too low fuel pressure

ready247 · Post by **ready247** » Sat Jul 29, 2006 11:45 pm

03 neon sohc
Ok fuel setup first
walbrow pump
spoolboy mod
-6an return and feed lines
venom fuel rail
begi 2035 fmu
stock injectors
missing link

car is running 14.7 to 1 afr @ base pressure of only 9 psi, tried useing 03 srt-4 stock injectors couldn't even run at all with these, it was so rich, so 2 problems i don't get the ultra low idle fuel pressure, and why cant i get the srt injectors to work. only able to boost to about 4psi with almost 80# of fuel pressure on stock injectors

any helpful hints would be appreciated

Kevin_GP · Post by **Kevin_GP** » Sat Jul 29, 2006 11:56 pm

Your AFRs are always going to be at 14.7 with stock computer no matter what your base pressure is. Your running to rich with the srt-4 injectors at idle? What are your AFRs, or are you just throwing a code?

Also do you have a one way check valve on your regulators vac line? I know no one on this site is going to suggest this but if you are to rich at idle you can just use a restrictor instead of a check valve so your regulator sees vacuum and lowers pressure. You already said your fuel psi is around 9 though. If you have a restrictor this will lower your fuel pressure more, if that is what you are going for.

ready247 · Post by **ready247** » Sun Jul 30, 2006 12:05 am

Kevin_GP wrote:Your AFRs are always going to be at 14.7 with stock computer no matter what your base pressure is. Your running to rich with the srt-4 injectors at idle? What are your AFRs, or are you just throwing a code?

Also do you have a one way check valve on your regulators vac line? I know no one on this site is going to suggest this but if you are to rich at idle you can just use a restrictor instead of a check valve so your regulator sees vacuum and lowers pressure. You already said your fuel psi is around 9 though. If you have a restrictor this will lower your fuel pressure more, if that is what you are going for.

we could adjust the rich lean at idle with the begi fmu and stock injectors, when i had the srt injectors in it was so rich it wouldnt run

Kevin_GP · Post by **Kevin_GP** » Sun Jul 30, 2006 12:14 am

You sure they are stock? They are pink/purplish color? I dunno why my stock srt-4 injectors work perfect. Not sure how to help you.

ready247 · Post by **ready247** » Sun Jul 30, 2006 12:52 am

yep pink/purplish

60trim · Post by **60trim** » Sun Jul 30, 2006 1:21 am

Get smaller injectors? I have 24# with a 12:1 FMU with a -6 return line. My car idles fine. What brand are your injectors? I have mustang 24 lbers and the impendance is pretty much on the money.

ready247 · Post by **ready247** » Mon Jul 31, 2006 5:51 am

Kevin_GP wrote:You sure they are stock? They are pink/purplish color? I dunno why my stock srt-4 injectors work perfect. Not sure how to help you.

whats your fuel system set up?

Kevin_GP · Post by **Kevin_GP** » Mon Jul 31, 2006 12:06 pm

Spoolboy with -6 return, drilled out stock fuel rail, srt-4 injectors, and a Vortech SFMU. I forgot what disks are in the vortech, but regardless of my rate of gain, I always idled fine with the srt-4 injectors.

ready247 · Post by **ready247** » Mon Jul 31, 2006 12:36 pm

Kevin_GP wrote:Spoolboy with -6 return, drilled out stock fuel rail, srt-4 injectors, and a Vortech SFMU. I forgot what disks are in the vortech, but regardless of my rate of gain, I always idled fine with the srt-4 injectors.

whats your static idle fuel pressure?

ready247 · Post by **ready247** » Mon Jul 31, 2006 1:23 pm

Kevin_GP wrote:Spoolboy with -6 return, drilled out stock fuel rail, srt-4 injectors, and a Vortech SFMU. I forgot what disks are in the vortech, but regardless of my rate of gain, I always idled fine with the srt-4 injectors.

also as we raised the idle pressure up from 8 it would get richer with stock injectors

Kevin_GP · Post by **Kevin_GP** » Mon Jul 31, 2006 2:36 pm

Statics somewhere between 20-30 psi. I have a restrictor and it brings the pressure down around 10 or lower.

ready247 · Post by **ready247** » Mon Jul 31, 2006 10:16 pm

Kevin_GP wrote:Statics somewhere between 20-30 psi. I have a restrictor and it brings the pressure down around 10 or lower.

ok but my problem is its 8 now with stock injectors and runs fine at idle

Kevin_GP · Post by **Kevin_GP** » Mon Jul 31, 2006 10:36 pm

Your not going to be able to use the stock injectors with boost. You need to make the srt-4 ones work. If your static pressure is at 8, thats way to low.

If you are still havings with those injectors they might be faulty, because ive had no problems at all with a similar setup.

ready247 · Post by **ready247** » Mon Jul 31, 2006 10:38 pm

Kevin_GP wrote:Your not going to be able to use the stock injectors with boost. You need to make the srt-4 ones work. If your static pressure is at 8, thats way to low.

If you are still havings with those injectors they might be faulty, because ive had no problems at all with a similar setup.

these are the injectors that were in the car and it ran fine and i know i need bigger injectors. it will run rich with stock injectors @ more than 8 psi fuel pressure

ready247 · Post by **ready247** » Tue Aug 01, 2006 12:04 am

the problem is that i cant have more than 8 psi of fuel pressure at idle or it runs rich with stock injectors, i know the rate of gain will off, with srt injectors, but if i put the srt injectors in even at 9psi it will run rich. i run out of fuel at about 4 pounds of boost on stock injectors, the fuel pressure is at 75, this is why i need a bigger injectors. i hope this makes my problem more clear. basically why is it running @ 14.7 afr on stock injectors at idle no boost. with only 9psi fuel pressure. What do u mean a check valve between the manifold and the rrfpr? And the begi 2035 has a way to compensate off idle before boost fuel pressure. i just need to know why the crazy low idle fuel pressure

http://www.bellengineering.net/Pages/pr ... ction.htmlthis is the 2035 regulator im using

lethalp1mp · Post by **lethalp1mp** » Tue Aug 01, 2006 10:43 am

Sounds like you need to put the check valve on the signal line instead of the bleed. Neon's are setup for static pressure from the factory, and putting the check valve in the signal line allows this for out of boost operation. It will make it easier to tune. I run SRT injectors with a Begi 2025 at around 15-17psi base pressure, because that's the lowest I can go. For the most part, they run fine at idle, they get a bit rich during some driving conditions, but otherwise not too bad. The only time I notice them running rich at idle is when I've had the battery disconnected and the pcm is relearning.

Ideally you probably want to be running 36# injectors. I would have went with them , but I am going MS and the SRT's will work great for that.

Kevin_GP · Post by **Kevin_GP** » Tue Aug 01, 2006 12:57 pm

I agree, using just a static fuel pressure works ok. I had it like this on my car for a while, now I use a restrictor which has a slight vacuum and my car runs better off boost now and cruises better. The only problem is my cars more sensitive to temp changes and needs to be warmed up. I guess its the trade off.

However ive runned stock srt injectors from 3 psi - 30 psi at idle and my car has runned fine the whole time. This is why I dont understand his problem, maybe im not familar with the begi unit. I looked at that link and it has a different vacuum set up, its probally more sensitive to vac changes than my SFMU.

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