Cadillac Jim

Taking an out-of-warranty car to a dealer, any make, is a risk. Repairs for cars in warranty is monitored by the manufacturer as part of their warranty cost management; they get the used parts and analyze them. Bad repairs aren't compensated. Part failures are used to revise designs to make the replacement parts more reliable (so always get the latest part number when getting parts for your car!). Repairs on out-of-warranty cars is not monitored by anyone. Some dealers are great, others aren't. My experience is that Penske dealers tend to be reliable in correctly reporting problems and in accurate charges, but I have found other dealers that are OK too. For an education on the subject, take the time to watch this 22:36 video of a Canadian consumer TV show on dealer service:

I once drove my Chevrolet Kingswood 9-passenger wagon up Mt. Washington in NH. Driving down, there were frequent signs to pull over and cool your brakes, but with ventilated front disks and huge drum rears I had no fade, so I didn't pull over. When I eventually did, they were smoking, particularly the rear. Some clown pulled up and wanted to squirt water on my brakes and I told him to leave the car alone. It was fine. I drove it for years afterward and never got a brake job. I think that the reviewer embarrassed himself on many levels.

Without elapsed times to compare, it's not a performance review, it's just a blog.

Two takes: The extreme and long-winded rant about the transmission and RPM range seem more to be about how he expects the engine management to work, as in keeping the RPM range high as needed for a naturally-aspirated car or a small engine, AND, brake smoke does not mean that the brakes are on fire, or even that there is anything wrong. This is a zero review.

Specifically, the worst bottleneck is the front exhaust header, which goes between the rear of the engine and the transmission, if I recall correctly. Mark had some tremendous numbers from his turbocharged STS for a few months. But his transmission turned to mush before he got one built for the extra 200+ horsepower. I don't think we've heard from him since. My favorite source for Northstar ports, cams, valve train, etc. was chrfab.com, which shut down a couple of years ago. I researched them and find that the key guy was a professional metallurgist who did precision welding on the side, and was the proprietor of chrfab, which specialized in Nortstar sand cars (!!!). He built one naturally aspirated Northstar that was campaigned in Europe in a Corvette at one time.

The only upgrades that I've seen of late model high performance intakes involves enhancing the factory setup, not replacing it. The GM setup on the E/K platform has the added complications of routing the air over the PCM to cool it, and having the IAT 1 sensor on the output of the air box. The whole path involves the air path behind the grille (usually the lower or under-the-bumper part, if the grille is split) to an air box, then through ducting to the throttle body. An air cleaner element is incorporated into the air box in a manner determined by the designer. For street or heavy rain use, the air cleaner must incorporate mechanical support to avoid tearing if it gets wet and clogged, which would then let liquid water into the ducting to the throttle body. Design of such a system ideally takes place with a mule on a dyno, with inspection of the entire torque/hp vs. RPM curve for each configuration tested. In some cases, changes in the rest of the engine tune accompany this design. In something like a GM engine development lab, this "tuning" process can include cam changes, value and port changes, spark plug position changes, etc.

There are three types of switching most often seen in relays: SPST, SPDT, and DPDT, and you can tell these apart by the number of pins on the case. Then, there are low-current (smaller) and high-current relays. A power seat relay will definitely be a high-current relay. Most cars use only two or three types of relays, and many have an extra relay in the box to give you one to try when looking for a problem. If it's a GM relay, you and probably get one just like it from Rock Auto by matching the appearance and pins with the one you have. If the relay is from the people who did the convertible top, maybe it's not a GM relay, and you need to find a logo or plate that identifies whoever built the convertible top. Note that sometimes convertibles are done on contract by GM before shipping to a dealer, and sometimes dealers have hardtop models made into convertibles without GM being directly involved.

I'm inclined to believe that you won't see much change by using a different air hose between the air cleaner and the throttle body. Just using a smooth bore there, changes in the air flow for different RPM ranges at full throttle, etc. will give you small changes everywhere, but 2 Hp is going to be in the range of run-to-run variation with no changes whatsoever. If you want a change, look at the whole air flow path: grille-to-air-passage, air passage to air cleaner box, air cleaner box to throttle body (your change is here), throttle body, intake manifold, valves, and ports. Unless the one you are changing is the biggest choke point, you won't see much improvement. Often the choke point is the throttle body, but without measuring the air pressure and temperature at each point in the air flow path during a full-throttle run then you are guessing. Most re-tunes of HP engines begin with a larger throttle body, larger fuel injectors, and improved cooling. You need an engine analyzer package that lets you look at the spark map and the mixture during a run. The mixture is very important because if you improve breathing to get better torque/horsepower then you are asking more of the injectors. If the injectors max out, you will run lean at full throttle, which is a recipe for engine damage.

