ELD issues after swap

MotorMo

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I swapped a USDM B18C1 into a EJ6 (97 Civic DX Hatch). After wards I noticed some charging issues that involved head lights and dash lights dimming. No codes, no other symptoms other than 'knowing' my car and the feeling that it was starving for amps.
I swapped my Civic ELD for the GSR ELD ( all the while swapping two wires so they are in the correct location in the different ELD) and the symptom went away. The car ran like a champ. I was stoked and thought the original ELD the culprit.
Several months later, I found a code for the ELD stored in the ECU. I'm guessing it is not considered an "emission's" related code as my check engine light never turned on. Upon further inspection I realized a wire had pulled out of its crimp on the spade. After I repaired the wire, I am right back where I started with the same issues of dimming lights and voltage drops.
I've done a far amount of home work, and while watching the inputs and out puts of my ECU and my cars reaction, every thing looks like it is operating as designed. Confirmed the ECU's voltage vs battery voltage vs alternator voltage all matches. When the alternator goes to the higher setting of 14.4 volts, Everything works great, but when it dips down into the gas saving mode of the 12.2 volt charge, things slowly get dimmer and dimmer. Never good while driving curvy back roads at night.
So far I have replaced my alternator ( with a OEM ), cleaned my 'resistor connectors' under the intake manifold ( used for the ELD wiring ), cleaned the basic, larger grounds ( including G101), and tested my battery.
The most voltage drop measured was @ .3 volt drop.
I am now thinking there may be more of a load with the different engine , and this may be a natural reaction with the cars electrical system. But this theory and the laws of electricity don't jive. It should 'in theory" all be the same, and should react no differently between the two engines.
Thought about simply disconnecting the ELD, having a code stored, until smog time comes up. But if there is some thing not right some where, I would rater fix it the right way, once.
For those of you who got to the bottom of this novel, thanks, and I welcome any input, past experiences, bypasses, or what not. Cheers

PS- All "stock", P72 ECU
 

MotorMo

Respected
Thank you for your reply.
Yes, the charging light acts as designed at the lamp check ( key on engine off ), and turns it self off after the engine has been started.
After the wire was reconnected, the code #P1298 is no longer present, but the symptom's returned.
-- "The ELD is a gas saving device that works by telling the ECU to turn off the alternator under low electrical load conditions" -- This was my understanding as well. And the ELD appears to be functioning as designed, I believe- I have followed the diagnostic tree per Honda, for the P1298 code, when every thing was connected right ( with no code present ), and all things checked with in spec. But the symptom's are as if the ELD isn't seeing a draw, or drain. I would think that the ELD would compensate for excessive resistance on the ground side of drivers and what not due to its design. Which leads me to ideas of maybe a voltage reference signal wire isn't wired in somewhere to a fuse block/multiplexing unit, or perhaps my fuel pump is showing its age causing more of a drain and less fuel.
I have no amps, or big speakers in my car- only an after market stereo deck, that's wired to the insisting harness.
Things that make me go hummm...
 


MotorMo

Respected
Thanks for your time. I have removed, inspected, and re-tensioned the drive belt. I've confirmed the brackets are all secure. And also have ensured battery voltage at the alternator. I've also ensured that the ECU is reading the correct battery voltage through a scan tool. I'm getting close to thinking the ECU may have a faulty driver, or problems with an internal ground. Or if my fuse box with the ELD in it is brunt/corroded. Also last time I opened up the fuse box I saw/smelt no damage.
 

MotorMo

Respected
Thank you again for your time.
The alternator cable is clean end to end. The connections in the fuse box and on the alternator have both been freshly cleaned and re-torqued. I have not yet ran a "bypass cable" from alternator to fuse box, to ensure that the original cable isn't leaking any voltage-
Ground location #G2 has also been cleaned and re-torqued. I even sand papered/scraped the surface of the ground wire eyelets and the mating surface on the upper radiator core support where G2 gets bolted down.
The alternator is a quality unit just bought last week- Its a Denso remanufactured from a reputable distributor- so I can 'swap it out' for another one....But as I just replaced the original OEM alternator out for the rebuilt OEM unit and got the same results, I'm suspecting the alternator isn't the culprit. At first I thought maybe the internal regulator was having intermitted issues, but I couldn't get them to fail any tests, including the last test of replacement haha.
I don't have a back up ECU, but it looks like I may be on the look out for one momentarily. Just so rare that this generation of ECU would fail as such. Wouldn't be the first time- many years ago, I had a faulty Integra ECU that lost control of the IAC control ( ground side )- I wouldn't have believed it true if I wasn't the one doing the repair.
Thanks for your time boofoo. Time is valuable, I appreciate it.
 


MotorMo

Respected
You have been most helpful. Sticking to the basics is the best advice you can give. Again thanks for the time.
I will keep this thread updated as time goes along.
 

