1994 Impala SS

Owner: John Feinberg
NAISSO member 3017
Updated 08/27/2001
150,000 miles and counting

This page covers my 1994 Impala SS and the various modifications I've added to it. All of the pictures are links to 640x480 JPG files. Many of the entries have the word "install" linked - those entries link to Rob Cheek's Impala FAQ & technical archive page. This is the bible for Impala SS owners, and has detailed descriptions of just about anything you'd want to add to your car!!


   I installed a Pioneer DEH-P75DH stereo, amplifiers, and speakers to replace the rather cheesy one that came with the car. I installed a new head unit and rear speakers, along with two amplifiers in the trunk and two replacement speakers in the front doors. Also I want to put in some Dynamat in the doors, but I haven't ordered any yet. I do plan on doing this sometime, especially after all the great things I've been hearing about Dynamat. By the way, after I installed the Infiniti speakers in the front doors of the car, I hardly heard any difference at all. And those speakers have their own dedicated 30w/channel amplifier! I ended up up fading the speakers so that most of the sound comes from the rear speakers, since those sound so much better than the front ones. I think it is mostly due to acoustics. The rear speakers send sound to the rear window, which is angled to bounce sound right to the ear level of the passengers. The front speakers, for the most part, direct their sound to your ankles. They are angled a little bit, but they are not really angled to point to your ears. I ordered my CD receiver from Crutchfield, whom I cannot recommend highly enough. If you just want to replace your stock head unit and nothing else, then Crutchfield is the way to go. If you order from them, you get an adapter bracket, which allows you to install the new unit without having to cut or alter a single wire in your SS. It plugs right in! The Pioneer DEH-45DH, DEH-P75DH, and DEH-P85DHR are all sized to fit the SS perfectly, and despite what Crutfield tells you will plug right in with the Caprice adapter kit of the same year.  
   Impala purists may be gratified to hear that not a single wire was cut or altered in any way to install this stereo, although I did have to drill six holes in the metal rear seat brace to mount the board holding the amplifiers.  
   I installed a handy switch for the power antenna, so I can have the antenna down when I'm listening to the CD player. Handy for car washes! Originally I had it hanging down from the dashboard, but recently I installed it into the top of the change holder. You can even see a parkway token peeking up. 
   I put Dynamat in all four doors. This was quite time consuming, even though I had removed the internal door panels earlier when putting in replacement front speakers (door panel removal instructions). This time I bought replacement fasteners so when I reattached the door panels they didn't rattle. The result was quite impressive, especially at idle. There is a noticeable reduction in noise, and the doors give a very satisfying thunk when you shut them. My friend Jerry (right) did most of the work in cutting out and rolling on the Dynamat.  
   I installed the woodgrain trim kit that Dal Slabaugh from Vandervere Olds used to sell (Description and order info). The kit looks fantastic! I am very impressed. It came with a replacement dashboard (updated picture 11/9/98) and also woodgrain inserts for the doors. Also it came with the needed fasteners to replace those broken when the door panels were removed for the installation. The dashboard was originally black.  
   Remote-mount radar detector - I took a Passport 5000 radar detector and had it retrofitted into a remote-mount unit. The Passport 5000 has an alphanumeric display that shows signal (X, K, KA, or laser) as well as the frequency! Relative frequency range (10 bars) as well as strength is shown. I installed it myself. I had the retrofit done by Remote Systems. I sent them my Passport 5000, and a week or so later they returned it as a remote-mount unit. Big Electric Cat 
   Tachometer - I installed my own tachometer. It was done in two steps. First I did all the wiring. The tach has four pins: ground, sense, +12v, and dimmer. There is a dimmer & ground hooked up to the bulb in the ashtray, so those were easy to get to. Also a switched +12v is easy to find. The sense pin is best to connect directly to the PCM. This would be pin a13. This is the red connector on the 94/95. You can't see the inside colour but it is stamped on the aluminum PCM casing. When you look at the harness there is no pin at the a13 location. So you will need to order one - GM part # 12084913. When I was done I had four wires poking out of my dash, and it didn't take too long. I wanted to wait until I found the perfect tach, but one weekend I decided I needed one immediately so I went to a parts store and just bought what they had. I plugged it into my four wires, taped it to the top of the dashboard, and 10 minutes later I had a working tachometer! It actually looks pretty good, and I like it high up, so I probably won't bother installing it in the gauge area of the dashboard. Additional Wiring tech notes
   Ceiling console - this is the Astro Van ceiling console. A fantastic addition! It runs from the front of the car to just past the dome light. It has four swivel lights, one for each passenger, a larger rectangular dome light, and three compartments. One for CDs, one for glasses, and one for a garage door opener. And on the front of the console is a display that shows temperature and compass direction (N, SW, etc.) It hooks up to your dimmer circuit (amongst many other pins) so it even dims when the headlights are on. It also hooks up to the speed sensor wire so the temperature display won't change when you're not moving. A nice touch! The install uses the orphaned wire harness in front of the radiator and two unused pins in an engine harness for the temp sensor. I cut a bit too much out of the headliner, but other than that I did a pretty decent job. The gap is on the passenger side, so at least I don't have to look at it! The pictures shown were scarfed from Basim Jaber's web site.