See my post, two previous to yours, dated June 28, 2010; I cited a study that Bruce did with a new STS on a 1996 STS when it was new, using performance meters and measured distances with recorded temperature and humidity. The drupal.caddyinfo link seems to be dead now (I get a message "Unable to connect to database server"); Bruce may know a good link for that page. Upshot is that "cold air" intakes that did away with the stock air box, which is a factory cold air intake system, actually hurt performance, apparently because they use a lot of hot underhood air. Cheaper K&N and other low cost aftermarket filters don't clean the air as well either. Nothing outperformed the stock airbox with a new, clean AC/Delco air filter, and nothing cleaned the air better either. Another issue that may or may not be important to you is hydrolock when driving through deep puddles. Water can splash into the air box in sufficient quantity to cause hydrolock. A combustion chamber is typically something like 65cc or four cubic inches, so it doesn't take much water to hydrolock an engine. The stock AC/Delco air cleaner is reinforced with a steel mesh that will hold and choke the engine if the air cleaner is totally wet and water clogged. Another brand of air cleaner, with or without a steel mesh behind the paper element, may give way and let bulk water into the intake. This is a known problem with some GM pickups using the LS V8 engines but hydrolock can happen to anyone who simply removes the air cleaner element and drives through standing water.

The car is old enough to be exempt from emissions rules that require exact OEM powertrain and emissions components, so you have a clean slate. The best pushrod replacement is the later 4.9 liter V8, but the 4.5 liter V8 may be simpler because of motor mount and accessory mounts; others will have experience with swapping the aluminum pushrod V8s. The 1991 STS was offered with the L26 4.0 liter V8 so that might be the best option. Be sure and get the transmission, wiring harness, and PCM with it. The Olds engine and the bowtie 350 that were used in some larger sedans may be an option, for a total conversion project. For a daily driver, I would recommend a bowttie 350 because of parts availability and such for simpler maintenance over the long haul, but an iron engine will require suspension changes because it weighs over 200 lb more than the smaller aluminum V8s. Even a Cadillac 425 weighs less than an iron bowtie engine, because Cadillac uses stronger alloys for its blocks and thus can cast them thinner and still be stronger. If a Northstar falls into your lap, you will be looking at a full conversion project as thorough as a switch to the Olds or bowtie V8s, except that added weight will be less of a problem. Just make sure that you get one of the transverse mounted FWD models and get the transmission, wiring harness, and PCM with it. For a full replacement project, the ECM might be simpler if you use a Holley fuel injector and ECM. The TCM is up to you, though. For a good time, look at a GM Performance E-Rod engine. They offer everything you need for a street-legal powertrain including engine, transmission, ECM, and PCM. The price may seem higher than for other alternatives but I think you may find that by the time you look at all the extras you need for other total replacements you will find this option a bargain. Weight is similar to that of the HT engines/transmissions.. Here's one: https://www.gmperformancemotor.com/parts/CPSLS3EROD4L65E.html Note that at 430 hp you may need to upgrade brakes, suspension, wheels and tires before you let your wife drive it.

For an older car that doesn't have lots of enthusiasts driving on the road today, it will be hard to find someone who sells chips. However, your PCM can be programmed by a dealer or anyone else with at Tech II. Some tuners have a Tech II and have offered this service in the past. My dealer did this for my 1997 ETC a few months after I bought it. Be warned that nearly all tuners begin by replacing the 195 F thermostat with a 160 F thermostat, then work in the spark map and fuel mixture vs. gear, speed and/or RPM. A 160 F thermostat isn't hot enough to keep moisture and sludge out of the oil. If this is your daily driver and you plan on keeping it for a long time, know that you may be shortening your engine life. If you use synthetic oil and/or change it every 3000 miles (4,828.03 km), that may be OK. Or not. If you can find a tuner with a Tech II, you may choose to tell him that you want to leave your thermostat alone. Your call there. One quick thing to do is to put ETC intake cams in an ESC.

