PDA

View Full Version : How could this be?



sexy240
06-12-2002, 12:24 AM
My car is running rich! I have a turbo KA and the only thing I have done to fuel is run a 4:1 FMU. I never go above 5 LBS and never floor it cause I am afraid to run lean on such a whimpy FMU. anyway my gas gauge is dropping really bad I have a 1/4 tank left and I have only gone 150 Miles http://www.freshalloy.com/ my car smells like its running rich and I back fire after some shifts. I am running a recirculating BOV. I havent pulled the plugs yet but will in the morning. how could this be?

Is my fmu screwed up and upping my pressure to much? any IDeas?

DuffMan
06-12-2002, 12:52 AM
Well when running an FMU, a fuel pressure gauge would be a good thing to have.

Annother possiblity is that the increased fuel pressure damaged the lower o-ring on an injector and it leaks into the manifold.

sexy240
06-12-2002, 01:11 AM
Yea I was just thinking that tonight. "Damn I guess Im gona have to buy a fuel presure gauge" Money I wanted to spend on AFC, fuel pump and injectors http://www.freshalloy.com/

ANOTHER QUESTION.

Is the US 240sx fuel pump the same as the SILVIA one? S-14 Shark eyes.

AND
will someone tell me what my fuel presure should look like at vacum, 1lbs 2lbs ect up to 7 lbs.

please I need vacum and boost presure levels.

any other thoughts on how this could be?

KenFuji
06-12-2002, 01:15 AM
make sure your plugs are or were good.
make sure the distributor cap is in good working order.
make sure you don't have a bad injector.
make sure your engine is grounded properly
make sure your timing is also good.

do you have a fsm? follow the proccess for running rich.

ken

sexy240
06-12-2002, 01:32 AM
Originally posted by kenfuji:
make sure your plugs are or were good.
make sure the distributor cap is in good working order.
make sure you don't have a bad injector.
make sure your engine is grounded properly
make sure your timing is also good.

do you have a fsm? follow the proccess for running rich.

ken<font size="2" face="Verdana, Arial[/img]Plugs are new

engine is grounded
timing is 1 degree less than stock
I dont have an FSM

06-12-2002, 05:25 AM
Originally posted by sexy:

please I need vacum and boost presure levels.
<font size="2" face="Verdana, Arial[/img]Fuel pressure at vacuum should be 34 psi, at 0 psi (what is normally WOT without the turbo) should be 43.5 psi. For boost, figure it out yourself! You have a 4:1 regulator, that means the boost goes up 4 psi for every 1 psi increase in manifold pressure.

As for your car running rich -- I'm not surprised. The tendency for cars running an FMU is to run rich in the mid RPM region. Here's why:

Say you're running 5 psi of boost, and the airflow meter says "wow that's a lot of air, I'm going to crank the injectors wide open". But the FMU has raised the fuel pressure, so you're injecting a LOT more fuel than you need in the midrange RPM...With an FMU and the injectors maxed out, the injectors inject the SAME amount of fuel at 3500 RPM as they do at 7000 RPM, but of course the engine doesn't NEED as much fuel at 3500 RPM, so you'll run rich.

Oh, and for the love of god, get an FSM.

Asad

sexy240
06-12-2002, 09:04 AM
Originally posted by asad137:
</font><blockquote><font size="1" face="Verdana, Arial[/img]quote:</font><hr /><font size="2" face="Verdana, Arial[/img]Originally posted by sexy:

please I need vacum and boost presure levels.
<font size="2" face="Verdana, Arial[/img]For boost, figure it out yourself! You have a 4:1 regulator, that means the boost goes up 4 psi for every 1 psi increase in manifold pressure.
</font><hr /></blockquote><font size="2" face="Verdana, Arial[/img]Duhh! I feel dumb for even asking.