New addition - I liked the console so much I bought a tan one for my 1999 Corolla!
   SmarTire pressure sensor - I installed pressure sensors on each wheel. There is a digital pressure display module, about 2" by 4" that you can velcro to your dash somewhere. This display will show the pressure of each tire, as well as temperature! You can set it to sound an alarm when the pressure falls below a level you set. It will show pressure of up to 6 tires. Perfect for trailering! I installed it inside the black dash bezel by cutting in holes with a dremel tool so that just the display and the two buttons show through. I then wired it directly to switched power. I have it sharing a power line with the tachometer. I did a pretty cheesy job, since I don't know how to use a dremel, but it still looks better than having it just velcroed somewhere and plugged into the cigarette lighter. Pictures and short install manual
   I installed a GM compass mirror to replace the standard electrochromic mirror. This mirror shows you the direction (N, NW, W, SW, S, SE, E, NE) you're facing in a little window on the top left of the mirror. Note: I removed this and put it into my Corolla after installing the Astro van overhead console, since that includes a thermometer and compass.  
   I installed a digital thermometer on the windshield above the mirror. Note: I removed this and put it into my Corolla after installing the Astro van overhead console, since that includes a thermometer and compass.
    I installed a Jotto desk, which allows you to mount a laptop computer inside your car on a convenient "floating" platform. 
   The main purpose of the Jotto desk & laptop computer is to be able to display the current position of the car on a street map. This is incredibly handy! While there are custom car systems available, nothing really compares to plugging a GPS receiver to a real laptop computer. Both products were purchased from Delorme. I am using the shareware program GPSy to interface with Street Atlas 66, running on various models of Apple PowerBooks.
   I installed a second trunk light, to make things in the trunk more visible. As an extra bonus, I upgraded the first trunk light too. The 1994 Impala trunk light has no dome cover, while the 95/96 lights do. Detailed Tech Notes 
   Emergency trunk release - When you open the trunk, at the very top (inside, naturally!) of the left rear fender, towards the middle, is an unconnected harness with two pins. Normally this is used for programming new remote units. However, if you short the pins for about a second, it will cause the power locks and the power trunk release to cycle. I noticed that the trunk light harness will plug into this perfectly. So when your trunk light blows out, recycle the harness into an electronic emergency trunk release! I decided not to use a button, and instead just have mine ending in bare wire that I taped over. Should I lock myself in (hey, you never know!) I can untape the wires and touch them together. Well it's more for the gee-whiz niftiness than anything else.
   I installed a "gas bib", which prevents gasoline from dripping onto the bumper when you are filling up. The gas bib came standard on white Caprices, but not with the other colours. -- Detailed Tech Notes  
   I put in the trunk mat that comes standard with the Police issue Caprice. It is a very thick rubber mat that keeps the trunk clean. The trunk mat comes with pre-cut holes so you can unscrew the net anchors, put in the mat, and screw the net anchors back in. GM part number10211580, cost about $75.More notes on the trunk mat
   I replaced the original silver bowtie emblem on the hood with a red bowtie from a Chevy Cavalier. Detailed Tech Notes  
   I put in the police issue wiper blades, which have little wings that supposedly keep the wiper blades from flapping around when you're going over 120MPH. I have not yet had a chance to verify if this is true... Detailed Tech Notes
Sequential Tail Lights - At the 1998 Atlanta event Scott Williams was selling his trunk boxes and sequential tail lights. I bought the boxes right away, but I hemmed and hawed on the tail lights. But later in the day I followed another SS with the tail lights installed, so I had to have a pair! The three bulbs light up sequentially, one-two-three, instead of one at a time. Nifty! Animated picture
   I put the "Use Overdrive for High Speed Pursuit" sticker right inside the instrument cluster. This comes with pre-94 police issue Caprices. Nifty! I put it right on top of the condescending "apply brake to shift from park" message, so that is an extra added bonus. I had to remove the clear dash cover, which is pretty easy to do. There are only two screws holding on the initial black bezel, but believe it or not there are EIGHT screws holding in the clear cover! GM Part # 10220597
   additional horns. I've installed two additional horns, High C Note and Low D Note which complement the current stock high A note and low F note horns very nicely. The sound has a lot more substance. I was able to conveniently get at the wire to the first two horns when I was installing the Evergreen cold air intake kit, as I had removed the air filter & the PCM. I ended up just installing the two additional horns in front of the radiator, since there were some easy bolt holes I could use. The horns don't rub against or bump into anything. The suggested location was inside the front passenger fender, but that looked VERY hard to get to! Perhaps some day if I feel ambitious I'll move the horns. They do look quite sloppy in front of the radiator. But they work!
9C1 Air Deflectors - The plastic pieces just in front of the front tires can be replaced by differently shaped air deflectors. Supposedly they direct more air onto the wheels, which cools the brakes a little better. Also you can see the front tires more clearly. This is standard equipment on the 9C1 police cars, but not on the Impala or the civilian Caprices.
Detailed Tech Notes