XpL0d3r

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I swapped a USDM B18C1 into a EJ6 (97 Civic DX Hatch). After wards I noticed some charging issues that involved head lights and dash lights dimming. No codes, no other symptoms other than 'knowing' my car and the feeling that it was starving for amps.
I swapped my Civic ELD for the GSR ELD ( all the while swapping two wires so they are in the correct location in the different ELD) and the symptom went away. The car ran like a champ. I was stoked and thought the original ELD the culprit.
Several months later, I found a code for the ELD stored in the ECU. I'm guessing it is not considered an "emission's" related code as my check engine light never turned on. Upon further inspection I realized a wire had pulled out of its crimp on the spade. After I repaired the wire, I am right back where I started with the same issues of dimming lights and voltage drops.
Did you swap the ELD itself or the entire fuse box?

Just out of curiosity, you mentioned that you found the stored ELD code... at that point was the car running fine? What happens if you were to re-disconnect the wire that pulled out of its crimp on the spade? If repairing that wire suddenly caused the issues, but the car was running fine before (minus the stored code), I would think the issue relates to that repaired wire.

I had some ELD issues in the past after I had my car tuned for boost. Do you have aftermarket stuff hooked up to your battery directly? Such as an amp, etc? Anything hooked up directly to the battery will not be detected by the ELD, so the ELD won't know to increase the alternators input.
 

MotorMo

Respected
Hey XpL0d3r, Thanks for your input- I previously swapped out only the ELD unit it self. The symptom was present before I did this- With the wire pulled out, it gave me a steady charge of 14.4 volts, so my symptom either was no longer present at that time, or the extra charge covered up the issues.
I also don't have anything aftermarket wired yet to the car. I installed factory wiring and components to convert manual locks, windows, and mirror control for manual to power- But these were all factory parts directly installed to the existing connectors. The symptoms do not appear to be related to the use of these installs.
Thanks boofoo, I will also follow this diagnostic tree and return with the results after I spend some more time on it this weekend. I also have heard of a TSB where Honda calls for dielectric grease in the alternator connector- so I will do this as well.
I have currently disconnected the ELD input wire at the ECU so that I can drive it without having issues for the past couple days. SO far this works well for the symptoms, but it does cause an ELD code to be stored.
 

MotorMo

Respected
Just wanted to respond- I didn't find the time to dig deep last weekend, and next weekend I'm on vacation, so it looks like it'll a couple of weeks until I find the time I need. I will keep y'all updated. Thanks again for your replies.
 

MotorMo

Respected
Found the time needed to run some tests- boofoo I followed the diagnostic tree you gave me, thank you. It lead to some interesting results.
IMG_2652.JPG I found 5.6 volts... does this mean there is a 5 + voltage drop some where on that circuit?


Image-1.jpg Following further down the diag tree- There was no continuity found between the ECU connect and battery / chassis ground. Well, basically no continuity (9,800 ohms).

The next and final step is to replace the ECU-- I have done this, with no change.

It seems the left over voltage in the first test is where I need to look. I'm open to any guidance as I try and sort this out. Thanks in advance.
 

MotorMo

Respected
You are the man, thank you for all your help.
Here are the results:
Ohm test at ECU Connector "A" pin # 19 (wht/grn) to battery ground with alt 4 pin connector plugged in=
= 8,000 ohms
Ohm test at ECU Connector"A" pin # 19 (wht/grn) to battery ground with alt 4 pin connector unplugged=
="open loop"= zero continuity.
 

MotorMo

Respected
Resistance between the alt control wire (wht/grn) at the alt connector , unplugged, to chassis ground/battery ground is 5M ohms...
 

MotorMo

Respected
Thank you- This test was done at the alternator 4 pin connector, with the ECU connector A plugged in. Sorry for the miscommunication.
Previous tests I have been testing the ALT C circuit, as pin # 19 (wht/grn) is the alt control wire.
Previously testing last night showed KOEO , ALT 4 pin connector unplugged at the alternator and testing pin #19 at ECU connector "A" showed no continuity, aka "Open Loop".
Which was different than 8,000 ohms when the 4 pin connector is plugged in.

You are the man, thank you for all your help.
Here are the results:
Ohm test at ECU Connector "A" pin # 19 (wht/grn) to battery ground with alt 4 pin connector plugged in=
= 8,000 ohms
Ohm test at ECU Connector"A" pin # 19 (wht/grn) to battery ground with alt 4 pin connector unplugged=
="open loop"= zero continuity.
 

MotorMo

Respected
So to confirm, you want me to unplug the alternator connector (4 pin), and measure resistance at the alt control pin at the alternator,(not the wiring harness), to ground, yes? Thanks
 

MotorMo

Respected
OK- That test yielded 9,100 ohms from the back of the alternator housing to the battery ground. That is with the 4 pin alt connector unplugged and testing the pin where the wht/grn wire goes if the alternator connector was plugged in.
 

