z-ya

Find out which wire is common to all 6 resistors. It is most likely the heaviest gauge wire. To be sure that it is the common, use your meter and measure the resistance between the common, and each of the other smaller wires. The resistance should be the same from the common to each of the other wires. Connect the common to you injector 12V, and then each of the other six wires to each injector individually. The rest of your schematic is correct.

Find out which wire is common to all 6 resistors. It is most likely the heaviest gauge wire. To be sure that it is the common, use your meter and measure the resistance between the common, and each of the other smaller wires. The resistance should be the same from the common to each of the other wires. Connect the common to you injector 12V, and then each of the other six wires to each injector individually. The rest of your schematic is correct.

It will not run without a functional VB921 because it fires one coil which fires all plugs through the distributor. Did you check the basics like spark on all cylinders? Did you check your timing with a timing light? Does the timing match what is set in you timing map? Have you checked to see that all injectors are firing? With the engine running, pull the injector plugs one at a time. If the idle doesn't change, you know that either the injector or the spark plug is not firing for that cylinder.

You can also tell by the shifter. The early transmissions have two small nylon bushings with a pin/circlip that hold the shifter in. The later ZX transmissions have much larger bushings, with a spring inside. So with the early transmission, the shifter has a small round hole for the pin, where the later ones have a large square hole for the pin and bushing assembly (and a spring).

Are you running an AFM? If so, that might be the culprit.

24AWG is fine for all sensor wires, and it should also be fine for relay control. Use at least 2 for 12V. Use at least 6 for ground. The problem with this type of cable is that all of the wires are twisted around in there together. You could have some issues with the tach input and injector outputs interfering with other sensor signals. If you run enough grounds, that will help shield the wires in the bundle. You can also run the tach signal through a separate twisted pair or shielded wire that is outside of the 25 conductor cable to be safe.

Super stealth!

Another option is to find a seller hear in the states that is willing to ship you an EFI manifold and N42 head. Or like Tony said, figure out how to use throttle bodies instead of SUs on the stock manifolds. I haven't seen it done, but maybe one GM TBI injector mounted in each throttle body. TBI is interesting because it is much lower pressure than port EFI, and I think the small stock return line would work with TBI. Or, talk to the guys at Extrudabody, maybe they will ship to Finland. They have a nice SU EFI conversion kit.

Nice work! Nothing like having the right tools to do the job. After just 2.5 hours, you can drive it, and enjoy it! People spend months trying to dial it in on the street. Investing in dyno time has saved you a lot of time and frustration. Nice HP numbers for stock boost. My car makes 245WHP at 12psi (stock long block and turbo). Not much more power than your setup, but it makes 310ft-lbs at 3000RPM Keep up the great work.

Like I said, if you have a stable tach display in MT, then your VR circuit is working fine. The VR circuit is on the trigger input. It sounds like your problem is on the ignition output circuit somewhere.

You think debugging one MS is hard, try two processors running asynchronously. This board is really designed to add additional I/O because of the addition of CANBus used a bunch of I/O. CANBus is an automotive serial data bus that is used in most all European cars. If you want to add some of the Extra code capabilities to the MS-II, it would be easier to add them to the MS-II code (I think someone is alreadt developing this).

If it runs, and the tach display in MT is stable, there is nothing wrong with you VR signal. You say the timing is always -20, you mean 20btc, right? Leave you trigger angle at 70 or so, and in the spark table fill in all the bins around where the engine is idling to 10. Now adjust the trim angle in the spark settings so that you read 10btc on the timing tab with a timing light. Now change the table entries to all 20. You should hear the engine smooth out with more timing. The timing light should show 20btc. If this works, fill in you timing table with approximate advance values for you engine.

Thanks Ron, all excellent points. How does the Audi sensor make a seal if there is no pipe thread? Do you need to machine a hole, then drill and tap a hole next to it for the mounting screw?

If the engine is completely stock, disconnect the vacuum advance, and plug the hose so that there is not advance at idle. Set the idle speed and then the idle timing per the service manual. Reconnect the vacuum advance and you are done. If you have made modifications, and want to run as much advance as possible to get more power, follow Jon's instructions above. This requires trial and error because your engine might detonate with 36 deg of advance. So adjust, drive, adjust, drive, until you get the max advance without detonation.

Editing the firmware is a band-aid type fix. The problem is that each time you upgrade the firmware, you need to remember to get the source for the new version, insert your changes, compile, and then download. Then you need to test it all over again to be sure your changes didn't screw something up. Although I have not had any problems mounting the sensor in the plenum and running the default code, Ron Tyler seemed to have discovered that thermal isolation of the open air sensors are not all that great. This would be the only reason not to mount it in the plenum. I'm wondering if you install it where the cold start valve usually is, but mount the IAT in a material that will do a better job of thermal Isolation. Use the two screws that would normally hold the cold start valve to attached the fiberglass, lexan, or other material you have the IAT mounted in. If you mount it in the IC plumbing, or another intake pipe that is not thermally connected to the engine (thermally conductive), you fix the thermal isolation problem. But now the air temperature reading will be incorrect, especially at idle when there is very little air flow through the intake manifold. In a race engine where you are either WOT or idle, it doesn't really matter where you mount it. But if you sit in traffic a lot, mounting it where the most accurate temperature measurement can be made is very important. Sorry if I have opened up this can of worms all over again...

PM me, and I will send you my address. Thanks

Yes, you can change them yourself. Once they are cracked, they are easy to pull off. To put the new ones on, slip the new cap on and then push the injector against something that won't damage the new tip, like a piece of soft pine. Any local injector shop should have replacement caps.

It is the high power device that drives the coil. It is in the MS.

I've been to both Hypertherm and Thermal Dynamics in Lebanon NH. I'm in the scope business, and they use them for power measurement. Both companies make some very impressive products. Hypertherm makes a battery operated plasma cutter that you wear as a backpack. It is used when the jaws of life can't get someone out of a wreck.

The damage to the VB921 may have already been done when the output was not inverted. Might be time to install a new VB921, and try it with the new coil.

I think either place you had it should work OK. Maybe because you have it in the middle, you are getting more of an average temperature across the intake manifold. I also usually mount them close to the middle of the intake. Racing or not, that is a good spot for it.

You don't want to run in fixed duty cycle mode with the VB921. The input pulse width is the dwell, so if you are at 50% duty cycle, the VB921 will be conducting current through the coil half of the engine cycle. At idle, it is going to get really hot. If you have a scope, the input to the VB921 should be a positive 5V pulse with the width being close to the dwell you have set in MT. On the output of the VB921 you should see a negative pulse, again close to the dwell time you set in MT. It should go from 12V to close to zero for the dwell time.

Brad, It is going to be a nice little truck with the SR20 in there for sure. Let me know when you are ready to start wiring the new motor up.

Is the coil still connected to the ignition switch? If so, that is where the 12V is coming from on the tach input. A coil (inductor), looks like a piece of wire to direct current (DC), so that is why you see 12V at the tach input.

The fuel pump relay is turned on by the ECU when it grounds pin 37. So unless the engine is running, you will see close to 12V on pin 37. If the ignition is on, and the engine is not running, pin 36 should have a positive voltage on it if it is connected to the coil. Without the coil connected, there should be a high resistance between pin 36 and the chassis (with the power on). Try starting it, and put your finger on the VB921. If it starts to get real hot, turn off the power.