Need Tuning Tips for 94 Cadillac SLS with Northstar....Please :-)

[Lee_Burough]

Just bought 94 SLS with 65,000 miles.

At WOT from a stop, there was some serious surging as the motor went through the gears. Two bottles of Chevron Techron later, and WOT is completely different: Smooth power through the gears up to 100 mph.

Cruising at 45-75 mph, I still feel a bit of surging whenever going up an encline. 600 mile highway trip and a very slight surge is still there at the speed limit. (about 24 mpg average for the 600 miles, same as my TTA ).

Any peculiarities I should know about as I chase this symptom? I'm thinking I'll inspect and replace plugs and wires, fuel filter, air filter as needed. Anything specific to this Northstar engine I should know?

Its OBDII, will need an upgrade to hook turbolink up and check things.

TIA

 

[Lee_Burough]

I know a few of you fellow boardmembers drive these Cadillacs as daily drivers....Don't hold back

 

[Rollin]

I'm a Lexus, Mercedes Benz guy However, I do know alittle about Northstars and can offer you a few suggestions. From least expensive to most. Check the MAF for contamination, I use Chem-tool B-12 to clean them esp if your running an aftermarket air filter. The B-12 cleans off the oil residue, and makes a pretty big difference if you have one that is contaminated. Check the TPS. Next do change the plugs, wires and filters. BTW Keep an eye out for coolant loss(headgasket) and oil leaks, ya don't want to know how long it takes to change a lower case leak
Other than that as far as longevity the Northstar motor is decent, good power and pretty smooth, hth.
Good luck.


Geoff

 

[Scott Atk]

Lee, I concur with everything Geoff said. I'm not for sure on that car, but I would doubt it is an OBDII car. OBDII was mandatory on all 96's and installed on a few 95's. I believe there has to be a ID sticker under the hood of any pre 96 car with OBDII installed, so check for that.
I own a 96 Aurora (same engine basically) and all 95 Aurora's were OBDI and 96 - 99 were OBDII. HTH

 

[Lee_Burough]

Thanks Guys

Where do you buy "Chem-tool B-12" ?

 

[Scott Atk]

Lee,
I think that's just a brand name of carb. cleaner. Probably available just about anywhere.

 

[Lee_Burough]

So, any carb cleaner will do as long as its safe for oxygen sensors?

 

[Scott Atk]

I would guess yes, but I Know the brand ROLLIN suggested is available just about anywhere.

 

[Brian Mc]

I would pull the vacuum line from the FPR and see if a vacuum is pulling fuel through the regulator. Seen it before. I'll do a bulletin search now.

 

[Scott Atk]

FPR's are notorious. Usually go bad in the 40-60K range. Easiest symptom to recognize is long cranking before start when hot.

 

[Lee_Burough]

It was just a plug gone bad....fouling intermittantly.

I guess I'll have to remind myself that I need to start at the basics before getting very fancy in troubleshooting

Thanks to all who replied