My 94' Accord Ex Sedan manual I just bought goes dead at stop lights but it cranks right back up. The previous owner said that he took it to a shop and they said it needed a new engine harness. I'm guessing it needs the correct one because I believe the previous owner bought just the motor w/o trans, engine harness or the ECU for the motor and just dropped it in. I have been doing so research and I think the problem is that the car is obd1 and the motor is obdII and if that's the case that means I need to convert the motor to obd1. I just can't figure out what it is exactly. I have seen that the F20B is a pain to swap and stuff. So any help to figure this out problem would be greatly appreciated, Thanks!

 

There's no converting the engine over to obd1, its more a matter of the harness and ECU. What ECU is it running? Because my H22A swap is running on Crome and it does that too sometimes.

 

Okaii I just thought you could, I'm not sure I'll have to ask him but I'm sure it's the stock 94 Accord Ex Manual ECU that came with it. So is there a fix for it??

Also the previous owner told me that if he unplugged the idle air control valve that it wouldn't shut the car off. So I'm guessing the ECU isn't getting a reading for Idle air control valve. So more then likely the IAC valve not getting a reading is whats causing it to cut off, right? So what would be the fix for this?

I seen where someone used A obd1 h22 Intake Manifold with Throttle body & IAC valve to run a F20B in a obd1 car.
Also some people said to get a chipped p28 or P72 to run the motor and some said to get the correct ECU for F20B.

So could I possibly fix it with anything that I mentioned?

I would just try it all but I don't have all that time to play hit and miss with it.

 

The F20B is a high-compression, high-rpm twin cam engine, and if you claim its operating on a stock Accord ECU, then that ECU still thinks that its controlling a much, much milder mill. Of course there would be problems with that.

You have a high strung engine, it needs to be appropriately tuned. Your car is OBD1 so that precludes using a F20B ecu.
The idle air control valve, when unplugged, closes. It doesn't take air away, only add it. If it stalls at idle its because the ECU cannot reconcile various parameters and maintain rpms.

First check to make sure everything is hooked-up properly. F20B (really a de-stroked H22) and F22Bwhateversubvariantisinyourcar are different in the way the ECU gets crank angle and the way the ignition is handled. If that all looks fine then look-up a performance shop in your area that is a Hondata dealer and has a dyno. Go there and pay the ~$800 it will cost to buy a new ECU socketed and chipped for a Hondata S100 and to have it tuned. Its expensive but you bought an engine swap with issues. (as did I).

 

The next time the car dies, keep the ignition on, jumper the service connector and check for any stored codes. You need to do this before you turn the ignition off so any stored codes don't somehow erase themselves. If not, then you need to hook up a fuel pressure tester from harbor freight and see if fuel pressure is cutting out when the car dies. It could be as simple as your main relay going out. Other possibilities could be your ignitor or coil.

It might even depend on your setup.

 

Okaii, well I figured out it has a chipped p28 ECU but it's not fined tuned to the car. So since it's a chipped p28 can I have it tuned with that ECU or do I need the Hondata s100? Everything looks plugged up right and everything.

I was missing with and noticed that it was idling really low like it wanted shut off.

So could it possible be the IAC valve causing it to idle like that?

 

If it's chipped, take it to a tuner and have em tune it. I doubt that is what's causing it to die but I suppose it's possible.

 

What else could be causing it to die randomly at the stop lights?

I mean in the research I did I seen where it could be the
Main relay
The distributor
ignition switch
IAC valve.

But I know the distributor and ignition switch has both been replaced.

So I'm lost on what it could be.

I don't get what's causing it to idle between 300-1000 RPM, it's like it's struggling to stay on. My civic did this until I cleaned the IAC valve.

 

No no No, I am having the exact same problem you are having and I have done *everything* else and it's just a bad tune. Set aside $600ish and take it somewhere for a S100 conversion and a tune, if it doesn't already have the s100 in it. Interrogate the previous owner as to the software on it, I'm going to hazard a guess its Crome.

Granted, it doesn't hurt to try the little stuff. Bleed the crap out of your cooling system, Ericthecarguy on YT has a nice tutorial on it. Remove and inspect, clean if necessary, the IACV and FITV, those will cause idle problems too. Those aside, on a modified and tuned car, the modification and tune becomes more suspect than anything else.

 

Do I need to get a different non chipped p28 for the s100 or will the one I have work? I'm just don't know where to take it in (Atlanta).
Also after I get tuned if i change the transmission, Air intake or exhaust does that mean I need to get re-tuned again ?

It's running chrome..
So there's the problem...

Later today I will be checking the IAC valve, fitv and draining the coolant system of any air for the idling problem.

