Hello there,
I have a 1995 del sol automatic Si
it has had the engine replaced with a JDM D16Z6 VTEC as listed per the receipt for the swap (the same thing that came out of it other than original was USDM)
ECU is a P28-A52 ECU's showing it's a 92-95 civic Si/EX and a USA Automatic code (A52) so I'm assuming its the cars original
It has K&N cold air intake
It has DC sports 4-2-1 Headers
It has a flow master exhaust

What was done with the engine (as per receipt)
New Timing belt component kit
New Water pump (unknown about gasket as it is not listed)
New Valve cover gasket set
New Thermostat and gasket

What I've Done
Changed IACV with a cleaned and tested used one
Changed FITV with a cleaned and tested used one (the one I put on was considerably different than the one I took out so it seemed that one was already a replacement as there was an "extension" in the feed hose) which has fixed some of my cold idle issues it is still idling too low in one specific range on the gauge
I have bled the cooling system

All Issues were unknown when I purchased the car so IDK when they started alls I can tell you is what I know so far

Now I'm confused about something.. on page 11-102 of the factory FSM (I'm sorry IDK how to post pics from a PDF {I know how to use the forums just not a PDF}) it says to set the idle to 420 with the IACV disconnected, then once the ecu has been reset and remapped its just supposed to idle at 700? is that something mechanical (maybe the reason as to why the throttle stop screw is NOT supposed to be touched?) or is it controlled by the ECU? The FSM doesn't specify. If I set the idle to 420 as stated, it idles around 600 not the 700 specified, although I'm using the in dash tach so I don't know the accuracy, then when a load is applied either electrical or physical {automatic in gear} it drops rather than raising, can anyone confirm that it IS in fact supposed to raise the rpm as the FSM states?

I have it set to 900 ish and with electrical load I can see a drop to ~700 and in gear its a solid 600-650. With just the load from being in gear it sits at a perfect 750!
But! When I have it set to the manuals specified 420, the engine will sit at a solid 6-650 with and without additional load! (electrical and in gear!) It will hold itself at 6-650 as if thats where its programmed to be.

And could this be related to a cold->warm idle issue?
Thanks!

 

Get an external tach and adjust the idle properly.

 

Just adjusted my idle this last weekend.. about the rpm supposed to pick up with additional electrical load, yes it IS supposed to increase rpms with load. they want you to set the base idle without the IACV (which adjusts additional air intake via the ECU, based on operating temperature/load at idle), then clear the ecu so any trouble codes thrown during the procedure are purged, and any NEW codes that might indicate a problem will present themselves appropriately. and yes, after you plug the IACV back in and restart your car, it SHOULD idle at 700 +/- 50 rpm, and should increase the rpm per the fsm specs when extra load is put on the electrical system. All that being said, I would first test with another known working IACV, failing that, I would suspect the ELD (Electronic Load Detector) and would troubleshoot that. However, the FIRST thing you should do is check all your ground straps for proper contact, and then move onto the previously mentioned components, it may save you time, or not...but it's a valid standard thing to check that a lot of people simply overlook. and yes, your idle may drop slightly when put into gear, at that point the IACV will compensate the idle according to signals from the ecu.

As for your throttle stop screw...the factory is right, leave it alone. RonJ is absolutely right, a proper tach hooked up to the tach lead is essential. Anyone else with better/clearer/sensible help please feel free to chime in/correct me/show me up like the turkey I am. *wink*

 

Thanks! Yes I was gonna check the ground connections first thing when I get a chance, I'll work on getting an external tach.
I have no access to a known working IACV as I know no one with a civic and I do not have the funds to get a brand new one

Is there any way to test the current one?

Also the only code I will get is 43 but it'll only go if I drive the car while its still cold, really weird. I'm gonna be trouble shooting that tomorrow as per the fsm

 

If you thoroughly cleaned the IACV, then you have a low idle problem most likely because you have not properly adjusted the idle speed following the service manual procedure that REQUIRES use of an accurate tach to measure engine rpms. This is the first step. If you can't do it, take your car to a competent mechanic.

