just installed new 450cc injectors BUT.......

[240sxvaj]

it had a bad idle about 15 to 25 minutes later (engine fully warmed up)

i just installed brand new d-werks 450cc injectors into my 91 ka-t25 untuned and drove fine til 15 to 25 later as i would pop it in nuetral while driving on 3rd gear i see my rpm drop from 3500 to 300-200 rpm and then it would raise rite back up. it would not die

it does this a few times.

a couple of minutes driving longer my car would just shut down on me.but then it would start rite up after that

what can cause that?

i have brand new z32 fuel filter, brand new walbro 255 fuel pump and 450cc

thanks!

[GTR PrYdE]

untuned?!

you're running pig rich if that's the case, a tune should clear it up

[240sxvaj]

i have AFC Neo and plannin to get it dyno tune as soon as i fix this problem, BUT..... if this is really the case then i'll have to tow it to get it tune and i hope it is.

it already had this problem w/270cc before i installed the 450ccbut with the stock 270cc my car will bog before it dies

Modified by 240sxvaj at 2:11 PM 12/22/2007
Modified by 240sxvaj at 10:05 AM 12/23/2007

[bruinbear714]

Drop your 270cc back in, fix your problem, then upgrade.

i have AFC Neo and plannin to get it dyno tune as soon as i fix this problem, BUT..... if this is really the case then i'll have to tow it to get it tune and i hope it is.

it already had this problem w/270cc before i installed the 450ccbut with the stock 270cc my car will stall before it dies

Modified by 240sxvaj at 2:11 PM 12/22/2007

[GTR PrYdE]

Drop your 270cc back in, fix your problem, then upgrade.

It's issues like this that keep me from turboing too...

[240sxvaj]

Drop your 270cc back in, fix your problem, then upgrade.

Well actually it was worse with the stock 270cc injectors. when heated up to normal temp the car would bog and it would seem like boost leak and then it would idle really low and dies. NOW with the new injectors the car doesnt bog anymore and it runs really good even when heated up to normal temp BUT then it dies after i let go of the gas. it seems like it wont die if i rev it when the rpm drops really low. and this happens really fast so if it doesnt die then i will go back to normal idle

I was told to replace the injectors and see what happens and yes there was improvement but just that the engine still dies.

[Zippy69]

You will never know anything until you have it tuned. Get that bad boy to a dyno pronto and have it tuned. That is why you don't drive around untuned. You are lucky because you are rich for the most part, but somewhere in your rpm range I'll bet you are lean, and you keep your engine there too long you'll be sorry.do the right thing, get a tune.

[GTR PrYdE]

You could also have some major vacuum leaks. I've had my car do close to the same thing, bogging down when you let off the throttle- but it was a combo of the IACV and some other vac leaks

[gaehrings13]

Check the temp sensor that goes to your ecu. It could also be a problem. If it is working improperly it can make the car runn erratic.

[240sxvaj]

i have no vaccum leakmy meter sits on 19 to 20

coolant temp sensor? already replace a brand new onewhere is this temp sensor that goes to the ECU located? or are you talking about the coolant temp sensor?

thanks
Modified by 240sxvaj at 1:43 AM 12/23/2007

[sunboys]

#1 You need to get an adjustable fuel regulator cause your walbro fuel pump. #2 Put back your stock MAF sensor. #3 and stock injectors. Now if you want to ugrade the way you want it before, upgrade your ECU also or just buy a 510 instead!

[240sxvaj]

#1 You need to get an adjustable fuel regulator cause your walbro fuel pump. #2 Put back your stock MAF sensor. #3 and stock injectors. Now if you want to ugrade the way you want it before, upgrade your ECU also or just buy a 510 instead!

#1 FPR is unesssary (spelling) til my old one goes bad. i have seen ka-t's with stock FPR

#2 i am running my stock MAF.

#3 stock injectors made my car bogs. thats why i replace it with the 450cc and the problem was fix.

ecu is not until i can get more money. a AFC will be fine at the moment

510? not interested

[spooled240]

let me ask you something, after the car dies and you start it up again does it run and drive really rich? I had a very similar problem not too long ago, maybe 2 wks ago and I'm pretty sure a bad mafs ground to the chassis that i connected not long before that. So I disconnected it and ran great w/ out any problems.

BTW, 450cc on a stock ecu w/ no tune!? That's crazy-pop the stock 270's in try and fix it that way because 450's aren't supposed to be running at all with out any tuning

[240sxvaj]

let me ask you something, after the car dies and you start it up again does it run and drive really rich? I had a very similar problem not too long ago, maybe 2 wks ago and I'm pretty sure a bad mafs ground to the chassis that i connected not long before that. So I disconnected it and ran great w/ out any problems.