 

Well, I was quoted under $200 by Pure Tuning in Toledo to convert from a Crome socketed ecu to Hondata so your ECU should be fine from a hardware standpoint. You will have far more options in Atlanta than I will in Michigan.

Intake and exhaust...it kinda depends on how wild you go. Tuning on the mods will always be best of course. It won't damage driveability, you just wont see optimal gains. What I would do is go on eBay, buy a2.5" megnaflow spun metal cat, a muffler you like, and take them both to a muffler shop to make a simple system. If you have the F20B, or a H22 header, then you will not see a meaningful power gain from anything costing less than $450. I would actually look on eBay for a stock Prelude intake snorkel and box, but that's just because I dislike the cone-filter whistle. A cheap $30 intake kit from eBay for the metal pipe itself, a BPI velocity stack, and an AEM dryflow cone to fit over the velocity stack are about the best you're going to do in terms of an intake unless you're spending big bucks.

Changing the transmission won't affect the engine tuning, things will just happen quicker. a domestically sold Prelude box will be cheaper, but no LSD. Whatever you do, an Exedy stage one should go in as well. do not buy any cheap brands, they are cheap for a reason.

 

Alright well I'm going to start looking for a tuning shop soon.

For the exhaust I plan on using a Apexi WSII or N1 for the car but I might get the 2.5 Manga flow cat to go with it. I'm not sure because where I live my car does not require emissions. Does using a cat make a difference?
I guess I'll go with BPI velocity stack, and a AEM dryflow cone and a decent pipe.

If I want a tranny with LSD would the install be any different the stock 94 Ex tranny I have now?
I want the T2T4 or whatever is next in line to that one. I just something better than the Stock Ex Tranny.

Plus I found out the car has H22A intake manifold.





So I found some antifreeze on top of my intake manifold and I don't know where it came from. It's like everyday I am having to top off the coolant.



I took off my IAC valve and it seems like the gaskets are not any good.
Plus it's very rusty. (Not sure if that matters). (Plus the bottom picture of the IAC valve was more dirty but I cleaned it)




Also could anyone tell me what this is? I it was under the stock air intake box and I want to know if it's okaii to remove it



Also I found this hose (on the left) is connected to this metal divider hose (on the right) which connected to nothing. I want to know what it is supposed to go to.

 

An off-the shelf exhaust will be just fine until you port the head and throw some new cams in. T2T4 is what I bought, though i have yet to install it and I'm not sure I can do it with the engine in the car... But like I said, even a box from a [vtec]Prelude on this side of the ocean will have the same ratios, just no LSD. I think that the intake manifold between the F20B and the standard H22 is the same. Don't quote me on that, if you look for F20B's on ebay, that's what it looks like it comes with.

As for the cat, put one in. If we're being wanton with our combustion of dead dinosaurs we can at least do our part to keep the Penguins safe. Like I said above, until you start doing serious engine work a catalytic converter, especially a spun metallic core unit, will not be a significant impediment to power. Plus, it will help muffle the exhaust a little bit.

Someone else will have to comment on what the mystery box is. That pipe might be for vacuum sampling, see where that hose goes. But that rusty area is rusty because the coolant was left to sit in the block for awhile. Clean the mating surface on the manifold and use a tiny bead of rtv when you put it back on. If you're losing coolant check all of the little coolant lines and make sure the clamps are in place and snug. Check the radiator hoses. Get the engine nice and hot, park it, pop the hood, and while its idling see if there's any wisps of steam coming from the radiator end tanks. Where that coolant is, it's the wrong place for a head gasket failure.

 

You can safely remove that box below the intake. EX's had it, LX and DX did not. I removed it with my H22A swap.

I'll be honest, I don't think you should spend a dime on anything aftermarket until you get that motor back up and healthy again to where it's not leaking anything.

My guess is the person who swapped it in didn't bother replacing any of the gaskets or seals and now you're paying the price for it.

I'd get an engine degreaser like EngineBrite and spray that bitch down, let it soak and then hose it off. Then we can have a nice clean starting point to see where stuff is leaking from.

Those metal pipes can mostly be deleted, they're for vacuum lines, I think I removed nearly all of them on my swap.

Transmission wise, you want the M2B4.

You should figure out what ECU you're using as well. It's behind the passenger footwell carpet, just pull it out and check.

This is why I wouldn't want to buy someone else's headache

 

You'll need some 3/8" fuel vapor hose to replace the valvecover vent there, and a 3/8" hose mender to plug it back into the stock intake tract. A/M intake pipes will have a nipple directly for the 3/8" hose.

And the M2B4 would be ideal, sharing synchro and bearing parts with USDM Prelude transmissions, the T2T4 would be a bit cheaper and Synchrotech (forum sponsor) sell rebuild kits for it.

My dad, me, and my brother twice have made this mistake. It's a curse that some people are hopelessly shackled to.

