Poor Mans Efie gave me check eng. lights

[SpecHunter]

I built my efie after mad scientists utube design which is just like DMBing`s design also. When I seen DMBing`s video I noticed he put his ground to his sensor, which was unplugged, then his output to the ecu. This gives the ecu a CONSTANT signal , not a fluctuating, realtime signal. It doesnt seem that he`s ADDING to the signal, just throwing a fixed voltage at the ecu.
My Sable 3.8 wagon did not like this at all.... after 5 miles it gave me a check engine light. So this morning I put it back the way I had it ... which was a single wire to my o2 senor from the enhancer, then ground the ground wire and keep the sensor plugged and operating. this config only allows me to add .35 volts cranked all the way up. ( dont know why) but it works.
I`m using a 1.5vlt battery but would like to tap into the cars 12 vlt supply .
But I dont know how to step it down (resistor?) ... If anyone knows how to do this , I would be gratefull , thanx Attachment 854

[hg2]

I built my efie after mad scientists utube design which is just like DMBing`s design also. When I seen DMBing`s video I noticed he put his ground to his sensor, which was unplugged, then his output to the ecu. This gives the ecu a CONSTANT signal , not a fluctuating, realtime signal. It doesnt seem that he`s ADDING to the signal, just throwing a fixed voltage at the ecu.
My Sable 3.8 wagon did not like this at all.... after 5 miles it gave me a check engine light. So this morning I put it back the way I had it ... which was a single wire to my o2 senor from the enhancer, then ground the ground wire and keep the sensor plugged and operating. this config only allows me to add .35 volts cranked all the way up. ( dont know why) but it works.
I`m using a 1.5vlt battery but would like to tap into the cars 12 vlt supply .
But I dont know how to step it down (resistor?) ... If anyone knows how to do this , I would be gratefull , thanx Attachment 854

Most likely you started too high with your adjustments.Try starting with around 200mv or .2v then bring that up slowly a bit a time while doing your mpg testing.Don't make radical adjustments or the ecm will catch on quickly as to what you're doing.The idea is to "fool" the ecm and sometimes you just have to tiptoe around so it won't notice.


Good luck with your tuning

[SpecHunter]

Most likely you started too high with your adjustments.Try starting with around 200mv or .2v then bring that up slowly a bit a time while doing your mpg testing.Don't make radical adjustments or the ecm will catch on quickly as to what you're doing.The idea is to "fool" the ecm and sometimes you just have to tiptoe around so it won't notice.


Good luck with your tuning

Thanx for the advice , but the ecu is expecting to see a fluctuating voltage and the "poor mans efie" is giving a constant.
For example:
My 3.8 idles with a reading of 180 mv. When I`m driving the readings are from 250 to 400 mv. depending on my rpm`s .
So using dmbing`s configuration, through the course of driving im giving it a constant signal that doesnt jive with the map/maf sensor info. So while I might be able to dial it in while at a constant rpm. The moment I let off the gas , my ecu expects to see a voltage drop in conjuction with my maf/map increased readings ( they work opposite of eachother). and Bang!... Check engine light.
Replacing fluctuating voltages with constant doesnt seem to be the answer.
Adding to the exsisting fluctuating voltage seems to be the common sense thing to do rather than trying to replace the signal all together.


Still hoping someone can give me an answer to my 12 supply stepdown to 1.5 issue.
thanx ppl!

[Painless]

Still hoping someone can give me an answer to my 12 supply stepdown to 1.5 issue.
thanx ppl!

Use a 5V voltage regulator to give you 5V constant, then a further resistor to get the 1.5v you need.

I had similar problems trying to wire the poor mans EFIE into my 4.7 Ram (2006), I found that the signal still varied, but not as much as before. This still caused CEL's and gave me no benefits.

I've decided to try the O2 extender route and then work on the ECT and IAT.

What I did discover as important with the potentiometer is to connect the original signal from the O2 sensor to the pots ground pin. This ensures that the voltage from the wiper is always somewhere between the ground and the input.

[SpecHunter]

Use a 5V voltage regulator to give you 5V constant, then a further resistor to get the 1.5v you need.


.

kewl Thanx painless
I take it the 5 volt regulator is regularly available @ radio shack , etc.
Would you happen to know the size resistor off haND? I`ve been told 150 ohm , up to 450 ohm. not sure what to believe.

[Painless]

kewl Thanx painless
I take it the 5 volt regulator is regularly available @ radio shack , etc.
Would you happen to know the size resistor off haND? I`ve been told 150 ohm , up to 450 ohm. not sure what to believe.

The size of resistor will depends on how many amps are in use. Volts = Amps * Resistance IIRC.

[SpecHunter]

The size of resistor will depends on how many amps are in use. Volts = Amps * Resistance IIRC.

can i determine amp usage with my meter using the 1.5 volt battery I have in it right now and cranking the pot all the way open? If so... is there an equation to then use to determine resistor? forgive me if I`m a pain in the *ss , Painless ,hehe

[Painless]

I'm not an electronics guru, but if I remember correctly you need to divide the volts you want by the amps you have to get the resistance in ohms.

Hopefully, one of the more knowledgeable electronics guys like ridelong can confirm this for you.

[SpecHunter]

I'm not an electronics guru, but if I remember correctly you need to divide the volts you want by the amps you have to get the resistance in ohms.

Hopefully, one of the more knowledgeable electronics guys like ridelong can confirm this for you.

Thanx painless ... Hopefully one of the electronics guys will chime in on this.

[crb]

SpecHunter, Did you get your poor mans efie figured out?