When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.
So I recently bought a Del Sol. I understand that is originally had a D16Y8 engine, which blew, so was replaced with a JDM D15B.
Now there's an issue that is really getting on my goat. When you get the revs up to 1600 in either idle or lower gears the revs bounce. When in idle not an issue, but when you're driving it is.
I've tried a few things:
- Changed the throttle positions sensor
- Changed the throttle body MAP sensor
- Changed the entire throttle body
- Changed HT Leads
- Changed spark plugs
- Put RedX in the petrol to clean the system
It's not worked. HOWEVER...
When I changed the sparks and the HT leads, it temporarily resolved the issue. For all of 5 minutes, the issue dissapeared and then re appeared again.
Please can someone make some suggestions. I'm thinking distributor, but I don't want to fork out if it's not.
Thank you for taking the time. Appreciate it. Much love x
You answered every question but one, pretty impressive.
When you turn the key to the on (II) position, does your CEL light come on for about 2 seconds and then go off as the fuel pump primes?
I've been looking and I'm not so confident that even in Japan the 95 ever saw a D16Y8. That's a 96+ motor from my understanding.
I am seeing the JDM would be D15B Vtec or if it is a 1.6L then it's the Vtec SOHC ZC (equivalent to the US D16Z6).
Can you pull down the carpet on your passenger side kick panel wall and post up what your ECU is? you should see a Pxx number i.e P2E or P2J or P06 etc etc.
I can confirm that there is no CEL at any point. I'll have to whip the dash out to see if the bulb is missing. I've attached the ECU photo too. Looks like a P08.
Just don't touch the Throttle Plate adjusting screw like the DIY seems to do (that's a pretty big no no). You just adjust the TPS itself so the Closed Throttle Position gives you 0.48v and then you aqre done. Wide Open Throttle isn't as important. Also make sure the TPS changes value smoothly as you open the throttle.
Okie dokes. So here's a little update on findings. So I took a look at the dash to see if there was a check engine light showing. NADA! No light. Took out the dash and the bulb had been removed.
Popped a bulb in and sure enough, lit up. I checked the blink codes and here's what came up.
3 MAP - manifold absolute pressure sensor (changed throttle body and this stopped now)
14 IAC (EACV) - idle air control valve
19 Automatic transmission lockup control valve
20 Electrical load detector
So I suppose I have an ECU for an Auto, which I guess would cause issues?
Also, do you think the other codes would be responsible for the jumping throttle? If it's going to be an expensive repair, then I'll just drop in a B16Y8 instead of the current engine.
The IACV can cause idle and surging issues. A good cleaning with non chlorinated brake cleaner and a new gasket (cheap) helps things a lot. Not sure if the surging could cause the bucking but cleaning it up won't hurt.
The other possibility is the ECU expects a 3 wire and you have a 2 wire or vice versa, expecting a 2 wire and you have a 3 wire. There is a conversion for that but I'll have to dig up some to find it.
Check your IACV and see if it has 2 or 3 wires, it may need to go the opposite of whatever you find. I'm not very familiar as some of the people here with the 2 wire/3 wire IACV stuff.
The ECU can be converted to Manual, it's just removing 2 resistors and added a jumper wire to convert teh auto ECU to a manual.
You clear up the map sensor, so after you convert the ecu to manual, doa solid cleaning on the IACV. You will be able to check to see if any other CEL's come on.
I also think there is a way to bypass the ELD being you probably don't have one, it's a USDM thing and sounds like your ECU is a USDM P08 while you have a JDM motor.
I believe you should be close to being in good shape and for cheap.
The ELD part is going to take a little more time and research but I'm pretty sure we just need to provide pin D10 of the ECU with 0.5volts and your ELD code will go away.
It will take a little work and not very much money but I believe you can get that ECU running properly on that car without a whole lot of headache.
I think you said you have vtec? That means you should have a 3 wire IACV and I am guessing you will only find a 2 wire IACV. Will need to hit the junk yard for a 3 wire if that is the case.
I've been doing a bit of reading on this ELD thing.
I made some errors in my previous post. JDM and USDM cars used ELD units while CDM did not.
Your ECU is JDM so expects the ELD.
I have read that if you nab an SI fusebox from the junk yard it should have the ELD unit.
Not 0.5V I said previously instead you short it to ground through a resistor/rheostat (looped potentiometer).
The ELD I guess ranges from 0V to 4.5V output to the ground.
The single component that makes Honda's charging system unique is the electric
load detector located inside the fuse box. In some cases the fuse box will have to
be dismantled to gain access to the ELD. This sensor informs the ECM of the
amount of electrical energy being used by the vehicle. The ECM sends a 5V
reference to the ELD and the ELD pulls the reference voltage to ground as
electrical load increases. There should be 2-4 volts found at the ELD terminal
when the vehicle is under low electrical load and 1-2 volts under high electrical
load.
So by this last bit you should be able to short D10 to ground through a resistor that only holds 1-2 volts. Not sure the current rating. A rheostat would let you have adjustability so you could get it set where you needed it.
Honestly, this has kinda put my mind frame in one that just wants to change the engine. I think I'm just going to put this D16Y8 straight in, which has no problems and the right ECU.
Do you know how easy it would be to get a wiring harness?
Going that route has it's own challenges, you would be putting an OBD2 motor into an OBD1 car, and if it's a USDM ECU you would still have the ELD problem.
The other draw back is the Y8 is known to spin bearings as Honda changed the journal oil design.
The D15B vtec motor you have is actually stronger from my understanding.
I think you could find a conversion harness to do the OBD2 on the ECU maybe, but then you have the IACV and also the Fuel Injectors that would be different. I think even the Distributor is different between OBD1 and OBD2.
You never did answer whether you have a 2 wire or 3 wire IACV in the car now.
03-29-2015, 01:04 PM
Del Sol D15B Bucking
Re: Del Sol D15B Bucking
