Hey, I am new here and am having some trouble with my SFMU. I have Crower stage 2 cams SFMU with Bleed valve, I am running the dark spring and the 2.72 disk with ring. I got everything hooked up and have my static pressure set at 25psi, my idle pressure will not go below 25psi and I'm trying to get it to 15psi. I have 440cc injectors and am trying to run 10lbs. I took it for a drive around the block and it idles shitty, and drives shitty like it's cutting out. At idle though, it says my afr is around 11:1 and varies, when I start to drive, my afr drops around 10 or 9:1, and it backfired twice so I parked it and came here. Help me anyone, I guess I start to go lean as I drive, any ideas on how to fix this?

Also, my car is puffing smoke out the tail pipe, I don't know why.

Originally posted by 98GSTurby
Also, my car is puffing smoke out the tail pipe, I don't know why.

I can't help with that, but someone who can will want to know what color. I'm not positive, but I believe white indicates a hg problem and blue is from running too rich

edit: btw welcome

Originally posted by 98GSTurby
when I start to drive, my afr drops around 10 or 9:1, and it backfired twice so I parked it and came here. Help me anyone, I guess I start to go lean as I drive, any ideas on how to fix this?

Sounds to me more like its way too rich at 9:1 Also seems a bit strange that your static is 25, but idle isn't any lower, maybe something with your vac source. If at 0 pressure your fp is 25 psi, then under vacuum it should lower

It's blue smoke, so it's gotta be from being too rich. Actually the fuel is at 22psi at idle now that I look at it, and it's 25 at static, it seems to boost ok, but it keeps backfiring when I let off the gas, any other ideas?

I also noticed when I idle, the smoke is sometimes black as well. I datalogged my idle and it's right around 10.6:1 to 11:1afr. At idle, it bounces from 400rpm to 700rpm, I am also pulling only 4-5 inhg at idle, but I have crower 2's and that's normal right? How do I tune the fuel curve?? when I start do get on it, it feels like it starts to clear up, but then when I let off, it backfires. Runs like shit.

anyone?

have a datalogger? It will tell you the STFT and probably that you're running to rich.

I just switched out the spring in the sfmu to the silver one, and I still can't get the fuel pressure down, then I started it again and got a check engine light, it was code 52 (fuel system lean) I am lost. I don't get it.

Also, when I rev it at all, it sputters up, sometimes it will clear and rev like normal, but it mostly just sputters like it wants to die. Can someone please help me?

well 4hg of vac . u definitly got a vac leak . also what size hose are u running on the sfmu and what do u have for a fcd ?

Do you think I have a vac leak?? I have the crower 2 cams in my car and I was told it was normal to pull low vac. Also, I have a missing link for an fcd and -4an fuel lines. Any ideas?

well 4 in/hg is pretty bad really. There has to be a leak somewhere.

Do you have a dedicated vac line to the fmu?

When I had 450's I had the static FP (without the vac line connected) at 12-14 psi. When I connected the vac line I got 20 psi. I had it raising around 3:1 and it ran good.

It's your stft that is making it run like shit. The ecu can only pull 25% +/- and I can guarantee at idle it's -25. You need lower idle FP.

What does STFT stand for?? Sorry, not up on my terms. Do you think it's the -4an return line holding me up as well?? I can't find a vac leak anywhere, any other ideas??

Ok, just got back in from looking for my vac leak, I can't find it anywhere, it was doing this before I went turbo, I was told that it was my big crower 2 cams. I am puffing black smoke from being too rich, it sputters when I get on the gas until it kind of clears up, then it will backfire when I let off. I know I'm running too rich, I have the 2.72 ring and disk, should I try a different one? I have tried the silver and black short spring to try and lower my fuel pressure. Help please.

I changed to the 2.47 disk and ring, it seems to be better, but I still can't get it to idle for shit and it sputters like mad when I get on it. Also, just threw code 51 at idle again, too lean???? I am so lost.

try doing a tune-up, and make sure your front o2 is good

Who put your cams in? You sure they were put in right?

4 in/hg seems more than a vac leak to me.

Just a thought, hope you figure it out.

did you block off your egr? there might be a leak there. TB? BOV? you have to check everything. If you spray starting fluid at the joints and the idle raises, theres a leak there.

I don't know what to say concerning the low vac. IIRC they should run around 10-14in/hg which is low compared to 17ish with a low mile motor.

STFT- Short term fuel trim.

It's what the ecu does to compensate the fuel when your foot is on the gas ie:accelerating

If you had a datalogger you could see this information.

The ecu can pull 25+/- STFT

So your sitting there idleing. Its chilling at 0 (stock)
You go and step on the gas to take off it can add up to 25 for when your getting up to speed. Now your cruising at 60mph, stft is sitting near 0 again.

What your trying to do is- DUMP a shitload of fuel into the cylinders and the computer 'feels' this shitty running motor and tries to pull the fuel back -25. Thats all it can pull. When people swap 310's in the ecu can compensate enough to run them like stock but not as large as 450's.

This is my scenario when I started my car and got it to idle:

I had an sfmu, 450cc inj. I used the silver spring and 2.72 disc. With my datalogger on I started up the car. It started right away and sounded like a v8. lol I got under the hood and watching my FP gauge I turned out the top adjustment on the sfmu to lower the FP down to 15 psi, as I slowly lowered the pressure it started running WAAAY better. I mean from 20psi - 12 psi was a big diff.

Then I checked out the scanner and seen my stft smarten up a bit and smooth out.

meh, I might be rambling now but I'm just trying to put you in my shoes when I was having the same problem. lol

edit: oh yea. The real nice idle came when I put in the safc. in the first increment of adjustment 0rpm-1000rpm I dropped 50% of the fuel right off the top and then I could raise the FP up a tad and have awesome fuel trims. :)

i think ur 4an line is the problem . u need to upgrade to 6an to get ur fp down

Does anyone want to trade 310cc injectors for my 440's?

lol

blue smoke is oil
black is fuel
white is coolant