Hey folks, been a long time lurker and a fairly new owner of a 90 crx hf.
This is my first honda I have ever owned and I am just learning about these engines.
I knew when I bought my HF that it had a newer engine in it but did not know what all had been done to it. It runs fine and gets 40-50 mpg. There are a few problems that I have been able to correct but as I have dug in deeper I have noticed some issues that I need help figuring out where I need to go...
so here is the deal
The engine that is in the HF is a SOHC ZC similar to the d16a6. the tranny is an HF high geared tranny. The intake is is a pm8 intake (hf) and the ECU is running on a pm8 as well. The pm8 ECU is just not the right ecu for this engine and is really holding back the car.
I am having some power lag issues as well as iradic idle issues. I have gone through this board regarding the idle issues and have solved allot of those problems but the rest I think is all related to the ECU.
So now here is the deal.
I got this HF for the sole reason of getting 40-50mpgs I drive allot and this vehicle has cut down on my fuel expense not to mention the reliability of a honda.
Anyone have any ideas what I should do about this. I am more concerned about mpgs than anything and feel that if I put a pm6 intake and a pm6 ecu in it is going to use allot more fuel. Any suggestions would be appreciated.
Is there anyone out there running my current setup or the pm6 setup with the HF tranny, would love to hear your input.
Thanks

 

You have that “lag” because the HF was not meant for power, it was meant for that’s right you guessed it MPG.

 

Way to rip someones first time on this board... I know not everyone on this board is a arrogant as you.

Obviously you do not have an HF tranny so why are you even answering me here?
You could have answered my question instead of trying to humiliate me.
The lag I speak of is a total power loss, much like a car when it is running lean...

 

Let's try this again...

Can you post the Engine Block code, transmission code, and confirm the ECU you are running, and the head? You have some of that info your original post, but some seems like speculation....

You could also post some of your RPM and MPH #s so people could speculate. Oh also tire/wheel size.

 

Sure, I checked the ECU last night, it says PM8 on the bar code and the sticker that says "void if removed" is attached. The engine plate on the block says ZC and nothing else.
At 70mph I am running just over 2k in 5th at 55mph in 3rd its around 2500
On the back on the intake it says HF-1 PM-8
The tires are 175-70-13s
Here is a pic of my engine...
Im sorry I do not know the location of the code for the head...a quick search did not show up where to look for it.

 

i was kinda wondering this as well, last time i had to identify a head i called the local Honda dealership and asked the parts department and they answered my question but werent to happy that i was using them as an alternate "Google" lol. is there a better way to identify heads??

as for you Jzak i am in ABSOLUTE LOVE with the HF models and hope that you can figure everything out, sorry i dont know too much about the ZC's

 

oops i guess i could have mention that there is a code on the front (or maybe the back i cant remember lol) of the head just under the valve cover.

i should have been more specific on my last post..... i do know how to FIND the code, i was more interested in actually identifying the head

 

I just went out and looked I can not find the code anywhere on the head. is it on the intake or the exhaust side. As you can see from my pics the engine is really dirty. Not allot of the roads here in Tx are perfect and we get all kinds of stuff under the hood.
This set up is nice and I think you would appreciate it. with the ZC engine I have enough HP to get through traffic and run the A/C yet still get 40-50mpgs Sure I am not as fast as an SI (I do not want to be) but I sure can not beat getting over 400 miles to the tank.

 

So it sounds like you have a sohc zc with a HF manifold on it. I don't think that the d15b6 head works with the zc block...I feel like there would be valve clearance problems, but I am not sure at all.


easiest thing to do would be to swap a SI manifold or a ZC manifold on the head and swap out your ecu with either a SI (PM6), ZC (PM8), 1st gen integra (PG7 runs rich). This is if you in fact have a ZC head. I don't remember where the head stamp is on it.

I had a sohc zc pared with a DX transmission and would get about 37mpg highway. I can only imagine better gas millage with the HF transmission.