   I put my NAISSO member sticker in the rearmost window, along with my member number. It looks very nice there!
   Mobil 1 oil cap. You can order a Covette Mobil-1 only badged oil cap, to remind people what kind of oil goes into your car. I also ordered and put on a Mobil-one oil "plate" which looks great. I was thinking of putting it on my bumper it looked so good!  
   One modification is to remove "home plate" which is a large air resonator that serves to reduce air noise at wide open throttle. It essentially serves as a muffler for air rushing into the engine, but it slows air intake and thus reduces maximum power. It was easy to remove and cheap to replace. The cost was $2.99 for the cap from a bottle of diet Nestea mix. And I still have the Nestea!  
Note - one fine day the Nestea cap fell out and my car instantly stalled. I was lucky it didn't crack and send plastic bits into the engine! I bought a polished aluminum puck from Larry Walker to replace the Nestea cap, and now all is fine. A regular hockey puck would also work fine, without fear of ejection or disintegration.
   I've installed an Evergreen cold-air intake kit, which gives a slight boost to maximum horsepower. When you install the intake kit you remove "first base", the PCM, and the air filter case. You also drill a 4" hole in the metal on top of which the air filter & PCM sit. Then you run a 3" pipe from the intake elbow, though the MAF, and then through another elbow and through the hole. Then you have a K&N cone filter that sits inside your front left bumper. The PCM is moved to sort of sit on a slant on the wheelwell. The PCM is now completely visible. Before you could not see it as it was hidden underneath the air filter. To remove it you have to dismantle the pipes, but you can get at the wire harnesses without having to remove anything. I am a little concerned about the PCM wire harnesses being out in the open like this. The installation puts the PCM out in the open. I cut some notches in the neoprene seal that went onto the MAF so that it would fit more snugly. I'm surprised the notch wasn't already there!
   I removed the "press brake to shift from park" interlock. I find it to be a rather condescending "feature". It wasn't as hard to remove as I thought it would be. You don't even need to unscrew any panels! Just crawl into the footspace, and look up underneath the steering wheel area. You just have to unplug a single-wire harness from the solenoid.
   After a great deal of trouble I was able to get my Thule roof rack with clamshell carrier installed on my car. The Caprice/Impala has a metal piece that is ideal for roof racks available, but that piece is inside the door underneath the rubber molding! So Thule includes a small (but strong) metal clip that attaches to the metal underneath the molding, and a little hook peeks out on top of the door. The rack then clips onto that hook. The handy part of this arrangement is that you leave the small metal pieces on all the time, and the rack can fairly easily be installed and removed when needed.
   I've installed a B&M Shift Kit, which will allow me to switch between regular, firm, and extra firm shifting as I drive. Basically it is a switch with some resistors that you wire up to your PCM. It alters the directions sent to the 4L60E electronic transmission, as the PCM is able to control how firm each shift is. I enjoyed the switch quite a bit, but recently I had my transmission rebuilt at Level 10. I got the "stage 3" upgrade. The shifting is now a lot firmer anyway, so I disconnected the switch. But it really is great for a stock transmission. Update: My transmission DIED this summer. Just as I was passing through an EZpass booth I lost all power. I coasted as far to the right as I could and then pushed the car the rest of the way to the side of the highway. Level 10 transmissions was about an hour from the scene of the incident, and I called them and had my car towed to their shop. They said the transmission was completely shot. I had them do their Stage 3 rebuild, with a 2500 stall torque converter. It cost, well, lets say it cost more than any other car I have ever owned! But the trans should never die again, and I will be getting a trailer soon so the extra insurance will be good to have! What does this have to do with the B&M shift kit? The new Level 10 transmission shifts much firmer. You shouldn't use a B&M with a firmer transmission, so I no longer use it. Rather than disconnect the switch, I tucked it inside the dash in the "off" position. I have read that using the B&M switch in the "hard" position all the time increases the transmission pressure in the entire system, instead of just increasing pressure at the right piston. So the B&M may have been responsible for killing my transmission. Be careful with this modification!
   I added a 120v outlet, 12v outlet, and stereo RCA input jacks to the back of my center console. I removed the console and glued the 120v inverter to the underside of the console, so you don't see it and it doesn't take up any room inside the storage cabinet. I cut a rectangular hole for a regular 2 plug outlet and then wired up a standard wall outlet. The inverter is activated by a lighted switch. I would also like to add a 10baseT hub, but I can not find a good place to mount it inside the car!