[/qb][/QUOTE]
As for your car running rich -- I'm not surprised. The tendency for cars running an FMU is to run rich in the mid RPM region. Here's why:

Say you're running 5 psi of boost, and the airflow meter says "wow that's a lot of air, I'm going to crank the injectors wide open". But the FMU has raised the fuel pressure, so you're injecting a LOT more fuel than you need in the midrange RPM...With an FMU and the injectors maxed out, the injectors inject the SAME amount of fuel at 3500 RPM as they do at 7000 RPM, but of course the engine doesn't NEED as much fuel at 3500 RPM, so you'll run rich.
[/QB][/QUOTE]

yea but its only a 4:1, and doesnt the TPS and RPM have any say on how long the injectors stay open?

also I think it is running rich even under A no boost condition. I have been TRYING not to go above 0 PSI, and never above 5

06-12-2002, 09:52 AM
Originally posted by sexy:

yea but its only a 4:1, and doesnt the TPS and RPM have any say on how long the injectors stay open?
<font size="2" face="Verdana, Arial[/img]TPS, no, RPM yes (because it's one of the factors that determines the amoutn of airflow). But what I'm saying is that at 5 psi and 3500 RPM (made-up numbers), you could be flowing enough air that the injectors will be wide-open.


also I think it is running rich even under A no boost condition. I have been TRYING not to go above 0 PSI, and never above 5<font size="2" face="Verdana, Arial[/img]Well...that's a bit trickier. I hate to say it, but...what if you remove the turbo and go back to the stock intake/exhaust setup to see if you're still running rich even without the turbo (I'd keep the FMU in though, because without a turbo you'd never be in a situation where it's actually doing anything). It would make it easier to narrow down your problems without having to worry if you're going to damage anything.

Asad

sexy240
06-12-2002, 10:06 AM
Originally posted by asad137:
Well...that's a bit trickier. I hate to say it, but...what if you remove the turbo and go back to the stock intake/exhaust setup to see if you're still running rich even without the turbo (I'd keep the FMU in though, because without a turbo you'd never be in a situation where it's actually doing anything). It would make it easier to narrow down your problems without having to worry if you're going to damage anything.

Asad[/QB]<font size="2" face="Verdana, Arial[/img]HEll no. that manifold was so hard to put on I had to turn 4 of the bolts milimeters at at a time. the car didnt run rich before the turbo was on.

[note] I had the Fmu on the car before the turbo was on. I just wanted everthing in place so the install would go quicker.

[antother note] when i got the fmu I played with it a bit (took it apart)and took the bottom apart as well (oops curiosity)but then put it on my car...didnt run rich though

240sxTurbo
06-12-2002, 10:29 AM
Originally posted by sexy:
My car is running rich! I have a turbo KA and the only thing I have done to fuel is run a 4:1 FMU. I never go above 5 LBS and never floor it cause I am afraid to run lean on such a whimpy FMU. anyway my gas gauge is dropping really bad I have a 1/4 tank left and I have only gone 150 Miles http://www.freshalloy.com/ my car smells like its running rich and I back fire after some shifts. I am running a recirculating BOV. I havent pulled the plugs yet but will in the morning. how could this be?

Is my fmu screwed up and upping my pressure to much? any IDeas?<font size="2" face="Verdana, Arial[/img]so let me guess you have no fuel pressure gauge on a setup where your using rising rate fuel pressure setup to maintain fuel under boost??

When will the madness end.....

Can anyone actually predict what his next question will be.....this is getting fun to watch.

[ 06-12-2002, 11:34 AM: Message edited by: 240sxTurbo ]

sexy240
06-12-2002, 01:25 PM
Originally posted by 240sxTurbo:
</font><blockquote><font size="1" face="Verdana, Arial[/img]quote:</font><hr /><font size="2" face="Verdana, Arial[/img]Originally posted by sexy:
My car is running rich! I have a turbo KA and the only thing I have done to fuel is run a 4:1 FMU. I never go above 5 LBS and never floor it cause I am afraid to run lean on such a whimpy FMU. anyway my gas gauge is dropping really bad I have a 1/4 tank left and I have only gone 150 Miles http://www.freshalloy.com/ my car smells like its running rich and I back fire after some shifts. I am running a recirculating BOV. I havent pulled the plugs yet but will in the morning. how could this be?

Is my fmu screwed up and upping my pressure to much? any IDeas?<font size="2" face="Verdana, Arial[/img]so let me guess you have no fuel pressure gauge on a setup where your using rising rate fuel pressure setup to maintain fuel under boost??

When will the madness end.....

Can anyone actually predict what his next question will be.....this is getting fun to watch.</font><hr /></blockquote><font size="2" face="Verdana, Arial[/img]Im glad this is entertaining for you.

My next question:

will someone help me read my spark plugs?

