AFPR Help ASAP please!!!

[Forced_Fed_TSI]

ok i had posted on here before about what FPR i need. so i bought the aeromotive FPR kit that is advertised on this site. well i installed it, followed all the directions, double check, even triple checked everything, well i set the base fuel pressure at 38 with the vacuum line disconnected and plugged, well i took it for a spin and as soon as i hit boost at 5k rpms my car starts backfiring like crazy. its not fuel cut because i know what that feels like, and so i turned up the FPR to 43 and again once i hit 5k rpms it backfired like crazy again. i havent looked at my spark plugs but it kinda feels like a faulty plug. do you think my plugs went out right when i happened to install my FPR or is there a problem i might be missing here?

 

[95-talontsi]

Replacing your plugs wouldnt be a bad idea especially if you were runnin them before without an afpr. I didnt have any trouble when I installed my afpr but maybe I was lucky double check everything if you havnt

 

[Forced_Fed_TSI]

well i replaced the plugs and its still acting up. this might be a stupid question but my FPR is mounted horizontally. could that have anything to do with why is making my car mess up? could there be some kind of air pocket? any advice as to what to do? it only starts acting up after 5k rpms which is kinda weird.

 

[Forced_Fed_TSI]

Anyone got any Help for me????

 

[FORMONTOYA]

I would think you could mount it upside down if you wanted, but I've never tried it. To test, just unmount it and temporarily affix it vertical.

Mine is mounted at about a 45 degree angle and I've had no problems.

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Are you still on 450s?

 

[Rex2342]

It sounds like your to rich/breaking up. The AFPR should be set at 38psi with the line off and plugged. This is the stock fuel pressure. Turning it up to 43psi is just making it worse. If you still running the stock 450's I would back the boost down to safer 14-15psi and drop the base fuel pressure to 35psi and see what happens. If you don't have a logger you're (we're) pretty much just guessing and have no real clue what your car is doing.

 

[Forced_Fed_TSI]

i dont have a logger, and i am at 15psi of boost. i am still on the stock 450 injectors. i set the base fuel pressure to 38 like the instructions said with the vacuum line disconnected and plugged. i was driving it more and more today and now its not backfiring but the car feels like it has a misfire and when i step on it again once i hit 5k rpms it starts to have a slight stutter. the car seems to run just fine up until i hit 5k rpms then it acts up, it boost fine til then.

 

[oldman]

Set the pressure @ 38psi and perform a boost leak test, then back the boost level down to 16psi until you have a logger. I suspect you're either running rich due to boost leaks or running lean (18psi) causing knock and pulled timing.

 

[Forced_Fed_TSI]

im at 15psi(boost) and as far as a boost leak i'll have to check for that, didnt have a problem with it before but i guess it cant hurt, wouldnt my boost bleed off if i had a boost leak though? my car holds a consistent amount of boost whether it was at 15 or 18 psi. is it possible that i got a crappy part and it isnt rising 1:1 with the boost like its suppose to?

 

[oldman]

What is the vacuum and fuel pressure reading at idle? Did you use thread sealant (teflon)on both the vacuum fitting and adjustment screw on the afpr?

 

[Forced_Fed_TSI]

my buddy did the teflon part and he just informed me that he didnt teflon either one of those so im going to try both of those hopefully that solves the problem

 

[Forced_Fed_TSI]

ok, so we took it off and put teflon on all the parts and now i took it for a drive and its still having a slight tug and now my car is overheating. i am going to do the boost leak test either tonight or tomorrow but i didnt think that a boost leak would lean my car out bad enough to make it overheat so i have no clue what to do about my car. it feels like it has enough pull til 4500rpms then it feels leaned out and then at like 5k it sometimes gives a little tug.. so what do i do?

 

[Forced_Fed_TSI]

according to my boost gauge my vacuum is at 19in.hg. and on my fuel gauge at idle my car is a little under 20psi with the vacuum line on and a little under forty with the vacuum line off and plugged.

 

[FORMONTOYA]

according to my boost gauge my vacuum is at 19in.hg. and on my fuel gauge at idle my car is a little under 20psi with the vacuum line on and a little under forty with the vacuum line off and plugged.

