: Northstar engine performance in my 01' DeVille DHS



DHSDaddy
07-17-08, 08:00 AM
I hope this is the correct forum for this issue....

I own a 2001 Cadillac Deville DHS, factory chrome wheels, loaded with 104K miles :thumbsup:; a nice ride.

As of late the "service engine soon" light will occasionally comes on; and then after extended 100mph+ blasts up the NJ turnpike it will turn off by itself - and I am aware of the "WOT" therory, so I'm hoping the ses light/speed thing is related (sorry NJ state troopers out there):tisk:.

What is really annoying me is from a standing start, for just a few moments, the Northstar feels like its "straining" somewhat on 7 cylinders or stumbling every so lightly, and then hang on, its lift off time:confused:. This is something relatively new and it is really knawing at me now, I miss the "instant" action.

Has anyone else experienced this phenomena? Is there a cure? Everything else with this car is perfect and I'm keeping it till doomsday.

codewize
07-17-08, 08:23 AM
Hmmm it's doubtful that the SES light has anything to do with WOT.

That bog from a stand still you're taking about sounds liek ignition. Has the car ever had a proper tuneup? 100k is the mark for that. Maybe you have a bad coilpack?

I'm just throwing out ideas based on experience.

The WOT treatment will clean carbon off the rings, pistons and it will blow out any pooled oil in the intake. I'm sure someone will nail it right down for you.

DHSDaddy
07-17-08, 09:34 AM
When the SES first starting to coming on; I took the car in to have it checked out. It was determined by dealer tech's this was some sort of "nuisance" or "errant" signal, as they checked for codes and nothing came up when reader was connected under the dash. I was there looking over shoulders to be sure I was not being hornswaggled, as best I could. I did not see any problem code(s) displayed other than the Quakerstate was a tad low. We ran thru this multiple times within 2-3 hours - same day. Same results -- I need to top off the QS (so I promptly fed her).

One day while the SES was lit; I just happened to push it to 125mph on the NJTPk.....,arrived at the toll gate, looked at dash - no SES. Stayed off for a few weeks. Came back on sitting at a lengthy stoplight on a slight upgrade. Fives days later, back on TPk, 110mph; goodbye SES.

Could this not be a pattern?

No, I'm ashamed to admit no tune up yet, but I HAVE been thinking of doing it. I've owned the car since 23K miles; with no problems until now. Perhaps that's the key. I dunno. I used to turn wrenches on old Mopars (HEMIs/4406paks) back in the day...carbs/points/ yada yada. All this "PCM", "OBD II" and programming stuff might as well be magical incantations to me.

misfit6794
07-17-08, 10:14 AM
Probably time for a tune up, make sure you only use a/c delco plugs, platnum tipped, N*'s don't seem to like anything else. I would get the codes read, while the ses light is on, autozone will do it for free.

DHSDaddy
07-17-08, 11:08 AM
Autozone, eh? This old dog learns new tricks everyday. Autozone...the "new" Manny, Moe & Jack". Much thanks.

JimD
07-17-08, 11:59 AM
You can display trouble codes on the DIC; no need for Manny, Moe, and Jack; here's how....

http://www.cadillacforums.com/forums/cadillac-tech-tips/55172-how-pull-codes-got-codes-warning.html

CadillacSTS42005
07-17-08, 02:49 PM
When the SES first starting to coming on; I took the car in to have it checked out. It was determined by dealer tech's this was some sort of "nuisance" or "errant" signal, as they checked for codes and nothing came up when reader was connected under the dash. I was there looking over shoulders to be sure I was not being hornswaggled, as best I could. I did not see any problem code(s) displayed other than the Quakerstate was a tad low. We ran thru this multiple times within 2-3 hours - same day. Same results -- I need to top off the QS (so I promptly fed her).

One day while the SES was lit; I just happened to push it to 125mph on the NJTPk.....,arrived at the toll gate, looked at dash - no SES. Stayed off for a few weeks. Came back on sitting at a lengthy stoplight on a slight upgrade. Fives days later, back on TPk, 110mph; goodbye SES.

Could this not be a pattern?

No, I'm ashamed to admit no tune up yet, but I HAVE been thinking of doing it. I've owned the car since 23K miles; with no problems until now. Perhaps that's the key. I dunno. I used to turn wrenches on old Mopars (HEMIs/4406paks) back in the day...carbs/points/ yada yada. All this "PCM", "OBD II" and programming stuff might as well be magical incantations to me.

right there i know theres something fishy
a DHS came with S rated tires and a 112 MPH limiter
so unless you spoke with AJ or Westers 125 is impossible in a stock car..

codewize
07-17-08, 08:36 PM
Are you sure all of them were. That crossed my mind too but it wasn't important at the time.


right there i know theres something fishy
a DHS came with S rated tires and a 112 MPH limiter
so unless you spoke with AJ or Westers 125 is impossible in a stock car..

CadillacSTS42005
07-17-08, 10:41 PM
DHS was powered by a vin y with 3.11 gears
only tires available were S rated

codewize
07-17-08, 11:11 PM
Huh, OK good thing we know some people huh. 112 LOL why oh why.

CadillacSTS42005
07-18-08, 12:29 AM
truth
to be honest in the bad pcm which isnt shifting right i have only once pushed it above the original 135 mph limiter...
the good pcm but wont run the car will be headed back to AJ and hopefully back in a about a week so i can get this thing dynoed soon hahaha

Highline Cady
07-18-08, 01:24 AM
Yep 112 on a stock DHS PCM, won't go over that at least it shouldn't. Unless like STS said you know AJ, or have lealt with Westers who can only bump up the fuel cutoff, they don't do anything else, unlike AJ.

MisterBlue
07-20-08, 09:01 AM
So then, bypassing the 112 mph fuel c/o is a pretty simple job?

codewize
07-20-08, 09:48 AM
For the now 2 people on the planet that can now do it, yeah it's real easy.


So then, bypassing the 112 mph fuel c/o is a pretty simple job?

AJxtcman
07-20-08, 08:01 PM
So then, bypassing the 112 mph fuel c/o is a pretty simple job?

I think a lot more people can do it




For the now 2 people on the planet that can now do it, yeah it's real easy.

It is easy