Mexican EFI conversion questions

[E4ODnut]

Hi All,
My son has built a very nice street Baja with a dual port 1600. The engine is basically stock but has some unidentified mild street cam. He's had no end of troubles trying get it to run right (carb issues) so I'm encouraging him to convert to EFI. He has no experience with this, but I have, having used Megasquirt since the time it was fuel only. Because the engine is basically stock my thinking is that the Mexican EFI route is the way to go. The DubShop in Monroe Wa. advertises conversion kits and parts, but I have had no success in contacting him at all, either by e-mail or phone. Today on a whim I had a look at the Samba and found an ad by Antonio in Mexico City advertising used and new Mexican EFI parts. I contacted him and he is still very much in business but admits that he knows nothing of EFI, so I'm posing these questions to the group here.

Because we don't intend to make much more than stock HP I'm assuming the the OEM injectors should work for us just fine, but does anyone know the flow rate and at what fuel pressure? How about the OEM fuel pump and regulator? Could we use them if they are available? Same for the OEM Idle Air Control valve. I can use PWM idle control with Megasquirt. Oh, by the way I'll be using and old MS1 V2.2 board with MSNS Extra firmware. I'm building a custom relay board that incorporates a VR conditioner, Tachometer circuit and coil drivers for waste spark ignition as well as relays and fuses for the whole thing.

[Bruce.m]

The Mexican EFI pump is a pierburg item using the pump from a golf inside a plastic “swirl pot” tank. This was so the original petrol tank (with an 8mm outlet) could be used without a new design with baffles. The pump is still available from Pierburg or you can pick up a Chinese copy for less than 50. The pump is rated at circa 110 LPH.

The fuel pressure regulator is a plastic part that is located behind the fan shroud. It uses a standard bosch style insert which is fixed at 3 bar.

[Bruce.m]

https://volkswagen.7zap.com/en/rdw/

If you use this copy of ETKA (vw part catalogue), and select the 1600i Mex model, you can look up the various part codes for the pump, regulator etc.

[E4ODnut]

Thanks Bruce, much appreciated.

[Clonebug]

Any Bosch style inline fuel pump will work. The Ford EF2000 pump was popular but I grabbed one off a 94 Volvo Turbo 740 and used a VW steel pressure fuel filter to hook up to the stock Banjo pump connector.
Put a Napa style prefilter before the pump to catch the big stuff from going through the pump.
My used pump has been going strong since 2013 and had probably 170,000 miles on it in the Volvo. I have at least 50,000 miles on it.
I like my pump because it has a 1/2 inch inlet on it and seems to get a nice supply of fuel out of the tank to support over 200 hp.

You can install a new pressure line and use the stock line for a return.

Page 41> on my build shows how I did the pump install and fuel line.

https://www.shoptalkforums.com/viewtopi ... &start=600

Your MS Ver. 2.2 might need to use low Z injectors. I used 32# injectors from the same Volvo and they worked fine till I hit 22 lbs. boost and they wouldn't keep up.
You can use an added injector driver board to use Hi Z injectors but I just upgraded to MS2 Ver. 3.0 and now MS3 EVO.

As for Mario.....he is a one man show so is very busy. I know he just got back from a much needed vacation and is trying to catch up plus expand his shop into a second 1000 sq. ft. of space.

As for the Mexican setup.... you could also just buy the CB Performance EFI end pieces and build your own center section like I did. The Mexican setup does have a hp limit N/A and boosted but I have pushed over 200 hp through the CB endpieces and a 1679cc engine using a turbo.
I use a stock 76-78 German TB and regulator for my setup but do not have an IAC valve hooked up at this time.
I'm kind of out of room with W/I nozzles and other Misc stuff attached to the intake.
My engine runs really nice when cold but does need between 3-5% TPS to stay idling until it warms up to about 120*F on the coolant temp sensor.
Some day I'll hook up an IAC valve since I have one from a Peugeot that I just need to find room for.

[E4ODnut]

Thanks for the response Clonebug.

I've been talking with Antonio in Mexico City about parts and we have come up with a list of stuff I think we are going to need. So far my understanding is that the stock injectors flow 144 CC/Min @ 3 bar fuel pressure, coil resistance is 14.4 ohms. The stock pump is ridiculously expensive so we will go with the Walbro GSL392 in line pump. I've used them before and they worked well for me. We'll use the stock fuel pressure regulator. MSnS Extra is fine with HiZ injectors.