And that's your problem. For some reason it's pulling down your fuel pressure more than it should. You should loose 1psi for every 2inHg. So you should be at a little under 30psi fp hose on if you're a little under 40psi fp with the hose off.


1) Where is the boost gauge source taken from?
2) And also where is the FPR source taken from?
3) What do you mean by "vacuum line off and plugged?

 

[Forced_Fed_TSI]

well by disconnected and plugged i mean that when setting the fuel pressure i disconnected the vacuum line and plugged it with my finger while setting it and as far as the vacuum line that im using for the FPR is the one that was hooked up to the stock FPR which is the vacuum line that has a blue dotted line on it. and the line that im using for the boost gauge is the line that goes to the intake manifold. its just a plain black line

 

[Forced_Fed_TSI]

ok well i drove the car to the store and came back and my fuel gauge reads a hair over forty with the vacuum line pulled and plugged and with it plugged it right at thirty.. could a weak battery or not having a 255 fuel pump rewire kit be to blame?

 

[FORMONTOYA]

The rewire kit is mainly for WOT so that the pump is giving maximum when it needs to maintain pressure while the injectors are max open and effectively bleeding off the pressure. It wouldn't be a big deal at idle and cruise when the injector duty cycle is lower.

The battery would have to be really weak to effect things to any noticeable extent at idle and cruise.

For reference, my boost gauge and FPR are tapped off the FP solenoid line to the intake.

 

[Forced_Fed_TSI]

well friends have told me im running a honda battery on my car because its so small so i was just wondering, i want to perform a boost leak test but just havent been able to get outside to do it quite yet. its like over 100 degrees outside right now so i dont want to pass out under my hood

 

[Forced_Fed_TSI]

and about the rewire kit, my car cruises just fine and idles just fine, its only when i go wide open throttle and my car hits like 5k rpms that the car feels like it has no power and it sometimes starts to buck a little bit like it has a misfire

 

[FORMONTOYA]

and about the rewire kit, my car cruises just fine and idles just fine, its only when i go wide open throttle and my car hits like 5k rpms that the car feels like it has no power and it sometimes starts to buck a little bit like it has a misfire

Now these symptoms can be caused from not enough power at the pump to maintain pressure when the leak (high IDC) is at it's worst.

Not enough battery, lack of re-wire.

 

[Forced_Fed_TSI]

whats high IDC? sorry... so i should rewire or possibly try a stronger battery? and is there anything wrong with the way i have my fuel pressure and boost gauge hooked up?

 

[FORMONTOYA]

whats high IDC?

IDC = Injector Duty Cycle. The higher the IDC the longer the injectors are open.

The longer that the injectors are open the harder it is for the pump to maintain pressure, as the open injectors are "basically" a leak in the system. That's why most people do the re-wire.

It's been a while since mine was stock, so I don't remember the line colors, I understand that you used the OEM FPR vacuum line for the new FPR. However, are you saying that you used the vacuum line on the entrance side of the FP solenoid? If so, then that works fine.

 

[Forced_Fed_TSI]

so are you saying between the firewall and the solenoid or after the solenoid? sorry im not too dsm smart(newbie)

 

[Forced_Fed_TSI]

ok so i tried to put a optima battery in my car to see if that would help get more power to the fuel pump, the fuel pump isn't very loud when you can hear it and there are other times where i will go into the back of my car and even putting my head next to it i wont be able to hear it. i just got the rewire kit and will be installing it on monday. anyone else got any ideas as to what the problem might be

 

[alex99gst]

I just installed my AFPR and 255 pump on my car recently and was running 18psi before with the car starting to cut out at around 7k. I was maxing out my injectors then. Now after the install I thought I had a problem too but it turns out I was just maxing out my injectors faster and the car would start to fall on its face at 5k rpms. I figured because the pump could supply fuel faster and keep up with the injectors easily that the weak link in the system was now the injectors instead of the pump. Try to borrow a logger and see what you injector duty cycle is. A boost leak test and re-checking everything is not a bad idea, but I don't think that is your biggest problem.