Rough idle question

ZL14ME · 07-13-2018, 03:37 PM

I know there has been rough idle discussion here in the past and I’ve gone back and read some of them. I haven’t seen a solution or follow up type response from the Op in those threads so I need a ask...

I went out to drive my ZL1 this morning. It’s been parked for three weeks. When started it fired right up but the idle dropped below 500 rpm quickly after that initial startup rev. It seemed to struggle to catch itself. It went through three or four almost stall or coughing spells before I gave it a few revs and then all seemed fine.

With all this talk of oil pump failure and electrical gremlins I’m throwing out a lifeline to make sure my issues aren’t related. It’s 100% stock and under warranty but I’d rather not if you know what I mean.

18’ ZL1 stock
700 miles
Started in sport mode with AC and everything off (if that matters).

Last question, what’s your idle oil pressure?

JRS · 07-13-2018, 05:49 PM

It's possible the fuel in the line wasn't the freshish because these cars don't use a return line anymore to move fresh fuel from the tank into the line right away. Another words the initial fuel was stale (three week old fuel is stale no matter what anyone says) causing it to run rough until you revved it up and moved some fresh fuel into the line from the tank. Just my 2 cents.

As for idle oil pressure it is close to 40 psi.

Did it start and run normal the next time? If so this just proves my point, if not it may be a underlying problem.

ZL14ME · 07-13-2018, 08:01 PM

It did seem to run fine afterwards. I thought, at one point, I had an issue but I had just turned the AC off and dropped that compressor load off the engine. I was probably a little hyper sensitive to the issue.

I didn’t realize that about the fuel lines. Thanks for the reply.

I noticed my oil pressure slightly above the hash mark right before 40 psi at idle. So... 32...33ish psi. I also noticed the rpm to be around 750. What’s weird is I have a picture of my dash where the car is idleing several months back and it was at 1000rpm and 38ish psi.

I’m probably making this a bigger deal than it really is but all that oil pump failure has me paying attention.

unavailablezl1 · 07-14-2018, 02:20 PM

I’m sure it is fine. Mine was a little rough but now 4000 miles on it. It is getting smoother all the time

07-13-2018, 03:37 PM	#1
ZL14ME Drives: 2018 ZL1 M6 Join Date: Apr 2018 Location: Birmingham, AL Posts: 93	Rough idle question I know there has been rough idle discussion here in the past and I’ve gone back and read some of them. I haven’t seen a solution or follow up type response from the Op in those threads so I need a ask... I went out to drive my ZL1 this morning. It’s been parked for three weeks. When started it fired right up but the idle dropped below 500 rpm quickly after that initial startup rev. It seemed to struggle to catch itself. It went through three or four almost stall or coughing spells before I gave it a few revs and then all seemed fine. With all this talk of oil pump failure and electrical gremlins I’m throwing out a lifeline to make sure my issues aren’t related. It’s 100% stock and under warranty but I’d rather not if you know what I mean. 18’ ZL1 stock 700 miles Started in sport mode with AC and everything off (if that matters). Last question, what’s your idle oil pressure?

07-14-2018, 02:20 PM	#4
unavailablezl1 Drives: 2019 Silverado Z71 6.2L A10 Join Date: Mar 2017 Location: Grapevine Posts: 2,075	I’m sure it is fine. Mine was a little rough but now 4000 miles on it. It is getting smoother all the time __________________ Current ride 2019 Silverado Z71 LTZ 6.2L L87 425hp A10, 4 inch BDS Lift with Fox Factory Race 2.5 Coilovers, Borla Cat back (15HP bump), BFG KM3's 33's. Past Rides 2017 M6 Camaro ZL1 Hyper Blue 2016 M6 GT350 White with blue strips 2014 M6 Mustang GT Premium Track Pack Ruby Red 2012 M6 M3 Melbourne Red Metallic

07-13-2018, 05:49 PM	#2
JRS Drives: 16 camaro M6/ 18 ZL1 camaro A10 Join Date: Nov 2015 Location: MD/PA LINE Posts: 202	It's possible the fuel in the line wasn't the freshish because these cars don't use a return line anymore to move fresh fuel from the tank into the line right away. Another words the initial fuel was stale (three week old fuel is stale no matter what anyone says) causing it to run rough until you revved it up and moved some fresh fuel into the line from the tank. Just my 2 cents. As for idle oil pressure it is close to 40 psi. Did it start and run normal the next time? If so this just proves my point, if not it may be a underlying problem.

07-13-2018, 08:01 PM	#3
ZL14ME Drives: 2018 ZL1 M6 Join Date: Apr 2018 Location: Birmingham, AL Posts: 93	It did seem to run fine afterwards. I thought, at one point, I had an issue but I had just turned the AC off and dropped that compressor load off the engine. I was probably a little hyper sensitive to the issue. I didn’t realize that about the fuel lines. Thanks for the reply. I noticed my oil pressure slightly above the hash mark right before 40 psi at idle. So... 32...33ish psi. I also noticed the rpm to be around 750. What’s weird is I have a picture of my dash where the car is idleing several months back and it was at 1000rpm and 38ish psi. I’m probably making this a bigger deal than it really is but all that oil pump failure has me paying attention.

User Name		Remember Me?
Password