MotorMo

Respected
Something changed because it looks like I lost 1000 ohms somewhere-- the last test should have shown less resistance not more---But anyways, I cut a alternator connector to use it as a piggy back tester- I tested all pins at alternator with this method- here are the results if it helps at all-
wht/grn= 9100 ohm to ground
wht/red= Open loop ( no continuity) to ground
blk/yel=2500 ohms to ground
wht/blu= 3500 ohms to ground
Side note--- I just got finished making a new wiring harness from another 97 Civic EX in case something was goofy in my exsisting harness- but there was no change.
Here is the existing thread on another sight if that helps as well. The wiring harness (2nd one) is on the last page.
https://www.ek9.org/index.php?threads/motormos-whip.72379/
Hope its ok to post that link in this site, if not I'm sure someone will let me know.
 

civteck

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Registered VIP
Just out of curiosity check the harness ground at the t-stat is clean then entice me and put a jumper lead from neg side batt to t-stat ground and retest.. i added a direct 8ga ground from batt to t-stat housing and tuner was impressed, i also have a braided ground from frame to trans no pic but did the same thing on my SS and made a diff. Boofoo narrowed it down im just trying to steal his thunder.. ;)

Sent from my boujea ass phone
 

MotorMo

Respected
Thank civteck- I does feel like bad grounds, it is that kind of symptom. The G101 is super clean and tight, but extra grounds aren't a bad idea.
I did the same resistance test on a 97 Civic EX (the alternator is still bolted up, so I back probed the altC pin on the back of it, and measured resistance to "engine ground")--- My results were ~12K ohms.
Mixed results. I get it that we are testing the internal circuit of the alternator- I recently replaced the alternator with the same results. Bench testing another Integra alternator I found it also has around 9K ohms with the same test....
Heres something else -- it does feel like a bad ground- the check engine light it on, due to me not yet hooking up the secondary O2 sensor, anyways, it flickers when I turn on electrical loads- blinkers make it flicker at the rhythm, and so on.
Thanks for every ones time and input. I put a lot of effort in this car and its kicking my ass.
 

MotorMo

Respected
I will perform theses, and report back my findings during/ after work today. Thank you so much.
I swapped the ELD from a 99 Integra GSR, because I thought my ELD may be the issue. The Civic VS Integra ELD's are wired different, But all that was needed was to swap two wires in the correct location. I didn't realize that wires are in different location on the ELD 3 wire connector at first- so the symptom my have be masked (less noticeable) by the car running full charge all the time (14.4 volts) as I later realized I had a code for the ELD, which brought me to finding the wiring schematics were different.
With the Grn/Red wire (ELD) disconnected the headlamps and all burn bright as they should, so I drove it this way for the last half of last year. I don't recall the Check engine light flickering as much, if at all, but it was also stuck at 14.4 volts all day.
I recently installed an Optima battery so I knew I had a good compositor (battery).

I added a ground wire from G101 to battery ground this morning- I also will use my DVOM to monitor voltage as I drive to work today and will report back. Thank you for being in the trenches with me!
 

MotorMo

Respected
Humm- I just re-looked up the schematics, and the wiring does look the same between OBD2A, and OBD2B..., so I will look up some paperwork when I get home. Either way, I put the wires back into their factory location after swapping back the original Civic ELD unit, cause the symptom ended up being the same. Never had any codes for the ELD afterwards- Until I unplugged it last year for the races.

The extra ground wire that I hooked up to ground # 101 to battery ground changed nothing.

So here is a brain twister- driving to work (10 miles) I monitored the battery voltage through the under dash fuse panel ( driver side )- it never got below 12.7 volts, no matter what. I found that during the 'low charge' times is when the lights got dim (12.7 volts). When it went full charge (14.4 volts) everything stayed bright, and even with every load on, it performed very well.
Another brain twister- I work at a independent Honda repair shop- a 99 CRV came in today, check engine light on, and I noticed that the check engine light also flickered at the rhythm of the blinker when turned on.......Again later today, I worked on a 97 Accord, with the check engine light on, and it did the exact same thing.
Now I'm wondering how 'normal' is this--- or how common of a problem this is and no one has talked up much about it.
It looks like I wont have time today to preform the diag trees for the ELD codes you have presented until later due to a lack of time.
 

MotorMo

Respected
Alright- so I have no idea where I got this miss information on the location of the wires in the ELD connector being different from Integra to Civic. So, moving on from that, Further testing has shown that my ELD appears to be working as designed at this time. I guess the reality is when you do an engine swap, and the focus is power not fuel economy. Honda's ELD system was mainly designated for fuel economy. Most stock 'eco boxes' are fine with these parameters. But I wasn't ok with how it affected my ride. So I felt the need to do something,.
Over recent weeks I've read about so many complaints about the ELD system- flickering of lights, not to mention the nightmares of after market stereos being installed- I decided to take the ELD out of the picture entirely. I played with this idea on my 97 Civic that is stock- I did before and after testing and found by cutting the ELD input wire to the ECU stopped the ELD function This allowed the car to charge like any other car on the road. The alternator still was in control with the internal voltage regulator, running 20%-60% . No check engine light either which is nice, altho there is a code stored. Further studies showed me that Canadian Honda's dont even have that system installed. They're alternator connector is a 3 wire, not a 4 wire. And the wiring schematics from Honda prove this as well.
Soooo...snip! The car now runs like a champ, no voltage drop, no charging issues at all. Thank you to all who helped me on this path of education.
 


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