Surges ?

Drivetrain discussion including Transmission, Differential, Driveshaft, and related items.
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HCSO249
Posts: 21
Joined: Thu Dec 13, 2018 6:47 am

Surges ?

Post by HCSO249 »

Have had an intermittent issue with my 2012 6.0 surging and lurching (i.e. uninitiated acceleration). On average seems to jump about 300 RPMs Last night / this morning at 0230, I was about home and noticed as I turned off the highway the temp gauge had gone from normal running temp to cold. It came right back to normal. The surging was very constant as I drove slow on my side roads to the house. Every time the engine surged, the temp gauge dropped and recovered. :?: :?:

Since I haven't had much opportunity to drive at night since I bought my car, my thought was leaning toward a battery issue. ???? Headlights have always seemed dim but attributed that to plain old halogen bulbs that are likely oem and in dire need of replacement. Volt readout on one of my 2-way radios at start up shows 12.6v and after car is running is 14.3 to 14.8v...so not a a battery / charging issue. Computer issue?

I have an appointment for the shop Monday morning for A/C charging and leak finding mission. Since this is the only Caprice in my immediate area, even the Chevy dealer hasn't seen one before...any others that had this issue and possible remedy??????
Sanford
Posts: 356
Joined: Mon Dec 12, 2016 9:38 pm
Location: Texas Gulf Coast

Re: Surges ?

Post by Sanford »

I would lean towards a coolant temp sensor getting wacky. My daughter had one act up in a similar way. It finally decide to act up at the house and I saw how the gauge was moving quicker than the coolant temperature could ever possibly change. Been wrenching on cars for about 45 years now I never have seen one act the way it was acting. Usually they will fail and stay failed. The most common leak point on GM autos, since the usage of R134, has been their high side charging port. I just replaced on one my Caprices. I always replace it when I have to do any work that will a complete recharge.
HCSO249
Posts: 21
Joined: Thu Dec 13, 2018 6:47 am

Re: Surges ?

Post by HCSO249 »

Thank you sir!

Would that explain the surging if temp sensor is going kaput? Guess I could see computer saying coolant is too cold and boosting idle... I will let them know about hi-side.

Thanks again
CrashTestDummy
Posts: 2300
Joined: Sat Feb 07, 2015 2:31 pm
Location: Pearland, Texas

Re: Surges ?

Post by CrashTestDummy »

HCSO249 wrote: Sun Apr 21, 2019 11:04 pm Thank you sir!

Would that explain the surging if temp sensor is going kaput? Guess I could see computer saying coolant is too cold and boosting idle... I will let them know about hi-side.

Thanks again
I would guess that when the temp sensor went full cold, the ECU would 'think' you've just started the car and it goes to cold startup setting which would set the throttle so the engine idles at about 1000-1200 RPM to warm it, instead of the normal 600-800 RPM.

It certainly couldn't hurt to have the battery load tested, though.

@Sanford, I guess you replace the entire high-side hose, because I'm not seeing a way to replace JUST the high side port? I think I may have an issue here on our 2012, since it has started to leak refrigerant out after an attempt to fill it using both hoses on my gauge set. I did note that after disconnecting the high side, I could hear the leak. I depressed the valve with a small flat blade screwdriver which seemed to get the valve to seat better, but I'm wondering if it's still leaking some.

I've been enjoying other issues with the car lately, and haven't had a chance to get the leak detector on it yet, but will just as soon as I can get the dang thing to pass inspection. In spite of having dye in the system, I'm not seeing any residue around the charging ports.
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2018 Tahoe PPV (her car)
1995 DGGM Impala SS
1985 Firebird - 310 LS1 C Prepared autocross car.
1980 Bluebird Wanderlodge
And some others
Do YOU have my SPID?
Sanford
Posts: 356
Joined: Mon Dec 12, 2016 9:38 pm
Location: Texas Gulf Coast

Re: Surges ?

