Prelude tuning problems

[TruDSMTuner]

me and my buddy are trying to tune his prelude, 93 h22a

it is running lean as hell with 450 dsm injectors and a vafc? any suggestions? running a t3/t4 turbo.. maybe to much air?

should he get a fmu, or need a bigger fuel pump.

any help would be appreciated..

if only he would get a dsm he wouldn't have these problems.
i feel bad i got more dsm parts and cars in his gaarage than he has honda parts lol...

but anyways.. thanks again. justin

[Don juan futon]

The fact that they are dsm shouldn't matter unless your wiring for the injectors is different. But if htat were the case, you would know because you wouldn't have any fuel at all? What kind of piggyback/standalone are you running?

[TruDSMTuner]

he's jstu got teh vafc....

i'm thinking he needs a fmu
.. without a oiggyback..

jsut trying to get some opionions.. it won;t even begin to run uder vtec.. way to lean.

[Don juan futon]

he's jstu got teh vafc....

i'm thinking he needs a fmu
.. without a oiggyback..

jsut trying to get some opionions.. it won;t even begin to run uder vtec.. way to lean.

The ecu is your problem man. Get a standalone or piggyback. Problem solved. I bet you 100 bucks!

[Feedman]

me and my buddy are trying to tune his prelude, 93 h22a

it is running lean as hell with 450 dsm injectors and a vafc? any suggestions? running a t3/t4 turbo.. maybe to much air?

should he get a fmu, or need a bigger fuel pump.

any help would be appreciated..

if only he would get a dsm he wouldn't have these problems.
i feel bad i got more dsm parts and cars in his gaarage than he has honda parts lol...

but anyways.. thanks again. justin

How do you know its lean?

Wideband ?
White Spark Plugs ?


With 450cc injectors in a Honda, I am assuming you used a Oem Honda resistor box or wired in a set of resistors.

Excuse my ignorance, I don't know much about Preludes and if they do come with a resistor box from teh factory.


Fmu's are junk.


Moving on, the only way to properly tune the car is on a dyno. Street tuning is effective only after the timing has been adjusted.

Vafc is great, once the timing has been compensated for. It will cause your car to run heavily ADVANCED....which is a big no no for a turbo vehicle.

A walbro 255lph fuel pump would be a great upgrade as well as a adjustable fuel regulator and guage.


Good luck.

8)

[Don juan futon]

me and my buddy are trying to tune his prelude, 93 h22a

it is running lean as hell with 450 dsm injectors and a vafc? any suggestions? running a t3/t4 turbo.. maybe to much air?

should he get a fmu, or need a bigger fuel pump.

any help would be appreciated..

if only he would get a dsm he wouldn't have these problems.
i feel bad i got more dsm parts and cars in his gaarage than he has honda parts lol...

but anyways.. thanks again. justin


A walbro 255lph fuel pump would be a great upgrade as well as a adjustable fuel regulator and guage.



8)


Word

[Feedman]

he's jstu got teh vafc....

i'm thinking he needs a fmu
.. without a oiggyback..

jsut trying to get some opionions.. it won;t even begin to run uder vtec.. way to lean.

The ecu is your problem man. Get a standalone or piggyback. Problem solved. I bet you 100 bucks!

I would take that bet. Assuming its on low boost, I don't see the ecu being confused...it should be able to handle anything under 10-11 lbs w/o a problem...the engine on the other hand...well thats a different story.... 8)

[Don juan futon]

he's jstu got teh vafc....

i'm thinking he needs a fmu
.. without a oiggyback..

jsut trying to get some opionions.. it won;t even begin to run uder vtec.. way to lean.

The ecu is your problem man. Get a standalone or piggyback. Problem solved. I bet you 100 bucks!

I would take that bet. Assuming its on low boost, I don't see the ecu being confused...it should be able to handle anything under 10-11 lbs w/o a problem...the engine on the other hand...well thats a different story.... 8)

Assuming it's on low boost I can kind of see your point, but I still think it's your ecu not being able to compensate enough for the fact of a positive pressure vs. a vacuum. Not able to adjust for enough fuel. VAFC's are nice, but I would never run one without tricking my ecu. And then I wouldn't get one unless my piggyback was unprogrammable (which is pretty gay)

[Feedman]

[quote=TruDSMTuner]he's jstu got teh vafc....

i'm thinking he needs a fmu
.. without a oiggyback..

jsut trying to get some opionions.. it won;t even begin to run uder vtec.. way to lean.

