DustinRose

Good evenning gentlemen.

I have spent the last 3 months, studying, creating, and re-creating my very own homemade custom engine harness. My harness was designed to run my PR3 B16 in my 1990 Honda Civic Hatch STD. I have made myself extensively knowledgable and literate to well over 25 Honda Wiring Schematics, from helms manuals, that are posted in different places online. Let's begin my story.

I owned a Ry Wire built OBD1 EF Harness, meant specifically for a D15B to be installed into a STD/DX hatch, it was my friends, i attained it, and went OBD1, also installing my new Hondata S300 P06 ecu. Everything was great. I crashed that car, pulled out the harness, took it apart, wrote down everything. Triple checked, read schematics, the info was reliable. I got another car, which is the one i have now. I recreated my own ry wire harness, man, it was gorgeous, tucked, totally heat shrinked. And instead of using a jumper, i soldered and heat shrunk an OBD1 plug to my chassis harness at the ECU. Got in the car, VROOM, starts first try, but.....i have a CEL for CODE 6 ECT......hmmm
I change the sensor......still have the code
I run wires directly to the ECU at D13 (ECT) and D21/D22 (SG1 SG2 respectively)
I install a P28, still have the code
Change the plug
still have the code

what the heck is going on here guys..........
my car is running rich, this code is mysterious, i thought i was an educated man, i used the search button so many times on honda tech, i was ready to kill every lucky who was able to simply re-connect a wire, or change his sensor, and all his worries vanished
but not i

this brings us to the real fun
harness number 2


wow look at that beauty
the ecu plugs are right on the harness, completely eliminating and fuss from the OND0 chassis harness, just like a chase bays harness, man that is great
i used many schematics to compare to eachother, and ensure whether they were right or not, but my favorite and executive schematic is one from Hondata's web site for the OBD1 GSR

here is the link to the larger image:http://hondata.com/images/gsrwiring_1.gif

here is the link to the other larger image: http://hondata.com/images/gsrwiring_2.gif

now, i created this harness, to the T! i am an expert at soldering and heat shrinking by now, and i own all the proper equipment for doing so, i just finished a course in digital electronics at school, man, i feel on the ball, and my last harness worked perfectly minus the ECT code 6
this harness has to be fool proof
no
wire it in, connecting all the right grounds, ELD, gauge wires, main relay power sources, even properly wiring the alternator and not using the S300 to turn off that CEL
and still, code 6 still stares me in the eyes
i am getting almost irritated at this point, but i am cool like miles davis

so

i do the same things as before,
run new clip and wires directly from ECT to the corresponding plugs on the ECU
buy another ECT, try all three of them
check everything over and over
try another P28
try my P06 S300 hundred in my friends EF DX OBD1 RYwired Hatch, no code on his car

and this time i notice something in my favourite schemtic, and another older DA schematic....
notice the yellow circle around point G, which indicates a location unknown
point G T's into the ECT in between the sensor and pin D13 @ the ECU....
hmmm

so, i hit the books again, really hard, i dig up many schematics, including OBD0, JDM, RHD, LHD, Preludes, Integras, you name it, and i find that in the DA 1991 Integra that this point "G" ties into the TPS siganl wire, which goes pin D11
this makes no sense to me, but i try it anyways

nothing, just a messed up TPS signal, which i monitor on my S300 in the datalog feature

so, i try adding +5V to the ECT D13 wire
nope
and +12V
nothing

i even called my good old buddy Peter at RyWire
man he is a nice guy, and helpful
he says......"whoa, you changed the sensor, wired it direct to ecu, tried another ecu, and still nothing?"
yup, it sucks a lot

also, this is important
when i simply turn on the ignition
and begin datalogging
the ECT sensor reads 150.9 degrees
whether the engine is hot or cold
my strongest theory is that some how
according to this chart http://www.tec-help.com/Honda_ECT_IAT.htm
there is a 1.5v signal reaching the ECU, or traveling with the ECT resistor circuit within the ECU

this is a super technical idea, when in reality it is all caused by a simple wiring issue
man o man

so.......if anyone out there can help me, please share your knowledge

i have done a TON of reading about this
please ask questions, i will be able to effectively answer them

my name is dustin, im 21, im a nice guy, ha





Modified by DustinRose at 7:16 PM 5/8/2008


Modified by DustinRose at 7:21 PM 5/8/2008


Modified by DustinRose at 3:52 PM 5/9/2008

DustinRose

ok
i have resized the picture
now i am sure you must be eager to aid me with my problem
right?