Also, have you replaced the PCV valve? It's a $3 part.

 

It's probably a bad O2 sensor, but do troubleshoot. In the meantime, for the heck of it, you could try unplugging the O2 sensor and take the car on a drive to see if the idle problem is eliminated.

 

Alright I'll try that, is it weird that there seems to be somie sort of "converter" connected to the o2 sensor? Is like a gray block that seems to change it from the factory plug to some other plug, I'll get pictures later/tomorrow, is it normal that an o2 sensor would only not work when cold?

The FSM also says the code 43 is related to the fuel supply system, now my fuel pump has be doing something weird, rather than being on for just two seconds and that's it it'll sit there and pulse for an unknown length of time even after I've pulled the key out... it'll turn on at regular intervals of five seconds for about two seconds each time and I know it will do it for atleast five minutes after I've shut it off and pulled the key out. The car does have an aftermarket alarm which has the fuse pulled ATM and I'm thinking it may be causing some of my electrical issues

 

Post pictures. Always post pictures.

The O2 sensor is not required when the engine is cold, so it really doesn't matter if it works or not under those conditions. Nonetheless, the ECU monitors the O2 sensor for problems anyway, even when the engine is cold.

The O2 sensor is part of the fuel system in the sense that it is used by the ECU to control the fuel trim. A faulty O2 sensor is the most common cause of code 43, when there are no performance problems when driving with the engine warmed up.

 

Okay, I will get pictures as soon as I can I don't get out of work till 7 so it'll probably have to wait until tomorrow

 

FYI - A forum has no time limits. You can reply in 2020, if you wish.

 

Sorry I just wanted to let you know..

 

Alright so after much trouble shooting I have come to the strong conclusion that my ecu is at fault, I pulled the 3p connector from the ELD and tested blk/yel and blk and got .800v I'm not sure what its supposed to be the FSM just states "battery voltage" I then checked the grn/red to blk and got .135v and its supposed to be 4.6-5v the FSM then states to swap the ecu with a known working one and seeing as I don't have one to do so I'm assuming that the ECU is at fault, does anyone have any idea what voltage the FSM means by "battery voltage" is it supposed to be ~12v? or just voltage? checking blk/yel to body ground or even straight to battery negative still gave this same .800v is it supposed to be more than that? indicating theres something else going on here?
the car does have an aftermarket alarm/remote starter in it so this could possibly creating interference as its not on (fuse is pulled) so maybe its acting like a switch or something, any ideas anyone? as I don't have access to an ecu to make sure that isn't the culprit

 

Battery voltage is exactly what the name implies - the voltage reading across the two battery posts (with the key off).

You have no code 20, but you do have code 43, so you decide to test voltage at the ELD wires. I am unsure about the logic here and whether your voltage tests were even done correctly. You sir, are all over the map. I don't think there's any possible way to focus you.

 

I tested the eld seeing as whenever there is electrical load the idle dies out, I also checked the map sensor IAT coolant temp made sure the throttle body was clean and clear in every port and evidently the eld test was useless as the charging system fuse had blown while I did the test so the figures are irrelevant. Considering I will only get the code 43 while the car is cold I saw it as irrelevant to the idle as why wouldn't it show up any other time, I'll check the o2 sensor next when I redo the eld test

 

If you think you really have a voltage problem, then don't test the ELD. Test the alternator in the car. This is done by measuring battery voltage of the system (across the battery posts) under no load versus high load conditions.

Why do you ignore the obvious?

Code 43 with a cold or warm engine could indicate an O2 sensor issue.

And still no attempt to acquire a proper tach and adjust the idle speed.

And no pictures of the O2 sensor "converter".

Instead, you make random stabs at the ECU and ELD.

It's baffling.

 

Ok so yes I have determined the O2 sensor is bad after doing the FSM's tests BUT I have more info.




This is the OEM plug (grey plug on left) attached to the adapter (the black box)





This black box converts the OEM plug to a plug that this O2 sensor uses which you can partially see here


Also! I tested the alternator and ELD again, the alternator I believe put out 13.01 v at idle no load and obviously went down from there bottoming out at 12.20 after adding load but! the idle does not increase as more load is added, also this 13.01 was achieved at the idle of 8-900 rpm as thats where I have it set so it doesn't stall at stops.