1)the insulator is slightly brown speckled (is this Detonation or too hot of a plug? Detonation is always described as peppered so i imagine black)

2)the center electrode looks slightly pitted (Hard to tell) Due to preingnition? or to hot of a plug?

3)the film deposit on the center electrode seems to go all the way to the top but is hard to tell cause its really patchy. so timing should be good right?

4) the burn mark on the ground electrode is just less than the thickness of a floppy disk (except cylinder one witch is half a floppy)
5)the ground electrode is slightyl brown speckled

this is after 70 miles or so.

Do I just need a colder plug? I think this will I am already one step colder

240sxTurbo
06-12-2002, 02:18 PM
Originally posted by sexy:
</font><blockquote><font size="1" face="Verdana, Arial[/img]quote:</font><hr /><font size="2" face="Verdana, Arial[/img]Originally posted by 240sxTurbo:
</font><blockquote><font size="1" face="Verdana, Arial[/img]quote:</font><hr /><font size="2" face="Verdana, Arial[/img]Originally posted by sexy:
My car is running rich! I have a turbo KA and the only thing I have done to fuel is run a 4:1 FMU. I never go above 5 LBS and never floor it cause I am afraid to run lean on such a whimpy FMU. anyway my gas gauge is dropping really bad I have a 1/4 tank left and I have only gone 150 Miles http://www.freshalloy.com/ my car smells like its running rich and I back fire after some shifts. I am running a recirculating BOV. I havent pulled the plugs yet but will in the morning. how could this be?

Is my fmu screwed up and upping my pressure to much? any IDeas?<font size="2" face="Verdana, Arial[/img]so let me guess you have no fuel pressure gauge on a setup where your using rising rate fuel pressure setup to maintain fuel under boost??

When will the madness end.....

Can anyone actually predict what his next question will be.....this is getting fun to watch.</font><hr /></blockquote><font size="2" face="Verdana, Arial[/img]Im glad this is entertaining for you.

My next question:

will someone help me read my spark plugs?

1)the insulator is slightly brown speckled (is this Detonation or too hot of a plug? Detonation is always described as peppered so i imagine black)

2)the center electrode looks slightly pitted (Hard to tell) Due to preingnition? or to hot of a plug?

3)the film deposit on the center electrode seems to go all the way to the top but is hard to tell cause its really patchy. so timing should be good right?

4) the burn mark on the ground electrode is just less than the thickness of a floppy disk (except cylinder one witch is half a floppy)
5)the ground electrode is slightyl brown speckled

this is after 70 miles or so.

Do I just need a colder plug? I think this will I am already one step colder</font><hr /></blockquote><font size="2" face="Verdana, Arial[/img]http://www.dansmc.com/spark_plugs/Spark_Plugs_catalog.html

try using google..... and get the FSM.....

sexy240
06-12-2002, 02:23 PM
well I have searched the net. for the most part all the sites use the same photos, witch are extrem cases. the detonation examples show the insulators spit in half ect. Im trying to do my best reading them. my best guess is that they are running fine.

PS if i bought everything I was told to...

Rims tires $2200+
Hks bov $140?
external wastegate and manifold mod $ 350
Apexi Suspension $1800
Cusco strut bars $450
FSM $100
ST sways $350
sAFC (better yet JWT) 320 (??$600)
Injectors + fuel rail 700
ACT clutch $300
Cobra MAF ?$130
jun flywheel ?450

Good thing no one has recomended Rods, pistions lightened driveshaft, or stand alone yet!!

Im only (planning) running 7psi! and 9-10 psi after I can afford fuel mods here

SORRY I just need to vent Point is I only have so much money, the only person i am going to try and make happy is myself, and so far I have done it http://www.freshalloy.com/ I finnaly got my turbo on http://www.freshalloy.com/ cheaply yes but Im fixing it. Give me a break at least im not worried about body kits ect, I have my priorities straight. again sorry Im not directing this any anyone. my financial situation is upsetting me.

[ 06-12-2002, 03:41 PM: Message edited by: sexy ]

240sxTurbo
06-12-2002, 02:29 PM
Originally posted by sexy:
well I have searched the net. for the most part all the sites use the same photos, witch are extrem cases. the detonation examples show the insulators spit in half ect. Im trying to do my best reading them. my best guess is that they are running fine.<font size="2" face="Verdana, Arial[/img]post a picture.....typically mine would be a light gray, but very clean......