Need help on fixing my TCU problem

[4thGen4dr]

Im posting this again since I cant figure out, jus put in the prelude TCU now when my car shifts at WOT theres a long ass delay and doesnt want to catch the next gear and it goes all the way to 8000 rpm somtimes and sits there! I have no problems using my accord TCU and it's weird I have this same problem even with trying two different prelude TCUs. Also accelerating it likes to rev up between shifts from 1st to 2nd.Someone have a idea what i can do? Is this a electrical problem?

[accordtunerx]

damn... same problem i have! does it sometimes shift really early too? like goes through 1st, 2nd, and 3rd, and is already in 4th gear at like 30-40 mph? well, that's a problem i had at least.

i know what you mean about the delay and stuff though.

my theory is that it's the wiring harness. the connector for the TCU on the F22 wiring harness is made for an F22 TCU. there could be a pin on the H22 TCU that's not connecting or a pin going to a wrong slot in the connector or anything.

so - does anyone have the wiring diagrams between the ECU/TCU and wiring harness for an automatic vtec prelude so that we can test this out? (page from an online service manual, page that you can scan from your own service manual, etc.)

also, i believe your revving up between shifts is caused by you manually shifting it every once in awhile (and i know you do it ). i'm NOT SURE about this - but it could be getting confused by that... thinking that you're getting ready to step on it. cause this is a problem that happens with my f22 tcu too. but these are both my personal theories.

[4thGen4dr]

I think that might be it Steve, mine is really bad now it doesnt shift anymore from 1st to 2nd at wot until I let off the gas for it to rev down or else it keeps goin. Can we find just the TCU wire harness you think then it will work straight?

[accordtunerx]

Originally posted by 4thGen4dr
I think that might be it Steve, mine is really bad now it doesnt shift anymore from 1st to 2nd at wot until I let off the gas for it to rev down or else it keeps goin. Can we find just the TCU wire harness you think then it will work straight?

well mine isn't that bad... that almost sounds like a tranny problem. but who knows, it could be electrical. as far as the wiring harness, i have the h22 wiring harness and could proably try and use the connectors on it for the TCU. but my dad was telling me that we should CHECK and even see if the pins are in the wrong spot or anything first. so we need the wiring diagrams for the h22 tcu out of a service manual.

[blazen_accord]

Re: Need help on fixing my TCU problem

Originally posted by 4thGen4dr
Im posting this again since I cant figure out, jus put in the prelude TCU now when my car shifts at WOT theres a long ass delay and doesnt want to catch the next gear and it goes all the way to 8000 rpm somtimes and sits there! I have no problems using my accord TCU and it's weird I have this same problem even with trying two different prelude TCUs. Also accelerating it likes to rev up between shifts from 1st to 2nd.Someone have a idea what i can do? Is this a electrical problem?

Same exact problem with my JDM h22 TCU, by 33mph i am in 4th gear already, but that with 25% throttle or less, it does go up to 7K when I floor it, the only other bad thing I know it does kick down gear correctly, at 30mph if I floor it, the TCU downshift to 2nd gear not first, since I can manual shift down to 1st and hit 7800rpm at ~45mph. my old F22 TCU was more responsive a blimp on the throttle and it downshift and go, with the h22 TCU it lag and I have to flooe it pass 70% for it to downshift. There must be some wiring issue or pin issue like u both say. I also notice my sportshift light (1990 coupe) no longer light up when I press it with the H22 TCU.

[accordtunerx]

yeah, i just use my F22 tcu right now and manually shift if i want to hit redline. but usually just a little bit of vtec up until 6,200 (f22 redline) keeps me happy... so i just floor it with the f22 tcu.

but if i'm racing, then i'll throw it down

but we need the wiring diagrams for that h22 prelude TCU

[4thGen4dr]

I usually use my accord TCU to because the shift lock and weird shifts get annoying. But I do like the way my car downshifts from 2nd to 3rd with the H22 TCU cuz it pulls! and I get alittle hop into 3rd wich is fun. I do Shift manually in a race from the line everytime, I dont think is too bad as long as your goin up gears seems like the h22 tranny is pretty strong and can take alot of abuse.

