st00pid

2000 prelude, FMax turbo, 720cc, Hondata s100, P28, custom jumper harness, resistor box etc..

when the car gets warmed up and you try to go into boost.. no matter what boost you run.. 6psi, 15psi whatever. once you get up to about 5-7krpms the car spuuters, backfires then drops to a 3500rpm rev limiter. you can shut the car off turn it back on and rev to 5-7krpms and start the process over again.

I have the boost cut at 28.5psi and disabled, rev limiter at 8500, vtec at 4800. AF is at 11.6:1. The car has been running fine for a few months after we dyno tuned.. then one day it started acting up..

I have checked the entire engine harness for unplugged sensors, changed the MAP sensor, changed the altenator, changed the resistor box, changed the ECU, harness adapter, ROM and Hondata S100; all from well running cars.

Ive tried everything I can think of.. at this point Im sure its something stupid, that I am over looking.. Im quickly going bald trying to figure this out..


any ideas?

done

does it throw a code? or is it disabled with hondata?

Adi Radoncic

This is a stupid question sence you are running that big of injectors and hondata on the system anyways but are you still using the MF2 on the vehicle...?

Adi

VaporTrail

would it be stupid to ask if you've tried a different distributor, plug wires, coil or plugs? Sounds ignition related.

93LSivic

Damn, you must really be stumped if your asking us here for help.

I will contribute with suggesting that you check the injectors themselves. Maybe datalog the duty cycle to see if it acts up at the same load on the injectors.

boostaholic

Jason, i'm assuming you're running a 3 bar map sensor? I've heard of certain 3 bar maps not working correctly with the Hondata and maybe the map sensor isn't reading right as soon as it starts seeing boost? Does it sputter if you rev it past 5k without boost? Just tossing some ideas into the mix.

st00pid

I changed the MAP sensor already..it reads fine with the honda logger, It doesnt throw any codes, The MF2 was removed from the car when the Hondata was installed. Ive changed the distributor and the plugs and wires. The ignition is all stock. Im still lost on this one,.

DSF

Checked the main relay?

I know, sounds weird. Just had a friend with a Prelude with similar symptoms (without boost, however) only when the car was fully warm. Changed his main relay on a last ditch effort and it's all fine. Weird

st00pid

Ill look into that

st00pid

any other thoughts?

RedHB

The same exact thing just happened to me when I put a turbo into my friend's SH. I changed the spark plugs and reduced the gap to .028" and that solved the problem. try that out and see if it helps. Talk to BlackSH on this forum and ask him about all the symptoms.

SiRkid

plugs is a good one! but i dont know if it would cause it to be stuck revving at 3500.

GraphiteAccord

my car acted like that when my timing was wayyy off..

st00pid

The part I cant figure out is why it goes to the 3500rpm rev limiter if there is a problem with tuning/plugs/misfire.

Bspec18

i can relate, have somewhat the same problem, im running an fmu /missing link though... at a certain RPM it acts up i've changed all the same parts too.... whats your A/F reading when this happens ?

Bspec18

hey what happens when you drive your car with out it warming up ? still have problems ?

st00pid

The car has Hondata, If you dont wait for the car to warm up fully you can beat the hell out of it and it will run fine. I dont like doing that cause its hard on the engine. The AF is 11.6:1 under boost until around 6krpms then it pegs rich on the wideband, backfires and hits a rev limit.

Jason kiDD

I would check the KS. I may be hearing something that is going on that you are not on the outside. And that will fully put the engine in safe mode hence the 3500rpm limit till you restart the car.. It may be faulty or it may be hearing detonation..

st00pid

There is no KS.. we are running the car on a P28 with Hondata.

tried the PGMFI main relay, another set of plugs, and it still has the same issue.

Ive checked all the connections they all seem to be good.

Im still lost.

Jason kiDD

Then I would blame either the Hondata or injectors..

st00pid

Hondata has been changed, injectors have been changed. The Hondata has been double checked in another car and works fine.

done

have you try different gaps? like red hb has said?

st00pid

Ive tried tightening up the gaps, but why would a misfire cause the ECU to go to limp mode?

VaporTrail

it sounds like the rom image has somehow deteriorated. I ran into a similar problem, changed everything under the moon, no affect. Out of pure desperation, built an entire new base map (not just reburning the same program) - voila, all fixed. I'll never understand it either....

The other thing to check is to make sure the ecu is switching fuel maps. I'm sure you've done all of these things but we gotta cover the bases.

VaporTrail

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by st00pid &raquo;</TD></TR><TR><TD CLASS="quote">The car has Hondata, If you dont wait for the car to warm up fully you can beat the hell out of it and it will run fine. I dont like doing that cause its hard on the engine. The AF is 11.6:1 under boost until around 6krpms then it pegs rich on the wideband, backfires and hits a rev limit.</TD></TR></TABLE>

this statement again makes me really believe it to be ignition related, especially reminiscent of ignitor difficulties.