Resolved 1g base fuel pressure.

[BIRDCLAWTSi]

i have read the forums and i am getting 37 psi with vacuum lines connected as the proper base pressure for a 1gT, what should i have at base vac. line on and off?

What is the base fuel pressure for 1g. auto, and n/t. My book says something totally different.
Will a n/t, or an auto fpr fit the fuel rail?

i am confused here. i just got a new sending unit and i am going to install it tomorrow. i am not sure what pump is in my car, the line is too rusty to touch and my base pressure is way higher than it should be.

thanks in advance.

 

[jeffo]

The problem is that the stock FPR's have a VERY tiny return orifice inside, which can't allow enough fuel volume to flow back to the tank at idle and light cruising when you have a big fuel pump upgrade.

What makes it so difficult to tune around is that as soon as you start making a little boost the pressure drops down where it should be because the fuel isn't backing up anymore, it is getting injected. Every car is different, and rewiring the fuel pump makes it worse. Some guys swear they have no problems with it, but IMO the only way to fix it is with a good AFPR.

 

[BIRDCLAWTSi]

The problem is that the stock FPR's have a VERY tiny return orifice inside, which can't allow enough fuel volume to flow back to the tank at idle and light cruising when you have a big fuel pump upgrade.

What makes it so difficult to tune around is that as soon as you start making a little boost the pressure drops down where it should be because the fuel isn't backing up anymore, it is getting injected. Every car is different, and rewiring the fuel pump makes it worse. Some guys swear they have no problems with it, but IMO the only way to fix it is with a good AFPR.

I have had the car since April and I have been building it over time and I got to the point where I needed a fuel pump but my sending unit was so rusty that it would break off if I tried to change it, so i got a new sending unit. When I changed it I lifted the numbers off of the pump. it is a 1020 mkiv pump. I was planning on a 190 but now that I have a big pump, I will get a regulator. It is not rewired but it is over running the reg.

I always had a thought that there was a bigger pump in there because my base pressure was always high, but I thought it was a n/t reg. thanks for the replies.

Does anyone know the part number off of the stock mt turbo regulator? Denso 1262 is the number on mine.

 

[Dharbeck]

Heres a question for all you guys just got a 4g63t in a galant gsx my FRP is reading 80psi, what would cause this to read so high and how do i get it down?

 

[steve]

Heres a question for all you guys just got a 4g63t in a galant gsx my FRP is reading 80psi, what would cause this to read so high and how do i get it down?

Making the assumption that it isn't the FPR, then the next guess would be a blockage in the return line. That's easy to test, disconnect the stock return line and connect a hose into a bucket to catch the fuel. If the pressure drops to where it should be then the return is blocked.

Where is the fuel pressure gauge attached?

 

[salisbury]

what kind of gauge do you use?

 

[Dharbeck]

Thats the problem, Im pretty sure its not the stock fpr but i dont know i just bought the car and the guy had no useful info on the car itself or any mods. I know when ## looking at the motor the fpr thats in it now is top right, its not mouted or anything just kinda chilling there, when i find out more info i will be posting my issues at a later date. The car also has a 2g mass and its a 1g maybe i need a safc, im not really sure what the pervious owner has done to it.

 

[BoostedPhoenix]

I have had the car since April and I have been building it over time and I got to the point where I needed a fuel pump but my sending unit was so rusty that it would break off if I tried to change it, so i got a new sending unit. When I changed it I lifted the numbers off of the pump. it is a 1020 mkiv pump. I was planning on a 190 but now that I have a big pump, I will get a regulator. It is not rewired but it is over running the reg.

I always had a thought that there was a bigger pump in there because my base pressure was always high, but I thought it was a n/t reg. thanks for the replies.

Does anyone know the part number off of the stock mt turbo regulator? Denso 1262 is the number on mine.

Sorry to dig this up from a few months ago but I'm in a similar situation. More like I want the 3.0bar to get the flow my injectors are actually rated at.

I have 3 regulators laying around with Denso 1382 stamped on them (that includes the one on my '94 TSi) and the only cars i have ever had/parted out are m/t turbos, except for a '92 N/T auto that is still completely together in my driveway that has your Denso 1262 stamped on the top. Now as far as I know this car has never been messed with so by your fuel pressure readings and that FPR number it would make sense that you have a N/T regulator on that beast. I considered running that N/T regulator but i don't want to be the guinnea pig that finds the point where the N/T regulator stops increasing pressure

Now to my question, what is the Denso number from a 1g turbo Automatic, I would really like to find me one of those

 

[gofer]

The part number is M04669055 for a N/A 1g fpr.

 

[BoostedPhoenix]

Thanks man but im lookin for a 1g TURBO automatic FPR since that is identical in function to a 2g turbo FPR but fits my rail without modifying anything

 

[gofer]

My bad, heres the 1g A/T fpr part number... MD165859 but I think they are about $75. I was thinking you wanted the N/A 1g fpr because its a 47psi regulator and its what most want to run going to E85. Sorry.

 

[Vincent Pandolph]

Always upgrade afpr when using a bigger pump. The larger pump will make more pressure and flow rate causing a rich condition, using afpr keeps this in check to keep a steady pressure that you can set according to the application. All the tuners and old school DSM shop owners I have spoken with are telling me to run 37.5-38 psi with a 255lph pump fuel lab afpr and full -6 fuel line setup. Hope it helps and good luck.

Ps take your time and do it right

 

[NOSLO2PT0]

Hey. Welcome to 11 years ago!!!

 

[steve]

So @Vincent Pandolph, what were you searching for when you found this old thread?

 

[Vincent Pandolph]

I'm in process of building a 1990 TSI AWD was looking for the correct psi to set . Didn't realize the thread was ancient. I guess they all are because not too many left and most have been fixed already