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Discussion Starter · #1 ·
When I hit the gas very softly to go from 0 mph to 10 mph, the engine starts knocking a little. When I hit the gas very softly to go from 25mph to 35mph the engine starts knocking little. I have the 4 cyl with about 1,200 miles. Does anyone else have this problem? Or, what would you do in my case?
 

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Re: Engine Knocking (4-cyl engine)

AllenCW said:
When I hit the gas very softly to go from 0 mph to 10 mph, the engine starts knocking a little. When I hit the gas very softly to go from 25mph to 35mph the engine starts knocking little. I have the 4 cyl with about 1,200 miles. Does anyone else have this problem? Or, what would you do in my case?
Are you aware of the tapping noise that DI engines make? Could that be the noise you are hearing?

This has been discussed quite a bit: http://www.equinoxforum.net/index.php?topic=171.msg923#msg923
 

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Re: Engine Knocking (4-cyl engine)

AllenCW said:
When I hit the gas very softly to go from 0 mph to 10 mph, the engine starts knocking a little. When I hit the gas very softly to go from 25mph to 35mph the engine starts knocking little. I have the 4 cyl with about 1,200 miles. Does anyone else have this problem? Or, what would you do in my case?
Is your MIL light flashing?
 

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Discussion Starter · #4 ·
Re: Engine Knocking (4-cyl engine)

Roesterman said:
Are you aware of the tapping noise that DI engines make? Could that be the noise you are hearing?

This has been discussed quite a bit: http://www.equinoxforum.net/index.php?topic=171.msg923#msg923
I do hear the tapping. Unfortunately, that's not the one.

Maybe I can share the exact same noise I heard from another vehicle......

In 1991, I purchased a 1986 Cutlass Ciera (4 cylinder) with about 45,000 miles. Few years later (when it reach 70,000 miles) it started to have this funny sound like the engine has been over-worked or stressed when you hit the gas very lightly. I figured, well it's a four cylinder, nothing I can do.

On my Terrain, I'm already hearing that over worked/stress sound coming from the engine of the Terrain at 1,200 miles. I have babied this car just like I did with the Ciera.
 

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Re: Engine Knocking (4-cyl engine)

We had a similar ECOTEC engine in our HHR as we now have in our Equinox. That 2.4L ECOTEC preferred 91 Octane fuel, according to the owners manual. It would burn 87, but did much better with the higher octane. Since the compression ratio is even higher in the newer 2.4L, I wonder if high octane wouldn't be a bad idea still?
 

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Re: Engine Knocking (4-cyl engine)

AllenCW said:
The MIL is not flashing.
Then its not knocking....If your engine was picking up knock, it would flash the MIL indicator. I experienced this many times while tuning my previous ecotec engine under heavy loads of boost (30psi :eek:)

If I had a "rough" guess its your transmission you are hearing. The 4cyl uses a different tranny then the 6cyl, its torque converter is designed to lock-up very early in an effort to save gas (fuel efficient tranny). Due to the noise effects of this, GM installed active noise cancelation. Most are under the impression its designed to "cancel" out the DI engine, but its actually to eliminate the sounds coming from the tranny due to locking up the converter so early. If this issues is annoying...I would have your dealer check the system to make sure it works. There are procedures for this.
 

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Re: Engine Knocking (4-cyl engine)

Easy solution..Take it back to Dealer for Service....
 

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Re: Engine Knocking (4-cyl engine)

Narg said:
We had a similar ECOTEC engine in our HHR as we now have in our Equinox. That 2.4L ECOTEC preferred 91 Octane fuel, according to the owners manual. It would burn 87, but did much better with the higher octane. Since the compression ratio is even higher in the newer 2.4L, I wonder if high octane wouldn't be a bad idea still?
Direct Injection is supposed to allow low octane fuel on higher compression engines according to the 2.4L Engine description by GM
 

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Re: Engine Knocking (4-cyl engine)

RIT333 said:
Direct Injection is supposed to allow low octane fuel on higher compression engines according to the 2.4L Engine description by GM
Its not required...The LLT guys have shown this many times....Adding 93 into the 3.6l SIDI that puts out 304hp gains nothing on 91+ gasoline that it doesnt have on 87. Both the LAF, LLT are 11.4:1 while the LF1 is 11.7:1 (much higher then the LE5). THe only HHR that required 91+ was the HHR SS, which came wtih the 2.0L SIDI Turbocharged engine, putting out 130hp per liter...and even then it was "recommended" not required (stock tune it would run 87 with little knock). If you added the GM Stage 1 Performance upgrade kit, which took power to 290hp/340trq then 91+ was required.

