Corrado Club of Canada VR6 Engine FAQ By: Dennis I thought I would snap a few pics of the engine compartment on my 1994 VR6 Corrado. First, this is the updated engine management system so it does have some things the earlier ones don't. This car uses and EGR valve, coil pack and air pump and the earlier ones don't. So we have the driver s side front of the engine compartment... PIC1: in no real order I will simply list what caught my eye and some will be repeated for reference. I didn't list the battery but it is the black this in front of the AC pressure switch. http://www.corrado-club.ca/enginefaq.html (1 of 9) [8/17/2004 9:52:00 PM]
1) is the air conditioning system high / low pressure switch. 2) This is the thermostat housing and you can see there are 3 switches in there. Brown is for high speed on the fan and input for the fan control module. Blue is for the ECU and yellow is for the temp gauge in the dash and the temp light. 3) This is the radiator Fan 4) This is the power steering fluid container. You must use a hydraulic fluid in here and nothing else. 5) Windshield washer tank, 8.4 litres as this car has headlight washers. 6) This is the coil pack. So this pic is the driver s side rear of the engine compartment... PIC2: 1) This is the fan control module which controls the rad fan and the auxiliary coolant pump. The first two speeds on the fan are turned on by the rad fan switch which is right under the AC pressure switch (PIC1, 1). The high speed on the rad fan is turned on by the brown sensor in the thermostat housing (PIC1, 2) http://www.corrado-club.ca/enginefaq.html (2 of 9) [8/17/2004 9:52:00 PM]
2) This is the radiator over flow bottle and the only colour of coolant that should be in that bottle is Pink which is G12 coolant. The older style coolant which is green - blue will cause the head gasket to be eaten away. 3) This is the brake fluid reservoir for the braking system in the car. Right under this is the master cylinder and the ABS control unit, pump and pressure accumulator. This reservoir also feeds brake fluid to the clutch master. 4) This is the Auxiliary Coolant Pump. 5) This is the coil-pack 6) This is the Exhaust Recirculation Valve. This valve re-introduces exhaust gas into the motor when it is under load to reduce Oxides of Nitrogen (NOx). 7) This is the rag that is always under my hood for checking the oil or cleaning stuff. It s back and out of the way so it doesn't get wet or anything. 8) This is the pin switch for the factory alarm. 9) This is the frequency valve for the EGR valve. This next pic is the back of the intake manifold... http://www.corrado-club.ca/enginefaq.html (3 of 9) [8/17/2004 9:52:00 PM]
PIC3: 1) This is the top of the EGR valve (PIC2, 6) 2) This is the brake master cylinder (PIC2, 3) 3) This is the Idle Stabilizer Valve (ISV) and its function is to allow air to bypass the closed throttle plate when the car is idling. It functions on a frequency of opening and closing and when the car is idling low its frequency is slower and when the idle is high it's opening and closing quickly. The problem is that internal combustion engines will have some blow-by (Combustion gases leaking past the piston rings) and this pressurizes the crank case and blows oil mist out the breather (PIC3, 7). The ISV intake hose is right across from this breather so it sucks in oilish air and after a while it gets gummed up and when it starts to stick you get a hunting idle. You can remove the ISV and spray brake cleaner in here and swish it around, do this a few times and the let it dry then put it back. You aren't always lucky but it's a cheap shot which may workout. 4) This is the throttle body where air enters the motor. Some times the throttle plate gets coated with oil so you might want to check when you change the air filter (PIC5, 1). 5) This is the intake hose which goes from the Mass Air Flow sensor (PIC5, 2) 6) This hose goes from the throttle body to the charcoal canister purge valve which is located just behind the air filter box (PIC5, 1) This hose goes over the exhaust manifold and can get cracked and then leak. The purge valve can also stick open and this will allow for a vacuum leak in the intake system. 7) This is the breather hose for the engine and goes right into the intake system. You gave to make this is sealed or you have a vacuum leak in the intake system. 8) This is the throttle switch for the ECU which tells the computer if you are idling or what load you're putting the car under. 9) This is a heating element that is used to make sure the oil doesn't freeze in the intake system in cold weather. 10) This is called a dashpot; its sole purpose in life is to stop the throttle from snapping closed. Bosch Motronic 2.8 management system is what is called a reactive system. It adjusts itself after the action has happened so if you allow the throttle to snap closed you will also blow raw fuel into the cat. If you run two free-flow mufflers you can blow flames out your tail pipe. The problem is that cats don't work for long when they are coated with fuel all the time. This also introduces a really rich mixture into the motor which can cause rough idle. 11) Everywhere my wiring harness meets metal it is covered with convoluted tubing then reattached. This stops all chafing and in high heat areas it protects the wiring from heat. Although not noted, the ECU is located at the base of the windshield right above the 'Ne' in 'Neuspeed' on the upper stress bar. This is the back of the cylinder where you get a view of the coil pack... http://www.corrado-club.ca/enginefaq.html (4 of 9) [8/17/2004 9:52:00 PM]
