Ddnspider's- Project Wrong-Way- Rear Mount Turbo Thread
More detail.
So where is that filter ? What size are those hardlines ? Are you sure that factory tee fitting...is full bore throughout ? Filter is in the stock location, just prior to the factory tee block. Feed line is stock whatever size that is, 5/16?? Not sure if the factory tee is full bite throughout but I would guess so.
What is the makeup of that return ? Image doesnt show much...but I assume the hardline nylon is in some shape or form the return ? Is it full bore throughout ? With no restrictions ?
Stock is Hardline from the tee block to that nylon line to the factory bulkhead return line. All I did was remove the 2ft section of Hardline and replace with braided AN and added the FPR. As far as I know it doesn't get pinched down anywhere...but that should cause HIGH FP, not LOW FP.
The vac signal...from where exactly ? Is it a dedicated line ? Have you tested the FPR with a Mityvac to ensure the top chamber does not leak ? ( Many actually do a little....not an issue with say a 1/4" vac line direct from the intake. But as you're maybe a few feet away a small leak could reduce pressure quite a bit.
I have a vacuum block off the intake manifold post TB. There is 1 line that runs back to the WG and it's tee'd off of that. I've tried pinching the vacuum line with the car running with no change in FP. I have not done a mityvac on the vacuum port. I could pull the FPR and add a gauge to the 1/8NPT port, 2ouldnt be a big deal.
A gauge tee'd off directly at the vac/FPR would indicate any issues there too. But a test with a Mityvac is good, and you may need some sealant around the adjuster threads.
( Although a leak there under vac, you'd think FP may rise as opposed to fall )
So where is that filter ? What size are those hardlines ? Are you sure that factory tee fitting...is full bore throughout ? Filter is in the stock location, just prior to the factory tee block. Feed line is stock whatever size that is, 5/16?? Not sure if the factory tee is full bite throughout but I would guess so.
What is the makeup of that return ? Image doesnt show much...but I assume the hardline nylon is in some shape or form the return ? Is it full bore throughout ? With no restrictions ?
Stock is Hardline from the tee block to that nylon line to the factory bulkhead return line. All I did was remove the 2ft section of Hardline and replace with braided AN and added the FPR. As far as I know it doesn't get pinched down anywhere...but that should cause HIGH FP, not LOW FP.
The vac signal...from where exactly ? Is it a dedicated line ? Have you tested the FPR with a Mityvac to ensure the top chamber does not leak ? ( Many actually do a little....not an issue with say a 1/4" vac line direct from the intake. But as you're maybe a few feet away a small leak could reduce pressure quite a bit.
I have a vacuum block off the intake manifold post TB. There is 1 line that runs back to the WG and it's tee'd off of that. I've tried pinching the vacuum line with the car running with no change in FP. I have not done a mityvac on the vacuum port. I could pull the FPR and add a gauge to the 1/8NPT port, 2ouldnt be a big deal.
A gauge tee'd off directly at the vac/FPR would indicate any issues there too. But a test with a Mityvac is good, and you may need some sealant around the adjuster threads.
( Although a leak there under vac, you'd think FP may rise as opposed to fall )
https://www.supraforums.com/threads/...-30psi.604888/
Random Google searching and I found a guy on the Supra forum with almost the same issue and he went through all the same stuff I did with checking voltages and swapping pumps and regulators blablabla. Turned out to be a failing wideband sensor that drifts lean when warm and not setting base pressure with a warmed engine. Not positive thats my issue but it was an interesting read with many similarities.
Random Google searching and I found a guy on the Supra forum with almost the same issue and he went through all the same stuff I did with checking voltages and swapping pumps and regulators blablabla. Turned out to be a failing wideband sensor that drifts lean when warm and not setting base pressure with a warmed engine. Not positive thats my issue but it was an interesting read with many similarities.
https://www.supraforums.com/threads/...-30psi.604888/
Random Google searching and I found a guy on the Supra forum with almost the same issue and he went through all the same stuff I did with checking voltages and swapping pumps and regulators blablabla. Turned out to be a failing wideband sensor that drifts lean when warm and not setting base pressure with a warmed engine. Not positive thats my issue but it was an interesting read with many similarities.
