WAY too rich
#1
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WAY too rich, still
got my diy setup running but i am having a drivablity problem. my set up is, 13g turbo off of a auto DSM, i think the wastegate is at 9psi(and thats as far as i noticed it went on the guage). first gen probe intercooler, VTA BOV with a ton of spacers so it stays closed at idle. and 310cc injectors from a 89 probe gt. and a cartec FMU.
the problem is that the car is really rich. idles around 12.5-13:1 but as soon as you hit the gas at all or try and drive around the block it basically stays pegged out at 10:1 on the guage (AEM ugeo wideband) car bogs and stutters pretty bad. timing is set to 6 btdc.
i have searched and havent turned up anything too usefull. i am going to try and adjust the afm, but i have read the screw is just for idle, and some people have adjust the spring inside the afm, but say thats also just for idle. so which is it?
and also i set the FMU by just turning on the fuel pump, engine not on. i have a adjustable fuel regulator with a guage it put in the feed line before the fuel rail with just the adjuster screwed all the way out so i just had the guage to read. i set it to 55psi with no vac on it, did i set the fmu right?
any help would be great
the problem is that the car is really rich. idles around 12.5-13:1 but as soon as you hit the gas at all or try and drive around the block it basically stays pegged out at 10:1 on the guage (AEM ugeo wideband) car bogs and stutters pretty bad. timing is set to 6 btdc.
i have searched and havent turned up anything too usefull. i am going to try and adjust the afm, but i have read the screw is just for idle, and some people have adjust the spring inside the afm, but say thats also just for idle. so which is it?
and also i set the FMU by just turning on the fuel pump, engine not on. i have a adjustable fuel regulator with a guage it put in the feed line before the fuel rail with just the adjuster screwed all the way out so i just had the guage to read. i set it to 55psi with no vac on it, did i set the fmu right?
any help would be great
Last edited by bryantaylor; 10-08-2007 at 03:37 PM.
#2
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there should be two adjustment screws on the FMU. one in the middle with an allen wrench, which 55psi is fine. anywhere between 48-55psi is good at no vaccum.
however, there should also be a needle vavle that allows for the rate of gain to change. sounds like you're at full 12:1 ratio. I betcha the fuel pressure is maxing out at 120psi, you probably only need like 70-80.
dont adjust your oem afm tension, it's best as is. however DO adjust the idle screw to idle at 14.7, it's under a little cap you have to drill out.
however, there should also be a needle vavle that allows for the rate of gain to change. sounds like you're at full 12:1 ratio. I betcha the fuel pressure is maxing out at 120psi, you probably only need like 70-80.
dont adjust your oem afm tension, it's best as is. however DO adjust the idle screw to idle at 14.7, it's under a little cap you have to drill out.
#3
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there should be two adjustment screws on the FMU. one in the middle with an allen wrench, which 55psi is fine. anywhere between 48-55psi is good at no vaccum.
however, there should also be a needle vavle that allows for the rate of gain to change. sounds like you're at full 12:1 ratio. I betcha the fuel pressure is maxing out at 120psi, you probably only need like 70-80.
dont adjust your oem afm tension, it's best as is. however DO adjust the idle screw to idle at 14.7, it's under a little cap you have to drill out.
however, there should also be a needle vavle that allows for the rate of gain to change. sounds like you're at full 12:1 ratio. I betcha the fuel pressure is maxing out at 120psi, you probably only need like 70-80.
dont adjust your oem afm tension, it's best as is. however DO adjust the idle screw to idle at 14.7, it's under a little cap you have to drill out.
#4
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just idle to car. make sure you have 35psi at idle. pull the vacuum line on the OEM FPR. kink the line so it doesnt foul the idle. turn the preload to hit 48-55psi. put the vacuum line back.
adjust the AFM to idle at 14.7. theres a little cylinder with a silver cap, you must drill the cap off and exposed a screw. turn it back about 1 full turn counter-clockwise. that shoudl get you to 14.7.
go driving in boost, continue to back the needle vavle more open and open untill 12:1
vacuum line goes straight into FMU. check valve on needle vavle, postitioned to prevent vacuum from pulling through the unit, boost should escape out.
adjust the AFM to idle at 14.7. theres a little cylinder with a silver cap, you must drill the cap off and exposed a screw. turn it back about 1 full turn counter-clockwise. that shoudl get you to 14.7.
go driving in boost, continue to back the needle vavle more open and open untill 12:1
vacuum line goes straight into FMU. check valve on needle vavle, postitioned to prevent vacuum from pulling through the unit, boost should escape out.
#7
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re-set the fmu with a new guage, and the bleeder is turn about 2/3 out, check valve after the bleeder to let boost out but no to pull vac. adjusted the idle on the AFM, so thats a little better. did about 1 1/2 turns out. but as soon as i hit the gas, pegs out rich. did a WOT 3rd gear run. turbo spools, holds 9psi, stays pegged rich on the guage. but the car just doesnt pull at all. i will try to turn out the bleeder more, but there i just not much more i can turn it out. i am starting to think these 310cc injectors are just too much for the stock ecu.
#8
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I don't understand why you people keep "tuning" your FMU with a fuel pressure gauge. who gives a **** what the fuel pressure is if the a/f is way off? tune that bitch with your wideband, throw the stupid pressure gauge away. how hard could this be? you're rich. back down fuel pressure. the end.
#9
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if you turn the bleeder valve all the way out and it's still pig rich, you need a restrictor on the vacuum line.
Ben, you at least need to correctly set the preload, after that the pressures are trival :gay:
Ben, you at least need to correctly set the preload, after that the pressures are trival :gay:
#10
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i am not tunning by a pressure guage, i have a AEM wideband. i have no fuel pressure guage on the car, only had one to set the base pressure on the fmu. i will bump upmy timing to 8btdc also to see if that will help it out some
#11
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alright screw this im putting the stock injectors back in. even at cruise with like 10in of vac, the afr is 10.2:1 and with the bleeder screw all the way out, the leanest it ever got was 10.3:1
#13
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I'm wondering if he doesn't have the center screw jacked down waaayyy too far. That would make cruise too rich.
also the needle valve only affects the rising rate, not the overall pressure. overall is adjusted with the center screw.
#17
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put the 310s back in. i can get it to idle 13-15:1 so thats not an issue. set the fmu again. base pressure is 48ish psi. kept the guage on and set it under the windsheild wiper and went for a drive. doesnt add any fuel in vac, starts adding in boost. at a full 9psi of boost, its at 65-70 psi of fuel pressure. idle afr is ok, but as soon as you start driving, stays at about 10-10.5:1 afr. looks like i need to adjust the tension spring now?
#20
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2-yes and yes. it is plugged in but its not in the downpipe, just hanging there while my wideband is in. i know it should make it a tad richer, but not as much as it is. the car has NO CEL on.