CT5-V engine surge / "porpoising"

[jkg]

its been well over a month since my car had the service visit to replace the cam actuator. I thought i would give some follow up. Mostly things are better and normal. the engine still surges a bit at times, but there has only been one episode when it was really bad - i was driving at about 40 mph in 4th or 5th gear going up a hill and it began surging. (rpms jumping up and down and car jumping back and forth at speed). i stayed on the throttle at the same part throttle and after about 5 seconds it came out of it on its own. Before the service visit, it would stay for 15-30 seconds and I couldnt stay on the throttle the same way. So, so far, much improved but not perfect. not sure if currently this is normal for this engine or if still off a bit.

 

[frankfast97]

40 mph in 4th or 5th gear uphill?

 

[jkg]

It did it again just yesterday. It’s usually third gear maybe fourth gear around 30 or 40 miles an hour with a slight uphill grade or even on level ground. This particular episode again sorted itself out without me doing anything different after just a couple of seconds. The engine is usually just under 2000 RPM when it happens

 

[dribs15]

Sorry, but you should bring that back in. You know your stuff and you know that's not right.

 

[jkg]

i guess you're right. but the problem is sporadic enough that i dont have any confidence in a regular dealership to do anything useful about it

 

[Ergoc5]

Having the same issue 230 miles on the car 5V BW manual. it happened to me twice ..engine cold, in second or third gear 2000ish rpm...car bucks and surges for a few seconds and it goes away. This happened on an even road...no incline.

 

[jkg]

since my post back in april, the surging while driving has not recurred. the repair done with the dealer seems to have improved the problem.

 

[NorCal Blackwing]

Thanks @jkg - so the fix is "replace the cam actuator"?

 

[jkg]

I don’t recall the name of the part offhand but I know it’s in some of my earlier posts. The service department spoke with Cadillac technical support on their end to get guidance on the plan.

 

[raptor5244]

Are you guys only seeing this happen while the engine is not up to temperature yet? I know these cars run in open loop and use data from a different set of tables vs when you reach operating temps and it goes into closed loop using real-time data from the MAF to control things.

 

[Ergoc5]

Are you guys only seeing this happen while the engine is not up to temperature yet? I know these cars run in open loop and use data from a different set of tables vs when you reach operating temps and it goes into closed loop using real-time data from the MAF to control things.

Yeah as it is coming up to temp ...I have felt it 4 times so far in the 150 to 180 deg F range. For me it was not as bad as what @jkg was describing though. Can feel it in second through fourth gears in the 2500 to 2700 rpm range.
Taking it to dealer on weds for that and a few other things. Other issues include steering wheel off center, noise from driver side window and rear view mirror with annoying vibration.

 

[jkg]

Yes seems like it happened when water temp was below 180. For my car it is markedly improved since the “fix” but I can still feel it once in a while but not bad

 

[Ergoc5]

I am hoping it's not the broken spark plug issue some people are having ...it's pretty mild on my case

 

[jkg]

Haven’t heard of broken spark plugs.

 

[Ergoc5]

Haven’t heard of broken spark plugs.

Yeah it's in the other thread but again doesn't mean it is that ..will just have them check

 

[Ergoc5]

Mine has become worse now..car bucking and jerking like crazy....taking it to the dealer on Weds

 

[jumpmanjay]

My car is at the dealer getting the spoiler installed, first oil change (1600mi) and rear diff fluid changed. I also asked them to check out the spark plug in cylinder 6 haha. I should get it back by tomorrow.

 

[NorCal Blackwing]

Mine has become worse now..car bucking and jerking like crazy....taking it to the dealer on Weds

If & when they fix it, it would be amazing if you can get details on what the cause of the issue was and the fix - both for the surging and for the buzzing/rattling.

I have both but I'm discouraged from taking mine in because any dealer's SOP is likely to go as follows: 1) ... let's have our most junior tech test drive the car ... 2) can't reproduce, maybe bad gas? ... 3) rinse and repeat

One possible cause of surging (behind a bad fuel pump) could be bad spark plugs, so it's easy to look at C&D's well-documented grenaded engine and draw conclusions.

As for the buzzing/rattling there was another post about needing to replace a door hinge. I'd love to get a picture or something real specific so we can just skip right by the tech hooning the car stage and go right to the fix...!

 

[Ergoc5]

So an update....dealer kept the car for a week and basically gave me the run around....after saying they initially felt it they claimed since there were no codes and could not recreate it to file a case they could not do anything. They did not fix any of my other stuff as well...buzzing in driver door, oxidation on strut tower brace, rear view mirror vibrating ....very disappointing

 

[M2Cto4BW]

So an update....dealer kept the car for a week and basically gave me the run around....after saying they initially felt it they claimed since there were no codes and could not recreate it to file a case they could not do anything. They did not fix any of my other stuff as well...buzzing in driver door, oxidation on strut tower brace, rear view mirror vibrating ....very disappointing

Yikes! Not very helpful.
Do you have PDR? Guessing no? Be interesting to have seen what they actually did. Did you notice how many miles they put on?