Random Google searching and I found a guy on the Supra forum with almost the same issue and he went through all the same stuff I did with checking voltages and swapping pumps and regulators blablabla. Turned out to be a failing wideband sensor that drifts lean when warm and not setting base pressure with a warmed engine. Not positive thats my issue but it was an interesting read with many similarities.
Here is the new bulkhead stuff.
https://www.racetronix.biz/customkit...kc=bcwa-fl98hd
If youre trying to use a wideband to fix drivability issues youre putting too much trust in it.
Thats what narrow bands are for.
Running on stock regulator that would not matter also which you did for a little bit.
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From: Norn Iron
https://www.supraforums.com/threads/...-30psi.604888/
Random Google searching and I found a guy on the Supra forum with almost the same issue and he went through all the same stuff I did with checking voltages and swapping pumps and regulators blablabla. Turned out to be a failing wideband sensor that drifts lean when warm and not setting base pressure with a warmed engine. Not positive thats my issue but it was an interesting read with many similarities.
Random Google searching and I found a guy on the Supra forum with almost the same issue and he went through all the same stuff I did with checking voltages and swapping pumps and regulators blablabla. Turned out to be a failing wideband sensor that drifts lean when warm and not setting base pressure with a warmed engine. Not positive thats my issue but it was an interesting read with many similarities.
Except fuel pressure dropping has nothing to do with the wideband. You could have 50 widebands fitted or none...still wont affect fuel pressure ( unless 50 draw too much current in the system I guess lol )
Gotta watch them ricers. The sensors they use dont like beef very much. ;-)
Here is the new bulkhead stuff.
https://www.racetronix.biz/customkit...kc=bcwa-fl98hd
If youre trying to use a wideband to fix drivability issues youre putting too much trust in it.
Thats what narrow bands are for.
Running on stock regulator that would not matter also which you did for a little bit.
Here is the new bulkhead stuff.
https://www.racetronix.biz/customkit...kc=bcwa-fl98hd
If youre trying to use a wideband to fix drivability issues youre putting too much trust in it.
Thats what narrow bands are for.
Running on stock regulator that would not matter also which you did for a little bit.
I believe he also had a bad FP gauge in that thread. I am aware that the wideband and fuel system are not related 🙄 it was an interesting read. I still plan to beef up the power wire from the alternator.
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Can you increase pressure by adjusting the regulator once it starts to drop?
Can you wrap some rubber around the return line and slowly clamp it to increase pressure once it drops?
I doubt its your pump. In order to drop pressure at idle, it would have to be flowing about less than 10% of its rated output. It should be able to hold pressure at idle.
Grab a can of freeze-off from the parts store. Use it to cool down your fuel pressure sensor and regulator while its idling at low pressure.
Can you wrap some rubber around the return line and slowly clamp it to increase pressure once it drops?
I doubt its your pump. In order to drop pressure at idle, it would have to be flowing about less than 10% of its rated output. It should be able to hold pressure at idle.
Grab a can of freeze-off from the parts store. Use it to cool down your fuel pressure sensor and regulator while its idling at low pressure.
Can you increase pressure by adjusting the regulator once it starts to drop?
Can you wrap some rubber around the return line and slowly clamp it to increase pressure once it drops?
I doubt its your pump. In order to drop pressure at idle, it would have to be flowing about less than 10% of its rated output. It should be able to hold pressure at idle.
Grab a can of freeze-off from the parts store. Use it to cool down your fuel pressure sensor and regulator while its idling at low pressure.
Can you wrap some rubber around the return line and slowly clamp it to increase pressure once it drops?
I doubt its your pump. In order to drop pressure at idle, it would have to be flowing about less than 10% of its rated output. It should be able to hold pressure at idle.
Grab a can of freeze-off from the parts store. Use it to cool down your fuel pressure sensor and regulator while its idling at low pressure.
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I just noticed how close your turbo is to your tank lol.
Your overheating the fuel. Hot fuel naturally cause pressure drop.
Gasoline vapor pressure is 5 PSI at 160 degrees and 15 PSI at 210 degrees.
If it goes over 210, things get bad.
Your overheating the fuel. Hot fuel naturally cause pressure drop.
