Hello All!

[mikew]

My name is Mike, I live in Oklahoma. My day job is computer geek, banking related systems in particular.

I've converted several of my carbureted cars to fuel injection.

My first project was in 2001, a 1959 Jaguar 3.4 MK-I. The MK-I came with a 3.4l straight six XK engine. My 3.4l was replaced with a newer 4.2l XK engine (they look identical) with a pair of 2" "SU HD8" side draft carbs. I removed the carb dashpots, leaving the body that contains the throttle butterfly, and machined an adapter for each carb that hold a 72# injector. So now I have a pair of throttle bodies on the car. I use a 1227727 ECU with a Romulator stuffed inside running $A1 code, which also means I'm running distributorless ignition. After lots of testing and dyno time I have a car that runs quite nicely. It's really just a street car but I take it to the drag strip on occasion and to a local 1.8 mile road racing course whenever I can.

I converted my 1974 Jaguar XJ-6 too, it has the same engine as the MK-I but has a pair of 1 3/4" Stromberg side draft carbs converted in a similar way to the MK-I's SU carbs. Same injection setup as the MK-I.

I've also given a 1949 Ford 239" "59AB" flathead a throttle body on the stock intake (don't recall what GM motor I sourced the throttle body from), 1227727 ECU with a Romulator and $8D code. Sold the truck kept the motor, just need to find something to stuff it into!

I've been a long time user of Tunercat, since 2001, but while Googling for more detailed info on $A1 code I ran across Robert Saar's very complete XDF file for TunerPro v5. Now I'm learning TunerPro!

I've built a couple of Arduino based ALDL loggers too, info here: http://www.xm381.com/xm381/aldl.html

And my final "addiction", I play with Army trucks; fuel injected, but fully mechanical diesel. The only thing electric is the starter and that's just for convenience, they "bump" start easily. Here's my Army truck website: http://www.xm381.com/xm381/Home.html

Regards,

Mike

[RobertISaar]

the 59(and i guess 74) jag, is the 7727 driving two low-impedance injectors off of its one driver? i wasn't sure the factory injector driver and sense resistor would allow the injector to operate normally with half of the current it would receive if run in parallel when run in peak/hold mode.

also, good to see that the A1 XDF has been put to use.... after i started the nAst1 project, i haven't really touched it even though i know there are things that need correction, i can't remember what they are anymore.

[mikew]

Robert,

Yes, the 72# injectors are "peak/hold" but are running at full current.

The two "Injector Ground" connections on the 1227727 ECU (pins D06 and D07) are connected together on the "ground side" of the injector driver inside the ECU.

As you know, for saturated injectors you'd connect D06 and D07 to ground and about 8 amps would flow with 8 saturated injectors connected.

With peak/hold injectors you'd connect D06 and D07 to D05, the Injector Sense pin, which runs through a .1 ohm resistor to ground inside the ECU and results in a 4 amp peak 1 amp hold.

What I did was connect D06, Injector Ground to D05, Injector Sense and then the trick... connect D07 to a 2 watt .1 ohm resistor that is connected to ground. Now I get an 8 amp peak and 2 amp hold, perfect for two parallel peak/hold injectors!

I've just discovered your nAst1 project and look forward to learning more about it.

I can't tell you how helpful your $A1 XDF file has been. I've been reading the BFUZ hack for years and still discover new things. You have already charted out all the variables in your XDF file so now I have a slew of new things to tweak!

Thanks for your hard work.

Regards,

Mike

[RobertISaar]

so that was done externally of the ECM? i guess that would result in doubling the current compared to a stock wiring setup. i'm used to dealing with modifying the internals with a .05(or parallel .1) resistor. that is a pretty neat method of getting what you want out of it, certainly a lot easier for most people that don't want to open up the ECM either.

but the driver itself has held up well, too? i imagine it would, since now you're temporarily dealing with the same amount of load that 8 saturated injectors would draw full-time, which obviously works for the 5.0/5.7 TPI engines that used the 7730 and 7727.

[mikew]

Yes, external and easy. If you ever had to swap a failed ECU on the side of the road you just have to plug in the replacement, no modifications required.

As far as the drivers holding up; I've been running the '59 Jaguar for more than a decade, and close to 100k miles, on the same ECU (pulled from a Beretta in the junkyard).

As I mentioned, I've also stuffed a Romulator inside the waterproof 1227727 with the RS232 lines connected to unused pins on the 1227727 (B2, B13, B17, B19, B22). I've connected a DB9 serial cable pigtail to those pins on the external plug so it's easily tunable without disassembling anything and with TunerCat RT or TunerPro RT you can make adjustments while going down the highway (let your co-pilot do it, that is).

Mike

[jim_in_dorris]

Wow, somebody else with a 59 Mk1. I have a 58 Mk1 that hasn't been started since 1960. I always wanted to hotrod it, but never have the money to work on it. Post pics please. My wife has finally convinced me to get rid of it, but I haven't tried very hard yet.

[mikew]

Hey I've got a '58 too... you can never just have one!

Here's some track pics and a dyno run too.
MK-I A.jpgMK-I B.jpgMK-I C.jpg