The url for wheel-size.com is https://www.wheel-size.com/ They refer to the wheel size as 7Jx16 ET51. Their "i" button explains that as 7 inch rims, mounting rim type J (most road cars), and ET51 means a positive offset of 51 mm, which is 2 inches. That's where I got the tire size, too. Width is 235mm, up from 225mm for older Sevilles, with a corresponding slight increase in rolling diameter (the aspect ratio of 60% is the same).

According to wheel-size.com, the 2003 Seville, both the SLS and STS, have this tire and wheel size from the factory: Tires: 235/60R16, load range 99, speed rating T (118 mph) NOTE BELOW Wheels: Rim 7 inches, width 16 inches, mounting flange type J, offset +51mm, 5 bolts on a 115mm circle. What isn't listed there is tire rolling diameter. From tyresizecalculator.com, the calculated (from the tire size) rolling diameter is 27.09 inches. The specs for the particular tire you have on the car will have that listed in the Goodyear catalog, and will be very slightly different, as in 26.9" or some such. Other calculated numbers are 747 revolutions per mile, etc. If you want the car to accelerate and brake without pulling on the steering wheel on bumps, you need the steering tire rotation axis to pass through the center of the tire patch. If you have a tire with the same rolling diameter and a wheel with the same offset, that will make sure that this happens. If you change the wheels, making that happen is on you. If you have a tire with a different rolling radius, as you apparently do with 20" wheels and the tires hitting the fender liners on bumps, this is like changing the final drive ratio, and the speedometer will read low too. Check with a speedometer shop or two and see if you can get that corrected. The formula for rolling diameter is [wheel rim width, as in 16"] X 2 X [(tire width as in 235mm) X (aspect ratio, as in 60 means 0.6)/(25.4 mm/in)]. You can use that as a spreadsheet formula to get rolling diameter for a bunch of tire sizes.

morty96 -- you can't tell what's wrong, exactly, from what you say. If we have the codes, they may be able to tell us what is up. The compressor may be turned off because a code has been set that says that the expansion valve or dryer is clogged, for example. If you have a gauge on it and it is reading 100 psi, it probably doesn't have a leak. BodybyFisher is right, a can of the correct Freon every year or two may be OK but that's not going to address whatever is stopping your compressor from running. Possibilities include, but are not limited to: Electrical problem, like bad compressor clutch ground, Bad compressor clutch, Clogged expansion valve, drier, condenser, evaporator, etc. Etc. If we have all the OBD codes we may be able to eliminate a lot of things or even focus in on something specific. As BodybyFisher says, get the codes (OnStar, Autozone, whoever), write them all down, and post them all here.

Let us know if there is a dash light on. Regarding the codes, if you have OnStar you can ask the operator to read the codes to you, and to email them to you. If you don't, AutoZone and others will read your OBD II codes for free. Then, you can buy a new air conditioner relay right there if that's the problem. The FSM says that if it's electrical, it's one of the wires to the A/C relay or it's the relay, or it's the compressor clutch ground. If you don't have a dash light on, check those first. Fuses to check in the underhood fuse block (A/C CLTCH 10 Amp, EMIS 2 FUSE 15 Amp). The A/C CMPRSR CLTCH relay is also in the underhood fuse block. There is a circuit breaker on the compressor. You can reset it. The coil for the A/C relay gets its power from the PWR/TRN relay, also in the underhood fuse block. If the car starts and runs OK, that relay is good.

Uh, like BBF needs anyone to back him up, but as an outsider in this thread I do think I have something that might help out here. Whenever the battery voltage drops below 9 Volts during cranking (or any other time, like sitting at a long light at night with the headlights and A/C running...), some modules will start throwing bogus codes. At least two of them will throw "Battery voltage low" codes to make sure the tech knows to ignore ALL the codes, charge or replace the battery (or fix bad connections), clear all the codes, and start over. Things that can cause voltage to the modules to drop below 9 Volts when the battery is new: Wrong battery -- too small, or one with not enough cranking power; or an ordinary battery when the car is designed for an AGM battery Corrosion on either battery cable connections to the battery Bad battery ground on either the engine block or on the car body Dragging starter or something on engine dragging or seized Battery too cold to start engine easily, particularly while engine is dragging due to extreme cold Engine taking far too long to start for any reason Bad connection or cracked Maxifuse or fuse Bad ground on module(s)

