Gator417

Just installed a Y5 with Y8 intake and exhaust manifolds in my '99 sedan. It ran fine for a day or so then cut out while the gf was driving. It has a P28 ecu, a harness from an auto car and a red plastic jumper to link the two. I was only able to drive it for a couple minutes before I had to leave town, but it ran really well and idled smooth at around 800 rpm. A 'Honda Guy' gave it a once over and confirmed it looked like everything was hooked up right. The fuel pump is priming, but I don't think they checked for spark at the plugs. The cap, rotor and wires are fairly new though. I don't know much about Hondas and have found almost nothing on the Y5, and less on the Y5/Y8 combo. Is there something we've missed, or something I should be looking for with this combo? Thank you for your help.
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eghatch9295

iTrader: (1)

y8 intake manifold is the same as hx, except hx has an egr valve. a p28 will NEVER run a y5 correctly without a chip/y5 map.

Gator417

I know its not the right computer for the Y5. Will it not run right just because the Y5 VTEC should kick in at a lower rpm, or are there other issues as well? Thanks.
Gator

Gator417

Nothing? I've looked at hundreds of threads & there's next to nothing here for my little Frankenstein. I guess most of you don't mess with the Y5 because its the economy version & not very well suited for making power. I don't blame you, but I had to try. Another option would be for me to put a Z6 head on it. The P28 would run it fine but I don't know about the intake & exhaust manifolds and the compression ratio on a Y5 block. I'll keep you posted & let you all know what I figure out.
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HondaPartsHero

Is this a manual car? If so and won't crank, have you checked the battery? Checked to see if the plastic plunger is missing at the clutch pedal to allow the starter to activate? Checked all your underhood fuses? Checked all your starter and ground wiring?

Gator417

I guess it always cranked just fine. I was out of town & my gf was doing the troubleshooting. I misunderstood her in that respect. I did check the important fuses, timing belt, fuel pressure etc. Turns out it was a bad distributor. $50 fixed me up at the local Honda farm and now it runs really well. I'll put in the new axles and lower ball joints tomorrow, give it a good road test and report back.
It is throwing code 22, VTEC pressure valve (?) & I'm stumped on that too. This car with the old engine didn't throw that one and niether did the other car with this engine. Are they different valves? They look the same, but I haven't really examined them too closely. It doesn't concern me much, since I won't ever hit the vtec anyway, but it would be nice to clear all the codes. The car pulls well up to 5k, but then falls off, presumably due to the tiny cam. Also, I did notice it idled much better when the O2 sensor was not plugged in. Not sure what's going on there, but I'll do some research & get it figured out.
Thank you,
Gator

Gator417

So now I've driven about 400 miles, including a 160 mile jaunt down the highway to talk to a judge and prosecutor. It got a solid 32 mpg whilst cruising at 80 mph with the ac on. Not terrible, but we'll see if it changes when I get the idle and timing set properly. The real story, though, is in the driveability. This setup has noticeably more power (torque) between 2k and 4k rpm. Since that is where I normally live, its much easier / less tedious to drive around town. There were some pretty good sized hills on my trip, but I never had to downshift or take the cruise control off unless I got hung up behind lap traffic. That hasn't been the case with the Z6 or the Y8. I know there is a lot less hp, but I'm sure its got a fatter and flatter torque curve than the Y8 or Z6 below 5k, even without the vtec kicking in. Overall, I'm quite pleased with how it is running. The idle is still jumping between 1200 & 1800 most of the time, as it was with the Y8 and the Z6 I had before. Besides that, the P28 seems to do just fine with the Y5/Y8 hybrid. I'll be meeting up with a local guru soon to see if we can get the idle & timing dialed in some time this week.
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Gator417

So now the car runs fine but for the idle. I've bled the coolant multiple times and gone through the process to set the idle I've read about here, but I still have a jumpy idle and jerking whilst driving at low speeds (like in a parking lot). I was very excited to hear from a local guru it most likely is the FITV. I read the thread here on removing and cleaning it & thought that would be it. This afternoon I was going to clean mine & found I do not have that part.
So my questions at this point are; has this been the reason all three of my engines, run by the same P28, have had the same crappy idle? Do I need to put on a Z6 intake so I will have one of these? Can I swap a Z6 TB with a FITV onto a Y8 intake? I'm stumped, but really think this might be it.
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tony_2018

I'm not sure why people would point to an fitv that this specific model does not have. This isn't the first time I heard someone tell another to check the FITV. You need to ensure your iacv is installed, cleaned and adjusted properly.

Gator417

Thanks Tony.
People probably suggest this because it works. My IACV is fairly new and was never suspect. I installed a Z6 throttle body with a freshly cleaned FITV and my engine now idles smooth and steady. The newer ECUs are set up to operate without a FITV, but not the P28. So in order to smoothly run a Y8/Y5 with a P28, one must install a Z6 throttle body, with a FITV. Now you know.
Gator