Name: Jon
Vehicle: 1990 Jetta Coupe
Engine: 1.8L 8v, Autotech 270 cam
Injection: Factory intake, Mustang GT TB with custom adapter, LC-1 wideband
Description: Replaced the ailing Digifant system with MS1 v2.2 with msns, runs unbelievably better.
1990 Jetta 1.8L 8V
Bump with the write-up I did on VWVortex.
After several requests I decided I would write up my DIY for installing Megasquirt on a 1990 Digi2 car. My 90 coupe had been plagued with idle problems, an over-rich condition, and abysmall mileage, I was lucky to get 20mpg with highway driving and forget about around town. Also it was time to get the car smog and safety inspected to title it in Texas and it had failed miserably when I took it in. The answer to all my problems was megasquirt. In theory this should allow me to take full control of my car with the ability to tune the car for future inprovements but with plenty of mechanical knowledge and very little on fuel and timing this would be interesting.
The first obstacle was sourcing the ECU, the easiest solution was to buy a complete unit including ECU, sensors, and harness from Patatron.com.
This was already set up for VW for fuel and spark, came with a rudimentary set up disc including set-up maps and is a good start if you have the time to wait for it to come. Second was to source the other required parts to complete the install. Beings that I have a digi car it was already equipped with injectors, fuel rail, and a fpr but lacked a throttle body with a tps. I would also need three relays, injectors connectors, heat shrink, butt connectors, and fuse holders. I sourced the electrical parts from delcity.net and picked up an automatic Passat throttle body from a local junk yard which seemed to be the standard TB to use in this situation. As far as the air cleaner goes I thought I’d run a cone filter off the stock duct and call it good, filter on a stick. The final part I was lacking to make the install easy was a small fitting to allow me to run the GM coolant sensor in the factory position, this was provided by Diggatron here on the boards and is a prototype so it was steel but his new batch are brass.
All parts and I am ready to start. I decided to mount the ECU in the car but didn’t want to eat up my glove box like had seen in several pictures so I thought the knee bar would make a good spot. Break out the trusty cut-off wheel and hack away, soon there was a hole big enough to stash my ECU and I can still use the glove box for gloves, well not in Texas anyway, but other stuff.
Having finalized the mounting spot I could now run my wiring mess and vacuum line out through a factory grommet that was in the rain tray behind the glove box and then through another factory grommet into the engine bay.
Now to start dropping off the wires where they needed to go.
Now the fun part, stripping and crimping. Make sure if you are using this method you buy a crimper, not one of those all-in-one stripper crimpers, a quality crimp is a good crimp. I also went to the trouble of heat-shrinking every electrical splice I made, better safe than sorry. I recycled the O2 and distributor connectors from the factory harness for the new harness.
I used the hole for the factory IAC valve for my new GM IAT sensor. Fits in tight, seals well, and is in the direct flow.
Having stripped, crimped, and heat-shrinked all of my connections the engine bay electrical was finished or so I thought. Next was to mount up the Passat throttle body, therein lies the problem.
Comparison of stock TB vs. Passat.
See the mounting post that hangs down for the TPS? This is what happens when you try to install it with a Digi fuel rail and intake.
As you can see it fouls the rail by a good bit, enough that in the upper right corner of the picture you can see how far off the TB is. Well what is that old saying, if the part offends, cut it off?
That didn’t work. I didn’t even take a picture because I was pissed at this point. The only way to make it fit was to take off the mount for the TPS which was the whole reason I needed it in the first place. So I go to the Vortex to research the problem and look for answers. The answers I got were not what I wanted to hear and they ranged from using a rare California only Digi Fox/Jetta throttle body, switch to a MKI right side entrance intake, or use a Weber/Redline TB. Well I happen to have a Weber/Redline TB and adapter, nope, same thing fouls the rail.
No Cali-only TB’s on the Vortex and there is no way I want my air cleaner and battery on the same side when I have all of this great room available on the passenger side.
I call my good buddy Diggatron and we start hashing it out. The TPS is just a potentiometer to help with fuel enrichment when the throttle opens and the air flow sensor is doing the same for the Digi car so why can ‘t we use that?
Reading closed.
Reading fully open.
Ding, ding, ding, we have a winner. Quick cut and splice into the factory plug and TPS is now recognized.This should work in theory, crisis averted. Back on goes the factory throttle body, air box, and all the mess associated with it. Electrical connections
1.Distributor
2.Coolant sensor
3.O2 sensor
4.Ground at the valve cover
5.Injector connectors
6.IAT sensor
7.Faux TPS connector
8.Wire spliced into ignition module
9.Ground ran all the way to the battery
10. Vacuum line for map sensor
A little bit of split loom and we are looking good.
Looks stock doesn’t it?
So now we are done in the engine bay with the electrical now back inside to finish the inside wiring. I followed the diagram off of Vintagewatercooled.com and wired my relays into the front of the fuse panel after pulling the factory fuel pump relay as seen here.
This is my own diagram as to how it was all wired including the wiring of a 7 wire Innovate LC-1 wideband.
