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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
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5,159 Posts
Discussion Starter · #681 ·
I have no idea why the mega thread here recommends the BKR8's, I had the EXACT same issue, covered in unburnt fuel... they are just too cold of a plug. Glad you put some 7's in. MSD should warranty your old coil, did you contact them?
No. Summit racing said it only had a 1 year warranty so I threw it away. :LOL: Maybe I was too hasty.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
Joined
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5,159 Posts
Discussion Starter · #682 ·
UPDATE:

The Cruze still idles like :poop:. I can't find any vacuum leaks ANYWHERE. So, the "new" theory comes from the "old" school: Thanks to the new cams, the intake and exhaust valves have too much overlap causing manifold vacuum to be insufficient at idle. Thankfully with the "modern-day" technology of Variable Valve Timing, that should be able to be adjusted in the ECM calibration.
 

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COTM Winner
2014 Cruze Diesel, 2007 Cobalt, 1981 Camaro Z28, 2017 Volt
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6,583 Posts
Yup, it's entirely possible that the larger cams and increased overlap are lowering your vacuum at idle just like big cams tend to...
 
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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
Joined
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5,159 Posts
Discussion Starter · #684 ·
Yup, it's entirely possible that the larger cams and increased overlap are lowering your vacuum at idle just like big cams tend to...
I'm not entirely sure how "big" these cams are. But then again we are talking about a 1.4L engine that needs a vacuum pump to create additional vacuum for the brake booster. :LOL:
 

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2014 Cruze Diesel, 2007 Cobalt, 1981 Camaro Z28, 2017 Volt
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I'm not entirely sure how "big" these cams are. But then again we are talking about a 1.4L engine that needs a vacuum pump to create additional vacuum for the brake booster. :LOL:
Yup - it doesn't take much for an engine that already doesn't produce any vacuum to begin with. :LOL:
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
Joined
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5,159 Posts
Discussion Starter · #686 ·
UPDATE:

Brian, my tuner, sent me the first calibration update for the cams. It made a some noticeable improvements. The hard start and rough idle are virtually gone.

Once the car warmed up, I took it for a short drive around the neighborhood and found out a little throttle NOW goes a long way. I'm still using premium 93 octane at the moment. It'll be interesting to see what happens when we get to the point of filling the tank with E85....
 

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Administrator
2014 LT program car, Pull Me Over Red, 1.4T Auto
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13,315 Posts
UPDATE:

I got the new water outlet installed and the system filled with coolant. While I was double checking the coolant lines before startup and I noticed that there was a loose wire on the upper charge pipe. Upon inspection I determined that the Ethonol sensor signal wire had come out of the ECM connector.
Hey, maybe the fixkit will take care of that for ya!😋
 

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Administrator
2014 LT program car, Pull Me Over Red, 1.4T Auto
Joined
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13,315 Posts
I have no idea why the mega thread here recommends the BKR8's, I had the EXACT same issue, covered in unburnt fuel... they are just too cold of a plug. Glad you put some 7's in. MSD should warranty your old coil, did you contact them?
Maybe @jblackburn can clue us in.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
Joined
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5,159 Posts
Discussion Starter · #691 ·
UPDATE:

This is the build that Never ends,
Yes, it goes on and on my friends!
When I started building it, not knowing what it was, but I'll continue building forever just because......Some of GM's parts have poor quality control.....

:LOL:

Today, I fixed the same coolant leak for the 3rd time. I've replaced the water outlet and the heater house and I've finally discovered the issue. The heater hose that I bought had a clamp on it from the factory. I re-used that clamp after replacing both the water outlet and the hose. I carefully examined the clamp today and realized the one edge of the clamp was razor sharp! It would hold coolant until the rubber expanded and then the clamp would cut into the hose.

I went to my local GM dealership today and bought an older revision of the hose without a clamp and then installed it with a worm gear clamp.

Currently I'm waiting on Amazon for coolant.
 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
Joined
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5,159 Posts
Discussion Starter · #693 ·
Oh yes, we knew this! You aren't reusing your coolant? I sometimes clean a drain pan real good and use a hose from the radiator drain to reuse.
No.. I figure it will help flush the radiator. It was open to the outdoor environment for 3 months, so I figure some dirt or bugs may have gotten in there. :LOL:
 

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Administrator
2014 LT program car, Pull Me Over Red, 1.4T Auto
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13,315 Posts
No.. I figure it will help flush the radiator. It was open to the outdoor environment for 3 months, so I figure some dirt or bugs may have gotten in there. :LOL:

 

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The Nuclear Option
2015 Chevrolet Cruze LT 1.4L Turbo
Joined
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5,159 Posts
Discussion Starter · #695 ·
UPDATE:

While waiting on Amazon, I found another modification in my office that I forgot I had bought. It's probably the cheapest modification I have ever done to this car at $12.

A new, colorful GM E85 fuel cap.
Automotive lighting Motor vehicle Automotive tire Rim Audio equipment
 

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COTM Winner
2014 Cruze Diesel, 2007 Cobalt, 1981 Camaro Z28, 2017 Volt
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6,583 Posts
+5HP!
 
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Premium Member
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318 Posts
UPDATE:

Brian, my tuner, sent me the first calibration update for the cams. It made a some noticeable improvements. The hard start and rough idle are virtually gone.

Once the car warmed up, I took it for a short drive around the neighborhood and found out a little throttle NOW goes a long way. I'm still using premium 93 octane at the moment. It'll be interesting to see what happens when we get to the point of filling the tank with E85....
May I ask what company does Brian your tuner work for?
 

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2013 Cruze LT
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3,907 Posts
That gas cap reminds me, I have a sticker on my fuel door inside that reads "Premium Fuel Required" The inspector last year opened it to do the evap test and commented "hmm I've never seen one of these cars with this sticker before" I just smiled and acted dumb and shrugged :LOL:
 
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