The ecu is your problem man. Get a standalone or piggyback. Problem solved. I bet you 100 bucks!

I would take that bet. Assuming its on low boost, I don't see the ecu being confused...it should be able to handle anything under 10-11 lbs w/o a problem...the engine on the other hand...well thats a different story.... 8)

Assuming it's on low boost I can kind of see your point, but I still think it's your ecu not being able to compensate enough for the fact of a positive pressure vs. a vacuum. Not able to adjust for enough fuel. VAFC's are nice, but I would never run one without tricking my ecu. And then I wouldn't get one unless my piggyback was unprogrammable (which is pretty gay)[/quote:a63e7]

Honda ecu's have extended fuel maps for boost. Part of the mathmatical algorithms. The map sensor's that see boost/vacuum are good until 10-12 psi.

So there is no reason, given that it can pump enough fuel via a pump and deliever it via injectors that it should run lean, unless there is a problem elswhere.....

The Vafc only allows the ecu to use the larger injectors, b/c it wasn't programmed from the factory to function with anything over 230cc I beleive..... 8)

[someone]

I know my friends 93' h22a prelude has a resistor box wired in. Its near the driver side strut tower, near the firewall..

Im thinking he should invest in a FPR, and Fuel Pump, The VAFC alone will not help his fuel problem. Then get that biatch tuned..

[Feedman]

I know my friends 93' h22a prelude has a resistor box wired in. Its near the driver side strut tower, near the firewall..

Im thinking he should invest in a FPR, and Fuel Pump, The VAFC alone will not help his fuel problem. Then get that biatch tuned..

Yea, I wasn't to sure on what they had, being pre obdII, I was under the impression they did, but didn't want to assume.

I would just double check his injector wiring, easy to make a mistake....or have one come loose and short out....easy way to burn up a cylinder......REAL FAST..... 8)

[Don juan futon]

Nice to know adam, thank you.

But like you said in the first post, how does he know it's lean? Still wondering that as well. Anything less than a wideband is crap. Even a tailpipe sniffer because you are still past the cat.


Hmmm.....

[TruDSMTuner]

tuned with wideband, installed fpr, runs better.. what is a good fuel pressure for a honda?
also it is a rising rate regulator.. so that should help out put what's a good start off point?

thanks for the help

[evilnissan]

I expect to be shot down for this one but I would say between 37-40 psi base.

[Feedman]

I expect to be shot down for this one but I would say between 37-40 psi base.


Depends...I don't know what Preludes run to be honest...

Mine is @ 43 ish.....

I do know that its better to have a higher fuel pressure and then lean it out in the Vafc, than to run a low pressure and add fuel.....

Can't tell ya why...just what I have heard.... 8)

[Don juan futon]

Hey I'm curious what you got. What year? H23 or h22? Turbo setup? Any mods? I know it's your buddy's, but I got a good friend with one.

[TruDSMTuner]

it's a 93 prelude h22a vtec 5sp. running a obx manifold and 60 trim turbo 450 dsm injectors, fpr, vafc, sidemount intercooler, downpipe open to apexi muffler,

ran a 9.45 in the 8th without the turbo..

still ahvn;t fixed the problem yet. lol

[Don juan futon]

Still no solution, huh? Hmmm...

[Feedman]

it's a 93 prelude h22a vtec 5sp. running a obx manifold and 60 trim turbo 450 dsm injectors, fpr, vafc, sidemount intercooler, downpipe open to apexi muffler,

ran a 9.45 in the 8th without the turbo..

still ahvn;t fixed the problem yet. lol

Sounds good...I don't think I could break my car into the 9's without a turbo N/a.....@ least keeping it stock....

9.45 isn't bad..... :thumbup:

[TruDSMTuner]

Got the lude running better, we wideband it, and ran colder plugs. thnaks to adavanced i think they gave us hotter plugs the first time.

oh well running ngkre7's
runns alot better pulls good, smoke tires in second, will be at knawaha valley next friday for the first track night WOOOHOO

[Feedman]

Got the lude running better, we wideband it, and ran colder plugs. thnaks to adavanced i think they gave us hotter plugs the first time.

oh well running ngkre7's
runns alot better pulls good, smoke tires in second, will be at knawaha valley next friday for the first track night WOOOHOO

Good luck, keep us posted man..

I run NGK BKRE7's also...

Good solid plug.... 8)