Our engines are VERY advanced...Constantly making adjustments in timing/fueling and ignition. Then add VVT which allows intake and exhaust timing corrections throughout the rpm band (unlike a vtec for example)....They are designed to run on 87, and will see no improvement doing otherwise. GM would not want the average person driving around on a engine that knocks, knocks would be bad on an engine, especially one that the manufacture warranty's for 5/100k
 

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Re: Engine Knocking (4-cyl engine)

Check your oil level!!!! I had a similar problem on my 4cyl. SLT-2, and ended up burning approx. 6-8 quarts of oil within the first 4500 miles. Needless to say, there was a problem with the engine (2 cylinders were bad). After extensive testing, GM decided to replace the engine completely, and I am now at 5100 miles, and engine #2.

I know it sounds simple, but do yourself a favor and check the level. I did have a post regarding this before......... search for "excessive oil consumption". It sounds like the same initial problems I had - but I hope yours is not on the same path.
 

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Re: Engine Knocking (4-cyl engine)

grometsc said:
Its not required...The LLT guys have shown this many times....Adding 93 into the 3.6l SIDI that puts out 304hp gains nothing on 91+ gasoline that it doesnt have on 87. Both the LAF, LLT are 11.4:1 while the LF1 is 11.7:1 (much higher then the LE5). THe only HHR that required 91+ was the HHR SS, which came wtih the 2.0L SIDI Turbocharged engine, putting out 130hp per liter...and even then it was "recommended" not required (stock tune it would run 87 with little knock). If you added the GM Stage 1 Performance upgrade kit, which took power to 290hp/340trq then 91+ was required.
Our engines are VERY advanced...Constantly making adjustments in timing/fueling and ignition. Then add VVT which allows intake and exhaust timing corrections throughout the rpm band (unlike a vtec for example)....They are designed to run on 87, and will see no improvement doing otherwise. GM would not want the average person driving around on a engine that knocks, knocks would be bad on an engine, especially one that the manufacture warranty's for 5/100k
My 2007 Solstice (2.4) recommended premium gas and my dads 2009 HHR (2.4) recommends premium gas. They will run ok on regular but to get best performance manual recomends premium. I found the difference quite noticeable but had no issues with knock or pinging running on regular.
 

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Re: Engine Knocking (4-cyl engine)

Roesterman said:
My 2007 Solstice (2.4) recommended premium gas and my dads 2009 HHR (2.4) recommends premium gas. They will run ok on regular but to get best performance manual recomends premium. I found the difference quite noticeable but had no issues with knock or pinging running on regular.
Type: Ecotec 2.4L I4 VVT
Displacement: 146 cid (2393 cc)
Engine Orientation: Longitudinal/Transverse
Compression Ratio: 10.4:1
Valve Configuration: Dual overhead camshafts
Assembly Site: Spring Hill, TN
Valve Lifters: Hydraulic roller finger follower
Firing Order: 1 - 3 - 4 - 2
Bore x Stroke: 88 x 98 mm
Bore Center: 95.48 mm
Bore Area: 243 cm2
Fuel System: Sequential fuel injection
Fuel Type: Regular unleaded[/b]Horsepower:
173 hp (129 kW) @ 5800 rpm (preliminary)
Torque:
167 lb-ft (226 Nm) @ 4500 rpm (preliminary
 

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Re: Engine Knocking (4-cyl engine)

grometsc said:
Type: Ecotec 2.4L I4 VVT
Displacement: 146 cid (2393 cc)
Engine Orientation: Longitudinal/Transverse
Compression Ratio: 10.4:1
Valve Configuration: Dual overhead camshafts
Assembly Site: Spring Hill, TN
Valve Lifters: Hydraulic roller finger follower
Firing Order: 1 - 3 - 4 - 2
Bore x Stroke: 88 x 98 mm
Bore Center: 95.48 mm
Bore Area: 243 cm2
Fuel System: Sequential fuel injection
Fuel Type: Regular unleaded[/b]Horsepower:
173 hp (129 kW) @ 5800 rpm (preliminary)
Torque:
167 lb-ft (226 Nm) @ 4500 rpm (preliminary
And........
 

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Discussion Starter · #15 ·
Re: Engine Knocking (4-cyl engine)

I've been using 87 Octane since day 1.

(New Info): The night of April 11th, 2010, I filled up with 92 Octane (on almost empty tank). I still hear the knocking, but it has decreased 60%-70%. I REALLY hear the knocking when I'm traveling 35-40 mph going uphill.
 