We'd like to use the OEM air temperature sensor and engine temperature sensor. These sensors have a thermistor in them that has a specific resistance to temperature relationship. Normally these are published specifications at 3 different temperatures. With this information I can use EasyTherm to calculate a lookup table that Megasquirt can use. Does anyone know what these specifications are or where I can get them?

Also, the engine temperature sensor screws into a tapped hole in the cylinder head near #4 cylinder. Do you know if non EFI heads can be modified to accept this sensor?

Because the engine is almost stock and we have no plans to change that all the OEM Mexican hardware should work for us. We'll also use the OEM IAC valve. MSnS Extra has code for PWM IAC control. I've never used it before but I'll give it a shot.

From what I could see on Mario's site he uses MS2 but still only uses 2 injector channels, same as MSnS Extra. I didn't see any place where he published his initial settings and I am curious if he recommends simultaneous or alternating injector firing strategy. Would anyone care to offer an opinion on this?

[Clonebug]

Thanks for the response Clonebug.

I've been talking with Antonio in Mexico City about parts and we have come up with a list of stuff I think we are going to need. So far my understanding is that the stock injectors flow 144 CC/Min @ 3 bar fuel pressure, coil resistance is 14.4 ohms. The stock pump is ridiculously expensive so we will go with the Walbro GSL392 in line pump. I've used them before and they worked well for me. We'll use the stock fuel pressure regulator. MSnS Extra is fine with HiZ injectors.

We'd like to use the OEM air temperature sensor and engine temperature sensor. These sensors have a thermistor in them that has a specific resistance to temperature relationship. Normally these are published specifications at 3 different temperatures. With this information I can use EasyTherm to calculate a lookup table that Megasquirt can use. Does anyone know what these specifications are or where I can get them?

Also, the engine temperature sensor screws into a tapped hole in the cylinder head near #4 cylinder. Do you know if non EFI heads can be modified to accept this sensor?

Because the engine is almost stock and we have no plans to change that all the OEM Mexican hardware should work for us. We'll also use the OEM IAC valve. MSnS Extra has code for PWM IAC control. I've never used it before but I'll give it a shot.

From what I could see on Mario's site he uses MS2 but still only uses 2 injector channels, same as MSnS Extra. I didn't see any place where he published his initial settings and I am curious if he recommends simultaneous or alternating injector firing strategy. Would anyone care to offer an opinion on this?

Mario has a modified GM coolant sensor that works well. I use one and it is mounted on the #2 cylinder tin screw where it works well for warmup.....better than the old style that was installed in the oil. I use the old one as oil temp and it works great for that.
Any sensor will work if you can get the values correct. The GM style ones that Mario and I use have default values in Megasquirt and are a no brainer for install.

If you want to use the original you just need to mount it somewhere on the head or even in the airflow under the head if you want to hang it there.
Once my temp sensor goes above about 120-130 Degrees I cut off all added warmup fuel.

My injection is untimed and alternating injection in the basic setup tab.

[E4ODnut]

What is your normal running temperature and how high have you seen it go?

[Steve Arndt]

Mario is very active on his company web page on facebook. Also on the aircooled EFI group. I would try to get the whole package from him.

[E4ODnut]

I would have liked to use Mario but I tried for a month to get in touch with him with no results so I've committed to Antonio. To his credit, Mario did finally e-mail me and explained that he has been extremely busy. There's no crime in that and I just hope he doesn't burn himself out. I know what it's like to be a one man shop.

[Clonebug]

What is your normal running temperature and how high have you seen it go?

My normal CLT cruise temp is 218*F on my Digital display in the PNW temperate climate.

On my trip to California I saw a max of 249.6*F pulling a 20 mile long grade in 100 degree ambient temps at 60-65 mph at about 2700-2900 rpm.
It will go to 300*F plus if going to idle and stopping at a stop light or at a rest stop. It takes a bit for it to cool down even if you rev it while standing still.
I would have to say that 190*F to 225*F would be considered a normal operating temp for my engine.

I gauge my engine temp by how warm the oil gets and the highest I've seen....which is on that same 20 mile grade....was 214*F.
My usual operating oil temp is 170-190*F. depending on the ambient temps and how fast I'm travelling. Local driving in 90*F ambient temps I saw a max of 200*F. at slower speeds in busy traffic. Most times I have trouble getting the oil over 170*F.

[E4ODnut]

Very good. Thanks for the detailed response.