Civic D15Z1 problems

[Tippaleipa]

Hey all, desperate guy here looking some answers. I swapped a d15z1 engine to my civic eg8 which had d15b2 engine. Weird? No. Normal engine in that car here in Finland. So i got it running and it runs absolutely perfect but i got CEL and code 48 and horrible MPG. I found out that one wire was open and i fixed it and CEL was gone. Now only code i have is 20 which i believe to be ELD. So i went out for a drive without CEL and it was awful. Everytime i tried to accelerate it felt like it has no fuel coming to cylinder. So i stopped and unplugged the o2 sensor, CEL came on and car was running perfectly. No hesitation at all. So what can cause this? I have checked the wiring few times, i have no codes (only that ELD). Is my o2 broken? I also have very low idle when engine is in operating temperature.

[Stubby79]

Some searching came up with this...

https://honda-tech.com/forums/honda-...oblem-2202829/

Which refers to the same engine you're running.

Seems code 48 refers to air/fuel ratio sensors - MAFs, MAPs.

Also seems the D15Z1 runs a wide-band O2. The wrong signal might trip the code 48.

Ok, so you've swapped in a different engine. Did you swap ECUs? Did you swap it with the exhaust manifold, complete with O2?

If you're running the original ECU, you need to be running all the original sensors. If you've swapped in the D15Z1 ECU, you need to make sure you're running the sensors that it's expecting to work with.

My guess is that you're running a wide-band o2 sensor with a non-wide-band ECU or vice versa.

I don't know how much and what else you've swapped in. I've only done this on a Geo Metro...where you swap in the long block and NOT the intake or exhaust manifolds and all their sensors, because silly things - like you're having - happen if you do.

Tell us some more details of how much you swapped in and didn't swap in.

PS: your engine is idling stupid low because your ELD problem. Dunno if it was that same thread or another, but it seems they decide idle speed based on the electrical demands...no ELD response, no reason to turn up the idle to compensate for electrical load.

There is is:
https://www.honda-acura.net/forums/d...-detector.html

[Tippaleipa]

Okay, so i swapped the whole engine without exhaust manifold. And i did obd0 to obd1 and dpfi to mpfi swap also. I have the d15b2 exhaust manifold but i swapped the o2 wideband from d15z1 manifold. So i am using the d15z1 sensors with d15z1 ecu, p07. And the idle reacts to electrical load, when i turn on headlights it raises but always drops seconds later.

[Stubby79]

Does that include the engine wiring harness?

If everything matches - ECU to sensors - then you might want to check that you don't have any broken wires going to the relevant sensor(s), and that the sensor itself is OK. Are we sure the donor vehicle was working properly?

The other thing that comes to mind is that it's staying in lean-burn mode, meaning it isn't recognizing/reacting to throttle input. That would point to TPS or MAP sensor, depending on which sensors these engines run. Disconnecting the wide-band O2 probably forces it to stay out of lean burn.

Your idle fluctuating when you turn on a load might have nothing to do with it reacting to the input from the ELD...the ECU could very well be noticing the RPM drop from the load and reacting to that, instead. I would assume it would maintain a higher idle when you put an electrical load on, if it was reacting to the ELD like it should.

Ground wires are important, particularly to O2 and other sensors that operate on very low voltage changes...it's a common issue to miss attaching a ground wire during a swap...or for corrosion to crop up after time...always good to locate and clean/check all your ground connections for your particular engine, and to the chassis.

Oh, and check your charging voltage...like having bad grounds, if the system voltage is low, the sensors don't appreciate it, especially on older generation fuel-injected cars. It could all be related to the ELD. Fix what you know is wrong before you try fixing suspected issues.

[Tippaleipa]

Yes, i changed the d15z1 engine harness too and repinned shock tower connectors. I drove the donor vehicle about 60miles and it worked like it should, it doesn't have ELD either. hmm about that map sensor, d15z1 uses TB map sensor but it was connected before to firewall mounted map. Now it is connected to TB sensor.

I installed two new ground wires, one to gearbox and one to engine itself and measured ground from o2 and it was 0.0 ohms. I have also checked tps wiring and it is correct and no codes from tps.

And there is also that when its cold like 5 celcius, outside, car doesn't start on first try. cranks but no start. i tried prime the fuel pump few times but still, no start. Second crank and boom purrs like kitten.

[Stubby79]

Check your charging voltages, if you haven't already. Check at idle with no load. Check again with a big electrical load. Check both while revving it up to at least 2000rpm. Check right at the battery, check at the + of the battery and at the - from the engine block. If you're not 13V+ all the time, it's not compensating for electrical load.

It seems very odd to have a code for something that wasn't part of the original set up. Is there a way to add it? Of course, they might use the same code for other means of detecting electrical load/alternator response. Low idle might mean no charging, might throw a like code.