When I would add load it would drop about .20 volts each time dropping to its lowest at 12.21v (all tested across the battery) that was with lights heater and wipers on

but as this was all at idle I know that it doesn't give perfect results

After testing the ELD I got the figures off of A26 and D10 as the FSM states

I got 2.22 volts average on the first (headlight switch first position {V2.5-3.5v} is the FSM values)
Second was 1.22 (headlight switch second position {1.5-2.5v} is the FSM's Values)

so from my understanding this would indicate a bad ELD as thats what the FSM states it would be but could a tiring alternator also cause lower voltages coming off the ELD? the Idle sat at 750 for the first test and 700 for the second so I don't believe its the idle as it was right where it should be anyways

I will be getting an o2 sensor soon but I'm curious if this would also indicate a bad alternator/ELD

plus





Are these wires supposed to be grounded here? I've tried looking at schematics and I can't figure it out, the black/red wire feeds the ELD and the car does have an aftermarket alarm so could these be tapped in/spliced wrong and is causing voltage to be lost somewhere between the ELD and ECU causing the massive load drops (from 900 rpm to 700)

Any Ideas?

 

Also, I've read that the o2 sensors with holes on the sides are better than the one hole in the top but how about bosch? bosch uses like 13 holes on the top and none on the sides and considering its bosch would this be a good replacement? as id rather go to auto zone and get it instantly if its gonna be the same price as online (50$) reference

Bosch/Oxygen Sensor 13007 at AutoZone.com

 

Those grounds look fine. As for your O2 sensor, here, first post, look for section discussing O2 sensors, deschlong has good info there.

Regarding your alternator vs. ELD...it would be an easy move to pull your alternator and get it tested (many places do this free, or for a minimal fee..check around, OR if you're very comfortable in your own work, test it yourself per the FSM directions), RonJ generally gives good advice regarding these vehicles, and he DID point to the Alternator being suspect. You might even get your alt tested at a few various places if you dont have a trusted mechanic/tester to see if your results vary ( Ive had VatoZone tell me an alt was good and Napa test it out as bad before...turns out Napa was correct, I had my OEM alt rebuilt, all was good afterwards), if it tests bad consistently then rebuild or replace at your discretion. If it tests good and the output is still within spec, THEN move onto the other electrical components, as they will likely be the more expensive and time consuming areas to diagnose/repair.

 

Based on results of your alternator test, the alternator is toast. I'm not sure how you came to the conclusion that the ELD is bad.

Your ECU expects a 4-wire O2 sensor, so it seems to me that is what you should install and that the "converter" should be discarded.

The ELD does not normally have a Blk/Red ground wire that grounds at G101. To what ELD wire is the Blk/Red wire spliced? The stock ELD has a Blk ground wire that should ground at G201/G401.

 

Alright, I'll work towards getting the alternator out and tested, I followed the tests on section 11 page 78 to test the ELD and the ELD was out of spec per those tests. I'm gonna start with the alternator though as that may be making the ELD show up out of spec so I'll start there and continue updating, Thanks for all your help!


The Wires were not actually spliced I just searched through the FSM and found the connection is G101 and the wires are not spliced they just looked it as someone had cut open the harness wrap and re-wrapped them

 

You tested the alternator and its output was inadequate (peak voltage 13V).

 

The ELD almost never fails but, when it does, code 20 is typically thrown.

I can't evaluate your ELD test results because I don't know exactly what you did. But again, I haven't read anything you posted to make me suspect an ELD issue.

 

Oh okay I didn't know whether that was an adequate enough test so I was going to bring it to auto zone, I'll just replace it then, Thanks!

I tested the eld output at the ECU and its out of spec but I have a feeling its related to the alternator as I get no code about it, I'll retest it once I get a new alternator in there just to be sure but I believe thats what it is too as it looks original (with 169k on it its about time for it to go)

Thanks for all your help!