Need help figuring out newly installed FORE return system issue(s)

[SVT_Troy]

I have two issues.

Issues #1: Fuel Pressure (Pressure drop across fuel injectors in tune does not increase with boost)

Right now i am experiencing a extreme lean condition that starts off fat then back lean. I'm not the best with data logs but am learning. I trust my tuner and he says it is not in the tune. This last tune he put more fuel in just to see what it would do and its still going lean.

I thought the use of too many T/Y's in the boost line would be an issue so i put together a mini manifold ran off the lower S/C boost port. Looking at vacuum manifolds I realized i did not want to remove my blower to install a nice vacuum/boost manifold to the firewall. I ended up with something that I think works just as good and is pretty small somewhat out of site. Basically I used a piece of silicone to connect the mini manifold directly to the lower blower boost port. It has three outputs. (pics below)

Here is the routing of the boost lines now.

1: To regulator
2. To cabin for gauges and hobbs switch
3. FRPS & boost actuator

This did not change anything.

Ok so here is what I have verified to be working so far:

• Both pumps turn on when manually applied 12V and the rail mounted pressure gauge goes up.

• With the car running and 5psi+ applied to the hobbs switch, it sends power to the second pump.

***My questions are: ***

1. My base fuel pressure is set to 50psi. With the car running and regulator boost reference connected it goes down to about 40psi. I believe the lose of pressure to be correct. Is it?

2. How much of a fuel psi increase should I see when the second pump turns on like I did with the car running at idle via the rail mounted pressure gauge. Currently it only goes up 2-3 psi if that.



Issue#2: Peak boost 12.5 should be 17 psi
I am running a stock lower and 3.0 upper. I am seeing about 12.5 peak boost for some reason. Boost goes up to 12.5 and stays there. I am using a new billet American racing tensioner and have not seen any belt dust. I just replaced my belt with a new Continental elite belt but no change. Still not seeing the boost it should.

So far i have checked the following:

• Boost leaks (I believe this to be the issue, i just have not found any leaks and all the lines are new silicone hose)

• Made sure my new FORE fuel filter was installed the right way

• Checked the S/C Boost Actuator. It moves the rod to the valve and holds both vacuum/boost pressure (Have not removed the S/C to make sure the valve is fully closed which could be a reason I am not seeing peak boost. I doubt this to be an issue though.

IMG_6943 by Troy, on Flickr

and painted so as not to be seen as easy

IMG_6946 by Troy, on Flickr

 

[Steve Cea]

Get rid of the hobs switch , this caused me all kinds of fuel pressure problems , removed it completely, put a jumper between the wires to ground it out , no more fuel issues

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[SVT_Troy]

Get rid of the hobs switch , this caused me all kinds of fuel pressure problems , removed it completely, put a jumper between the wires to ground it out , no more fuel issues

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The hobb switch appears to be working as advertised though. Plenty of people use them..... I can try a jumper and do a log just for shits & giggles though.... I would rather not have both pumps running full time though.

 

[01yellercobra]

I'm thinking one issue is causing both problems. If you have a leak somewhere the FPR won't increase the pressure correctly. I'd concentrate on finding the boost leak first.

You shouldn't really see much of an increase with the second pump. That's what the regulator is for. To keep a constant pressure.

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[cj428mach]

Pressure drop across injectors will always show the same whether or not your in boost or at idle. Thats the nice thing about logging pressure drop across injectors is the FRPS takes boost/vacuum into account and will show your true base pressure.

In my opinion the easiest way to set the fuel pressure is to leave the car running and adjust the regulator until the pressure you see on your datalog is what you want it to be in the tune.

Make sure you're not pegging your injectors. I fought a lean condition that sometimes I'd see other times. I'd add fuel and it wouldn't help at all, I finally logged my injector duty cycle and the injectors were pegged. It would only show up sometimes because in shorter bursts, or lower loads it wouldn't show up as quickly as in higher gears. So out with the old ID1000's and in with the ID1300's and my problem was cured.

 

[03' White Snake]

50 seems high to me as a base pressure. I have mine at 40, make sure you set it with the car off but the pumps running. I am running a magnafuel regulator. It increases 1 psi per 1 lb of boost. I am running 20 lbs of boost and the pressure increases with that. I am running a deadhead setup on my car.

Sounds like you don't have a boost reference on your regulator. Check the part number to make sure it is the right type.

I am running 2 465 pumps full time without issues. Ditch the hobbs switch and simplify it.

 

[SVT_Troy]

50 seems high to me as a base pressure. I have mine at 40, make sure you set it with the car off but the pumps running. I am running a magnafuel regulator. It increases 1 psi per 1 lb of boost. I am running 20 lbs of boost and the pressure increases with that. I am running a deadhead setup on my car.

Sounds like you don't have a boost reference on your regulator. Check the part number to make sure it is the right type.

I am running 2 465 pumps full time without issues. Ditch the hobbs switch and simplify it.

My tuner told me to set it at 50psi. To set that I removed the boost reference, started the car then set it while it was idling. I then reconnected the boost reference and it went down to 40psi

I am also running dual 465's dead head. What are you talking about a part number for?

