AFPR problems help much needed
- Thread starter chevy110
- Start date
sytyguy
Moderated User
Re: AFPR problems help much needed
The entire fuel system from the pump to the regulator is under pressure, and in a pressurized system, a leak can occur anywhere. Ignoring all external leaks (something that would let gas escape into the atmosphere, such as a leak at a union or a hole in a line) and assuming you don't have any added items (fuel cooler, 7th injector, wet nitrous kit, etc...) to the system besides a pressure gauge, the most common areas a depressurizing leak can occur are:
- Fuel Pump
- Fuel Injectors
- Fuel Pressure Regulator (to the vacuum line)
- Fuel Pressure Regulator (to the return line)
To test a leak at the FPR (to the vacuum line), pull the vacuum line off after running the engine or while it's running. Is it wet or smell of fuel? If so, diaphragm is busted and FPR needs rebuilding or replacing. If not, leak is elsewhere. Unsure? Grab a MightyVac tester and pull a vacuum on the port (with engine off) and see if it holds vacuum.
To test a leak at the FPR (to the return line), clamp a rubber section of the return line (at FPR or at transfer case), prime the system with the ignition or test port, let system pressurize, turn off ignition or remove test jumper, and observe pressure. Does it fall as before? If so, leak is elsewhere or the clamp isn't good enough. Does it hold pressure just fine? If so, leak is at FPR....replace it.
To test a leak at the injectors, clamp a rubber section of the return line (at FPR or at transfer case), prime the system with the ignition or test port, let system pressurize, clamp a rubber section of the feed line (at transfer case), turn off ignition or remove test jumper, and observe pressure. This method will "trap" pressure in between the two clamp points. Does pressure fall as before? You have a leaking injector. If not, you most likely have a leak at the fuel pump.
To test a leak at the fuel pump, clamp a rubber section of the feed line (at transfer case), prime the system with the ignition or test port, let system pressurize, turn off ignition or remove test jumper, and observe pressure. Obviously, you will need to plumb a gauge in between the clamp point and the fuel pump (easiest is in place of fuel filter) to make this test accurate. Does pressure fall as before? If so, you have a bad pump or leak in the the sending unit. Does it hold pressure? If so, have you performed all other tests? If yes, you have a mystical leak that will cost tens of thousands to fix. Sell me your truck for cheap and get out of this headache while you can. :lol:
Okay, I'm going to do this again....
The entire fuel system from the pump to the regulator is under pressure, and in a pressurized system, a leak can occur anywhere. Ignoring all external leaks (something that would let gas escape into the atmosphere, such as a leak at a union or a hole in a line) and assuming you don't have any added items (fuel cooler, 7th injector, wet nitrous kit, etc...) to the system besides a pressure gauge, the most common areas a depressurizing leak can occur are:
- Fuel Pump
- Fuel Injectors
- Fuel Pressure Regulator (to the vacuum line)
- Fuel Pressure Regulator (to the return line)
To test a leak at the FPR (to the vacuum line), pull the vacuum line off after running the engine or while it's running. Is it wet or smell of fuel? If so, diaphragm is busted and FPR needs rebuilding or replacing. If not, leak is elsewhere. Unsure? Grab a MightyVac tester and pull a vacuum on the port (with engine off) and see if it holds vacuum.
To test a leak at the FPR (to the return line), clamp a rubber section of the return line (at FPR or at transfer case), prime the system with the ignition or test port, let system pressurize, turn off ignition or remove test jumper, and observe pressure. Does it fall as before? If so, leak is elsewhere or the clamp isn't good enough. Does it hold pressure just fine? If so, leak is at FPR....replace it.
To test a leak at the injectors, clamp a rubber section of the return line (at FPR or at transfer case), prime the system with the ignition or test port, let system pressurize, clamp a rubber section of the feed line (at transfer case), turn off ignition or remove test jumper, and observe pressure. This method will "trap" pressure in between the two clamp points. Does pressure fall as before? You have a leaking injector. If not, you most likely have a leak at the fuel pump.
To test a leak at the fuel pump, clamp a rubber section of the feed line (at transfer case), prime the system with the ignition or test port, let system pressurize, turn off ignition or remove test jumper, and observe pressure. Obviously, you will need to plumb a gauge in between the clamp point and the fuel pump (easiest is in place of fuel filter) to make this test accurate. Does pressure fall as before? If so, you have a bad pump or leak in the the sending unit. Does it hold pressure? If so, have you performed all other tests? If yes, you have a mystical leak that will cost tens of thousands to fix. Sell me your truck for cheap and get out of this headache while you can. :lol:
Re: AFPR problems help much needed
Thanks Hood. Sorry for making you explain it again. I figured out where my confusion about the pressurized section of the fuel system was coming from. And when I figured it out, I felt like a dumbass.
