3.4 V-6/T-5 Engine/Tranny swap Phase I

[namba209]

1972 OPEL GT 3.4 ENGINE/S-10 T-5 TRANNY CONVERSION Phase I

Let me preface the installation with what I’m doing. First off I needed to see if the engine, with computer and harness, I bought off E-Bay would run and just how good was it and what problems would I have with a totally computer controlled engine.

There is no distributor, the computer controls the ignition timing and advance, also when and how long the injectors spray fuel into the combustion chambers.

There are over 49 inputs to the computer that dictate what the output to the ignition pack and injectors will be. Kind of mind boggling to say the least.

For that reason, I decided to keep the engine as complete as possible, even to the exhaust manifolds. The only actual modification was to remove the auxiliary air injection pipe from the right manifold and plug the manifold where the tube screwed in.

I spent the better part of two weeks using a V.O.M. and testing each of the computer and engine wires and finding out where each one goes.

I took Mike Pilkenton’s advice and bought a Chiltons manual for both the 95 Camaro engine and the 92 S-10 transmission. Both manuals had disparities. Both indicate the pilot bearing for the transmission shaft is in the flywheel, it is not. The pilot bearing is pressed into the rear of the crankshaft.

The manuals for the Camaro/Firebird indicates by drawings of the fuel rail that the smaller of the two fuel lines is the fuel inlet line and the larger of the two is the return line to the fuel tank. It is just the opposite. I found out the hard way.

Knowing the Opel fuel pump would not have enough pressure and flow to operate the fuel injectors, I searched the AC Delco fuel pump book and found an in-line fuel pump that put out 70 PSIG, it was pricey at $125 but my USAF training is that more is better. The fuel pump is a “Master Fuel Pump #E8168” that has three ports, one inlet, one outlet and one pressure bypass. I also got a FRAM G3895 fuel filter that also has its’ own mounting bracket.

I hooked up the fuel pump as indicated by the drawings in the manual and could not get the engine to start. I double checked the fuel pump ports to make sure I had fuel flow and noticed fuel was being bypassed by the pump pressure regulator. I disconnected all the hoses and checked for clogging, all hoses were clean. Then I pulled the fuel rail to look for a plugged passage. It too was clean. Looking at the passages in the fuel rail I discovered then that the book was wrong.

I was putting pressure to the bypass side of the fuel rail pressure regulator, so I wasn’t getting fuel to the rail at all. The pressure regulator bypasses fuel at a pressure in excess of 49 PSIG.

I was concerned about the actual fuel pressure at the fuel rail so I purchased a fuel injection pressure gage that will work on all fuel injected engines, after swapping the hoses at the fuel rail, I actually had my fuel pressure regulator relieve pressure at 50 PSIG.

I had the engine mounted on an engine stand soon after I got it shipped from Florida. The first thing I did was a visual inspection. The oil pressure transmitter was broken at the oil filter housing and I was missing the plate the coil pack mounts on.

A call to Gil at OpelGTSource got me the correct Opel oil pressure sending unit and coolant temperature sensor, and a trip to one of the local auto recyclers produced the mounting plate for the ignition/coil packs.

There are two coolant sensors on the engine, one for the computer by the thermostat housing and the other for the temp gage in the left head behind the coil packs.

While I was waiting for the sensors from Gil, I decided to flush the cooling passages in the engine. I purchased a submersible 500 Gallon Per Hour aquarium water pump, pulled the thermostat and cycled 5 gallons of water and a pint of radiator flush through the engine for over 12 hours. When I was done, there was only clear water coming out of the engine.

Also I pulled the spark plugs and checked them for color, they were all light chocolate brown, a good indication, and I drained the oil and replaced the filter and put Castrol 20-50w oil in the engine.

During the interim of getting the parts from Gil, I got an instrument panel from E-Bay for a 95 Camaro/Firebird, it was more economical (cheaper) than buying individual mechanical gages.

I found out then that the Chiltons is not all comprehensive in the wiring diagrams as far as the instrument panel is concerned. I ended up getting a Haynes for their instrument panel schematics.

Between both manuals I decided I needed the other half of the connectors on the wiring harness and the instrument panel harness.

The instrument panel on early V-6 Camaro/Firebirds has the connector on the left side of the panel with 32 connector pins. The 95 has the connector in the center of the panel with 34 pins and it is solid mounted to the dash structure. Hard to get to, but not impossible to remove with about 8 inches of pigtails to work with.

Using the schematics from both manuals I was able to trace almost all of the wires from the computer to the instrument panel and decipher which wires needed to be cut and spliced into a power panel. Having the other ends of the connectors made this chore fairly easy, being color-coded the same as the engine harness for the most part. I only had to cut three wires from the computer harness for power leads, only because I could not get a power distribution panel for the connector.

