Got it fired! Now a fuel pressure issue...
07-14-2008, 09:13 AM
#1
Got it fired! Now a fuel pressure issue... My car had been down for a 7 month stretch since late last November. I bought the old hiflo turbo kit from Turbo LS1 SS on the board. Super nice guy, sold me exactly what I needed to get the kit going on my car and everything installed very smooth (he fixed the headaches on his build) and I was able to inherit a great working kit.
After finally tracing down a fuel pump wiring issue, putting a new battery in the car, and sealing up a leaky fuel rail, we got it to fire up on Saturday. I attempted a startup vid, but it didn't turn out well (stupid fuel rail sabotaged us again after it ran for about 30 seconds). We ended up pulling the rail completely off, reinstalling the injectors in it and reseated it. We got it to hold pressure and checked around, no other leaks. We let it run for a bit, threw it in gear and it went into reverse, D, etc great (bought a used 3200 vigilante converter in the middle of the build that seems to work great as well). Took it out for a drive and took it thru some RPMs...turbo really starts to make some noise from around 2500-4K! Sounds kinda goofy at idle (open downpipe), kinda like a boat or something. The tune needs a little work, but it was good enough to fire it and get it driveable. Still need to tinker with the idle (its SD now with a 2 bar MAP sensor).
All in all its going well, but something odd that I noticed. When we finally got the stupid rails to seat and the injectors to hold, we set the fuel pressure at 43 lbs on the aeromotive 1000-6 regulator with the key in the 'on' position. When it fired, pressure shot up to about 65 lbs on the electric autometer fuel pressure gauge. It is a boost/vacuum referenced regulator, but I assumed this would cause the pressure to decrease when it was running, not increase. At the time we didn't think about the boost reference line, and it was connected as we attempted to turn the pressure down on the regulator when the engine was idling around 1500 rpm, but the gauge didn't move, stayed around 65 psi.
The fuel system is: 2 walbro 255 pumps wired up together in the tank that both run all the time, stock feed line, stock line adapted to a 6AN into a 6AN Y-fitting, then a feed line running to each rail, out of the rails into the 2 in's on the regulator, and a 6AN return out of the regulator going back and tapping into the line that was originally on the T-fitting right behind the fuel filter (hold in the T plugged up).
So do you guys think the system is adjusted correctly for the appropriate fuel pressure if it was set at 43 with the engine off (per tuners recommendation) Why does it jump up to 65 lbs when running? I was reading around on aeromotives website, they suggest setting it at 43 lbs of pressure running with the vacuum line OFF, we didn't do that and I was going to check that out tonight. I figured with a vacuum line connected the pressure would drop lower than 43 if anything. I'm hoping it's just a weird issue with the voltage being low or a bad ground on the gauge itself...figure it out tonight I guess.
After finally tracing down a fuel pump wiring issue, putting a new battery in the car, and sealing up a leaky fuel rail, we got it to fire up on Saturday. I attempted a startup vid, but it didn't turn out well (stupid fuel rail sabotaged us again after it ran for about 30 seconds). We ended up pulling the rail completely off, reinstalling the injectors in it and reseated it. We got it to hold pressure and checked around, no other leaks. We let it run for a bit, threw it in gear and it went into reverse, D, etc great (bought a used 3200 vigilante converter in the middle of the build that seems to work great as well). Took it out for a drive and took it thru some RPMs...turbo really starts to make some noise from around 2500-4K! Sounds kinda goofy at idle (open downpipe), kinda like a boat or something. The tune needs a little work, but it was good enough to fire it and get it driveable. Still need to tinker with the idle (its SD now with a 2 bar MAP sensor).
All in all its going well, but something odd that I noticed. When we finally got the stupid rails to seat and the injectors to hold, we set the fuel pressure at 43 lbs on the aeromotive 1000-6 regulator with the key in the 'on' position. When it fired, pressure shot up to about 65 lbs on the electric autometer fuel pressure gauge. It is a boost/vacuum referenced regulator, but I assumed this would cause the pressure to decrease when it was running, not increase. At the time we didn't think about the boost reference line, and it was connected as we attempted to turn the pressure down on the regulator when the engine was idling around 1500 rpm, but the gauge didn't move, stayed around 65 psi.
The fuel system is: 2 walbro 255 pumps wired up together in the tank that both run all the time, stock feed line, stock line adapted to a 6AN into a 6AN Y-fitting, then a feed line running to each rail, out of the rails into the 2 in's on the regulator, and a 6AN return out of the regulator going back and tapping into the line that was originally on the T-fitting right behind the fuel filter (hold in the T plugged up).
So do you guys think the system is adjusted correctly for the appropriate fuel pressure if it was set at 43 with the engine off (per tuners recommendation) Why does it jump up to 65 lbs when running? I was reading around on aeromotives website, they suggest setting it at 43 lbs of pressure running with the vacuum line OFF, we didn't do that and I was going to check that out tonight. I figured with a vacuum line connected the pressure would drop lower than 43 if anything. I'm hoping it's just a weird issue with the voltage being low or a bad ground on the gauge itself...figure it out tonight I guess.