Hope that helps

 

ill be home within the hour ill go outside when i get there and check for you cause honestly i cant remember right now.

but yeah thats cool that you have a HF ive been looking for one to buy FOREVER and only found two, one sold for 400 bucks 20 mins before i called the guy (blown tranny btw) and the second wasnt for sale.

only thing that makes me sad is that somebody swapped your motor the original HF motor was BA, less piston rings and smaller crank journals for less friction with a plastic valve cover for weight reduction! how awesome is honda for creating the epitome of economic vehicles in the freakin 80's when everyone else still fails to do as well in 2010

 

The guy that I bought this one from had 2 of them. The other was an stock HF that had over 400k on it. And at best would get 70mpg on the highway. Now the down side was here in Tx it gets so freakin hot and being in a car like that without a/c would almost kill you.
Glad to see there are still some out here who appreciate the HF

here are a few pics of the outside

 

dude none of your pics show up... you know how to post pics with the little mountain and sun looking picture option right?

 

heres the pics of the head code... i started far out so you could see where its at then got closer and closer as the pics move along. its like sideways and really effing small so you might need to wipe some texas dust away haha

 

here i circled it lol

 

Apparently this site did not like yfrog, I am trying another service....

http://img261.imageshack.us/i/596671...824910669.jpg/
http://img573.imageshack.us/i/659061...825810669.jpg/
http://img264.imageshack.us/i/p1970796.jpg/
http://img514.imageshack.us/i/p1970803.jpg/
http://img44.imageshack.us/i/p1970797.jpg/

 

nope haha still cant see sheeeought

 

click the go advanced button under the window that you type in and the click manage attachments and upload them from your system, its easier that way

 

Thanks for the pics, but where you say it is there is nothing there, not even a remnant of numbers.
Could it be located elsewhere. I might need to take off the exhaust shroud and see if its farther back. it gets in the way a little. I will check back when its daylight and see if I can find it better.

 

I think because I am a trial user still and new to the board, they are not allowing me to post pics. Guess afraid I might spam or post **** lol

 

haha its ok... as far as the number goes i have no idea. thoroughly check the head there has to be something somewhere... i know that on the exhaust side by the timing belt cover (on the head) are the numbers "96" and my motor is out of a 96 civic so i dont know how relevant that is or if thats what it actually means but if you were to find that at least you could narrow it down... idk for sure though man ive never owned a crx unfortunately so i wouldnt know where to tell you to look

 

the head code for the HF is on the front side of the head just below the valve cover between the #3 and #4 exhaust ports - my HF says PM8-1 - right next to the code is the year code which is numbers in a circle - my 88 HF says 88 in the circle - you could also just pull off the valve cover and see if it has 8 valves, 4 int and 4 exh (HF) or 16 valves, 8 int and 8 exh (anything but HF) - i could take a picture of the head code if you need it

 

nice! see i tried but a fellow HF owner def helped more than me... sorry!

 

Sorry guys that I have not been around, my wife just had a baby and been busy with that...
I could not find the head code but I assure you the head has 16 valves. I pulled off the cover to replace the gasket and it has 4 per cylinder.
I have been reading on another forum, one that is much smaller than this one, and a few guys are telling me that the setup I have the way it is will work. And if I get a new intake/and pm6 ecu I am going to see a huge drop in mileage. Right now the setup the way it is gives it way more power yet also fuel efficiency. Currently getting 52-54 on the highway without the A/c on.
OH and yes I can run the A/c and not loose too much power My mileage does drop about 10mpg. Lets just say the worse tank of fuel I ever had was 37mpg and that was a/c on all day in town driving.

 

i think you just need to give the car a good tune up, new plugs and whatnot.

having a normal 16 valve engine isnt holding you back much in mpg if the rest of the HF stuff is on.

can you describe the erratic idle issues more? maybe you need to just clean out the IACV.