB Tune bump the idle up to 600 at 1000 miles and that seemed to eliminate it for the time being. I'm at 4.5K now and the idle was starting to get rough again. I decided to use seafoam spray (https://seafoamsales.com/sea-foam-spray/) into the intake, let it sit for about 8 minutes. Drive the piss out of the truck and now my idle is smooth as silk and looks like the instant MPG is better by about 4-8MPG. Before it would sit around 20-22MPG and barely stay in V4 mode going about 42-45MPH while now its sitting 28-32MPG at the same speed. Giving it enough gas to push it down to 20MPG while crusing at 42-45MPH will actually make it accelerate now instead of barely keeping it at the same speed.

Have a catch can on order and will be installing it within the next week or so, I'm convinced GM messed up big time with how dirty the intake valves get on these DI engines. I think my engine accelerated the problem due to a lot of multiple remote start warm ups and being below freezing temperatures.

Could you more specifically tell me where in the intake did you add the seafoam please?