I visited my local Radio Shack to get some terminal strips that would make the connections easier, and found they have a new type of connector strip called a “European style”. They are nylon plastic and have 12 connections possible per strip, all you have to do is insert one wire into a copper tube, tighten a screw, then put the other wire in the same tube, opposite end, and tighten its’ screw and, voila, connection is made. I used 2 of these strips for all the instrument panel connections.

Also I built a power and starter panel using a project box from Radio Shack with aircraft type circuit breakers. I plan on rewiring my GT fuse panel with this type of circuit breaker, no more fuses to worry about. The circuit breaker will pop almost immediately to save the circuit and can be reset forever, it also serves as a switch for the circuit. You can pull on the exposed head of the breaker and it will pop out breaking the circuit just like a switch.

After I got the correct sensors from Gil, I found I needed an adapter for the temp gage sensor. A trip to my local hardware warehouse produced the correct pipe external thread in a brass fitting with a small threaded center, I drilled out the center and using a 1/8 inch tapered pipe thread tap, I ran the tap clear through the center of the adapter, the sensor fit really good and screws all the way into the adapter and doesn’t leak.

I used c-clamps to hold the instrument panel to the engine stand, also to hold the fuel pump and filter in place. “Rube Goldberg” for sure but it worked.

I had my local muffler shop flare and bend some 2½ inch exhaust tubes for temporary headers and to direct the exhaust away from the instrument panel, again “Mickey Mouse” but they worked also, and it sounded really great.

Leaving the thermostat out of the engine, I attempted to start it. All I got was a hot starter. The engine would rotate, but not fire. This was when I found the fuel hoses were hooked up wrong. When I removed and reinstalled the fuel rail I cut an o-ring. So I replaced all the o-rings with new ones from my local Chevy parts store. The book says to put one color toward the head, another color in the fuel rail. The new o-rings can be used in both places, just be sure to get the package with backing rings and replace the whole set. You’ll have enough left over for two spares, the package is set up for all GM SFI engines, including the V-8s.

I got everything back together, hooked up the battery cables, reset all the circuit breakers, checked for fuel pressure and hit the start button. The engine lit off immediately………… then died, over and over again, continuously. I started checking the schematics again trying to find out why.

I purchased an engine scanner to see if I could find out why this thing would not run, but to no avail, the scanner said it was scanning the computer but it would not respond.

After going over the schematics again for hours, I saw a blue wire coming out of the computer going to a theft deterrent module or Vehicle Anti-Theft System (VATS). A further check of the schematics showed the VATS module interconnected with the starter solenoid circuit. Since I had bypassed that circuit I saw no problem. WRONG. The blue wire tells the computer to turn on the injectors. I did some research at my local Pontiac/Chevy dealers and found a module for $289.00.

A long and time consuming search through the internet produced a Pass Key II circuit that might work. Why not try. $25 at Radio Shack and I had the circuit built and jumpered it in the circuitry. On the first attempt to start, the engine lit off and died. The second attempt, the engine roared to life and continued to run. FANTASTIC!!!

Below is the information I got off the internet for the Pass Key II system.

There is a feature on newer GM fuel injection computers that will not allow the ECM to turn on fuel delivery until it recieves a certain signal from the car's security system. This signal is sent when the system detects the correct PASSkey- encoded ignition key in the ignition. Since I no longer have the rest of the Camaro security system, and need the engine to run in a 1972 Nova, I had to defeat this system, or at least reconfigure it to do what _I_ want it to do!

All this PASSkey II signal is is a 50 hertz square-wave pulsed-ground. The diagram in my Haynes manual for the 1991 Camaro shows the PASSkey wire going into the ECM, this is the wire you connect the bypass circuit to. If you wish to interface an alarm to it, it's easy to let the alarm's "grounded when armed" wire ground this wire constantly, therefore preventing the ECM from seeing the signal, and keeping the engine from running, even if they have the key, the engine won't start until the alarm is disarmed. Even if they hotwire it it will not start until tha PASSkey signal is applied to the ECM. So anything that grounds out or breaks the path of the signal, or interrupts power to the oscillator will prevent the engine from starting.
On my Nova, the oscillator is in a housing about the size of a pack of smokes, with a 3 pin connector. If I am goint out of town, or feel the need for extra security, I simply unplug it and take it inside. Without this part, the car is just as useful as if it had no ECM. It is visible in the collage on the previous page, right at the bottom of the ECM, sitting at a slight angle. (middle right pict.)
This circuit will produce the signal to allow General Motors ECM's with the VATS PASSkey II systems to start fuel delivery. It produces a 50Hz, square wave 50% duty cycle pulsed ground signal. Just get a 555 timer IC and connect it up as follows. A small IC circuit board from RadioShack can hold the 555 and most of the other components.

