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Discussion Starter #1
I’ve had my GXP for a year and a half now, and absolutely love it. But, it has a few symptoms that I wanted to see if any experts could help diagnose. The car has about 58000 miles now, and the water pump was replaced at some point.

1. Hesitation - when the engine isn’t fully warmed up, I notice hesitation, particularly accelerating moderately through 2nd gear. I’ll feel 4 or 5 very brief (half second) drops in power as I go through 2nd gear. Normal?

2. Vibration - there’s a vibration in the engine with a resonance tied to engine speed. It has a period of about a second at about 2500 rpm.

3. Rattle - there’s an obvious rattle from the engine, especially noticeable at idle. You can hear it in this video...
Engine rattle

Any thoughts? Since the car is doing a lot of sitting right now, it’s a good time to address this.
 

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This is nothing more than a guess from reading a ton of posts. I could see the water pump being replaced incorrectly, causing the WP chain tensioner to fully extend resulting in excess strain on the guides,which are plastic,and breaking them over time. Its been reported though,that a broken timing chain guide will result in the hesitation and vibration youve described. Broken chain guides are very common on these engines. Either way,youll have to remove the timing cover to inspect.
 

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You have 1 of 2 issues. I'm more apt to think its the first...
1. When they did your WP, they let your balancer chain slip. A lot of people here don't know that our cars 2 chains...a balancer chain that runs the WP and the 2 balance shafts that take out the vibration of the engine, and in front of that chain is the timing chain that runs from the crank to the camshafts. When they did your WP they probably let the balancer chain slip and it tightened your balancer chain. I'm assuming you didn't have the WP replaced and it was done before you bought the car. When the PO drove the car, he destroyed the balancer chain guide. It's probably broke in there and thats the rattling and vibration you're feeling. Or...the tensioner failed. Does this eventually all go away as the car warms up? If so, your tensioner is shot...they're oil pressurized to keep pressure on the guide to take the slack out of the chain.

2. Since I can't really tell and this rattle could be a HPFP (high pressure fuel pump). If it is, I can tell you already you're HPFP is shot. I would need a video up by it to be able to tell for sure. Your HPFP sits right up in front of the driver and should have a consistent tick once the car warms up (after 90-120 seconds). If its sporadic, your HPFP is shot. But...you should have a raw gas smell to your oil and eventually a p2188 (or p2187...can't remember) which is "too rich at idle". You would also get some backfiring at "coast down while in gear". I've had this issue and now I have the balancer chain issue. I'm sure my tensioner is either shot or the guide is broken....and was done by a local tire shop. They took it on a 6 mile drive for a leaky tire.... :censored: And since my redline was raised to 7k, and my car gets there very quickily if you aren't expecting it in 2nd gear, I'm pretty sure he hit my rev limiter.

Here's a vid of an uneven, inconsistent HPFP tick......
 

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Discussion Starter #4
I checked out the HPFP, and it sounds pretty good. The rattling definitely seems to be more in the timing chain area. This video is the HPFP right after startup, and then a couple minutes later...
Solstice HPFP
 

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Discussion Starter #5
Is there a good tear down procedure out there for getting to the timing chain / tensioner in a GXP?
 

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cloyes.com has a great video on it.
 

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Wish there was a way to just put a new guide and tensioner back in and call it good. I really don't want to mess with the camshafts...
 

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Discussion Starter #12
I installed 9-4201SA and 9-4202S over the weekend and just have to get it all buttoned up again. Wasn’t too bad.
 

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Discussion Starter #15
I got the engine all back together, and the fix was successful! The rattle is gone, the vibration is gone, and the hesitation is gone!

One question though... now that it’s back together and I hear it with the cover off, there’s a clicking/ticking coming from the valve area. Quiet at idle but I hear it with a little throttle.
A concern?
Solstice engine ticking
 

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The ticking can be the high pressure fuel pump on the engine. They added a cover on the last (2009) cars but is your car earlier? If that's what it is, it isn't cause for concern.
 

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The ticking can be the high pressure fuel pump on the engine. They added a cover on the last (2009) cars but is your car earlier? If that's what it is, it isn't cause for concern.
My '07 has an acoustic insulation cover over the HPFP.
 

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Sounds normal,bet you couldnt hear it over the other racket your guides were making. Buy the new HPFP insulator. The part number is in the link in post 18
 
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