Post by Sanford »

Gene,
If you have an OEM hose, the fitting just screws into the hose. Delco offers a replacement and I would imagine the aftermarket also has one. It is an o-ring seal and they are usually come out pretty easy. They are an 8 sided fitting and I usually just grab the flats with a smooth jaw Vise Grips. Just don't tighten the pliers too tight. One of these days I am going to buy a socket that fits.

David
CrashTestDummy
Posts: 2300
Joined: Sat Feb 07, 2015 2:31 pm
Location: Pearland, Texas

Re: Surges ?

Post by CrashTestDummy »

Thank you, David. I'll have to go have a second look. I may hand this task over to a shop that can recover the freon, since I don't have that apparatus. But I'll go over the system with my sniffer first, to make certain that's where the issue resides.
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2018 Tahoe PPV (her car)
1995 DGGM Impala SS
1985 Firebird - 310 LS1 C Prepared autocross car.
1980 Bluebird Wanderlodge
And some others
Do YOU have my SPID?
Sanford
Posts: 356
Joined: Mon Dec 12, 2016 9:38 pm
Location: Texas Gulf Coast

Re: Surges ?

Post by Sanford »

The system on the Caprices only holds 24oz, which is only 2 cans. If you system is low, they will probably only recover 1 pound if they are lucky and it might be safe to say they would not even hook it up to a recovery machine. If you have a vacuum pump and R-134 gauges, it is an easy job. The Delco part # is 15-5439 and the GM # is 52458184.

David
HCSO249
Posts: 21
Joined: Thu Dec 13, 2018 6:47 am

Re: Surges ?

Post by HCSO249 »

A/C recharged. Working great. Scanned computer. Had several codes but most notably temp sensor voltage. Cleared codes. It acted up on drive home. Taking car back today for rescan and having trans serviced. Figured I would have it done since I have no way of knowing if it has ever been done. Told them Monday, if the temp sensor is suspect, we will change it too even if a preventative maintenance. We will see...
HCSO249
Posts: 21
Joined: Thu Dec 13, 2018 6:47 am

Re: Surges ?

Post by HCSO249 »

[/quote]

I would guess that when the temp sensor went full cold, the ECU would 'think' you've just started the car and it goes to cold startup setting which would set the throttle so the engine idles at about 1000-1200 RPM to warm it, instead of the normal 600-800 RPM.


[/quote]

Exactly how it acted and what I was thinking the ECU was "thinking" Went from 600-800 RPMs to about 1200 each time. I can see how one could launch a car through the side of a building. I got to work. Parked in my spot and was about to shift to park and it did it. I didn't have loads of brake applied since I was stopped and the car lurched. Think I pooped a little lol
CrashTestDummy
Posts: 2300
Joined: Sat Feb 07, 2015 2:31 pm
Location: Pearland, Texas

Re: Surges ?

Post by CrashTestDummy »

Sanford wrote: Tue Apr 23, 2019 6:49 pm The system on the Caprices only holds 24oz, which is only 2 cans. If you system is low, they will probably only recover 1 pound if they are lucky and it might be safe to say they would not even hook it up to a recovery machine. If you have a vacuum pump and R-134 gauges, it is an easy job. The Delco part # is 15-5439 and the GM # is 52458184.

David
Good to know the full charge capacity. I do have a vacuum pump and gauges. Hopefully, I'll get some quality time in the shop to run the sniffer over it and verify. I do still need to replace a rear wheel speed sensor. Thank you for the P/Ns, too. I may go ahead and order one up when I go in to pick up the senor.
Gene Beaird,
Pearland, Texas
2012 Caprice 9C1
1992 B4C 1LE Camaro
2018 Tahoe PPV (her car)
1995 DGGM Impala SS
1985 Firebird - 310 LS1 C Prepared autocross car.
1980 Bluebird Wanderlodge
And some others
Do YOU have my SPID?
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