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Re: Engine Knocking (4-cyl engine)

Most of the GM engines I've owned in the past 10 years have knocked noticeably on 87 octane. I usually burn 89 or higher and get great results. I guess it's the result of the higher compression.
 

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Re: Engine Knocking (4-cyl engine)

AllenCW said:
When I hit the gas very softly to go from 0 mph to 10 mph, the engine starts knocking a little. When I hit the gas very softly to go from 25mph to 35mph the engine starts knocking little. I have the 4 cyl with about 1,200 miles. Does anyone else have this problem? Or, what would you do in my case?
New member here, just joined today.

We got a 2LT 4cyl. 'Nox in November. The vehicle has 3700 mi. on it, it's my wife's daily driver.

At around the 3500 mi. mark she said she started to hear some spark knock. It wasn't harsh but there. I'm quite sensitive to such things (the engineer's curse,I guess), and sure enough it was light spark knock. It would happen in city driving, especially with the AC on, in about the same conditions you describe. I had it in the dealer yesterday to check it out since I was taking it in anyways for the HVAC software update and evap. canister campaign. The tech found nothing but the problem has gotten better in the last week. It was cool yesterday and the problem doesn't show up in cooler weather so it doesn't surprise me the tech found nothing right now.

I've asked on the GMinsidenews.com tech forum if anyone there had experienced this and no owners have seen it there. There are now two of us that have the issue, so it's something I'd wager is more common that I originally thought.

One thought on the other forum was the switch from winter to summer gasoline. That may explain why the problem is getting better in our 'Nox as the pinging is going away slowly by itself. I'll be back at the dealer if it keeps up, and since summer is coming it'll show up soon enough if indeed it's a problem. Don't be surprised if there's an ECM update to correct it in the future.

In the meantime, I'd suggest you take it to the dealer and see what they find. If you fill up with 92 octane it should never ever have spark knock. In our case, the car is running on 87 octane exclusively and the knock is very light.
 

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Discussion Starter · #18 ·
Re: Engine Knocking (April 22-update)

As of April 22, below is the latest update. Since everything is in limbo, I apologize for being little vague as there's a lot more to this story than I can share at the moment.

The dealer looked at it today. They told me what they "guess" is the problem (spark knock).......but they can not fix it. Since the diagnostics does not show a problem, GM would not cover guess work. We (myself, service manager, and the technician) know there's a problem and it's getting worse.......sounds like it has 100,000 miles on it. So this afternoon, the dealer called GMC. GMC called me back to gather information from me. One question they ask was "what would make me happy"? I replied "I'd like my money back". Her follow up question was "how many GM vehicles have I purchased in my lifetime"? Has anyone else received questions similar to this from GM?
 

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Re: Engine Knocking (April 22-update)

AllenCW said:
As of April 22, below is the latest update. Since everything is in limbo, I apologize for being little vague as there's a lot more to this story than I can share at the moment.

The dealer looked at it today. They told me what they "guess" is the problem (spark knock).......but they can not fix it. Since the diagnostics do not show a problem, GM would not cover guess work. We (myself, service manager, and the technician) know there's a problem and it's getting worse. So this afternoon, the dealer called GMC. GMC called me back to gather information from me. One question they ask was "what would make me happy"? I replied "I'd like my money back". Her follow up question was "how many GM vehicles have I purchased in my lifetime"? Has anyone else received questions similar to this from GM?
What you think is "spark knock" is not...If you engine was knocking you would have a flashing MIL light. Have them drive around with you in the car with the TECHII hooked up. It will show any issues the ECM is picking up, and the ECM will pickup knock before you do. But search any forum of a car that has a SIDI engine and you will find similar post

I do not expect an ECM update in the nea future to correct an issue GM does not have.
 

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Re: Engine Knocking (April 22-update)

AllenCW said:
As of April 22, below is the latest update. Since everything is in limbo, I apologize for being little vague as there's a lot more to this story than I can share at the moment.

The dealer looked at it today. They told me what they "guess" is the problem (spark knock).......but they can not fix it. Since the diagnostics do not show a problem, GM would not cover guess work. We (myself, service manager, and the technician) know there's a problem and it's getting worse.......sounds like it has 100,000 miles on it. So this afternoon, the dealer called GMC. GMC called me back to gather information from me. One question they ask was "what would make me happy"? I replied "I'd like my money back". Her follow up question was "how many GM vehicles have I purchased in my lifetime"? Has anyone else received questions similar to this from GM?
So what do they think is the cause of all of this? And the question from the GMC rep is rather odd.
 
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