 

I pulled the carpet back to see what ecu it's running and it's a p28


So I drove it for the first time today and when I would come to a stop or put the car in neutral to coast to a stop the RPMs wouls drop all the way and shut off. It would crank right back up and It only did it sometimes.
Also when I shifted the car would jerk if didn't give it gas as I was shifting.
(My civic started doing this too but it's also running a chipped p28, so I'm guessing a ECU problem all the way around)

I also discovered that IAC valve that's on it bolts up right to it but it isn't the same shape as the one that should be on it....

This is one big headache.... I would love to get it fixed because it's a fun car. Well when it wants to be...

 

A bandaid that might help with the stalling, try unplugging the IACV at idle. The engine should stall. Adjust the screw under the throttle cable cam so the throttle plate is a little open, just a hair, and then adjust the TPS so with the throttle closed it reads .5V. Doing this, you will not be able to get WOT to read 4.5v unless you file the throttle body.

The goal is to be able to unplug the IACV while the car is idling and not have it stall. Granted, doing this you would have to restart the engine in order for it to drive after plugging it back in.

You will probably still see rpms drop dangerously low when coming to a stop, or the car may even stall out on you, but the frequency should drop. This is a stopgap until you get a professional to look at it.

 

Is it actually a P28? Or just have sharpie on it?

There should be a white label on one of the sides that explicitly states what it is.

It may also be worth your time to open that ECU up and see if it's a socketed chip - I'd maybe get like Phearable or a local tuner to take a look at it and at a minimum put a fresh, new basemap on it.

 

So I took out the ECU... Turns out there is no label saying it's a p28 anywhere....


Also I opened it and I couldn't tell if it was chipped or not.. So I included a picture.


I was looking at Phearable but I wouldn't know where to start or what to get because if I did I would have probably already ordered one by now.
what should I get for it, if I order through them?

 

Upper right hand corner, just above the two small chips. That's normally a bare spot on the board. That chip will pop-out and you'll see the socket.

 

Okaii, So the one on the right isn't chipped but the one on the left is? Right?


So I am trying to figure the whole basemap thing on Phearable, Because I don't know the exact year of my F20B, The Injector Size (All I know is that the car is running a H22 Intake manifold), Map Sensor ( I am assuming stock) , Engine Details ( Because as far as I know it's stock), Fuel Octane (because my car takes 87 but I put 89), Rev Limit and Vtec Engagement ( I want it set to factory Rev Limit and Vtec Crossover), I would want to disable the oxygen sensor because I don't have emissions. To be honest I don't know anything about base maps or stuff like that. I want the chip itself but I don't if to get it or the ECU plus the chip through them.

Vehicle Year/Make/Model: 1994 Honda Accord Ex
Engine Model & Year: F20B
Injector Specs:
Map Sensor:
Engine Details: Stock
Rpm Revlimit: 8200
Vtec engagement point: 5600
2 step launch point rpm:
Cel shiftlight point rpm:
Ecu Model: p28
Fuel Octane:
Disable Oxygen Sensor: Yes

 

You put 89 octane in a F20B with a questionable tune? 0_0' That is an engine that *needs* 93 octane!

And you have it the other way around.



I highlighted in blue the area in question. A socket has been soldered down and a chip plugged into it. The red lines indicate the actual sockets themselves for the pins on the chip.

 

Okaii I didn't know it needed 93 :/ *Sigh*
My bad I got confused in typing the last post up.

So what about the Phearable base map? Is worth it and what else am I missing for the info?

was reading where it could be the map sensor too..

 

H22A, F20B, etc take 93 octane

Regarding the chip, take a picture of the chip area in your ECU before buying anything. If it's soldered in and not socketed it'll be a huge pain to mess with. If it's socketed it'll come right out.

If you order one:

Year/Make/Model: 1994 Honda Accord EX
Motor: 97-01 F20B
Injector: You're probably running stock
Map Sensor: You're probably running stock
Engine details: Stock (11.0:1 compression)
RPM Revlimit: 8200rpm
VTEC Engagement: 5500rpm
2 step: N/A
CEL shift: N/A
ECU Model: P28 (get the full code if you can find it on the board)
Fuel Octane: 93
Disable O2: N/A

Reference (https://en.wikipedia.org/wiki/Honda_F_engine#F20B)


That should get you going with a known good starting point. Technically you could leave it running there but ideally you'd have a tuner fine-tune it for you.

 

It's socketed I pulled it out so I could count the pins to it make sure it was a 28 pin.

On the board all I can Find is 02D01720-1500 A8Y-D. I tired googling it and I found some people said it was a p28.

So if i get the chip and it runs better and doesn't cut off anymore would it be fine till I can get the money up to take it to a tuning shop?