Last edited by Photochop; 07-14-2008 at 10:27 AM.
07-14-2008, 08:58 PM
#3
First off, you should never attempt to adjust the regulator unless the engine and/or fuel pump is running. The pump prime is not sufficient & you can over thghten the regulator trying to get the pressure up.
Remove the vac line, start the car & set the pressure.
Then reconnect the vac line.
Remove the vac line, start the car & set the pressure.
Then reconnect the vac line.
07-14-2008, 10:31 PM
#4
I didn't see any other springs in the pump box. I'll verify that with the paperwork though.
Hope we didn't mess up the regulator...the steps we followed were per a local shop, so I guess they don't know the correct way or I didn't follow what he said correctly (probably the latter).
I didn't do anything with the car today, I'll do it the correct way tomorrow and hopefully the gauge will read correct and the reg. isn't busted.
Hope we didn't mess up the regulator...the steps we followed were per a local shop, so I guess they don't know the correct way or I didn't follow what he said correctly (probably the latter).
I didn't do anything with the car today, I'll do it the correct way tomorrow and hopefully the gauge will read correct and the reg. isn't busted.
07-15-2008, 10:17 PM
#5
Well I figured out the fuel pressure issue. I followed the procedure as Lonnies Perf. mentioned, however when I was setting the pressure the electric fuel pressure gauge wasn't showing a change at all. So per the aeromotive instructions, I took the adj. bolt pretty far to the left (counter clockwise) to bring the pressure down. We had to kill the car and restart it to see the pressure change show on the gauge. We got it set after about 4 restarts, once the vacuum line was connected it dropped 2 lbs and landed right on 43. Success!
07-17-2008, 11:50 AM
#6
First off, you should never attempt to adjust the regulator unless the engine and/or fuel pump is running. The pump prime is not sufficient & you can over thghten the regulator trying to get the pressure up.
Remove the vac line, start the car & set the pressure.
Then reconnect the vac line.
Remove the vac line, start the car & set the pressure.
Then reconnect the vac line.
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07-22-2008, 10:43 PM
#9
Another question for Lonnies.
I got the regulator set as you stated above - was targeting 43 psi at idle with my Autometer Sport Comp II Electric Fuel Pressure Gauge. To verify the gauge, we removed it and installed a 1 1/2 autometer mechanical pressure gauge right off the regulator. The electric ended up being 1 lb off, so we adjusted it according to the mechanical gauge and called it good.
Now I'm seeing some fluctuation in the electric gauge inside the car after driving it for any kind of distance. Cold idle it fires up at 47 on the gauge, falls off to 43, then slowly continues to fall to about 31 on the electric gauge after driving the car for more than about 10-15 mins. I'm pretty sure its a gauge issue, as the mechanical showed ZERO fluctuation when hooked up. Do you see these electrical gauges changing/fluctuating often after a car has been running a while?
I was considering buying a t-fitting and hooking up a permanent 1 1/2 mech. fuel press. gauge at the end of a rail just to make sure when we go to dyno tune it, but thought I'd ask before spending the money.
I got the regulator set as you stated above - was targeting 43 psi at idle with my Autometer Sport Comp II Electric Fuel Pressure Gauge. To verify the gauge, we removed it and installed a 1 1/2 autometer mechanical pressure gauge right off the regulator. The electric ended up being 1 lb off, so we adjusted it according to the mechanical gauge and called it good.
Now I'm seeing some fluctuation in the electric gauge inside the car after driving it for any kind of distance. Cold idle it fires up at 47 on the gauge, falls off to 43, then slowly continues to fall to about 31 on the electric gauge after driving the car for more than about 10-15 mins. I'm pretty sure its a gauge issue, as the mechanical showed ZERO fluctuation when hooked up. Do you see these electrical gauges changing/fluctuating often after a car has been running a while?
I was considering buying a t-fitting and hooking up a permanent 1 1/2 mech. fuel press. gauge at the end of a rail just to make sure when we go to dyno tune it, but thought I'd ask before spending the money.
09-22-2008, 07:25 AM
#10
Well I figured out the problem I may have been having since day 1. Lately the fuel pressure has been really low and I thought maybe it was a regulator problem. Decided to buy a T-fitting and run a small mech. gauge right before the rail. In doing this, I realized that the pressure was still low, showing only 20psi on the rail. So I decided to do the trap door mod. I'd previously dropped the tank, etc. but didn't wanna fool with that again. So I cut the hole out, pulled the pumps, and noticed a small tear in the main feed line. Sure enough, replaced that section of hose and all is well now. In the process of changing the fuel pressure, etc I think I've messed up my regulator. Not sure exactly how, but no matter what I adjust it to, it stays just above 60psi of pressure and the car is tuned for 43psi of fuel. Sooo now I'm going to order a rebuild kit for the regulator and hopefully the goofy fuel pressure issues will be solved.
