OBD 1 Controller Options

[jsawduste]

Built my stroker a couple years ago. .080 Diamonds, Eagle Rods, Mopar Rollers etc.

While I have no issues with how it runs. Suspect there is a better cal available in the ECU then the stock OBD 1 (93 vintage) that I am running.

Honestly I have not taken the time to really research the subject. But I read about Uni-Chips, Jets and "other" hi end systems that can change the fuel and ignition maps.

Have no laptop to plug into anything. Plus don`t have a ECU data link to plug into the harness.

What options do I have ?

Convert to an OBD II system ? Some kind of stand alone box the interfaces with the OBD 1 ECU ?

Frankly not convinced a UNI-Chip does much if anything on a OBD 1 system. What does ?

Thanks !!

[Plechtan]

Well, i guess it depends how adventurous you are. I cheap solution would be to use a Megasquirt http://www.megamanual.com/index.html The basic unit is $400. you will probably have to add a trigger wheel, because it will not use the stock crank sensor. The basic Megasquirt is about $400, but then you have some work to do the interface it to your current electronics. If you have a computer controlled trans, the megasquirt has no way of comtroling it.

I am working on a harness for the Renix right now, When i finish that i will look at the ODB1 and ODB2 applications.

[jsawduste]

Interesting link, Plechtan.

Lots of reading and studying but within grasp. Only thing that concerns me is the lack of ignition curve mapping. MS states that they are only controlling the fuel curve. Logic would dictate that both curves should be considered for optimum results.

Does anyone have a copy of the OEM spark curve of mapping ?

Running a manual (NV4500) trans so no heartburn interfacing there.

The MS does seem to be a much better solution then a UC. Somehow the way UC changes fuel delivery by changing injector duty cycle is a band aid at best.

Still game for the MS system as it sems to be a big improvment over the OEM system at a resonable cost.

Plechtan, you mention doing some harness work. Just what is it that you are doing ?

Thanks for the link !!

[Plechtan]

You didn't read far enough, the web page is a little confusing because they have information about all the models of the MS. They start with the original version and work their way up. Just go the the latest model and ignore all the old stuff. The "mega Squirt II" does do spark control,http://www.megamanual.com/ms2/ign_timing.htm and they are also coming out with a Sequential unit next year. The Sequental unit will support Coil per cylinder.

What I am working on is a harness that will plug into you existing harness and then go into a Megasquirt. I am also probably going to make one for the Haltech cpu as well http://www.haltech.com

As for not having a laptop, you do not need a very powerful one for tuning purposes, You can probably get an old one for free or real cheap.

[gmakra]

You didn't state what OBD-1 system you are running? If its a GM based system there are a lot of things you can do with a very basic laptop. There are also guys out there that will burn you a new chip based on your engine. If you scout around third generation. org you will find guys on there that can burn you a chip typically $100-150

[jsawduste]

You didn't state what OBD-1 system you are running? If its a GM based system there are a lot of things you can do with a very basic laptop. There are also guys out there that will burn you a new chip based on your engine. If you scout around third generation. org you will find guys on there that can burn you a chip typically $100-150

Well ok, I did not know there were different "levels" of OBD 1. In my case it would be 93 vintage. Not sure what that means but I`ll check the link and try to learn.

Thanks !!

[gradon]

Comanche91 has great results from the Unichip($400) on his 91 obd1 pcm. It had to be soldered into the harness(add another $100 or so if you have someone wire it for you) and then had Hesco tune it on their dyno($150). It controls fuel and timing curves. Anyhow, you should talk to him about it. I wish I had those rods, pistons, and rollers, lol.

[amcinstaller]

i think by omitting the make of the controller, its a jeep unit.

[jsawduste]

i think by omitting the make of the controller, its a jeep unit.

I would have to agree. Recall in my GM days we burned OBD 1 controllers fairly often. These were non production OBD 1 ECM`s directly from Delco. However production controllers were ROM and could not be reflashed.

The link doesnt work and the controller is not a Delco..

[amcinstaller]

as well, i havent heard of any reflashing of factory obd1 JEEP ecus, only the obd2s. i HAVE however, seen on obd 1 chip reflashed on gm. i saw them do it on trucks on the spike tv channel. not sure how well it would work with the strokers here, and i think the megasquirt would be the same effort and cost.

[oletshot]

So am I correct in assuming on an OBD1 jeep ecu your only control options are:
1. Adjustable MAP.
2. Injector size
3. Fuel Pressure

Use any one or combination of all three to get the Air/Fuel Ratio correct?
Are you only adjusting the MAP for during warm up and WOT? I would assume the ECU keeps the A/F ratio correct during normal driving.

[jsawduste]

So am I correct in assuming on an OBD1 jeep ecu your only control options are:
1. Adjustable MAP.
2. Injector size
3. Fuel Pressure

Use any one or combination of all three to get the Air/Fuel Ratio correct?
Are you only adjusting the MAP for during warm up and WOT? I would assume the ECU keeps the A/F ratio correct during normal driving. :huh:

This would be my understanding also. However I would love to be proved wrong.
MS would be a viable option and may be (only) the way to go.

The other option I see is to convert to OBD 2. Then you have to add the reflash at a min. or an aftermarket controller.

[SilverXJ]

If an adjustable MAP sensor mod will work on OBD 1, then any of the other aftermarket piggy back computers should work. I know for a fact that an Apexi will work.

[1bolt]

Doesn't Unichip work on OBDI systems? 99% sure it does.

I know that Perfect Power piggy backs will work (SMT-6, SMT-7 etc.) and are cheaper than Unichips and lap top tunable.

[SilverXJ]

Doesn't Unichip work on OBDI systems? 99% sure it does.

I know that Perfect Power piggy backs will work (SMT-6, SMT-7 etc.) and are cheaper than Unichips and lap top tunable.

I don't know about unichip.. it seems that they can do more then screw with the map setting... but you nailed the one thing that turns me away from them... you can't tune them your self... so even you had access to a dyno or brave enough to do on road tuning (there is a perfect hill about 1/4 of a mile form my apartment.. its a 55 mph zone but I have done 80 in it before and I really wasn't in a hurry), you can't do anything yourself.

Basically the major piggy backs need a value from the TPS, RPM and MAP as well as an out to the MAP... they interrupt the MAP signal with their own values which changes the AFR ratio. Being that OBD II is adaptive some what (I haven't actually seen it effect open loop) they should work even better on an OBD I system. On my OBD II system with the limited control of the Apexi SAFC II could force it from 11.0:1 AFR to a 15:1 AFR in open loop. It doesn't have as many RPM spots to modify as the better units but it works and allows me to modify the AFR as necessary.