[silverredline]

Haven't heard anything after I spoke with service manager Friday. They were going to do a bunch of stuff. I informed him the loaner Equinox got 29mpg first time I filled it using old fashioned miles on trip divide by gallon put in. Second fill was 26.8. Second tank high 2 days 50mph wind gust and never once downshifted to 5th. So if a suv with 4mpg less rated with same eng/trans gets that much better if the Malibu can't exceed that then it's got a major issue somewhere. Will update again once I hear back.

 

[silverredline]

Got Malibu back yesterday. The calibration update does seem to have increased the power a fair amount. I can say it seems fuel mileage may slightly increase. Dealership stated they got 26mpg but was not specific to what speed they drove the 100 miles. I averaged 28 with 3 fill ups on the equinox. So I will confirm the calibration update did give more power. I'll get some miles and average a couple fill ups to report fuel economy change. Was told to allow some more break in time ( not buying that) to see mine continue to increase. I have just turned 9000 miles on odometer. If by 10,000-11,000 I haven't met or exceeded the Equinox then I am unsure what to do next. I'll also have a oil analysis to evaluate once sample is sent in. Now to figure out assuming economy is on par with 26-28 mpg range in current weather if gm will compensate anything for the hassle and multiple visits to get issue addressed or if they will just say it's fixed now. That's assuming the economy is where it should be.

 

[RcClockman]

You don't know what speed? Why didn't you reset all the Trip computers/Mpg/ Ave speed? ect..

 

[silverredline]

You don't know what speed? Why didn't you reset all the Trip computers/Mpg/ Ave speed? ect..

All that was reset. I drive 96 miles a day at 75mph. The avg speed always says 56 mph. Plus when they flashed the ecm and test drove the tech reset trip b that I did not reset. They did not state on work order drove 100 miles at 70mph. Just states hwy for 100 and in town for 10. They could have went 50 and could have went 80. Only person driving at that time knows. Point is if they drove 60 mph but I drive 75 the 26 they recorded will be off from what I will record. Once I run a few tanks I'll report back to service manager what I got. I keep track of odometer reading, fuel receipts and use a fuel app to log as well.

 

[campb292]

It sounds like you are doing everything you can so far @silverredline. It still think even in cold you should be averaging more than 26 but at least that is closer... I look forward to reading what the digital and manual calculations show after a couple thousand miles. Hopefully this calibration or whatever else they repaired fixed what was amiss but if not, I have another option in wait should it be necessary.

 

[dale195]

My 2018, when running properly, gets around 25city and 36highway. I have got as much as 40highway when driving down in the Mississippi delta which is really flat. I haven't had a chance to get mine out on the road since some air shutter harness was replaced and the computer was reset. Will update when I do.

 

[silverredline]

It sounds like you are doing everything you can so far @silverredline. It still think even in cold you should be averaging more than 26 but at least that is closer... I look forward to reading what the digital and manual calculations show after a couple thousand miles. Hopefully this calibration or whatever else they repaired fixed what was amiss but if not, I have another option in wait should it be necessary.

Thanks. I will give it a chance and run some miles on it and see what happens. I'm in agreement I should exceed 26 and be at least comparable to the Equinox I had as a loaner that was pulling 28. If it's not close to that by the next month I will reach out for options. I'll likely update weekly or so to keep this going. Also hopefully this also helps many other owners who are in similar situation. At least it's currently holding 6th gear on interstate and doesn't struggle to maintain speed now.

 

[cp-the-nerd]

If it's holding 6th on the highway, that seems like a huge difference compared to the problems you were having. Fingers crossed!

 

[DirtyAndy]

Wow. You're having a heckuva time with that car. I just wanted to toss in what my 2017 1.5L gets according to the computer. During winter I typically get 30-33mpg AVG over 400 miles(this really takes a hit if it idles for long periods). During summer it will be 34-40 depending on how easy I go. It has gotten 40-41 on LONG trips with all highway. Remember, that's AVG over 400 miles and according to the computer. I've never really calculated my mpg the old school way with this car since it does good enough that I don't bother to really check it.

While my car isn't a rocket, it isn't terribly slow either. I've been contemplating a Trifecta tune for a while, but unsure. Hopefully you get this resolved, man.

 

[JordanL]

Hey silverredline , is there anyway you can message me the info about the calibration update ? Is there a tsb number for it ? I’m told the part for my car won’t be in until March 26th but I want to mention the reflash while it’s sitting at the dealer . Thanks

 

[JordanL]

Got Malibu back yesterday. The calibration update does seem to have increased the power a fair amount. I can say it seems fuel mileage may slightly increase. Dealership stated they got 26mpg but was not specific to what speed they drove the 100 miles. I averaged 28 with 3 fill ups on the equinox. So I will confirm the calibration update did give more power. I'll get some miles and average a couple fill ups to report fuel economy change. Was told to allow some more break in time ( not buying that) to see mine continue to increase. I have just turned 9000 miles on odometer. If by 10,000-11,000 I haven't met or exceeded the Equinox then I am unsure what to do next. I'll also have a oil analysis to evaluate once sample is sent in. Now to figure out assuming economy is on par with 26-28 mpg range in current weather if gm will compensate anything for the hassle and multiple visits to get issue addressed or if they will just say it's fixed now. That's assuming the economy is where it should be.