On another note, I think I figured out where the pressure loss is coming from. I'm pretty sure it's the fpr. I removed the vacuum line, pressurized the system with the ignition, and checked for a leak/fuel smell. It again lost pressure pretty quickly, but I couldn't smell any fuel and couldn't feel any leaks around the ports on the fpr. Then, I tried clamping the return line and and pressurized the system again. Just like last night, it lost pressure at a much slower rate. Instead of bleeding down to 0 in less than 2 minutes, it lost less than 10 lbs of pressure in 5 minutes of we watching it. While I was staring at the gauge, I caught a slight fuel smell. So I went back to check fpr for leaks again and there it was. The seam between the top and bottom sections of the fpr was wet. So the fpr definitely has a leak. I'm guessing that it was leaking through the return line and the started leaking through the seam when the fuel line was clamped to give the fuel somewhere else to go. Again, that's just a guess.
Thanks Hood. Sorry for making you explain it again. I figured out where my confusion about the pressurized section of the fuel system was coming from. And when I figured it out, I felt like a dumbass.
On another note, I think I figured out where the pressure loss is coming from. I'm pretty sure it's the fpr. I removed the vacuum line, pressurized the system with the ignition, and checked for a leak/fuel smell. It again lost pressure pretty quickly, but I couldn't smell any fuel and couldn't feel any leaks around the ports on the fpr. Then, I tried clamping the return line and and pressurized the system again. Just like last night, it lost pressure at a much slower rate. Instead of bleeding down to 0 in less than 2 minutes, it lost less than 10 lbs of pressure in 5 minutes of we watching it. While I was staring at the gauge, I caught a slight fuel smell. So I went back to check fpr for leaks again and there it was. The seam between the top and bottom sections of the fpr was wet. So the fpr definitely has a leak. I'm guessing that it was leaking through the return line and the started leaking through the seam when the fuel line was clamped to give the fuel somewhere else to go. Again, that's just a guess.
RAR1TY
New member
Re: AFPR problems help much needed
Much thanks,
Bryan A
862-881-7065
Threeon400@gmail.com
PS- feel free to call or text any info or pics that may help my build.....
Ok so not to Beat a dead horse.... I read this ENTIRE thread, and I somewhat understand. No pics of AFPR completed though? Anyway, I did this to my last TY 2 years ago, and since then Cancer, multiple Surgeries and drugs have crushed my memory. I have a 3 bar map and TurboTweak in my hand, along with AFPR from RPM. Also have a fuel rail gauge ready to go. I'd like to put these things on correctly and in order as to lose no driveabity until my guy can tune it. Starting 9am EST tommorrow (Sat) . I'll be in the shop, tell me, if you please, or point me to the thread aLready if it's outhere, the order of all said parts. After that's done, I'll install 2 pod pillar with boost and oil temp gauges. Then making a custom CAI. RPM catback Magnaflow Kit already Installed. Any and all help is greatly appriciated as I give the Aspen it's proper new reliable setup and power.
Much thanks,
Bryan A
862-881-7065
Threeon400@gmail.com
PS- feel free to call or text any info or pics that may help my build.....
![Quickstop [UK]](/data/avatars/m/5/5165.jpg?1570199786){kind=avatar}
Quickstop [UK]
Combating adversyty.
Re: AFPR problems help much needed
All the stuff you want to do is on the forum. You said to help out and the best piece of help I can offer is this:
Your truck is a rare example of a stock, unmolested extremely rare Typhoon. Putting all that stuff on it expecting a big power increase means it's going to break or need even more stuff to maintain it. It will very quickly lose the unmolested status.
A 3 bar MAP will need bigger injectors, a fuel pump, a fuel pump mod for wiring etc. You will need a wide band to "tune" it with. That means potentially hacking into the existing wiring but certainly opening up the ECM. I put "tune" in quotation marks because you say you have a TurboTweak chip already and then your guy will tune it. The Turbotweak is by all accounts very good and adds some driveability to the truck but you're into the ECM, MAP sensor changes and lots of other stuff and your guy probably hasn't worked on these before. I could be wrong and apologise if you think this is unhelpful or irrelevant. At the end of the day it's your truck.
