We got a ls vtec with a t3/t4 garrett on it.. Walbro fuel pump, aeromotive rising rate fuel pressure regulator and 750 cc injectors with crome management on it. For some reason when you rev the car up as soon as it gets into vtec the car leans right out. It dosent matter how much fuel I put in it wont richen up. I changed the fuel pump because it was making a sound that didnt seem right but it made no difference. I cant understand what could be causing this problem. On the dyno the fuel pressure would rise to 60 and then fall to about 40.

Someone please steer me in the right direction.

 

if you are losing pressure under boost, you have a restriction in the line, check the filter. and for the hell of it do this, pinch off the return line while it is idling and see that does. if the pump deadheads and pegs the gauge, then the pump is doing the correct thing. but thats not to say the reg is / isnt bad.

for the hell of it, where is your base?

 

Things to check:
- Fuel Pump
- Fuel Pressure Regulator
- Fuel Rail Dampner (on the front side of rail)
- Fuel Filter

 

Fuel Dampner? How could this cause the problem?

We changed the fuel pump but it did'nt make any difference.

In regards to the FPR, we had installed the Aeromotive (P/N 13116) on the rail but had the guage on top of the fuel filter (which is brand new) and it had read 100psi and we could not get the pressure down any lower than that using the adjustment on the reg. We decided that even though the FPR was brand new, since I had bought it second hand then perhaps the previous owner had somehow modified it... We opened it up and decided that it may not have had the correct spring inside and then we cut one coil off the spring to see it it alleviated the pressure. It didn't.. We then thought that moving the guage to the FPR port might show differently and it did. It showed 90+psi at the filter and 20+ on the FPR. We then adjusted the regulator to 45psi (idle) and went along with the rest of the build....
It may sound like I am trying to convince myself that this is the problem but I cant figure out how could this be the problem since it reads the correct pressure at idle and raises to about 60psi?
Like I said before it raised to 60 on the dyno and then dropped off to 40ish? wtf?

I just had brand new fuel lines installed and there are no blockages in the return......
I am using the stock rail

Could this be poor voltage to the pump...? This is next on the list to check.

Please help, I am participating in the Targa Newfoundland in like 3 days I dont want to blow up. :S

 

ok, dumb question but did you try richening up the nonvtec portion of that map where you have vtec coming in and a bit after. On some crome maps it doesn't switch maps when it is suppose to.

 

Well, the funny thing is that sometimes is becomes lean quickly and others you can stay on the gas a while longer and see that it clearly isn't going to get any better.... Perhaps worth a try though. I open to any suggestions

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Targa4Life &raquo;</TD></TR><TR><TD CLASS="quote">Fuel Dampner? How could this cause the problem?</TD></TR></TABLE>

well the damper is designed to quiet the injectors ( i think ) and it can actually be a restriction in the line.

ok so you had over 100 psi of pressure, so you took the reg apart and cut a coil off of the spring.

how are the lines hooked up? i dont htink it is a fuel map issue as the pressure is dropping off.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by boostedcivicsir &raquo;</TD></TR><TR><TD CLASS="quote">
how are the lines hooked up? i dont htink it is a fuel map issue as the pressure is dropping off. </TD></TR></TABLE>

My fault.. definitely missed that part some how. I had a car that had a big slit in the line coming right out of the pump into the hard line.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 93turbo16 &raquo;</TD></TR><TR><TD CLASS="quote">ok, dumb question but did you try richening up the nonvtec portion of that map where you have vtec coming in and a bit after. On some crome maps it doesn't switch maps when it is suppose to.</TD></TR></TABLE>

Try that. If the issue still is not resolved... Does the car have any kind of aftermarket ignition systems or funky distributor or ecu wiring ?

Watch the FPR gauge and make sure the fp is staying at a static amount during a pass.

 

Everything you just typed tells me it is the dampner...I had the SAME exact things happen on a car I was tuning.

The dampner was prohibiting flow past it...so fuel pressure at the filter was 100+ psi and after the dampner it ranged from 20-45 psi. As soon as we switched out the dampner...normal operation.

Sounds crazy...but give it a shot.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Targa4Life &raquo;</TD></TR><TR><TD CLASS="quote">Fuel Dampner? How could this cause the problem?

We changed the fuel pump but it did'nt make any difference.

In regards to the FPR, we had installed the Aeromotive (P/N 13116) on the rail but had the guage on top of the fuel filter (which is brand new) and it had read 100psi and we could not get the pressure down any lower than that using the adjustment on the reg. We decided that even though the FPR was brand new, since I had bought it second hand then perhaps the previous owner had somehow modified it... We opened it up and decided that it may not have had the correct spring inside and then we cut one coil off the spring to see it it alleviated the pressure. It didn't.. We then thought that moving the guage to the FPR port might show differently and it did. It showed 90+psi at the filter and 20+ on the FPR. We then adjusted the regulator to 45psi (idle) and went along with the rest of the build....
It may sound like I am trying to convince myself that this is the problem but I cant figure out how could this be the problem since it reads the correct pressure at idle and raises to about 60psi?
Like I said before it raised to 60 on the dyno and then dropped off to 40ish? wtf?

I just had brand new fuel lines installed and there are no blockages in the return......
I am using the stock rail

Could this be poor voltage to the pump...? This is next on the list to check.

