94pain Posted June 14, 2011 Report Share Posted June 14, 2011 You know how you drive down the road and your Caddy Northstar just Purrrrs along..? I'm missing part of my purr. From a dead start she runs fine. At highway speeds she runs fine. WOT is orgasmic. BUT that time in between these speeds is... sloppy? It almost feels like it's misfiring a cylinder or running on cheap gas. (I'm using 93 octane + octane boost at each fill up- so not the problem.) It's got new plugs, wires, fluids (800 miles ago) and catalytic converter (100+ miles ago) AND NO CODES (and I have preformed the "Driving Cycle Reset Procedure" 5 times in the last 24 hrs to try and uncover any possible problems with the new parts) The periods between 25-40 mph kinda sucks (and those are the "around-town" speeds) (runs around 28mpg hwy and 12 city!) Without any codes showing I don't know where else to look but here... You guys have a cornucopia of experience so ANY ideas? An suggestions of how to better diagnose? Thankyou for the help- if there's anything I can clear up or more clearly describe- say the word. Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 14, 2011 Report Share Posted June 14, 2011 Please describe this better: BUT that time in between these speeds is... sloppy? It almost feels like it's misfiring a cylinder or running on cheap gas ALMOST?, what is it doing exactly Are you getting what feels like a 'fishbite' Could this be TCC shudder? Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
joeb Posted June 14, 2011 Report Share Posted June 14, 2011 you replaced cat? what caused you to do that? and plugs/wires? thought you had COP? no plug wires? how about intake plenum? Link to comment Share on other sites More sharing options...
94pain Posted June 14, 2011 Author Report Share Posted June 14, 2011 "what is it doing exactly Are you getting what feels like a 'fishbite' Could this be TCC shudder" -bodybyfisher OK, I just drove another hundred miles trying to better diagnose this. Motor was replaced and timeserted 800 miles ago. (hence the new plugs, wires, fluids, TCC solenoid, front motor mount and the torque converter) but yes, it almost feels like a TCC / TC issue. I cannot isolate the feeling to an RPM or a speed, but... "what is it doing exactly?" - I guess it's a "fishbite"..? Pulsating, maybe? As I slowly accelerate or let off the accelerator there is a "shimmy" or a "shudder". IF I get on it (drive it like you stole it) it runs smooth as pie, but that slight on-off the pedal leaves an unmistakable feeling of sputter. (NONE of this shows on the digital Tach... but I'm not surprised.) Also no codes. Does any of this help? Is there something I could try to better diagnose? Link to comment Share on other sites More sharing options...
94pain Posted June 14, 2011 Author Report Share Posted June 14, 2011 JOEB, The nice men who did my motor work "degreased" the engine compartment for me... which filled the smog pump with water... I brought it back twice and they cleared the code and told me it was because of all the new work and it should reset... It didn't. (P0410) I put in the new pump and a week later I got an incessant P0420. The cat was definitely shot, it was rattling by this point. Also, I said "new plugs & wires" as apposed to coil packs, which I believe mechanic reused. But I will got inspect the plenum right now, thank you. Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 14, 2011 Report Share Posted June 14, 2011 The plenum should set a lean code for both banks Check the EGR pipe, we have seen that create a fishbite, if loose or corroded. Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
94pain Posted June 14, 2011 Author Report Share Posted June 14, 2011 Plenum seems fine. Not sure where the ERG valve or its pipe are on the 2002 4.6, so I will break down and buy a repair manual tomorrow. Can't believe I made it this far without one! I remember changing the ERG valve on mt '94 SLS, but that was different. Do dealerships have a scan tools for random code-less problems like this? Link to comment Share on other sites More sharing options...
Ranger Posted June 15, 2011 Report Share Posted June 15, 2011 Don't waste your money on a Chiltons or Haynes manual. Get a real FSM by Helm Inc. Ebay is your friend. The EGR valve is the black canister on the crossover manifold close to the master cylinder. Link to comment Share on other sites More sharing options...
joeb Posted June 15, 2011 Report Share Posted June 15, 2011 not sure if bad headgaskets will wreck a cat. my car does not have airpump. does water injection into the cat cause issues? it sounds possible. i did get a code for bad sensor before cat. after cat sensor is original. is my cat ok. must be. no codes now. Link to comment Share on other sites More sharing options...
94pain Posted June 15, 2011 Author Report Share Posted June 15, 2011 "Get a real FSM by Helm Inc. Ebay is your friend." -Ranger Seriously? $129.99 http://cgi.ebay.com/ebaymotors/2002-CADILLAC-DEVILLE-SHOP-SERVICE-REPAIR-MANUAL-02-/380344170536?pt=Motors_Manuals_Literature&hash=item588e477828 Is this what they go for? Link to comment Share on other sites More sharing options...
BodybyFisher Posted June 15, 2011 Report Share Posted June 15, 2011 Yep, they are great bed time and bathroom reading! Pre-1995 - DTC codes OBD1 >> 1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/ Cadillac History & Specifications Year by Year http://www.motorera.com/cadillac/index.htm Link to comment Share on other sites More sharing options...
AndyUK1 Posted June 15, 2011 Report Share Posted June 15, 2011 You could go to alldata.com where you have unlimited access to the factory service manual online for $30 for a one year period-I know mechanics who use it and they highly recommend it. Link to comment Share on other sites More sharing options...
Ranger Posted June 16, 2011 Report Share Posted June 16, 2011 "Get a real FSM by Helm Inc. Ebay is your friend." -Ranger Seriously? $129.99 http://cgi.ebay.com/ebaymotors/2002-CADILLAC-DEVILLE-SHOP-SERVICE-REPAIR-MANUAL-02-/380344170536?pt=Motors_Manuals_Literature&hash=item588e477828 Is this what they go for? They sell for $135 brand new from Helm. $130 for a used one on Ebay is sucker bait. You should be able to find one for half that (or less). Link to comment Share on other sites More sharing options...
94pain Posted June 16, 2011 Author Report Share Posted June 16, 2011 Any experience with, or opinions of Alldata? I purchased it for a Mercedes I had ($25-$30) and found it covered everything. BUT... It wasn't a Cadillac Northstar... Link to comment Share on other sites More sharing options...
Ranger Posted June 17, 2011 Report Share Posted June 17, 2011 I have not heard anything bad about alldatadiy. Only good reviews. Link to comment Share on other sites More sharing options...
Recommended Posts
Archived
This topic is now archived and is closed to further replies.