PIC4: so this is the shot where you can see the coil pack and a bunch of vacuum lines. I marked just a few with x's, someone wrote they couldn't see any. 1) This is the coil pack which fires the spark plugs. In reality, the coil fires two plugs at once. It fires one cylinder around top dead centre and there is another cylinder that will be 180 degrees out and this cylinder will also get a spark. I guess it makes it cheaper to fire two cylinders at once instead on just one. 2) This is the crank angle sensor, it tells the computer where the motor is in its rotation of 360 degrees. 3) This is another shot of the Auxiliary coolant pump which circulates coolant when the car is really hot or all of the time if you have the updated version of the fan control module. 4) This is the multi pin connector that connects your motor into the electrical system of the car. These contacts can get corroded so you guys in the East may want to check it out if you are having funny problems. 5) This is the valve for the EGR valve. 6) This is the side of the thermostat housing again. Here's the passengers side front... http://www.corrado-club.ca/enginefaq.html (5 of 9) [8/17/2004 9:52:00 PM]
PIC5:There's not too much on this side of the motor that can be seen. 1) This is the air box that holds the air filter in the car. There are clips all around the bottom that hold the top on. There is also a fine screen inside the box in the front. This screen stops big chunks of crap from going into the air box but it is a fine enough screen that it can get plugged so you have to clean it. Some people just throw it away but it does work so I check mine every month or two. 2) This is the Mass Air Flow wire and it measures the air going into the engine so the computer knows how much fuel to add. Point to note, any air that leaks into the engine past the front of this device will not be measured thus giving the car a lean mixture. This isn't such a big deal when the car is driving but at idle it can really make it run like crap. 3) This is pure bling. I thought this would look really cool painted so I went to Canadian Tire and bought some blue & red paint and had a buddy hand paint that for me, looks so cool. 4) This is injector #1, there are 5 more across the fuel rail (PIC5, 6). 5) This is the automatic tensionor for the drive belt. 6) This is the fuel rail and it feeds fuel to the injectors. There are seals on the top and bottom of the injectors that can leak air or fuel when they get old. There is a pressure relief valve on the other side of the http://www.corrado-club.ca/enginefaq.html (6 of 9) [8/17/2004 9:52:00 PM]
fuel rail that I didn't get in a pic. This relief valve is called a fuel pressure regulator and its job is to adjust the fuel pressure in the rail by the amount of vacuum in the intake system. 7) This is the fuel feed and return line from the fuel rail. If you look closely, you will note each hose is double clamped as these have a bad habit of leaking. I also double clamped the connection at the frame rail under the MAF where the rubber fuel hose meets the hard line. These are crimp clamps, they are a one time shot but they are far superior to screw clamps. 8) This is the throttle body again. 9) Once again there is convoluted tubing over the wires where they may meet metal (the hood). 10) This hose is where the air pump takes its air from. The pump operates when your car is cold to supply extra air to help the idle because of rich running. PIC6: This is the front of the block on the car and there are a few more things here of interest. This is from a VR6 with a distributor so there are some things that are different. The first thing is that this motor doesn't have an air pump on it. It also doesn't have the updated interior so it doesn't have an oil temp sensor. http://www.corrado-club.ca/enginefaq.html (7 of 9) [8/17/2004 9:52:00 PM]
1) This is the oil cooler for the motor, there is a seal on the front that can be replaced if you have any problems with leaks. 2) This is the coolant cross-over pipe that goes from the waterpump to the thermostat housing. The pipe gets really brittle once it gets old so you may have problems with it breaking of you try to remove the coolant hoses going to the oil cooler. 3) This is the lowest point in your cooling system and this is the drain for the block. The motor in the pic is missing the AC compressor but when this is the car there is very little room to get hands up there. Again, this drain can get really brittle and break when it is old. 4) Oil pressure switch, low 5) Oil pressure switch, high 6) Temp sensor for oil temp in the MFA 7) Engine RPM / crank angle sensor 8) This goes to the front knock sensor for cylinders 2, 4, and 6 9) Oil filter housing, uses a 36 mm socket to remove filter cartrage PIC7: If you have a VR6 with the newer style interior you will have a oil pressure sing unit like the one circled in http://www.corrado-club.ca/enginefaq.html (8 of 9) [8/17/2004 9:52:00 PM]
the above pic. There you have it, a very general view of all that crap that you always wondered about. Feel free to point out anything I got wrong and I will correct it. http://www.corrado-club.ca/enginefaq.html (9 of 9) [8/17/2004 9:52:00 PM]