Please help, I am participating in the Targa Newfoundland in like 3 days I dont want to blow up. :S</TD></TR></TABLE>

 

im in for a resolution to this.

i am right in the middle of the same exact problem. ive switched regulators, fuel pumps, map sensors, richened my fuel map (low cam and high cam) to the point where it should flood the car....and still the same result. lean.

i actually get good 11.5 a/f up to about 10-13psi, by the time it hits 16psi it goes from 11.5-14 something. its a new motor and its scaring the **** out of me.

this may be a noobie question, but the fuel dampner? what and where is it?

 

what type of clamps did u use to hold the fuel pump to the fuel hose? make sure u use one of those screw down type clamps.

put a stock regulator in the car just to check to see if the regulator is the problem. i never had an experience with a bad fuel dampner but do what xenocron says and give it a shot.

 

my fuel pump is held on by the stock clamp, and fwiw my fuel pump is the new 255 that xenocron offers.

my setup is this
xenocron 255 fp, stock lines from tank to engine bay, swegelock pipe fitting to -8an line, earls inline fuel filter, str competition fuel rail, gauge on rail, stock fpr, stock return line. also running pte 750's on cromepro.

my issues start about 6k-6500 and at that point im making just over 10psi.

i need to get this figured out asap as well, i have a race saturday, and this is the only thing holding me back....

HELP

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by xenocron &raquo;</TD></TR><TR><TD CLASS="quote">Everything you just typed tells me it is the dampner...I had the SAME exact things happen on a car I was tuning.

The dampner was prohibiting flow past it...so fuel pressure at the filter was 100+ psi and after the dampner it ranged from 20-45 psi. As soon as we switched out the dampner...normal operation.

Sounds crazy...but give it a shot.

</TD></TR></TABLE>

I have actually had this happen on 2-3 cars that I have worked on. But this always gave them problems even revving off idle. You could barely even get the cars to move when the dampener was the problem. I would give it a shot as well, very simple to change.

 

ok, i hope the OP doesnt mind me joining this thread, it sounds like we have VERY similiar problems...

i have been doing a ton of reading/searching, and the fuel dampner thing sounds promising...i know that i am running a STR fuel rail, it just has a nut on the end of it, no fuel dampner. so im going to try and add it to the STR rail when i get home tonight to see if it works....

my other question is, dont guys that run an aeromotive type fpr run into problems? or does the -an line and the remote fpr act as a dampner??

 

anyone else have an experience wiht the fuel dampner??

or anyone else have any suggestions? im at work, but very anxious to get this solved, as im sure the Original Poster is as well

 

Ok I took off the fuel line going from the filter to the rail and found that I had it on backwards.... I thought the two banjo fittings were the same until I looked a bit closer and saw that one side is open on one of the fittings to allow fuel to get into the dampner... I going out now to see if all is well.

 

well that would be really good news then! cause that means no fuel was getting to the dampner....wich is good for me too, cause im not running a dampner at all

 

Ok I fixed that and it fixed the differing pressures between the rail and the filter but still the car leans out same as always. Theres another option though, I had new fuel lines (factory lines) installed fairly recently and since this last week was the first time the car has seen anything over 4000rpm we are thinking that maybe the feed line was somehow partially kinked during the install. I am heading to the shop tomorrow morning to put it up on the ramp and inspect all the lines.

Does anyone know if the banjo bolt in the top of the fuel filter will fit into the banjo fitting at the tank??? I have a special fitting in the top of the filter to fit a gauge and I wanted to test the pressure at the tank to compare.

 

well i went out tonight and couldnt find an adapter to put my stock dampner onto my str fuel rail....so i went out and spent over a 100 bucks on -an fittings. i will be fitting up my aeromotive fpr and -6an lines tommorow. guess ill see if that fixes MY issues lol...

good luck targa4life.

 

Finally found out what the heall was going on.
Once we tested the fuel pressure at every point as well and removing lines and checking flow we hooked up a fuel pressure gauge to be visible inside of the car (I am getting one next because of all this) and found out that the fuel pressure was no longer dropping off in VTEC like it was before I fixed the fuel line. So then we went straight to the ECU and the tune. First of all we replaced the batteries in the ostrich just in case, made no difference. Then we checked the whole ECU board and there were no problems. then we went and made a whole new tune starting from scratch and still it made no difference. We then said WTF because none of this was happening the year before and there wasn't that much changed so we knew what had changed and the only thing we hadn't discounted was the NEW VERSION OF CROME!!!!!! Turns out that version 14.0 (or whatever it is) has a major glitch. What was happening is that it wasn't switching to the VTEC maps or something because we started a whole new tune (AGAIN) and used version 12.5 and voila it worked perfectly. So after oh say $800.00 of trying to diagnose and replace parts retune and dyno time... The car is perfect runs perfect and pulls like a train without leaning out. I would be interested in hearing about other people using the new version of crome to see if they have similar problems. Anyway, just figured I would repost the end results I hope this helps someone out.

 

dang, really?

i myself am doubting crome right now too...as a matter of fact i just downloaded 1.4 because i thought my 1.2 was corrupt somehow...hmmm...i hear ya on the cash, my fuel system is ALL -an lines now because of this problem, i got a very expensive FPR because of this...i just redid my entire fuel system and its STILL the same. guess ill go dick with some different versions of crome now. damnit.

BTW glad you got yours figured out

 

hmm tried 3 different versions of cromepro last night...none of them fixed my issues...damn.

 

Did you try testing the pressure at the tank and comparing it to the pressure at the rail? Try testing that and going from there. Perhaps you need a new fuel filter or something. Try testing the pressure at the filter and maybe take off the feed to the filter to test flow. Put a rubber hose on it and let the pump push fuel into a jerry can or something.