Troy


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[Bdubbs]

I might have missed it, but what gauge are you using to monitor boost?

 

[SVT_Troy]

I might have missed it, but what gauge are you using to monitor boost?

An Aem gauge that I checked with my mighty vac to verify it was reading correctly.


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[cj428mach]

Again fuel pressure drop across injectors should show what you set your base pressure at all times on a return style system.

If you're going WOT and pressure drop across injectors is holding steady but you're still going lean its one of two things. 1 either you need more fuel in the tune, or 2 your injectors aren't cutting it. If it was a pump/delivery issue pressure across injectors would begin to drop.

 

[SVT_Troy]

Let me attach my tune data logs later this evening and you tell me what you think. From memory I do not think my injector duty cycle was that high but I really don't remember. I am only running a TVS with a 3 upper/stock lower on pump 93. I don't think my ID 1000's are getting maxed but we will see. My tuner said they should be good with E85 so them being maxed out on 93 seems like a stretch to me.


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[cj428mach]

Let me attach my tune data logs later this evening and you tell me what you think. From memory I do not think my injector duty cycle was that high but I really don't remember. I am only running a TVS with a 3 upper/stock lower on pump 93. I don't think my ID 1000's are getting maxed but we will see. My tuner said they should be good with E85 so them being maxed out on 93 seems like a stretch to me.


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If you're on gasoline then its not an injector issue with the 1000's.

If the pressure stays constant at your base pressure, on the pressure drop across injector pid then you don't have a supply problem as you have full pressure at the injector.

It could be some sort of clip issue in the tune, maf pegging, or something like that.

 

[MG0h3]

Plenty run a hobbs and have no issues.

Cool thing is you can have the engine off and run one pump by sticking a mini fuse in the connector to jumper it. I did this and cranked the FPR to max for a few minutes to check for leaks.

I'd do that and crank the FPR to max to ensure that it will hold what it needs to. I think mine got up in the 80s or something. Then return it back to 50psi. FWIW thats what 04Sleeper had me set mine at as well. With the vacuum hooked up its around 40 at idle.

After that I'd use a blow gun in conjunction with a boost gauge and see if the pressure increases at 1psi per lb of boost like mentioned above.

On the other hand you said you aren't seeing the boost that you should so you may very well have a leak or cracked connector or something.

 

[SVT_Troy]

Here are my last two data logs with the same tune. The only changes made to R4 Log two was adding the mini vacuum manifold and changing the old belt with a new one. My tuner (04 Sleeper) added alot of fuel to this tune just to see what it would do.

What do you guys think?

 

[cj428mach]

Here are my last two data logs with the same tune. The only changes made to R4 Log two was adding the mini vacuum manifold and changing the old belt with a new one. My tuner (04 Sleeper) added alot of fuel to this tune just to see what it would do.

What do you guys think?

I tried looking at your logs but I don't have livelink on this computer so its only excel and its tough to interpret the data that way. It looks like your second log shows the car extremely rich (I'm sure Kevin's trying to keep it safe while figuring this out) and you let out before it ever goes lean so whats the issue there?

Also are you looking at Boost off your boost gauge? It looks like you're logging boost through livelink and if the formula is in livelink incorrectly it could explain low boost readings.

Your fuel pressure holds steady at 50PSI which is exactly what its supposed to do when logging fuel pressure drop across injectors. The problem isn't a delivery issue up to the FRPS so its either injectors (unlikely) or you need more fuel (the second log looks like it has plenty)

 

[SVT_Troy]

Analog 7 (red fire wire) is AFR
Analog 8 ( orange fire wire) is boost

Boost is peaking at 12.96 and AFR at 17.01. Something is not right.

Also i was told that pressure drop across fuel rail should increase 1 psi for every psi of boost. Mine is going up maybe 2 psi. I was thinking that it should be higher but come to think about it..... is 52 psi right?

50psi base goes down to 40 psi running 40 plus 12.96 psi is 52.96 is this right?

 

[MG0h3]

No. 0 vacuum will net you 50psi if that is how you set the fuel pressure. You can just blip the throttle while stationary and you should see 50. Then you will see 1psi per lb of boost.

So 50 plus whatever boost you are seeing.

I see right around 70psi under full boost.

 

[SVT_Troy]

Ok well my fuel pressure is low according to my log of pid fuel rail drop across fuel injectors.


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[MG0h3]

I don't know what boost/pulley configuration equals on your setup but if you are way lower than what you should be (according to the boost gauge) I'd take a close look at the hoses/Ts.

I did one T up by the firewall to run a line down to the FPR and one more to behind the glove box for the hobbs.

 

[SVT_Troy]

My pulley combo should bet 17lbs. I am seeing just under 13lbs. Understanding that this is more than likely my issue. I just can't find anything wrong.

I've checked for leaks over and over. Verified my boost garages are calibrated.
At this point I need to remove every line and test them individually. Past that remove the blower and check its gaskets maybe.....


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