Modified by DustinRose at 7:32 PM 5/8/2008

grog

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DustinRose &raquo;</TD></TR><TR><TD CLASS="quote">
now i am sure you must be eager and ready to aid me with my problem
right? </TD></TR></TABLE>

come on, now others can easily read it without scrolling back and forth, i think I've aready helped.

thats a dusey, you have checked everything/done everything (so it seems) and still nothing huh. I mean the helm manual doesnt even go as far as you have.

so you have eliminated the harness the sensor, and the ECU

could there be a short somewhere that some how makes its way to the sensor.

damn, what was different with you buddy's setup? grounds, accessories, motor,A/C?

could you CEL curcuit be the cause, or the cabin harness?

does it have an A/C diode?



Modified by grog at 7:51 PM 5/8/2008

barely4dr

well look on the bright side, you've tried pretty much every conceivable method of fixing that CEL; eliminating/ruling out complications.

IMO the culprait [sp?] to ur problem is most likely something rather simple that you may have (somehow) overlooked.

GL in ur quest

bobjohnson

I dont think G would be the TPS sensor. Where ever you read that, id say its wrong. Since those diagrams came from hondata, maybe try giving them a call and see what they have to say about it.

The only other thing i could suggest would be trying another OEM ECT sensor. Maybe you got really unlucky and got 2 duds. But first i would try finding out where that wire is actually supposed to go.

jlicrx

not trying to be a smartass, but are you checking the correct temp sensor? - the one on the end of the head below the distributor with 2-wire connector

the red/white is the 5 volt signal wire and goes to ECU pin D13 - the green/white wire (on some OBD1 it is green/blue) is the sensor ground and is connected to other sensor grounds, like TPS, MAP, etc., and ends up at ECU pin D22

is the engine full of coolant with all of the air bled out?


Modified by jlicrx at 12:02 PM 5/9/2008


Modified by jlicrx at 12:03 PM 5/9/2008

DustinRose

grog:
a short? that's my best guess too, somehow before the engine has even run, and is at 0 degress, i can turn on the ECU and monitor with the s300, and the ECT will read 150.9 degrees. this has not failed, which means, that somehow, there is at least 1.2V traveling through the ECT circuit
now that being said, the only way i can think of that being possible, is that somehow the ECU is not properly wired to the main relay, those wires would be:
IGP1 IGP2 +12V from main relay
PG1 PG2 Ground (thermo ground)
LG1 LG2 Main Relay ground (thermo ground)

well, such an "imbalance" is caused by a "short" or in other words a bad ground
so, i beefed up the ground from my main relay, and i re-soldered some of the questionable pins in my main relay.
i beefed up these grounds by teeing into the 2 black wires and grounding to the frame
this was last week
still ECT

ha

my engine is heavily grounded, i have a 2 gauge cable from the trans to the body, and 2 seperate 4 gauge wires running from the head to the body on the other side of the engine bay

i agree barely 4 door, it is probably something simple, which is the scariest of all, ha

i contacted hondata about the schematic they provided, and they gave me no aid, and directed me to helm's website to purchase their stuff
they didnt even tell me what book had the schematic they used
i have hunted for that same integra manual online, but the ones i have found do not match the one on hondata's site

DustinRose

talked to chase
mr. chasebays chase
thanks

i will try testing the circuits inside the ecu

anyone?

sanimalp

My theory, may not even be possible, but here goes..

my guess is that your current ecu might have been chipped poorly, which is causing the ECT sensor to be overloaded somehow, damaging the new sensors before you test them using a different ecu. when you go to test using the other ecu the sensor is bad from the overloading, and when you switch to your friends car, the ecu maybe wasnt plugged in long enough to damage the other sensor.

to be honest, I dont know if the ecu is sending or receiving on that line, so if it is receiving, then my theory doesnt make sense, unless it is grounded poorly on the other side.

here is what i would do. try another known working ecu, and go buy yet another ECT sensor or use one that checks out according to the book. install both at the same time and try it out. if you get the cel, then it has got to be a bad ground somehow. if you dont, then your ecu might be bad.

Thats all ive got.. good luck.

mra4886

im not trying to sound like a smart *** or saying you are stupid or anything. but i had that code before and when i looked it up ive found where alot of people change the wrong sensor(they would change or check that two wire sensor) butwhen realy its the one wire sensor. have you checked it or changed it. gl on fixing it.

jlicrx

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by mra4886 &raquo;</TD></TR><TR><TD CLASS="quote">im not trying to sound like a smart *** or saying you are stupid or anything. but i had that code before and when i looked it up ive found where alot of people change the wrong sensor(they would change or check that two wire sensor) butwhen realy its the one wire sensor. have you checked it or changed it. gl on fixing it.</TD></TR></TABLE>sorry to disagree, but the one wire sensor on the end of the head is for the temperature gauge - the 2-wire is the temp sensor for the ECU






Modified by jlicrx at 10:37 AM 5/10/2008

JOE BD-0

Maybe I missed something by not reading the WHOLE thread, but I'm wondering if the OP reset the ecu after replacing the sensor? ...just an idea, from someone with limited knowledge (me)......good luck....