You're starting to head down a path of fixing that truck until it's broken. The best piece of advice I can offer for your build is not to do it. There are so many other trucks that need some love, why not adopt one of them?
All the stuff you want to do is on the forum. You said to help out and the best piece of help I can offer is this:
Your truck is a rare example of a stock, unmolested extremely rare Typhoon. Putting all that stuff on it expecting a big power increase means it's going to break or need even more stuff to maintain it. It will very quickly lose the unmolested status.
A 3 bar MAP will need bigger injectors, a fuel pump, a fuel pump mod for wiring etc. You will need a wide band to "tune" it with. That means potentially hacking into the existing wiring but certainly opening up the ECM. I put "tune" in quotation marks because you say you have a TurboTweak chip already and then your guy will tune it. The Turbotweak is by all accounts very good and adds some driveability to the truck but you're into the ECM, MAP sensor changes and lots of other stuff and your guy probably hasn't worked on these before. I could be wrong and apologise if you think this is unhelpful or irrelevant. At the end of the day it's your truck.
You're starting to head down a path of fixing that truck until it's broken. The best piece of advice I can offer for your build is not to do it. There are so many other trucks that need some love, why not adopt one of them?
RAR1TY
New member
Re: AFPR problems help much needed
My "guy" tunes only Turbo cars for a living. Been doing it for 30 years. He has 2 GNs and a GNX, one nicer than the other. He's a 60 year old computer perfectionist and has worked on SyTys plenty, including my last POS that, with all the same mods, ran like an animal, eeryday. This Aspen I bought is rare, beautiful and special. Yet needs some upgrades. It sat for 5 years, a big no no, and now she's breathing daily, and like a champ. Already have the FP, and Im no restaurant waiter. I've hand built many cars, I own a body shop. So my plan is to do the minor, correct, unharmful mods to enjoy this truck the way it should be. I DRIVE my vehicles. No $XX,XXX paper weight here. So thanks for your opinion, feel free to do to your truck what you want. What I'm doing , adding quality parts and upgrades won't hurt the value that is 1 of 28. Now anyone have some insight to my questions, I'd appreciate it.
My "guy" tunes only Turbo cars for a living. Been doing it for 30 years. He has 2 GNs and a GNX, one nicer than the other. He's a 60 year old computer perfectionist and has worked on SyTys plenty, including my last POS that, with all the same mods, ran like an animal, eeryday. This Aspen I bought is rare, beautiful and special. Yet needs some upgrades. It sat for 5 years, a big no no, and now she's breathing daily, and like a champ. Already have the FP, and Im no restaurant waiter. I've hand built many cars, I own a body shop. So my plan is to do the minor, correct, unharmful mods to enjoy this truck the way it should be. I DRIVE my vehicles. No $XX,XXX paper weight here. So thanks for your opinion, feel free to do to your truck what you want. What I'm doing , adding quality parts and upgrades won't hurt the value that is 1 of 28. Now anyone have some insight to my questions, I'd appreciate it.
RAR1TY
New member
Re: AFPR problems help much needed
Oh and I have Stage 4 Stomach Cancer, so my time is short. When this truck goes back up for sale someday, with all the right shit in it with 70k miles, I doubt very much it won't sell for what I paid for it. These things are a labor of love(and hate), I love my truck and will enjoy it till I'm gone. I just hope one of you lucky guys has the dough when it comes. What a truck...
Oh and I have Stage 4 Stomach Cancer, so my time is short. When this truck goes back up for sale someday, with all the right shit in it with 70k miles, I doubt very much it won't sell for what I paid for it. These things are a labor of love(and hate), I love my truck and will enjoy it till I'm gone. I just hope one of you lucky guys has the dough when it comes. What a truck...
Slyclone
Well-known member
Re: AFPR problems help much needed
I would not put that on........at all......
Why? Some say Thats a big NO NO. I had thought early on I was going to do THAT as well. Put a gauge on the rail. Until some one pointed out how the gauges are top heavy and can snap the schrader valve from driving under load and the engine shifting. I mean it is a very thin wall to begin with.
I would not put that on........at all......
Why? Some say Thats a big NO NO. I had thought early on I was going to do THAT as well. Put a gauge on the rail. Until some one pointed out how the gauges are top heavy and can snap the schrader valve from driving under load and the engine shifting. I mean it is a very thin wall to begin with.