Hear Hear. I could not agree more with this statement.

Also go and buy yourself a ROM. I have it in both hard copy and on CD they are cheap on CD.

 

Agreed, $20 on eBay.

 

if you think i would shell out $400 for a megasquirt system and keep the factory harness, your crazy.

i think this thread deserves some attention no matter whos doing it.

 

I am going to go Megasquirt and Megashift. It has been done before and there are loads of resources on the MSextra forums. It is not difficult if you start with a working engine and use the itteration approach to implement the changes in stages.

I will not get around to this until later this or early next year as I want to upgrade all of the mechanicals first. Suspension, steering rust and paint etc.

Then working from a running engine implement:
1) Megashift to control my 4L60e transmission.
2) Megasquirt fuel only- once this is running
3) Ignition control.

Then modify the engine TC, SC etc.

 

Completely agree.

 

but you still haven't confirmed yet that the wiring harness is at fault either. You could replace both and inroduce two new variables into the system, and still remain with the same problem after shelling out $$$$$.

Return EVERYTHING back to stock. Fix the car. Then upgrade.

 

I ran an MS II on a V3.0 board on my Locost project. It was a great system and I learned a lot about how engine management systems work. I bought the ECU, relay board, stim kit, and cable from DIYAUTOTUNE.com

If you only use if for fuel, you are giving up one of the great advantages of electronic controls. Give you an example: One of the strategies for maintaining idle speed is for advance to INCREASE when the engine starts to fall below your desired idle speed. There is no way to implement that on the existing manual system. And that's not the only spot on the ignition map that might need something that's opposite of what a vacuum/mechanical system can provide. If I were doing a V12, I'd use a pair of EDIS6 modules. An MSD on the distributor would be my second choice. But I would definitely control the spark thru the MS.

The old sensors can be used, but why? GM IAT and CLT sensors are cheap and have nice weatherpak connections and you won't have to rune the calibration program. You can use almost any TPS. Megasquirt has a calibration screen to set idle and WOT for the TPS sensor. The MAP is on the board so you won't need one of those.

You can use the old injectors, but if I were doing this, I would grab a dozen 19lb injectors from a 300ci Ford truck or a dozen 24lb ones from a GM 3.8 V6. The high impedance injectors are just easier to use with the MS. Make new fuel rails and get a good aftermarket adjustable FPR.

On my inline six I fired the injectors in an alternating pattern; front three, rear three. You can set up the MS to do the same. Sequential is a great tool for emissions and low speed, but above about 2500 rpm the injection events are so rapid they are effectively no different than batch fire anyway.

You will want to budget for a wideband sensor. The LC-1 is a good one and you can use either a gauge or the laptop to monitor the AFR. Without it you are really just guessing at VE tables.

I used the relay board to do all the underhood connections. I put the relay board inside a molded plastic box so I could snap a lid over it. Then I used the cable to connect the relay board to the computer. You have to run a vacuum line to the ECU as well.

Read the manual. It has a lot of data that you need to understand even if you don't solder it together yourself (which is not that hard and only took me two nights). YOu need to pay particular attention to how to boot the .S19 files into the processor with the correct version of firmware.

There are a couple of different software downloads to do tuning. I prefer the tunerstudio over the megatune.

The forums are helpful, but don't expect someone to post a working .msq that will make your Jag plug and play.

BTW, using the MSII, 200 cube six cranked out 186 RWHP, naturally aspirated, with a near-stock cam. There is probably over 300 hp in the old 5.3 with just a well tuned system.

 

i think you might have gotten these confused.
NA 3800's are 19.5# injectors.
SC 3800's are 34# injectors.

 

,,,,

 

what the duece? it keeps moving your post down.

 

I did get them confused. The Ford 300 is definitely 19#. I used a set of injectors from a Buick but they were 21#, not 24#. I have a set of 24# and 30# from a Mustang that I did not use. Either way, Bosch or Rochester, they were physically interchangeable.

You don't want to go too big or too small. Too large and you'll play hell trying to get a small enough pulsewidth to idle properly. Too little and you run out of capacity to make optimal hp. You can tinker with fuel pressure, but tuning that way is a crutch.

19# is probably more than adequate. At a reasonable BSFC of 0.5 lbs/hp twelve of them can support 400hp at about 90% duty cycle; there's really no need for anything bigger in a stock, naturally aspirated 5.3 unless you are using it in a boat or aircraft where you sustain full power for long durations.

Newer style injectors will also have an advantage in flow pattern with a better atomization than some earlier ones. In any case, replacement stock injectors are easy to find and very inexpensive.

 

drifting post won't stay in one place???

 

lol. anyways, ive got a full set of 26# injectors from when i was modding my old NA 3800. the injector body is too small though. bummer.

 

i know this is the megasquirt thread, but there is this efi system by holley called teh dominator which my friend has on his bmw v8 and it is supposied to be able to work on the distributor and provide self tuning, its WAY more money than the 400$ ms2 application but its what im looking into using when i get around to building my xjs rally car

 

you should check out james may's ralley XJS.

 

Sorry Im late in on this one.... Just pulling the engine out!

Im running Megasquirt MS2 v3.0 mainly to get rid of Lucas gremlins which I couldn't locate. Both the computer and the amplifier tested good.

I have the controller on the cover in front of the battery with a cable to the relay board which is now located where the old Lucas was under the pillar. I used two 12 foot lengths of cable with a 4mm vaccuum hose and followed the old cables throughout the interior. Th joining point I used a male and female DB37 plug. Coincidently it worked out that it is located beside the shifter or gearstick for no USA. As a side note I found the source of all my electrical problems was some historical shoddy electrical repairs behind the drivers side wheel where the old loom runs from the foot well into the engine bay. Too late for me but it would pay to check that area out.

The original coolant and air temp sensors are compatible and the ROM has the resistance values for them to convert. The only thing needed is a TPS which I bought a generic BOSCH one from Germany for 30 euro. I can get part No. if needed. Im running the car without cold start injectors or the MAP in the front corner. Ive also changed the ignition to a Crane Cams with their Coil.

Im only running the fuel for now off the coil but I will be putting a trigger wheel and am working on uprating the engine. If you have the money buy the premanufactured one. I built mine it wasn't too difficult but if there is a problem it takes a lifetime to trace the part and Digikey sting you heaps for postage on what sometines is a $0.10 part.

Future plans to put a LS1 Oxygen Sensor in the exhaust to save all the pennies from wasting fuel and out them on more power!

The potential for the Megasquirt is massive. I agree there is too much information on their websites and it takes a while to read a lot of the informationbut it will be worth every cent if you modify your engine as you can set all the parameters yourself.

As for why Im pulling the engine out...it hasn't been running since I got it. Now it runs with the new electronics it also has decided to leak every fluid through every brittle gasket.

Cheers

Steve

 

ok, so how does the stock ECU on my 85 get the injector signal? is it based off of a Crank position sensor, or a distributor signal?


also, Warjon, what ECU did you end up bying, and what software were you planning on running?

 

All the inputs on your '85 are those you've already worked on - TPS, CTS, vacuum signal, binary input from the half-throttle microswitch, and for "trim" the IATS and O2 sensors. The dizzy and ignition amp aren't involved.

 

ok. so does the injector pulse based on a guess as to the engine rpm? or does it pulse based on what the Tach says, which isnt very accurate? or does it have a cam sensor?

 

The ignition amp feeds pin 16 of the ECU to provide a tach signal.

Pretty good writeup here:

LUCAS EFI / AJ6 Engineering