Gasoline vapor pressure is 5 PSI at 160 degrees and 15 PSI at 210 degrees.
If it goes over 210, things get bad.
1. This will happen on a dead cold start within 10 min of idling where the turbo isn't generating any heat over what a muffler would.
2. I can put my hand on the heat shield above the turbine and it's warm but not hot.
3. I can go for a 45 min cruise on the highway and maintain fuel pressure, it only happens and idle/stop and go.
4. I reached under the car after a drive and the fuel pressure reg isnt hot, not even sure I would say it was warm, more like ambient.
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Have you confirmed actual pressure is dropping? Do you see injector pw or % increase when pressure drops? Where is your meter ground connected when measuring fuel pump voltage? Voltage drop on ground side has caused many to chase their tail. How difficult would it be to cap the return from press reg to read fp dead head/max pressure when problem is occurring?
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Freeze-out on the pressure sensor would rule out engine bay heat soak causing bad readings.
Those sensors are typically only able to compensate for temperature variations up to 170* F. Any higher and the readings start to fall.
They stop working complete somewhere before 250, a lot less if they are your typical $16 China ones.
Just don't freeze the sensor, it'll do the same thing at 0* F.
It almost sounds like a false reading more than anything, especially if you don't think the fuel temps are really getting over 160.
Those sensors are typically only able to compensate for temperature variations up to 170* F. Any higher and the readings start to fall.
They stop working complete somewhere before 250, a lot less if they are your typical $16 China ones.
Just don't freeze the sensor, it'll do the same thing at 0* F.
It almost sounds like a false reading more than anything, especially if you don't think the fuel temps are really getting over 160.
Have you confirmed actual pressure is dropping? Do you see injector pw or % increase when pressure drops? Where is your meter ground connected when measuring fuel pump voltage? Voltage drop on ground side has caused many to chase their tail. How difficult would it be to cap the return from press reg to read fp dead head/max pressure when problem is occurring?
Freeze-out on the pressure sensor would rule out engine bay heat soak causing bad readings.
Those sensors are typically only able to compensate for temperature variations up to 170* F. Any higher and the readings start to fall.
They stop working complete somewhere before 250, a lot less if they are your typical $16 China ones.
Just don't freeze the sensor, it'll do the same thing at 0* F.
It almost sounds like a false reading more than anything, especially if you don't think the fuel temps are really getting over 160.
Those sensors are typically only able to compensate for temperature variations up to 170* F. Any higher and the readings start to fall.
They stop working complete somewhere before 250, a lot less if they are your typical $16 China ones.
Just don't freeze the sensor, it'll do the same thing at 0* F.
It almost sounds like a false reading more than anything, especially if you don't think the fuel temps are really getting over 160.
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At this point I'm willing to try just about anything....and I think he is more referring to freeze spray on the fuel pressure sensor.
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You know, I actually stuck a large box fan under the hood at the sensor to try and rule out the sensor doing something flakey with temp, but freeze spray is a good idea and more pointed. It is a typical Amazon 100 psi transducer so who knows when the engine is sitting at 180 lol.
The pressure sensor readings would be ~20 PSI when the engine was at normal temp and would taper off to zero by the time I shut the car off.
Even at normal temps around 185, I can't trust the sensor readings, and only use it to measure quick spikes/dips for lifting heads or blow hoses.
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From: Norn Iron
Cheap sensors can often give odd readings, especially if subject to nasty fluids or temperatures.
A good quality sensor not so.
But cooling system pressure with the sensor installed on the engine itself, due to water movement within the system as well as pressure fluctuations due to coolant temp....you will see swings of pressure in the system. That is expected, you just need to work out what is normal for your setup.
You will get more stable readings from a sensor installed in an air space in a header tank, although it may not be quite as responsive here to very minor head lifting.
It is a whole other topic in itself though
A good quality sensor not so.
But cooling system pressure with the sensor installed on the engine itself, due to water movement within the system as well as pressure fluctuations due to coolant temp....you will see swings of pressure in the system. That is expected, you just need to work out what is normal for your setup.
You will get more stable readings from a sensor installed in an air space in a header tank, although it may not be quite as responsive here to very minor head lifting.
It is a whole other topic in itself though