It was much easier and cleaner than splicing into the factory fuel pump wiring. SO I chose not to use a Fidle solenoid so I only needed two relays, one for the main relay and the other for the fuel pump, and I wired these as seen in the diagram and mounted them to the factory mount for the fuse box. Next I ran two wires for the switched power and the fuel pump under the dash back to the megasquirt ECU. The power wire was ran into the fuse holders, one for the ECU which uses a 3 amp fuse, and one each for the two injector circuits which use 5 amp fuses and connected them to the ECU. Alright a quick test before plugging in the power to the ECU and I have power in all the right places. By this time you should have loaded all the needed software on to your laptop and typed in all of your start-up parameters in expectation of this moment.
Plug in the ECU, plug in you laptop to the ECU, and turn the key. Mine started within a couple of revolutions of the engine, but alas another problem. After warming up the EGO isn’t showing any change, hmmm, O2 sensor is bad. It’s 9:45 and Autozone closes at ten and that store is 10 miles away, you know how this ends up, hop in the wife’s A3 and roll. I roll in at 9:55 and order up a one wire O2 for a 84 Rabbit and spend a hard earned $20. Back to the house throw it in real quick and fire it up for the second time. Car warms up and the gauge starts recognizing the signal.Bingo, it was all worth it, but that is just the start. I needed to adjust the idle stop screw for warm idle and get to tuning. By this time I had spent the better part of three days to install this but to be fair at least a day and a half or more was spent trying to track down a TB solution. Now I was getting to be in a bind because this is my daily driver and I hadn’t registered it in my name yet due to no current
Inspection, the tags were up in November and it is now January, and the wife was leaving for her job out of state in three days, I figured three days should be long enough to tune it and get it inspected. The PO had taken out the catalytic converter in an effort to make it run better and I knew that might bite me in the bum. I get up the next day start up the autotune function and drive around the neighborhood for 15 minutes or so and go back to the house. A few more tweeks in the lower end of the VE table to lean it out and I decide to drive it to a shop a mile away and get a baseline on the smog to see where needed to tweak it to pass. Watching for the police the whole way I make it there and they load it on the dyno to test. Twenty minutes goes by and the owner of the shop comes in and says that’s it, here’s the bill, it passed! No cat and all. Gotta love megasquirt.
Oh yeah, forgot to thank Adrian and Kevin for all their help.
Stay tuned for part two, more speed parts and a Mustang throttle body. ;)
Link to original thread
http://forums.vwvortex.com/zerothread?id=3139811&page=1
Currently the car is running an ABA crossflow swap that just turned over 5K miles as my daily driver. This last weekend it made the trip out to Eureka Springs AR, for a yearly VW show, 980 miles one way, total of 2200 miles in five days without a hiccup.
After several requests I decided I would write up my DIY for installing Megasquirt on a 1990 Digi2 car. My 90 coupe had been plagued with idle problems, an over-rich condition, and abysmall mileage, I was lucky to get 20mpg with highway driving and forget about around town. Also it was time to get the car smog and safety inspected to title it in Texas and it had failed miserably when I took it in. The answer to all my problems was megasquirt. In theory this should allow me to take full control of my car with the ability to tune the car for future inprovements but with plenty of mechanical knowledge and very little on fuel and timing this would be interesting.
The first obstacle was sourcing the ECU, the easiest solution was to buy a complete unit including ECU, sensors, and harness from Patatron.com.
This was already set up for VW for fuel and spark, came with a rudimentary set up disc including set-up maps and is a good start if you have the time to wait for it to come. Second was to source the other required parts to complete the install. Beings that I have a digi car it was already equipped with injectors, fuel rail, and a fpr but lacked a throttle body with a tps. I would also need three relays, injectors connectors, heat shrink, butt connectors, and fuse holders. I sourced the electrical parts from delcity.net and picked up an automatic Passat throttle body from a local junk yard which seemed to be the standard TB to use in this situation. As far as the air cleaner goes I thought I’d run a cone filter off the stock duct and call it good, filter on a stick. The final part I was lacking to make the install easy was a small fitting to allow me to run the GM coolant sensor in the factory position, this was provided by Diggatron here on the boards and is a prototype so it was steel but his new batch are brass.
All parts and I am ready to start. I decided to mount the ECU in the car but didn’t want to eat up my glove box like had seen in several pictures so I thought the knee bar would make a good spot. Break out the trusty cut-off wheel and hack away, soon there was a hole big enough to stash my ECU and I can still use the glove box for gloves, well not in Texas anyway, but other stuff.
Having finalized the mounting spot I could now run my wiring mess and vacuum line out through a factory grommet that was in the rain tray behind the glove box and then through another factory grommet into the engine bay.
Now to start dropping off the wires where they needed to go.
Now the fun part, stripping and crimping. Make sure if you are using this method you buy a crimper, not one of those all-in-one stripper crimpers, a quality crimp is a good crimp. I also went to the trouble of heat-shrinking every electrical splice I made, better safe than sorry. I recycled the O2 and distributor connectors from the factory harness for the new harness.