[blazen_accord]

the h22 tranny and axles should hold about 300hp, that a good ~270fwhp good for high 12's low 13's

hey will any bad happen if I replace my JDM P13 with a USDM P13? The darm JDM ECU got an 118mph limiter and I have not found a person or place to remove the speed limiter that cost less then $100. Remeber I have an automatic even harder to find a chip for it... any home garage tuner wanna earn some money chip my ECU for me

[4thGen4dr]

Originally posted by blazen_accord


hey will any bad happen if I replace my JDM P13 with a USDM P13? The darm JDM ECU got an 118mph limiter and I have not found a person or place to remove the speed limiter that cost less then $100. Remeber I have an automatic even harder to find a chip for it... any home garage tuner wanna earn some money chip my ECU for me

Faster than 118mph? Thats crazy! Iv only been up to 110 and I aint goin any faster than that. What would the USDM TCU go up to?

[blazen_accord]

USDM ECU/TCU suppose to have 130mph or no speed limit.
late a night on the highway with barely anyone on the road a 5-10sec rush of speed can be exicting. my 3rd gear top out at ~114mph, so most of the time I don't even shift to 4th when Floor it since the speed limiter kick in as soon as I shift, plus for $25 at a track you can go full throttle for up to a minute going lap around the track , best place for a safe place to push your car to the max and no cop to worry , 130+mph is the normal speed limit there

[Kurobei]

I'm having the same problems but i'm running a CD6 h22a tcu!

Hmm and I thought I was the only one having problems with the the jdm tcu.

I'm actually kinda liking my F-series tcu more than the H-series tcu right now. I aquired a jdm tcu from a CD6 h22a equiped accord.

Part # is 28100-PON-J01

I'm guessing u guys are running the P13 prelude version 28100-P19-003

I'm guessing Accords and preludes have the "P__" series for their tcu's
I remember also seeing a POF series for the h22a accords version of the P13 ecu.

From what I understand Accords use POx for the A6's and PO4?? for a4's, a1's? correct me if i'm wrong.


I'm debating whether or not this is a h22a tcu coz when I floor it from a stop, I cannot get into the 7grand range keeping it in D4. What does the jdm h22a accords redline at? If i remember right looking at a JDM CD cluster, I think it was lower than a the preludes redline of 7200. i think it as around 6800??

Anyways I'm experiencing the same things u guys are. It seems like the car drives more responsive....but yeah....it really does shift too quickly tho.

It goes like 1st.2nd...3rd.4th when normal acceleration
The downshifting is much smoother coming to a stop as it doesn't like "rev up" as much as it did when disengaging to the lower gears.

However kinda fast acceleration, it goes 1st..2nd...3rd...............4th. The third is really annoying coz it will hold in 3k rpms and not shift until I take it a little over 50mph.

But yeah, my car already can be in 4th gear at about 30mph which....i dunno is annoying? or right. Driving my sisters 93 prelude S (f22a4) I did notice her prelude shifts much sooner than my old f22a6. I'm curious to try her tcu over my accord P0x f22a6 tcu.

I do experience the lag u guys are talking about and I hate this one road I have to travel on everyday. The speedlimit is 50mph and if i excelerate normally.

[Kurobei]

Oh another thing... is anyone else experiencing this after swapping the h22a auto? I noticed with my old engine, the car will almost stay put when idle... however when i let go of the brakes, the car just kinda wants to go off on it's own. I mean not literally like if I was gassing it hard...but it will kinda be a little over 1,200 rpms and just coast around there. I remember before my car was swapped, the car will stay put and until i gas it a little it'll just go and eventually just stop after rolling. My car however will keep on going like it has a mind of it's own. It will only do this when I just give it a slight tap of the gas pedal...then it'll just coast until i put the car to 0mph.

I'm thinking it could be the throttle body is sticking or could be the throttle cable.....or is this tcu related?

[4thGen4dr]

For some reason after changing my oil it shifts real weird and im geussing it has to do with my oil level. My shift pattern goes like this undr normal driving 1st....2nd.3rd....4th.... And with your with your car not stayin put its probally cuz your idling too high. Mine is set to idle at 900 rpm and I still coast, from what I heard this is normal for a auto transmission, I coasted with my F22 too at a stop in d4.

[Kurobei]

Trying to revive this thread....

Anybody come up with a solution? I've been doing some researching on the internet and found that 97+ Preludes have the transmission control unit built inside the OBD2 ecu. Would it be possible to get a OBD1 to OBD2 wireharness adapter to use this ecu correctly? Will this effect other things on the OBD1 engine like throw codes etc. since no other OBD2 equipment is on it? Oh and yes I know their auto's are sportshifts..... but still just an idea i'm throwing out.