BBF, next time you get in a tight spot and need an FSM for 2002-2012, send me a PM (I'll get an email). KingCadillac: The 4T80E has its own FSM separate from the one for the rest of the car. If you're doing significant internal work on a 4T80E, you need this manual. Anytime I take one down beyond the solenoids and such, I recommend a rebuild. That way you get seals, thrust washers, clutches, etc. and end up with essentially a new transmission. On an old transmission, anything less is really just a patch. The torque converter is not part of most rebuild kits and is purchased separately. You should change it too because the parts involving the electronically controlled torque converter clutch wear out too, and in fact that is a common failure in old 4T80Es. Note that the TCC vicious clutch "was replaced with EC3 (electronically controlled converter clutch) in 2004." (Wikipedia) If you want to cut your losses, a used 4T80E from a recycling yard is an option. Be sure and get the right one for your year. Otherwise the connectors may not match up. BBF will have more insight on that.

I have the 06 DTS service manual on DVD. I believe that the question is where the battery grounds are. From the FSM, the main battery ground cable is G303, "Battery negative cable ground, under the rear seat on the right floor pan" while there is another ground cable wire, if a smaller gauge. The FSM schematic from starting circuits is attached. My IE has updated to the point that the GM SI TIFF viewer isn't there anymore. I'm trying to re-install it...OK. The smaller battery ground wire goes to the BCM, apparently as a BCM ground. It seems that there is an engine ground strap, between G110 "In the engine compartment, right side ground strap to the right frame rail below underhood - fuse block", and G111 "In the engine compartment, right side ground strap to the right frame rail below underhood - fuse block". Since they say "right side" there may be another ground strap.

From memory from my 1997 Eldorado, the battery ground cable is double. One full-size black cable goes to the body or frame, the other goes to the engine block somewhere. This means that you don't need an engine ground strap. This is important because the starter motor and solenoid is in the "lifter valley" which is available in DOHC V8 engines, and one of three battery positive cables goes directly to the starter solenoid. This puts solid connections of both battery cables right to the starter motor. I can get my 1997 FSM from the garage if needed, but BBF has a 1996 FSM that will be identical here. NOTE: I had a good mechanic do a Northstar engine swap some years ago, and he stretched the wiring harness where it connects to the ABS and ruined the connector. He patched it and didn't tell me. Some time later it started giving trouble and it took months to find it. BBF helped me find the parts to fix the connector. A dealer found a wire pulled out of a connector and just pushed back in an fixed that to end the problem. This is a big argument to support what BBF says about being very careful about cables and wires when you drop the cradle. Another might take this incident as an argument for DIY. I had it done because I needed the car every day and didn't have time for a project.

If you have OnStar, push the black button and ask the lady to read you the OBD codes and write them down and post them here. You can ask her to email them to you, which might be simpler and avoid an error in writing them down. If you don't have OnStar, find and Autozone near you and ask them to read your OBD codes for you. Look at the sticker on the underside of your spare tire compartment cover and write down the RPO codes related to your radio. I would take a cell phone photo of that sticker, which has all your RPO codes, paint numbers, etc., and keep that photo on my computer for reference. The radio codes for the 2007 CTS are (this list may not be totally complete because I just now picked it out of the FSM): UAV Infotainment System 005.1 U2J Digital Audio System S-Band, Not Installed U2K Digital Audio System S-Band U2R Infotainment System 001 U2S Infotainment System 002 U2X Infotainment System 007 U2Y Infotainment System 008 U57 Speaker System 8, Dual F/D Pillar, Dual FRT DR MTD, Dual RR DR MTD, Subwoof PKG Shelf, I/P CTR, Amplif, Bose U66 Speaker System 7, Custom We will need that information to get the right schematics in the factory shop manual (FSM). If you have a Volt/Ohm meter, you can check for power at the radio and a good ground. Power to the radio is through the RD/WH wire, ground is through the BK/WH wire. If you have premium audo (Bose, probably) you have the 30 Amp AMP fuse with power directly to the power amp on the RD/BK wire. If there is more than a small fraction of an Ohm resistance from the BK/WH wire to chassis, check ground G402, which is In the rear compartment, to the rear of the left rear shock tower, below audio AMP.

There are two fuses in the rear fuse block. After you try rockfangd's solution, which will restart any modules that have locked up, you can look for a 10 Amp AUDIO fuse and a 30 Amp AMP fuse. Since the whole radio went black, the 10 Amp fuse is the first one I would look at.