I used the hole for the factory IAC valve for my new GM IAT sensor. Fits in tight, seals well, and is in the direct flow.
Having stripped, crimped, and heat-shrinked all of my connections the engine bay electrical was finished or so I thought. Next was to mount up the Passat throttle body, therein lies the problem.
Comparison of stock TB vs. Passat.
See the mounting post that hangs down for the TPS? This is what happens when you try to install it with a Digi fuel rail and intake.
As you can see it fouls the rail by a good bit, enough that in the upper right corner of the picture you can see how far off the TB is. Well what is that old saying, if the part offends, cut it off?
That didn’t work. I didn’t even take a picture because I was pissed at this point. The only way to make it fit was to take off the mount for the TPS which was the whole reason I needed it in the first place. So I go to the Vortex to research the problem and look for answers. The answers I got were not what I wanted to hear and they ranged from using a rare California only Digi Fox/Jetta throttle body, switch to a MKI right side entrance intake, or use a Weber/Redline TB. Well I happen to have a Weber/Redline TB and adapter, nope, same thing fouls the rail.
No Cali-only TB’s on the Vortex and there is no way I want my air cleaner and battery on the same side when I have all of this great room available on the passenger side.
I call my good buddy Diggatron and we start hashing it out. The TPS is just a potentiometer to help with fuel enrichment when the throttle opens and the air flow sensor is doing the same for the Digi car so why can ‘t we use that?
Reading closed.
Reading fully open.
Ding, ding, ding, we have a winner. Quick cut and splice into the factory plug and TPS is now recognized.This should work in theory, crisis averted. Back on goes the factory throttle body, air box, and all the mess associated with it. Electrical connections
1.Distributor
2.Coolant sensor
3.O2 sensor
4.Ground at the valve cover
5.Injector connectors
6.IAT sensor
7.Faux TPS connector
8.Wire spliced into ignition module
9.Ground ran all the way to the battery
10. Vacuum line for map sensor
A little bit of split loom and we are looking good.
Looks stock doesn’t it?
So now we are done in the engine bay with the electrical now back inside to finish the inside wiring. I followed the diagram off of Vintagewatercooled.com and wired my relays into the front of the fuse panel after pulling the factory fuel pump relay as seen here.
This is my own diagram as to how it was all wired including the wiring of a 7 wire Innovate LC-1 wideband.
It was much easier and cleaner than splicing into the factory fuel pump wiring. SO I chose not to use a Fidle solenoid so I only needed two relays, one for the main relay and the other for the fuel pump, and I wired these as seen in the diagram and mounted them to the factory mount for the fuse box. Next I ran two wires for the switched power and the fuel pump under the dash back to the megasquirt ECU. The power wire was ran into the fuse holders, one for the ECU which uses a 3 amp fuse, and one each for the two injector circuits which use 5 amp fuses and connected them to the ECU. Alright a quick test before plugging in the power to the ECU and I have power in all the right places. By this time you should have loaded all the needed software on to your laptop and typed in all of your start-up parameters in expectation of this moment.
Plug in the ECU, plug in you laptop to the ECU, and turn the key. Mine started within a couple of revolutions of the engine, but alas another problem. After warming up the EGO isn’t showing any change, hmmm, O2 sensor is bad. It’s 9:45 and Autozone closes at ten and that store is 10 miles away, you know how this ends up, hop in the wife’s A3 and roll. I roll in at 9:55 and order up a one wire O2 for a 84 Rabbit and spend a hard earned $20. Back to the house throw it in real quick and fire it up for the second time. Car warms up and the gauge starts recognizing the signal.Bingo, it was all worth it, but that is just the start. I needed to adjust the idle stop screw for warm idle and get to tuning. By this time I had spent the better part of three days to install this but to be fair at least a day and a half or more was spent trying to track down a TB solution. Now I was getting to be in a bind because this is my daily driver and I hadn’t registered it in my name yet due to no current
Inspection, the tags were up in November and it is now January, and the wife was leaving for her job out of state in three days, I figured three days should be long enough to tune it and get it inspected. The PO had taken out the catalytic converter in an effort to make it run better and I knew that might bite me in the bum. I get up the next day start up the autotune function and drive around the neighborhood for 15 minutes or so and go back to the house. A few more tweeks in the lower end of the VE table to lean it out and I decide to drive it to a shop a mile away and get a baseline on the smog to see where needed to tweak it to pass. Watching for the police the whole way I make it there and they load it on the dyno to test. Twenty minutes goes by and the owner of the shop comes in and says that’s it, here’s the bill, it passed! No cat and all. Gotta love megasquirt.
Oh yeah, forgot to thank Adrian and Kevin for all their help.
Stay tuned for part two, more speed parts and a Mustang throttle body. ;)
Link to original thread
http://forums.vwvortex.com/zerothread?id=3139811&page=1
Currently the car is running an ABA crossflow swap that just turned over 5K miles as my daily driver. This last weekend it made the trip out to Eureka Springs AR, for a yearly VW show, 980 miles one way, total of 2200 miles in five days without a hiccup.