Is there a Throttle Position Sensor? They can assume/calculate throttle position based off the MAP sensor, but not having a TPS on a lean-burn engine seems...silly.

I'm new to lean-burn, but reportedly the Insight can be forced in to lean-burn by backing off the throttle just shy of going into regen, and then re-applied, thereafter it will be in lean burn mode...if you're driving it gently for MPGs, and haven't tried it, try driving it like you stole it, with the o2 sensor plugged in, and see if it stays perky.

The other thing that comes to mind is that one of your cylinders isn't firing - weak spark and/or too little fuel getting in - and so the o2 sensor is detecting unburnt oxygen and throttling back the fuel on all cylinders in response. Very much like lean burn, just in an uncontrolled way. You could have a bad spark plug wire, a bad/dying coil pack, oil down the spark plug hole, or, the first thing that comes to mind, worn/over-gapped spark plug(s). I'd think running lean would make it that much more difficult to fire the spark plug, so I would naturally assume a lean-burn engine would have a smaller spark plug gap. But that's me, and assumptions tend to be the mother of all f'k-ups.

There's also the injectors. One of them could be stuck on, or not responding properly, or clogged enough that running lean means there's not enough fuel to overcome the poor atomization....bla bla bla. Way too many if's going on here.

Your MAP sensor, being on the firewall, rather than right on the manifold - if that's how the D15Z1 engine usually runs it - could be an issue. Wrong sensor, or there's issues with the vacuum hose going to it. Blocked/collapsing or leaking. Or it really doesn't like the delay caused by there being a hose between it and the manifold.

Right now...we know you have a code that points to something you say it doesn't use(which makes no sense), and you use to have a code 48...

...

https://axleaddict.com/auto-repair/H...what-they-mean

...

ok, that gives a different wording to what code 48 is. Sigh. Heated o2 sensor.

You've most likely either messed up with the wire you repaired - or one that you repinned - or you simply need a new O2 sensor. There's procedures to test non-wide-band sensors, there's probably ones for wide band too. The heated circuit is pretty dang important on these things, as they operate at a higher temp, so the first thing to do is to check that you're getting 12v power to the heated circuit pins, preferably in the right polarity, and that the heated circuit itself on the sensor is reading a proper resistance while disconnected. Don't know what proper resistance is, but infinite and zero resistance automatically mean it's bad.

Heated o2's run theri own ground wires for each circuit in it, unlike early/simple non-heated ones that get ground from the manifold itself. Test your resistance on the ground pins, all of them, to the block. Should be close to zero. Check that you aren't showing +12v on what should be a ground pin too, in which case you've probably found your wiring issue.

That being said, again, if you have a cylinder that isn't firing, it's dumping oxygen (And fuel for that matter) in to the exhaust, the o2 might be reading right, sees the oxygen, and automatically starts dumping more fuel in. Check all your ignition parts, and check your spark plugs both for gap and the color of the darned things, looking for rich mixture or even wet from a plug not firing.

Hows the gas mileage with the o2 disconnected?

[Stubby79]

Oh, glossing over something simple...a leaking exhaust manifold (gasket/crack) would also induce oxygen in to the exhaust, with the similar results as a dead cylinder...You did have it off during the swap, after all...

[Tippaleipa]

I also cleaned head and exhaust manifold surfaces and sprayed some copper gasket spray thingy to exhaust manifold gasket because its metal. There is no other connections before o2 sensor. I dont think that its cylinder not firing because car pulls very good when o2 is disconnected. Idles very nice but low. I have driven about 120miles and half of tank is gone which is about 5.2 gallons. The donor car was same kind of swap so that is the reason why ELD is missing. D15z1 uses it but i dont have that kind of fusebox where eld is located.

I have replaced piston rings, cleaned and lapped valves, and much more. New spark plugs, cap, rotor, new timing belt, new alternator belt, checked mechanical timing, checked dizzy timing, new intake manifold gasket, cleaned idle valve and TB, checked vacuum hoses, sensor wiring checked few times, also measured o2 wires with honda instruction when i found the open wire that triggers code, fixed it and code 48 is gone but car doesn't work with o2 connected.

I gotta try driving harder. Im also new to lean burn system and that hesitation scared me badly and i quicky unplugged the sensor. I will also check the charging voltage

[Stubby79]

Yeah, I have no idea what one feels like when it goes in to lean burn. I'd assume it's something that kicks in when you're cruising steady at low power levels, and that it would automatically stop lean burn if you had to accelerate or climb a hill. But, you know assumptions...

There are other HX owners on the site, hopefully they will chime in. Me, I'd stomp on the gas if it was being gutless and see what difference it made.

They do use a TPS, so it should know what you're trying to do if you do. I'd say throw a new o2 sensor in there, but at 300 bucks...I'd test everything first. Unless you know a friend with one you could try swapping it with?

[Tippaleipa]

I ordered new ntk wideband from ebay, paid only 150 euros, so lets see if that fixes the problem