mylildelsol

I swapped out my d15 for a d16y8 in my 93 del sol s, I am currently running the motor on the factory d15b7 ecu. My question is, would that cause my motor to run lean or is the another cause, it runs great and drives great, with no check engine light. Any ideas or anyone that has been here b4? Thanks guys!

B serious

iTrader: (1)

What makes you think its running lean?

mylildelsol

well i pulled the plugs and there pure white... i will b honest i have not done anything yet to try and cure the problem, just wondering if this ecu is the issue. i know a vacum leak could cause this or clogged fuel filter but just not sure about the ecu is all, i dont like just throwing money at a problem.

Former User

You are running the engine with the wrong ECU. Install the correct ECU and go from there.

mylildelsol

Well I know its not the correct ecu, but wouldn't the o2 sensors pick up that it's lean and make it a ill more rich? I am a mechanic and I understand that ecu's have a limit on there parameters so it might b at its limit. Just wondering if anyone has done this swap and had the same problem?

B serious

iTrader: (1)

It's probably not running any leaner or richer than it needs to. A white color on the plugs is pretty normal for these types of vehicles.

TomCat39

If you look at the main lobe specs for the D15B7 and the D16Y8 the Y8 has slightly smaller lobes on the main lobes for the intake. So the valves won't stay open quite as long or open quite as much. The P06 ECU in stock condition will never operate the head on the upper (vtec) lobe or surpass the 6500 rpm limit. And your power is plateauing at around 4800-5200 rpm and not going higher for the rest of the power curve. Due to the lower lobe height and shorter open duration, I would think you would be topping out closer to 4800 than the 5200 of the typical B7.

The O2 sensor is making up for it so you are getting a nice clean burn. If it's really really white, it might be running a little too hot. What spark plugs are you running?

The D15B7 (by ECU) should be running NGK - ZFR5F-11 v-power plugs for best performance and temperature range.

mylildelsol

Ok now that makes sense, I knew there was some differences in peak power just wasn't 100% sure what. I do plan on getting a different ecu eventually just haven't got there yet. One other thing will the d16z6 ecu b what I want considering that I want to keep it obd1? The plug number is, pkj16cr-l11 it's a denso double platinum plug. Thanks for the great input by the way!

tony_2018

Your concern was not about peak power, it was about running lean. White plugs are normal for these engines.

Former User

For a D16Y8?

Matt_EH3

The O2 sensor will give feedback to the ECU only in closed loop. When it goes into open loop, it uses maps that were meant to work with the d15b7 (it then stops caring about O2 sensor readings).

You need to match your ECU to the engine.

TomCat39

Tan is normal for the D15B7 not pure white. A light tan from my experience. Really white would suggest it is running a little hot for the spark plug.

I still suggest using the normal v-power plug I posted and check in in a couple weeks of driving to see if it's closer to the proper temp range.

Open loop is only running for about 5 minutes as the engine warms up and the heated O2 sensor heats itself up to proper temps. Also you have it backwards, he's using D15B7 maps on a D16Y8 motor, so even in open loop it will probably be a bit leaner than the Y8 maps by a hair due to the slightly smaller CC of the engine being expected. No cylinder wash to be expected.

What the OP hasn't verified is if by white he means stark white or a really light tan. Really light tan is fine but a bright stark white could mean improper heat range spark plug. Thus my suggestion of trying the stock plug for the D15B7 and see if it gives better color.

mylildelsol

i actualy did say pure white, i do know the dif as i am a auto tech... i will try and c about the plugs but i forgot to add, i took out the champian plugs and they were white, and added the denso plugs . i need to pull them and c if it is the same as they have been in there for about a week or so, i will try and get to it today if i get a free min. thanks!

Former User

Partially correct. Basically, the ECU only runs in closed loop when the engine is fully warmed up and the car is idling, cruising at constant speed, or very slowly accelerating. When the warmed engine is rapidly accelerating or decelerating, the ECU goes into open loop.

Former User

I completely agree.

