Running better but not the best.

[Sevy14]

Well folks I’ve done most of the basics, it’s running better but still ugly. Hot wire, fuel pump, injectors, TT chip, FPR.
1. idles but stalls chokes and misses when I drop it in gear. I’ve now changed plugs twice. First set fouled. Changed all vacuums lines I could find.
2. Installed the adjustable fuel pressure regulator, its running at 70 psi. I can’t seem to turn it down. ( Racetronix). Turn the screw either way, fuel pressure goes up but doesn’t go below 70.
3. First thing I did was change the MAF and pipe with Translator. Sine I did that I’m getting codes 33 and 34. Completed the trouble shooting of these but can’t seem to find anything.
Other things I ve done, Cleaned IAC, Adjusted TPS.
All Scan perimeters seem to be in the zone.

 

[dynoman]

Fuel pressure is WAY to high . Maybe a restricted return or bad regulator . get the fuel pressure in check first .

 

[dynoman]

Double check the FP gauge also to make sure it's accurate .

 

[Sevy14]

Double check the FP gauge also to make sure it's accurate .

I ve tried two different gauges both the same reading. One on the regulator and a externa.

 

[BRAD_PADGETT]

Google Turbobuick Fuel Pressure too High. Start finding the problem. Common culprits are the fuel pressure regulator or restrictions on the return line to the fuel tank.

 

[Sevy14]

Google Turbobuick Fuel Pressure too High. Start finding the problem. Common culprits are the fuel pressure regulator or restrictions on the return line to the fuel tank.

Thanks Brad, never would have thought of that. I may just replace that line as well.

 

[BRAD_PADGETT]

Thanks Brad, never would have thought of that. I may just replace that line as well.

I had the same problem. My tuner solved it by having ECUGN control the voltage to fuel pump. Low rpm low voltage to pump. High rpm- full voltage to pump. This enabled me to run a helcat fuel pump with 120 injectors and stock fuel lines. Others open up fuel return line at all the connectors or replace them some swap vent line for fuel return line.

 

[dynoman]

Thanks Brad, never would have thought of that. I may just replace that line as well.

See post #2

 

[1KWIKSIX]

If you’ve installed a fuel pump any bigger than 255 lph you’re likely to run into this issue of not being able to turn down fuel pressure to correct level. The solution most do is install larger fuel return line which fixes the problem

 

[Sevy14]

Found a potential culvert. I was removing O2 sensor. Someone in the past sliced then sensor wire and it fell apart when I removed he sensor.

 

[Sevy14]

I’ll be check the return line tomorrow. Likely replace. It is a 255 pump That I upgraded to.

 

[salvageV6]

There's a fitting on the return line in front of the motor that you can separate and blow air through to see if it's blocked, mine was blocked at that fitting once.

 

[Sevy14]

I’ve installed a new pump(255). I can’t get either the stock regulator or new adjustable to adjust down to below 60 psi. Has anyone had this situation? Could it be the stock return line is too small? All lines seem to be clear, blew air through no problem.

 

['87 Turbo "T"]

I’ve installed a new pump(255). I can’t get either the stock regulator or new adjustable to adjust down to below 60 psi. Has anyone had this situation? Could it be the stock return line is too small? All lines seem to be clear, blew air through no problem.

No. Not with a 255. You problem lies elsewhere. Or there IS a blockage somewhere. Also make sure there's no blockage in the fuel rail.

 

[Sevy14]

Man, I’ve blown air right from fuel rail back. Maybe just replace the line and see what happens.

 

[BRAD_PADGETT]

Run a test. Buy 30 feet of rubber fuel line and bypass the return line to the tank. I had to verify the return line was restricted. My fuel pressure would no go below 42 with the return line fitting cleaned out. I solved mine by having ecugn control fuel pump. I run 120 lbs injectors.

 

[THensley]

Run a test. Buy 30 feet of rubber fuel line and bypass the return line to the tank. I had to verify the return line was restricted. My fuel pressure would no go below 42 with the return line fitting cleaned out. I solved mine by having ecugn control fuel pump. I run 120 lbs injectors.

30 ft of fuel line is better than a 2000. ECU.
It time to drop the tank and check your work back there. easy to kink the hose and be able to blow through a restriction.
it has restriction not blocked if it was blocked fuel pressure would be 90+ lb

 

[dynoman]

So you blew air through the lines and pressure went down from 70 to 60psi ...you still have a restriction . Like what was suggested before , get a length of fuel line and return it into a 5 gallon bucket or get enough to go back to the tank .

 

[Chuck Leeper]

U inspect the jumper line at the frame hard line to tank?
Just because it shows "clear", remember the return pressure is nowhere near what you applied with the air compressor.

 

[Sevy14]

Well there you have it, new return and bang able to adjust the fuel pressure. Next problem…. Car idles pretty good but soon as I drop it into gear it chokes and coughs. Same as when driving, low throttle chokes and coughs and it seems to get all sorts of boost and it sounds like the waste gate is opening with hardly any throttle.