Can anyone share information about the Calibration update on the 2018 Malibu ? My dealer says there is no such thing . I see Silver Redline Malibu says he got the update (unfortunately he don't want to share this top secret TSB number) . So either his dealer told him he got something he did not or my dealer is just not very smart . Any help would be greatly appreciated

 

[campb292]

Can anyone share information about the Calibration update on the 2018 Malibu ? My dealer says there is no such thing . I see Silver Redline Malibu says he got the update (unfortunately he don't want to share this top secret TSB number) . So either his dealer told him he got something he did not or my dealer is just not very smart . Any help would be greatly appreciated

It possible silverredline couldn't share as there might not be an actual TSB yet. The calibration update exists but whether it has been validated and a TSB created is another story.

Here is what I do know: Taking a generic 2018 VIN (this calibration update is not for 2016-2017 Malibus) and searching the TIS/SPS website nets you an update with part number 12703214. The description is "New calibration to address customer complaint of lack of power and hesitation."

You guys did have bulletin #PIP5610A checked right? I think I read that somewhere in here. That is the prelim bulletin for low power hesitation and sluggish acceleration that calls for inspection of the high pressure fuel pump roller follower pin moving and smashing into a cylinder. It causes extremely reduced ignition timing and possible cylinder damage. That one definitely needs to be thoroughly checked for those with these symptoms in addition to the calibration update. Again, all for your dealer to determine and do.

Anyway, the pic:

 

[JordanL]

It possible silverredline couldn't share as there might not be an actual TSB yet. The calibration update exists but whether it has been validated and a TSB created is another story.

Here is what I do know: Taking a generic 2018 VIN (this calibration update is not for 2016-2017 Malibus) and searching the TIS/SPS website nets you an update with part number 12703214. The description is "New calibration to address customer complaint of lack of power and hesitation."

You guys did have bulletin #PIP5610A checked right? I think I read that somewhere in here. That is the prelim bulletin for low power hesitation and sluggish acceleration that calls for inspection of the high pressure fuel pump roller follower pin moving and smashing into a cylinder. It causes extremely reduced ignition timing and possible cylinder damage. That one definitely needs to be thoroughly checked for those with these symptoms in addition to the calibration update. Again, all for your dealer to determine and do.

Anyway, the pic:

Thanks for the information! Yep we did have the high pressure fuel pump replaced under warranty and the dealer said he seen no issues but changed it anyway. I'm really losing confidence with this dealer as I called him again with the information you just shared and he says he will call me back. The last time he said that I called him back after 3 days lol. I guess the good news is in 2 days the car will be at the dealer for over 30 days with the issue unresolved for the 3rd time. So the Lemon Law Lawyer in Michigan says they would gladly take the case. I'm trying to be patient and not go that route but good grief something has to give here . Thanks for all the input guys

 

[silverredline]

I'll check the service record when I get home. There should be some reference to a doc id at least. My car so far is doing okay. Mileage isn't spectacular but last 2 fill ups have been 26 mpg. have not had a downshift issue since update. My problem now is assuming this holds is gm selling me a vehicle with improper ecm parameters and taking so long to address it. for 8000 miles I have fought and complained about it and was treated like I was a pita and inconvenience/low priority. I'd like to see me exceed the Equinox average I had for a loaner, but will give more miles and time to see what happens.

 

[silverredline]

Here is the info from repair order. There is reference to a doc ID and a wcc #.

 

[dale195]

I guess putting a new aero shutter harness and resetting my computer didn't work on mine. This is the third time going back to service. The car started getting 17mpg around town with loss of power again.

 

[cp-the-nerd]

Here is the info from repair order. There is reference to a doc ID and a wcc #.

I'm really curious what the recalibration included, because it's not like they're putting a higher power performance tune on the car, they're correcting some electrical gremlin–that causes the car to run limp and suck down gas–in order to make it run as intended from factory.

I'm also wondering why this seems to affect 2018 models. I saw that the 2018 1.5T uses a new PCM that carried over to 2019 CVT models, and I wonder if that's the source of the error.

 

[silverredline]

Here is the info from repair order. There is reference to a doc ID and a wcc #.

I'm really curious what the recalibration included, because it's not like they're putting a higher power performance tune on the car, they're correcting some electrical gremlin–that causes the car to run limp and suck down gas–in order to make it run as intended from factory.

I'm also wondering why this seems to affect 2018 models. I saw that the 2018 1.5T uses a new PCM that carried over to 2019 CVT models, and I wonder if that's the source of the error.

Whatever it is I agree, would be a factory programming glitch/error that definitely affected the way the car both performed and as result affected fuel economy. The difference is quite significant after the updated calibration. And I also agree has something to do with the ecm change. It's crazy to think how many don't highway much and or pay attention that are as well affected and have no idea they have a problem. Hopefully this will shed light and give other 2018 1.5t owners something to know to correct the described issues I had that seems to plague other owners as well. I feel GM should make something right to those of us affected, as it's more than apparent a bad batch was released. I'd like to know other owners date of assembly to find a trend. Mine is 9/2018.

 

[campb292]

If anyone still needed the TSB number for the calibration update, it is #19-NA-032 dated Feb 18 2019. That popped into my alldata account today. Again, this is 2018 only and based on the wording probably only applicable to those that had problems with the high pressure fuel pump.

 

[silverredline]

If anyone still needed the TSB number for the calibration update, it is #19-NA-032 dated Feb 18 2019. That popped into my alldata account today. Again, this is 2018 only and based on the wording probably only applicable to those that had problems with the high pressure fuel pump.

That's interesting the high pressure side would be mentioned. Both my bleed down and cam roller test came back ok. I still insisted on a oil analysis for the rise in engine oil level and concern of a combustion issue. Seems the main issue to address is I never had a CEL. Also no codes present. Keep hearing from service dept misfire code would come up if fuel issue. I personally don't agree with that. I had fuel dilution with other direct injection vehicles and never had codes or CEL. And they also passed fuel system bleed down test on high side.