The OP acknowledges an ECU/engine mismatch, yet seeks other explanations. Installing the correct ECU should be the first order of business. I also think the ECU/engine mismatch may not allow for full O2 sensor compensation in closed loop due to fuel/ignition timing differences and possibly other differences.

mylildelsol

ok i just pulled the plugs and they r a nice tan color! it turns out that the champ plugs that were in the car were the problem. i do plan on getting the correct ecu soon anyway as i have no v-tec at this time and i am sure i an not gaining anything from the swap at this point or at least not much. the p28 would b the ecu i need correct?

Former User

NGK plugs are clearly the best for Civics. But what specific Champion plugs did you install?

I believe you would need an OBD1 Civic ECU with a Y8 chip if you want the engine to run properly.

mylildelsol

i no longer have the champ plugs i took them out about a week ago now i am running denso double plaitnum plugs. i do agree i need to go to ngk plugs, but all we had at the time was denso plugs and there a heck of a lot better than champ plugs! lol...

isnt the p28 a obd1 ecu? the d16z6 is an obd1 motor and i thought it ran on a p28 ecu. correct me if im wrong.

Former User

Let me explain where I am going with this. If the Champion plugs were the correct ones for the engine, then I don't think they would cause a lean condition. Maybe you installed the wrong type of Champion plug?

That's correct, but the Y8 chip also could be placed in other OBD1 Civic ECUs, such as P05 or P06.

TomCat39

I believe that is correct but I don't think the Z6 and Y8 have the same parameters so that's why Ron talked about a chipped OBD1 ecu. You can chip that P06 and wire it for V-tec and then with a good tune you'd be all set.

Thanks for the additional info on open/closed loop Ron.

And sorry missed the "pure" white snippet in our original post mylildelsol.

Overall though, the P06 stock is about the best OBD1 non vtec ecu for the D16Y8 motor. It can't possibly pump too much fuel, just emissions might be a problem.

The lobes on the intake are very close to the same. The displacement difference is very minimal. I firmly believe you won't hurt that motor with the P06 ecu. Just like I was told I could get away with putting the Y8 head on my B7 block without any issues on my stock DX (Canadian CX). I might loose just a smidgeon of power but no harm will be done to the motor while running the stock P06 ecu.

mylildelsol

i actually didnt put the champ plugs in the motor... they were in it when i bought the motor. long story short the d15 blow up one day and i had the d16 setting there waiting for a nice freshing b4 i put it in the car, but the d15 had other plans... i was forced to just drop it in after work one night.
and for the ecu, i understand what ur saying now. thanks for all the help guys!

mylildelsol

ok great, i will def look into that more. u have been a big help and thanks for all the good info! thi is my dd and i am not trying to build a race car just a good rounded car is all, as for emissions i am not worried about all that as i am from ny and anything 95 and older dose not get plugged in for nysi! yay! plus it just so happens i do the inspection.

TomCat39

Hey Ron, I'm hoping you are still monitoring this thread. You talked about moving the Y8 chip over to an OBD1 ecu (my god that looks like a lot of work just asking for trouble).

Which one of the 3 large chips would need to be un-soldered and re-soldered in, 1, 2 or 3?



I still think addeding the zif socket into the empty location under #1 for adding a programmable chip might be an easier task than moving one of the hard mounted chips over.

Chip #1 numbers from the P06:




Chip #2 numbers




Chip #3 numbers




Does anyone by chance have the chip numbers from a D16Y8 ECU by chance? I'd like to see if I can look up the pin-outs of all the chips.

mylildelsol

Well from looking at that I'm thinking a programmable chip socket would b easier, but I would still b interested in seeing exactly what he meant.

TomCat39

Just wondering, the Denso plugs you put in, were they the match for a D16Y8/D15B7 motor (come to find out they take the same plugs)?

Being your Denso is the pretty tan color, I think the motor is burning about right even with the mismatched ECU.

By the way you don't need to worry about switching to the NGK if you got the right Denso plugs. Looks to be the same model plugs for both the Y8 and the B7 motors. Denso and NGK are the only two brands recommended in the FSM.

ZFR5F-11 (NGK)
KJ16CR-L11 (DENSO)

When you did the swap, did you keep the B7 Intake Manifold or did you only keep the fuel rail/injectors from the B7?