Lude won't rev over 3k

[wurlycorner]

Bloody thing.

[youtube]UVA_kfPpmLY[/youtube]

What's going on with it?

My suspicions have been lambda sensor related cause when it had warmed up to the point where it starts using lambda rather than coolant temp sensor, idle started rising (fine from cold until warmed up where it would switch over). Haven't managed to change that yet (it's not coming off on the drive - exhaust has got to come off, which means over to the barn, which I can't do just yet unfortunately...) so I tried unplugging the lambda sensor on the basis it would then run on a default value but... Have discovered it wont rev over 3k when cold either.

The ecu has logged a fault code but won't divulge anything (jumping service connector achieves nothing unfortunately).

FWIW the car has an unknown chipped ecu (this was either running in the h22 swapped BA8 that I broke and has been running fine)l, or was already in the car when I got it - I can't remember which tbh!) and an r spec vtec controller plugged in via pukka interrupt harness. I installed the latter myself, swapping from the h22 BA8, which had been running fine.
When I installed the r spec controller, I found some damage on the original car wiring harness (one of the words had been cut and badly rejoined) which I repaired.

So, it could be any of the above mods etc (which I can obviously reverse out for testing) but... Assuming all that was OK, what could cause this on the original car?

HT leads, plugs, distributor cap, rotor arm were new last year and look fine.

[Scott560]

Sounds like one of the low rpm launch limiters? I think that can be programmed into a custom ECU chip, disables when there is speed detected?

Not sure what would cause it to come on by itself if nothing else changed.

Otherwise I'd check the coil for arcing or blocked cat/exhaust.

Sent from my MIX using Tapatalk

[wurlycorner]

I had wondered about the cat, but I think it's far too 'clean'a cut to be that. It's definitely ecu limiting.
I don't think the chip is that clever to have a limiter. It's just a different map chip, Not programmable.

Knock sensor...

[RattyMcClelland]

I'm sure you may have checked but in case I would do following.

Reset ecu
Pull plugs and check
Open dizzy and check
O2 sensor replace possible
Knock sensor if I have a spare
Fuel injectors out and check
Fuel rail off and pressure check
Iacv unplug and rev check

[wurlycorner]

Ta

I think I'm gonna grab the following from my spares stash;
Ecu
Knock sensor
Distributor (for spare crank sensor)

And try them in that order at home (will be this evening before I get on it)
Lambda sensor will have to wait till I can get it over to the barn, so will try them first.

[lewd lude lover]

knock sensor wont do that mate. IMHO thats ecu limiting to safe mode of some kind.

[bennyboy]

It deffo stinks of ECU to me, whether that's the unit itself or its doing something because of a faulty signal its receiving, I wouldn't know enough to say.

[Drax]

It deffo stinks of ECU to me, whether that's the unit itself or its doing something because of a faulty signal its receiving, I wouldn't know enough to say.

I completely agree, swap the ECU

[crxdriver]

Did this have launch control? If it did and was set at 3k my money would be on a vss or signal wire. Its not in limp mode i dont think as every Honda including my 5th gen seem to limit at about 3500-4000 on the rev gauge in limp mode.

[NafemanNathan]

It doesn't have launch control.