i wonder if anybody has done this before. i get weird ideas to made things easier and/or save money.

when converting to mpfi on a 4th gen, you have to swap to a 7 wire dizzy. the 2 extra wires being the cps gives the ECU a resistance value of ~400ohms (correct me if im wrong). since this resistance barely changes i wonder if a value 1/4 watt resistor crossed between the 2 cps pins on the ECU would make the original 5 wire dizzy work with MPFI.

i guess the real question is - how much effect does the resistance value of the cps have on the driveability / performance of the engine?

the only downside of converting to mpfi on an EF is the Si dizzy. You have to spend $300 for a new one or $100 for one that is whether broken or soon to be broken. 5 wire dizzys dont break.

 

no chance

it is a sensor, therefore the change is measured and required

 

well im still trying it

before i mount on the dizzy, ill put a resistor across the cps and see if it runs. ive heard of people sucessfully doing mpfi swap with the 5 wire dizzy.

 

yes-use your car as the gueni pig.

let us know how it runs/performs

 

Ahhh, just look around, you'll find a dizzy for cheap, picked mine up for 30 bucks, just look around...

 

have fun driving w/ no crank angle sensor

The crank angle sensor is basically a coil (therefore it has resistance) when the wheel inside rotates, a tooth passes the coil. The tooth causes a moving magnetic field and a voltage is generated in the coil. The ecu picks up this voltage and uses it to determine the crank angle. just a resistor it will act as though there is no wheel rotating, it will throw a code and run like ****.

Go ahead and test it. Switch your VOM to volts instead of ohms and spin the dizzy. It is a very low voltage, which is the reason the wire is shielded.

-Dustin

 

ive had problems with getting a code from not having the cps wires separated. i totally forgot about that. .... i mess with similar things at work and they have to be so far away from each other so they dont pick up noise.

 

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

Go ahead and test it. Switch your VOM to volts instead of ohms and spin the dizzy. It is a very low voltage, which is the reason the wire is shielded.

-Dustin</TD></TR></TABLE>

Hey quick question regarding this..

I did a mpfi swap and i had to cut the shielding. Now its not sheilded, will the car run like crap? its not throwing any codes.

should i re-shield it?

 

good info here, let us know if it works....

 

the sheilding is more of a precation, if you are not getting codes, it's not getting interference. I would recomend sheilding it, but mine is not shielded either.

-Dustin

 

I have done the conversions numerous times without shielding, it should be fine.

 

If you do start to get random CEL's, you can shield it or look for other problems. Ignition wires with insulation worn off could cause RFI problems.

-Dustin

 

cant you just cut the wires on the dual point injector plugs and splice and dice to 4 injectors...do you need a resistor box.....basically two injectos on 1 set of wires and two more on the other set of injector wires

 

yeah only with obd1 injectors

 

I got a better idea.
Don't bother with the experimentation.
It would appear that you have been experimenting a little too much.

Enroll in a rehab clinic and stop smoking crack.


It won't work!
Your MPFI ECU needs to know precise times to fire off the individual injectors.
There is a sensor in the distributor that lets the ECU know that exact info.
The DPFI distributor only supplies info for 2 injectors... not 4.

 

the dpfi doesnt even do that. they just fire randomly and whatever cylinder needs gas gets it.

 

what if icompletely change over to obd1... you know switch the whole harness and ecu over to get that baby runnin mpfi and a higher rev limiter right?

 

damn newbs