hey guys
been having a issue with my 93 prelude s model and had it at honda for over a week. still having issues, the car has a f20a4 engine with all the smog stuff from the f22a1 with a 97 accord f22a auto transmission i could not smog it because timing was off and it had a accord flex plate so Honda machined and installed a new prelude flex plate for me and it still had timing issues, i had replaced the timing belt and balancer belt since water pump went out. so i had Honda pull apart the engine again and re do those to make sure i didn't have it of a tooth or so since was firing at approximately 22 degrees before top dead center after Honda fixed the belt and adjusted the distributor. it was still at 21 degrees btdc. also before all this i replaced cap and rotor, and wires and plugs, and miscellaneous hoses and of course the gaskets. also after the failed smog i was told to replace the o2 sensor and the cat for high NOX and HC. which i have done and also i pulled the egr valve and clean it and replace gasket. so Honda dug into the car some more and said there was a lot of oil inside the distributor housing so it may be causing issues. so i went and got a remanded distributor from auto zone ($300) as opposed to the ($1000 Oem) and they installed it with a oem cap and rotor the car fired up and timed perfect at the 15 degrees btdc that its supposed o fire at so took the car for a drive around the block maybe about 2 miles and back to re check the timing and is was firing right on TDC witch made no since went back to Honda and they were clueless to what had happened. the distributor was tight and had not moved and the belts were all tight as there were supposed to be and all the timing marks were still lined up, no oil in the distributor at all. so only thing the Honda tech though it could be is maybe the aftermarket distributor as opposed to a Oem one. so they said if i can get a oem distributor they will install it for free and re time etc, so i took the car and went to lunch about 3 block away car seamed to be a little gutless off the line to about 2k rpm but would drive fine once got to 2k and when came out from lunch in the 115 degree heat car fired up but would die when tried to give it any gas, I found a loose ground so fixed that but same issue. so called the tow truck to tow car up to my house got it home where it was 70 degrees and the car fired right up and ran drove it around the block a few times was running great so i check the timing and it is now firing around 5 degrees after top dead center but it acts like it is running fine no misfires plenty of power no hesitation etc. but it till wont smog with the timing not firing at 15 degrees btdc. i think the heat issue not starting might be the main relay behind the dash. but what I can't figure out is why the timing is changing itself so much also every time it's be timed the jumper wire is plugged in to disable the computer like it says in the Honda Manuel any help would be greatly appreciated as it has completely stumped me. also on the aftermarket distributor it looks like the housing is exactly the same as the Honda one only the ignighter is aftermarket. also Honda had another prelude in the shop with a known good ecu and plugged it in and it had the same issue. also there is no check engine light on and when you plug n the jumper wire it does light up the check engine light to tell you the computer is disabled.

 

Also Ecu is a 37820-p12-a51 which says is for a 92 to 95 prelude f22 with automatic. P12 Ecu

 

ok well i'm stupid still have the issue but i re checked the the timing today after replacing the main relay put the jumper with in to disable the ecu and use timing gun i rotated the distributor as far asI could advanced ( toward firewall) and with the gun at 5 degrees advanced the white line lines up with timing mark so i need to advance it 10 more degrees to be correct. all the cam/crank timing is still lined up as well as the cam etc lined up to the tdc mark on flexplate in the trans. so the car is actually retarding the timing not advancing it like i thought. does anyone have any idea what would retard the timing so much? no check engine light is on could it be the knock sensor?

 

well after more searching i can not find the stupid knock sensor there is a oil sender where the knock sensor should be and a plug where oil sender should be. also is no unplugged pig tails and no engine lights one and no codes when you plug in the jumper wire.

this is all pictures of behind engine from underneath







this sensor is away from engine on fire wall and has a line going from it up to the power stearing is only other sensor i can see on rear of engine other then the oil sender one

 

I don't know much about this motor, but I can't imagine it having a knock sensor on it.

http://en.wikipedia.org/wiki/Honda_F_engine
F20A

This engine series was used in the Honda Accords and Honda Preludes in Japan and Europe. The DOHC F20A was also derived from this engine (see below).
Specifications

• Bore × Stroke: 85.0 × 88.0 mm
• Displacement: 1997 cc
• Compression ratio : 9.5:1
• Valve Configuration: SOHC, 16 valves
• Max output : F20A2 110 PS @ 6000 rpm (carbureted)
• Max output : F20A3 110 PS @ 6000 rpm (carbureted)
• Max output : F20A4 133 PS @ 5400 rpm (PGM-FI)
• Max output : F20A5 135 PS @ 5400 rpm (PGM-FI)
• Max output : F20A6 90 PS @ 6000 rpm (carbureted)
• Max output : F20A7 135 PS @ 5600 rpm (PGM-FI)
• Max output : F20A8 145 PS @ 5900 rpm (PGM-FI)
• Max torque : F20A2 16.1 kg m @ 3800 rpm (carbureted)
• Max torque : F20A4 18.5 kg m @ 4300 rpm (PGM-FI)
• Max torque : F20A7 19.3 kg m @ 4400 rpm (PGM-FI)
• Max torque : F20A8 138 lb·ft @ 4400 rpm (PGM-FI)

• Fuel consumption F20A8 Urban - 25 mpg Highway - 34 mpg
• Fuel consumption (Japan Combined Cycle) : 9.6 km/l (PGM-FI), 9.8 km/l (carbureted)

This engine also spawned many variants, according to market, but the specs remain largely similar.
The F20A5 is used in the CB3 and CB4 Chassis.
The F20A7 is only used in the edm 1992-1993 Accord Coupé (CC1).


I am really surprised that Honda is even touching this car since they rarely if ever touch swaps. But they appear to be making money so I guess that's why. That bottom pic appears to be the power steering switch in green.


Also, I guess it's safe to assume that you're not in cali since this engine was never made for the US and there is no comparison motor to use as a swap guide for emissions testing.



The only thing I could suggest is to somehow try to get a hold of the ecu for the engine not for the car.

 

Or you could try a tunable ecu.

 

I actually am in Cali took car to the bar station for ok on swapped engine he said that enginef20a4 is almost identical to the f22a1 block wise and since the distributor and manifold and all sensor are for f22a1 gave the ok. After doing some more research I found that the ecu is for the 49 state version of the car so I orderedthe correct p12 ecu for Calif spec. Hopefully that will fix the issue if not been considering a tunable ecu or just pulling it all and swapping h22 or h23 in.

 

I'm just curious if you're timing gun has an advance mechanism built in and if maybe that thing is getting turned prior to each time you're using it which would cause it to fluctuate when you try to set the timing.

 

On my timing gun is a dial to manually advance timing is how i have been figuring how far its of i know it should be on the red at 0 and white at 15 advanced. But also when car was at the dealer they used 2 completely different timing guns and were having same issues

 

i got the new computer and swapped it in and no luck still the car is at 7 btdc now gun on 7 white mark lines up but not close enough to the 15 btdc needed to smog. car runs great no miss fires, and pretty much everything is new in it so i don't understand it at all. if anyone has any more ideas would appreciate it other wise i think i'm gonna have to give up on the lude.

 

You got the distributor fully advanced and it only goes up to 7 btdc ? Is it steady or does it vary ? I hate to ask cause you probably did, but I assume you are shorting the service connector AND the check engine light comes on solid confirming that it's shorted ?

 

the jumper is plugged in and check engine light is on solid confirming it's shorted it stays at a steady 7 btdc when checking it with distributor fully advanced.( turned all way back towards firewall)