BTW, 450cc on a stock ecu w/ no tune!? That's crazy-pop the stock 270's in try and fix it that way because 450's aren't supposed to be running at all with out any tuning

after it dies it starts up fine. it runs rich too.i havent try disconnecting the MAF yet. let me try that.i did more research and some people had the same problem and it was the Distributor.so im gonna head to the junk and pick one up and see how it turns out.

im gonna get my car tow to the dyno tuneing shop

[emo_tactical9]

It's funny that you know what your problem is but you keep saying it might be something else. You shouldn't worry about any of that other stuff till you get it tuned.

[Tx-Sx-FS]

did u try adjusting the decel air settings on the afc?? thats what matters between shifts if runnin open bov

[neverlift]

do you have a wideband are you running suck thru?

if you didnt know this, upgrading while you have issues adds issues

[240sxvaj]

my AFC NEO hasnt been installed yet. im haveing the shop do it for me.

im gonna get the car tuned by wednesday the latest.

[Zippy69]

Good deal dude. Keep us posted. I hope it all goes well for you.

[240sxvaj]

did u try adjusting the decel air settings on the afc?? thats what matters between shifts if runnin open bov

between shifts i am fine either boostin or not it shifts fine.(AFTER CAR WARMS UP) i found out that if i let go of the gas AFter boostin the cars rpm drops really low and goes right back to normal for a quick sec. and sometime it dies. Unless if i keep my foot on the gas to keep the rev up then it wont die. One other thing i found out that if i dont boost and just drive light then i dont have that rpm droppin on me. Could this be because i am Open atmospheric BOV?

SOrry for sayin so much but i dont want to make a trip to the dyno shop and find out its another problem because its far from where i live.

[coolbone28]

Yes. Having an vta bov is probably the most likely cause to your bogging, as well as having injectors twice the size untuned.

[S13FX]

First off, dont go into boost on stock injectors with out at least a rising rate regulator, second of all there is no way 450cc injectors will run on a stock ECU, with out having the AFC compensating for them.

Thats your problem right there.

Now is the car boosted yet or stock? If it's stock pop in your stock 270cc injectors in there first and work out all your kinks.

For just a Z32 fuel filter a walbro and everything else stock you shouldn't need anything else.

Also a Wideband would be a very good idea. I would never dare run a boosted car with out having a wideband to monitor but thats just me I know people do it all the time.

[240sxvaj]

First off, dont go into boost on stock injectors with out at least a rising rate regulator, second of all there is no way 450cc injectors will run on a stock ECU, with out having the AFC compensating for them.

Thats your problem right there.

Now is the car boosted yet or stock? If it's stock pop in your stock 270cc injectors in there first and work out all your kinks.

For just a Z32 fuel filter a walbro and everything else stock you shouldn't need anything else.

Also a Wideband would be a very good idea. I would never dare run a boosted car with out having a wideband to monitor but thats just me I know people do it all the time.

The car have been boosted for over a month now. everything was running fine since i bought the car and tune-ups was done on time before i decided to Turbo. the only reason why i was laggin on the injectors was because i was waiting forever to get 370cc injectors instead i decided to go d-werks 450cc. (wait time was over a month) Bought the AFC neo and was deciding to get a wideband but was told that if i was gettin dyno tune then it wasn't needed unless if i was tunning myself, But planning to get one in the future.

Dyno tune is set for this friday and hopefully everything turns out good. the only reason why i was running the car boosted and untune is to make sure i didnt have any boost leak and any other problem. i want to make sure that everything was fine before i make a LONGG trip to the dyno shop.

[eazye2000]

Well get that mug' tuned and report back!

I was thinking the Open Blow Off was the cause. But the fire-hose injectors would do that too I suppose. Possibly a mixture of both.

I've never run my car with an Open BOV. I have a suck through MAF. And my BOV is recirculated. Maybe I'll try it one day for the 'wow' factor..

[240sxvaj]

I just got back from JER DEVELOPMENT dyno shop and i got bad and good news ....Bad news! stupid me, the oil return line was crap which caused black smoke and the smell of oil burning at high rpm, the guy told me to redo the line and then come back for the real dyno tune. he is 80 percent sure that it's the problem. IF you see my JGS oil return line it looks like crap such as it having too many curves. dumb me

ALso of course running rich as hell. this caused the car to stall on me many times and took forever to start up which f**K up traffic. i had my mechanic check it out and pull out one of the gas line and it started up fine. the whole time i was stuck in traffic i was gasin it like helll. which explained why i couldnt start it.

WOuld a feul pressure regulator solve this problem?HELP!

THe good news!(not really) we did a rough tune, AFR is good until about 3900rpm where the AFR dropped to Low 10's. Steady boost of 6 psi not gasing all the way, making 184.2 whp!

I was told that the engine is really healthy and idles good.He also predicts good 200+ whp when i get my problems fixed.

also for the bov, we did about 5 runs and car didnt die so i guess dont need to recirculate bov.

This was dyno on DYNO DYNAMICS the guy told me that hp reading were a little lower than dynojet meaning if i ran my car on dynojet then i'll make higher numbers. can anyone confirm this?

[eazye2000]

Sounds good man! Fix those problems, and head back to the Dyno. It's the little things that hold you back. I hate it...