i have a dx. buying an si motor. about the dpfi mpfi and ecu. if i convert the dx wiring harness to mpfi, would the dx ecu control the si motor well? assuming i converted the dx wiring harness to work with mpfi, and i then later bought an si ecu, would the rewiring of the harness disrupt the flow of information to the si ecu?

since i am putting in a si motor, should i save and get a si harness and ecu at the same time? drivability as soon as possible is a plus so would this be the way?

all suggestions appreciated.

thanks

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by quizical &raquo;</TD></TR><TR><TD CLASS="quote"> if i convert the dx wiring harness to mpfi, would the dx ecu control the si motor well? </TD></TR></TABLE>

Nope...the DX ecu is setup to only control two fuel injectors, therefore, there is no way it will run the MPFI Si motor. You will need the Si ecu for that, and that will need to be done at the same time as the MPFI conversion.

 

so i need the si ecu. that will be done. should i convert the dx wiring harness? i have heard and seen diagrams and it doesn't seem to be that impossible. what do you think. rewire and save money, or buy si harness.

 

If your comfortable doing the wiring, go for it, it's not really that difficult.

Here are some links that will help.

http://www.angelfire.com/d20/h....html

http://www.geocities.com/teampimports/fuelinj.html

http://www.geocities.com/c_rexboy/mpfi.html

http://www.bladesilver.net/crx/

http://www.fourthgenhatch.com/mpfi.html

 

thanks very much.

off from the question, what are the major things you would recommend replacing on the engine before installing it. d16a6 with about 160,000 miles. should i replace ALL of the gaskets? or just the main ones, could i use the water pump from my 150,000 mile d15, or should i replace that too. if you wouldn't mind making a quick list of the stuff i should replace before i put the engine into my car, i would be grateful.

thanks for your help

 

Can't remember if you can PM either anyway...

I'd replace the Timing belt, water pump, cap , rotor, plugs, and wores to start. You'd be surprised but most of the gaskets will probably be just fine.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 96-EJ6 B18C &raquo;</TD></TR><TR><TD CLASS="quote">

Nope...the DX ecu is setup to only control two fuel injectors, therefore, there is no way it will run the MPFI Si motor. You will need the Si ecu for that, and that will need to be done at the same time as the MPFI conversion. </TD></TR></TABLE>
I begg to differ. Ihave been researching t6he same concept for quite some time both from swap shops and the bet.Iv'e been told that you can run two new wires to the injector resistor box, and then you should be able to use your MPFI with your DX ECU(provided you also completed the rest of the neccesary hard wiring....

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Civiclized &raquo;</TD></TR><TR><TD CLASS="quote">I begg to differ. Ihave been researching t6he same concept for quite some time both from swap shops and the bet.Iv'e been told that you can run two new wires to the injector resistor box, and then you should be able to use your MPFI with your DX ECU(provided you also completed the rest of the neccesary hard wiring....</TD></TR></TABLE> Nope, the DX ecu is intrinsically different in it's hardware and circuit design; it cannot even be chipped to support four fuel injectors.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Civiclized &raquo;</TD></TR><TR><TD CLASS="quote">
I begg to differ. Ihave been researching t6he same concept for quite some time both from swap shops and the bet.Iv'e been told that you can run two new wires to the injector resistor box, and then you should be able to use your MPFI with your DX ECU(provided you also completed the rest of the neccesary hard wiring....</TD></TR></TABLE>

You can not do it.
As the replies have been rolling in, it doesn't work.

another main factor is the distributor.
There are 2 "missing" wires on the DX distributor when compared to the Si.
The wires I'm talking about tell the ECU when to fire the injectors.
If you converted to the Si distributor and coverted your harness to Si spec the DX ECU still wouldn't have the circuitry to support it.
Then you still have the 2 missing outputs for the injectors.

The only way you could do it is if you ran the DX intake manifold and distributor on the Si motor and left the wiring alone.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 4drEF &raquo;</TD></TR><TR><TD CLASS="quote">You can not do it</TD></TR></TABLE>

Listen to the people who know.

You could batch-fire the injectors, but that's lame and the wrong way to do it. You would also have a terrible tune, and you couldn't do anything about it becase the PM5 ecu is a marginal paperweight at best.

Get the Si ECU.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by EFRue57 &raquo;</TD></TR><TR><TD CLASS="quote">you could use either. changing that part of the wiring doesn't have an effect on which ecu you use. you could still use your dx, or you could use any other obd0 ecu.</TD></TR></TABLE>

Please don't talk about things you don't know about. Thank you.

 

Nope, nope, will never work...

 

I stand corrected, and have learned something new-But thats why I like this site!
Good Look'n guys