Parts:
555 timer
16 pin DIP IC PC board
two 0.1 µF ceramic capacitors
1 µF electrolytic capacitor
3.9 K resistor
22 K resistor
100 Ohm resistor
14 Volt Zener diode
Plastic enclosure

Pin 1 is Ground. Pin 8 is + input. Connect a 0.1 µF ceramic cap between these pins, with short leads, for filtering. Otherwise it may misbehave. Connect pin 8 to 100 Ohm resistor. Connect a 14V Zener diode between pins 1 and 8, banded (+) end to pin 8, to absorb voltage spikes from starter solenoid or system overvoltage.

Other end of 100 Ohm resistor connects to ECM's "Crank" signal wire. This is best since the oscillator signal is only needed once at cranking.

Tie pin 4 to pin 8.

Tie pin 6 to pin 2.

Add a 3.9K resistor from pin 7 to pin 8. (A 3.3K will be close enough)

Add a 22K resistor from pin 6 to pin 7. (You could adjust this one for precision setting, but it's not needed for this application)

Add a 1 µf capacitor (electrolytic OK) + side to pin 6, - side to pin 1.

Add a 0.1µf cap from pin 5 to pin 1.

Output is on pin 3. Connect to VATS wire of ECM. Also connect alarm to ground this pin to disable fuel delivery when armed.


I shut down the engine and hooked up the cooling setup. That consisted of a five gallon bucket, the aquarium pump, the upper and lower radiator hoses for the Camaro engine, and a PVC one inch to one half inch adapter for sprinkler systems. The pump I bought had a standard half-inch thread on it and the adapter screwed right on and the lower radiator hose slid right over the adapter. Hose clamps on each end of the lower hose, drop the pump into the bucket full of water, plug in the pump, route the hose from the thermostat housing back into the bucket and light off the engine again, twice.

For some reason that I cannot fathom yet, the engine will not start and run on the first attempt, but always run on the second try. It could be a couple of things, one is that I’m using the tach output for the signal to the circuit, the other is I didn’t use a polarized capacitor as indicated in the schematic for the VATS bypass system.

Right now, I’m happy the darn thing is running. I ran the engine for two days, over 12 hours each day at idle, with numerous excursions slowly up to 5000 RPM, I didn’t want to move the throttle to quickly, I might have torqued the whole mess over on its side. The engine didn’t hiccup, it accelerated slowly in response to the throttle valve right up the scale.

Now some interesting stuff. Without the thermostat and with constant water flow through the engine and back into the bucket, with the scanner hooked up, maximum coolant temperature was 168 degrees, just enough to make the plastic adapters soften and take a weird set. The pump outlet also got soft and the threaded output spigot bent.

With the thermostat installed and the output from the thermostat housing going down the driveway, the temperature fluctuated between 181 and 186.3 degrees, as indicated by the scanner.

Another thing, the coolant loss was surprising, I had to add water to the bucket about every half hour. The thermostat would open and dump about a quart of water before the thermostat closed and only a small trickle came out of the hose.
First phase of the swap complete, the engine runs, has no leaks, and sounds great with the 2½ headpipes. It is sitting behind the GT, with the transmission installed on a wheeled pallet, waiting for Phase II. Both engine/transmissions sitting side by side for measurements and fabrication of mounts.

Prologue: Although not necessary, I found hooking up all the wiring was simpler by having both ends of the connectors available with about eight to twelve inches of pigtails to work with. There are three connectors that go inside the vehicle from the computer and two that are underhood. They are identified by color and location and have pin location along with the actual wire color codes.

With the power panel I built and all the connectors, I only had to cut the three power distribution panel wires and splice them into the power panel. It took a long time to do, but if it helps making the swap easier for other folks, it is worth it.

I picked up an “Auto X-Ray” scanner system that has all the scanner plug-ins for all computer equipped vehicles, now I have a base line of sensor readings that should prove valuable if the engine hiccups and starts doing funny things.

The MFG has an update webpage that shows a jumper needed to read the 95 Camaro/Firebird computers. It appears some GM and other manufacturers installed OBD II connectors without the OBD II computers. Without the GM connector (pre 95) you can’t read the computer even with the OBD II connector plugged into the scanner. You have to use the older GM connector plugged into the scanner and jumper the OBD II connector in the car/harness to get the scanner to function. Also configure the scanner to a 94 year vehicle with the “S” VIN ID, at least that’s how it is with the scanner I bought.