# Misfires all cylinders new engine



## Johnny B (Jun 4, 2019)

Well, I'm pretty confident you have a wiring issue. As always I suggest stating with the easy stuff first.

1) Clean and inspect the ECM wiring connectors. First disconnect the negative battery cable. Then unplug all 3 wiring connectors. Inspect closely. Look for corrosion, blackened pins, and damage. THEN clean with electrical contact cleaner spray. I would removed the ECM to inspect and clean the connector pins.

2) Inspect the wiring harnesses for signs of being pinched or damaged. Mice can cause a lot of electrical damage.

3) Check the battery and battery connections. Have the battery load tested. Remove and clean all the wiring. Ensure they all re-tighten properly.

If you do all this the problem should be revealed.


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## Shrednc336 (Apr 3, 2021)

Johnny B said:


> Well, I'm pretty confident you have a wiring issue. As always I suggest stating with the easy stuff first.
> 
> 1) Clean and inspect the ECM wiring connectors. First disconnect the negative battery cable. Then unplug all 3 wiring connectors. Inspect closely. Look for corrosion, blackened pins, and damage. THEN clean with electrical contact cleaner spray. I would removed the ECM to inspect and clean the connector pins.
> 
> ...


Thank you for the quick reply. Is there any certain electrical spray that you would recommend?


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## Johnny B (Jun 4, 2019)

CRC contact cleaner is fine, it is sold most places including Wally world. They are all good but some are crazy expensive, the pro stuff may cost $30 a can.


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## Shrednc336 (Apr 3, 2021)

Johnny B said:


> CRC contact cleaner is fine, it is sold most places including Wally world. They are all good but some are crazy expensive, the pro stuff may cost $30 a can.


Sounds good. I'll let you know the outcome!


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## snowwy66 (Nov 5, 2017)

Why didn't the dealer do the swap?


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## Shrednc336 (Apr 3, 2021)

Shrednc336 said:


> Sounds good. I'll let you know the outcome!





snowwy66 said:


> Why didn't the dealer do the swap?


The dealer did swap it. They don't know whats going on.


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## Shrednc336 (Apr 3, 2021)

Johnny B said:


> CRC contact cleaner is fine, it is sold most places including Wally world. They are all good but some are crazy expensive, the pro stuff may cost $30 a can.


So I've cleaned everything. It all looks very clean internally. Some road grime on the outside but made sure to clean everything I could before i took the connections apart. Battery voltage was 12.5. When I cranked the car I had (5 misfires on cylinder 3) (2 misfires on cylinder 4) and coming down in rpms I had around 15 in cylinder 1. And afr jumped to around 15.2 while it was missing. I also noticed driving around in deceleration the car would go super rich. Like 12.2


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## Johnny B (Jun 4, 2019)

Well, dang it.

I agree, your afr could be the issue.
Use the same cleaner on your MAF sensor.
Check fuel pressure.
And check the intake manifold for leaks.


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## Shrednc336 (Apr 3, 2021)

Johnny B said:


> Well, dang it.
> 
> I agree, your afr could be the issue.
> Use the same cleaner on your MAF sensor.
> ...


I'm honestly wondering if it just needs to be ran. Once it gets up to temp it does pretty well. Also on the bill it says 5w30 when they switched to 0w20 on the new engines correct? Could that for whatever reason be why it's misfiring when coming down in rpm? I also have a throttle body leak from one of those darn plastic clips falling out. Should I go ahead and throw my bigger intercooler on to completely fix in hot and cold side leaks that could possibly be there. And while I'm doing that I can take my throttle body off give it a good cleaning and look for intake leaks?


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## Luis R (8 mo ago)

Did the misfires start as soon as engine was replaced or did they start 500miles after??

did you use oem injectors?
Whenever the 2nd gen Cruze break pistons and blow out the crank seal, the throttle body compensation always needs to be relearned otherwise it will run badly.

Was a crankshaft variation relearn done with the new engine?
Both of these should’ve been done.

a leak at the the tb will also cause issues.


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## Shrednc336 (Apr 3, 2021)

Luis R said:


> Did the misfires start as soon as engine was replaced or did they start 500miles after??
> 
> did you use oem injectors?
> Whenever the 2nd gen Cruze break pistons and blow out the crank seal, the throttle body compensation always needs to be relearned otherwise it will run badly.
> ...


Misfires started with new engine. Yes oem injectors. I'm not sure about the crank being relearned.


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## Shrednc336 (Apr 3, 2021)

Johnny B said:


> Well, dang it.
> 
> I agree, your afr could be the issue.
> Use the same cleaner on your MAF sensor.
> ...


Also at light throttle fuel rail pressure jumps up to around 2900 psi.


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## Fireworks234 (Jan 4, 2018)

Shrednc336 said:


> Also at light throttle fuel rail pressure jumps up to around 2900 psi.


Not sure about the rest but this one specifically is normal.


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## ctheham (May 31, 2013)

This is probably too simple, but when the spark plug boot is removed from the spark plugs, look inside the boot and adjust the connector as needed. It is basically a spring. It can get caught up and not make good contact when reinstalling. Wishful thinking that it is that simple.


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## Blasirl (Mar 31, 2015)

Johnny B said:


> Well, dang it.
> 
> I agree, your afr could be the issue.
> Use the same cleaner on your MAF sensor.
> ...


So you are saying that MAF cleaner is just relabeled contact cleaner?


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## Blasirl (Mar 31, 2015)

ctheham said:


> This is probably too simple, but when the spark plug boot is removed from the spark plugs, look inside the boot and adjust the connector as needed. It is basically a spring. It can get caught up and not make good contact when reinstalling. Wishful thinking that it is that simple.


It is an issue on the Gen I's.









Help please


2014 CHEVY CRUZ , ROUGH IDLE , LOSS OF POWER , CHANGED THE SPARK PLUGS RAN FINE FOR ABOUT 100 MILES WITH SLIGHT LOSS OF POWER AND ROUGH IDLE, SAYS MISFIRE CYLINDER 3 ( REPLACED ALL SPARK PLUGS) AND THE CHECK ENGINE LIGHT FLASHES AND SERVICE STABILITY TRACK MESSAGE FLASHING .IT IS A TURBO AND HAS...




www.cruzetalk.com


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## Johnny B (Jun 4, 2019)

Blasirl said:


> So you are saying that MAF cleaner is just relabeled contact cleaner?


Yes. There are at least a half dozen types of what I would call electrical contact cleaner. 
I would, and do, use Maf cleaner for any electrical connector. However, I would not use all contact cleaners on a Maf.


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## Shrednc336 (Apr 3, 2021)

Coil boots looked good, Delco plugs gapped to .026 replaced with ngk plugs gapped to .026 and misfires immediately went away. Possibly a bad batch of plugs.


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