Two things occur to me: the car's network connector (the PPL wire), and the three power connections: always on (RED), on in start and run (PNK), and ground (BLK). There are the speaker connections, too. There is also the dimmed power connector (I forget the color) and the speaker connections. I would start by making sure that the radio has a good ground, then the two hot connections. If the factory radio has been flaky, I would check for cracked fuses. If you have a voltmeter, check for A/C voltage across the speaker connections at the radio. If there is a current real-world problem with a 1996 Deville, someone with a 1996 FSM can step up, or I can locate my 1997 FSM and scan the radio schematics to identify all the wires and their colors. You may need to know the factory option for the stock radio. The RPO numbers are on a sticker under the spare tire cover. If that is missing, an internet search on your VIN may turn up such a list for your car. The radio options are of the format U1x, where x is another letter or number, or, for premium radios, Unx, where n is another number besides 1.

From the FSM schematic, the rear left, or driver's side, tail/stop/turn lamp circuit is identical to that of the right side. EXCEPT for the ground, a BK wire going to G402 (BK wire tied to body behind the back seat, high, near the door frame), the trailer connector (check it for pinched wires or shorts), and its own connector on the BCM (check for pushed-in terminals in the connector). There are three fuses in the underhood fuse block that provide power to the BCM, BCM 4, 5 and 6, all 10 Amp. One of them may be for the left rear. Since the rear lights have a trailer connector, I'm sure that each side has its own fuse, probably BCM 4 and BCM 5. Does the dashboard flasher arrow for left turns work? If it turns on at all, the problem is probably in the connector or the ground. You have already checked the light itself. EDIT: Usually I ask people to check their OBD codes first, but on your car and mine you can't do that yourself from the driver's seat. You can ask the OnStar operator to ready you the codes (and email them to you!) or you can use a code reader. This problem seems pretty straightforward if you have the schematics, which I do, on a GM SI DVD. But this goes on for much at all, and we can't get 12 Volts to at least one of the YE wires to the left rear tail/stop/turn signal lights, the fuses are good, and the trailer connector isn't shorted, we will want the OBD codes. You can check the ground by putting a voltmeter on the BK wire on the left stop/tail/turn light; if there is 12 Volts on either or both of the YE wires but the BK ground line has zero volts when the dashboard flasher arrow is on or blinking, then the logic in the taillight assembly may be bad. Autozone and others offer to read your OBD codes free.

The Allante intake/fuel injection for the 4.5 gave it 200 hp, and the Allante kept that engine when the 4.9 came out. That's known to give a performance boost with minimal or no problems while an engine switch is... an engine switch. Engine cooling and lubrication such as the oil-cooled piston skirts may not be sufficient for 150 hp more than what the engine was designed for. It really takes a clean sheet of paper to do a supercharged engine that has sufficient reliability to actually drive normally on the streets and highway. The STS-V, for model years 2005-2009 model years, used a 4.4 liter supercharged Northstar that is rated at 465 hp. A full swap of engine/transmission/ECM may or may not be feasible. EDIT: I don't have a parts manual that has both the regular 4.5 l and the Allante special 4.5 l, but I would consult one to make sure that they have the same cam timing and lift, and the same valve sizes. If not, you can decide whether to update the cam and heads to match the Allante intake/fuel injection.

The first thing I would do is run the OBD codes to see what the car's computers think. See the link in my signature block for a Caddyinfo page on reading your OBD codes. If the car passes emissions testing, that means that it has no current emissions codes, not that there are no problems. Nearly always, if the Check Engine light is off, the car will pass emissions testing as it is done lately. There may be History codes or intermittent problems, or there may be something that is not detected by the car's OBD system. But often a check of History OBD codes and codes other than emissions codes will tell you something important, occasionally about a problem that you weren't aware of. If there are not OBD codes that reflect on your problem, I would check the plug wires, the coils, the crank sensors, MAP sensor, and also for clogging in the catalytic converter. If you are mechanically inclined, you might check the plugs for odd or non-uniform appearance, but be aware that anti-seize compound and silicone plug boot compound must be used when replacing the plugs, and proper torque must be used. A real code reader that provides misfire counts by cylinder can be helpful in identifying plug, ignition wire, or coil problems. Each coil fires two cylinders, and problems on both for a particular coil point to the coil as opposed to the plugs or wires. Moving wires from coil to coil can verify that a coil is bad - or good, but the wires or plugs are bad.