Oil pressure sender. Although the Impala SS does have an oil pressure gauge, it is really just an idiot light. The gauge is real, but the sensor will send only "OK" and "not OK" so you'll always get one of only two different readings. The Police & taxi issue Caprices came with real sender units. I installed the proper sensor. Then I had to remove a wire bundle behind the glove compartment and change a bias resistor. Why Chevy scrimped on this part for a car that has heavy duty and deluxe parts everywhere else I don't know!
Brake proportioning valve - The Impala SS comes with four wheel disc brakes, as opposed to the front disc/rear drums on the standard caprice. The braking fluid distribution system is the same as that in the regular Caprice, so as a result not enough braking fluid pressure is sent to the rear discs on the Impala. The front discs do virtually all of the stopping for normal (less then full force) braking, and they wear out much quicker. Note that when you hit the brakes hard, the pressure in the stock system is correct. So, flat-out performance is not affected. Only front disk & pad lifetime is affected. By doing Dave Zeckhausen's brake modification, you remove a small needle from your brake proportioning valve, and then your rear brakes will get the proper proportion of fluid pressure for normal stops. The result - the front discs last a lot longer, and braking feel is improved. I attended a Brakefest event in Long Island and this modification was done for my by Dave Zeckhausen. Detailed Tech Notes
   I installed a black Fleetwood carpet in my car, since the stock grey carpet was starting to look pretty bad. The black carpet is a lot thicker, and looks very nice. When I had the carpet removed I added a full layer of dynamat (pic1, pic2)to the floor of the car. My old carpet was a real mess (pic1, pic2), plus it had "The Hole". Detailed installation notes
Scott Williams trunk boxes - these are panels that fit into the left & right side of the trunk. It protects the sheet metal from getting out-dented, plus it gives you compartments for storing crap in your trunk without clutter. They are fantastic! Animated picture
My friend Dan Hutt has built me a custom trailer out of aluminum to match my Impala SS. The entire trailer is aluminum, other than bolt-on parts such as the axle and locking latch. All the panels, beams, and parts are welded, down to the aluminum door hinges! Pictures during construction. Update - the trailer is now finished and licensed! Pictures coming soon. This trailer was inspired by a trailer I saw at the Impala show - pictures of the original trailer
   Trailer hitch - I have a DrawTite Class III hitch for the SS. It looks very good, and fits nicely between the stock exhaust tips. To install I only needed to drill two holes in the frame - the rest of the bolts used holes aready present for the bumper energy absorbing cylinders. I used a DrawTite wiring harness (Harness #18347). You don't have to cut or splice any wires, since it is a pass-through arrangement. The wiring harness wasn't easy to find - the Plattsburgh Spring Inc, 800 527 1740, had it in stock so I ordered mine from them.
   Garage door opener - OK this is not really that Impala related but the pictures are nifty. The roof in my garage is rather high so it was somewhat difficult to install my opener. I enlisted the help of my snowblower.  
Donut spare. The spare tire that comes with the Impala is huge! It takes up the whole trunk. Also it no longer fits now that I have installed amplifiers on the back of the rear seat! Right now I am making due with a can of fix-a-flat and a triple A card, which even taken together are a lot lighter than a full size spare. I'd like to buy a donut spare, but the right size costs $125 new. Someday when I get around to it I'll stop by a junkyard and see if they have the right size. Update I have ordered a donut rim for $50 from Dal, GM part # 9591766. The right tire size is T145/80D16, which I will try and order from a local tire shop.
Power window mod - by putting a jumper in the right spot in the fuse box I will be able to open & close the windows when the car is off. Why aren't all cars shipped like this? How to
External Oil Cooler - this is a "mini radiator" that mounts in front of the regular radiator, about 6 by 12 inches. You re-route your oil tubing so that it flows through this external cooler, instead of through the oil line that passes through the regular radiator. Detailed Tech Notes

Upcoming modifications

The Impala has the Chevy LT1 engine, which is technologically quite impressive. It generates a lot of power, yet is capable of decent mileage.


I attended IATG in Atlanta in April 1998. It was a great show! Here are a bunch of pictures I took.

These pictures were taken when I was checking out the car

The car was purchased from Frank's Auto Sales in Ansonia, CT 11/23/97.


Dan Hutt helped me to look at the car 11/16/97 and also he used his crane to tow my car home the next weekend Sunday 11/23/97. Thanks Dan!!