DustinRose

thanks jili
i am going to run all those tests tomorrow

i also talked to my dad about burping. i hadn't thought of that
i just put this motor in....so, it has new coolant, and i really bled the block out good when i had the engine out

thanks!

ktp1598

Are you using sealant on the threads? That can cause a problem with some senders.

DustinRose

neither ecu can produce 5V through the ECT
my hondata worked great in my friends car, but not in mine
there is something wrong with my harness elsewhere
in some of the other wires....its bizarre though because erverything else on the harness works great

there is .06V traveling through my ECT circuit

mra4886

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by jlicrx &raquo;</TD></TR><TR><TD CLASS="quote">sorry to disagree, but the one wire sensor on the end of the head is for the temperature gauge - the 2-wire is the temp sensor for the ECU


Modified by jlicrx at 10:37 AM 5/10/2008</TD></TR></TABLE>
not to disagree but i had that code and i searched it up and code six was to change the one wire sensor. i changed it off a spare head and now no code for six. i know if code six is beeing thrown you temp gauge on the cluster still reads the temp right. but your ecu will not this causing the code. just my experience and the turn out that i read up on and fixed my problem.

o.p. maybe just check you wire you have running to the one wire temp sensor. maybe the problem is in that one wire somewhere. gl.

DustinRose

UPDATE:

today i went out there and plugged my ECU in, and unplugged every single sensor minus the ECT
.....and IT WOKRED!!!
the ECT worked and read 55 degrees on my laptop
i then proceeded to plug in the IAT, at which point i got my ECT code 6 back again
but for the first time, code 6 was gone
mr. RyWire suggested grounding to the chassic with the ECT, that's next

does the sequence matter? does it matter which grounds hit the SG2 first&gt;
like:
ECT-----IAT-----TPS------ and so on
i think my SG2 grounds go like this:
IAT------ECT-------TPS-------O2-----

mra4886

one thing to try real quick is to change out the one wire sensor. i had code six and found it to be the one wire sensor.

just like when you get code43 its says your fuel pump. but most of the time its an o2 sensor bad. but gl to ya.

bagpipe goatee

The ground shouldn't matter unless it's bad, which is a possibility. Maybe it happened when flexing the harness, plugging it in and stuff.

Another thing possible, unplug your harness from the ecu and the sensors, check for continuity between the two sensor signal wires. A little bit could have pushed through and they could be shorting together. That way, with two sensors plugged in, it would be about half the resistance, possibly outside of the sensor's range.

DustinRose

well, yesterday was an emotional rollercoaster,
when i came home, i unplugged everything except for the ect
the computer was hooked up to the ECT only
and the ECT code was gone! but now i have IAT, and VTS
no big deal
i ground IAT and the engine, it started working, i plug in the VTS, its cool, while sitting, not running, i have no check codes
i ground the TPS to the engine with the IAT, aswell as the O2 signal wire's ground (which didnt make a difference)
i plug in everything else, COOL no codes, and Hondata reads correct temps on the IAT and ECT, i start the car...
it runs perfectly again, YAYYYYYY
i was so happy
i let it run for twenty minutes
ECT code comes back (ECT was wired to d13 and d22 sg2)
so i tee the sg2 wire from the ect to and engine ground, and the code goes away, i let it keep running
i double check the changes i had made, and pull the harness off to make the changes permanent
i solder and shrink the IAT, TPS, O2, and ECT grounds to the thermo grounds
re-install the harness
and the ECT code is back again
i was heart broken
i messed with it for hours, grounding in different places, and beefing up my battery grounds, and engine grounds (to chassis)
and cannot make ECT go away again.
tonight, i am sitting out here, trying the same thing i did yesterday, and i cannot get my ECT sensor to work
i tested the sensor and it reads 320 ohms (which from the helms spec, that means it a good sensor, and it worked great yesterday)
again, i am confused, baffled, and about to set the car on fire

also, now the tac no longer works, and the check engine light in the dash will no longer illuminate

this car is having some serious issues

grog

damn i would have broken down and bought a rywire or chase bays harness at that point.

good luck

DustinRose

third time's a charm!

today i built a third harness, went to the junk yard, got all new connectors
bought all brand new wire
heat shrink
everything
and made another harness completely
it works great, car runs great

i think the thermo grounds werent up to par before
i made new ones this time with 4 14 gauge wires

im in business now

xsirenax

one correction i wanted to make

having no ground isnt a short

it means your circuit is open

but its not a short

DustinRose

excellent work correction man

xsirenax

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

i just hope it sort of helps....maybe its an open

or maybe its a short