L98

Key On Engine Off 45 PSI

Running at Idle in Park with vacuum plugged in 37 PSI

Running at Idle in Park with vacuum unplugged 47 PSI


If I prime it it goes to 45

drops to 40 in 44 seconds

drops to 30 in an additional 44 seconds

drops to 20 in an additional 1:33

drops to 10 in an additional 2:12

drops to 5 in an additional 4:31




Car has some quirks and I wanna out rule a fuel problem.

 

The PSI is right on for TPI, but it shouldn't bleed down that fast.

I had a 92 LB9 that bled down much faster than yours but it ran perfect so I let it be.

The most likely cause is a bad check valve in the fuel pump assm. and if it cranks a while before starting that would point to the check valve.

Another cause for it would be a leaking injector(s) and if it's not running right or if its too rich that could be the problem.

To check the injectors remove the fuel rail and leaving the fuel lines connected, energize the fuel pump and watch for fuel leaks.

If none of the above then check the fuel pressure regulator for leakage by removing the vacuum line, if there is fuel in that line then the regulator is leaking. Since this is the easiest thing to check you might want to do this first.

Hope this helps.

 

no,running at idle in park.vacuum unplugged and capped it should be 43.5 psi

 

capped at the manifold or on the vacuum line for the regulator?

the thing is that right now cold start wide band reads lean ( used to read rich before the fuel pressure was tinkered with a little by a moron) when it goes into closed loop the blms climb to 138-146 area and runs good.

but it blows this white smoke that stinks like fuel ( gutted cat because after bosch 3 install one got stuck open and melted it) its not coolant like a head gasket and does subside after a little bit of running, i still think its more then just condensation last too long and more so at idle. nwo i just for ***** and giggle raised teh fuel pressure about 3 psi to see if it would change anything and still reads lean. so i dont know.

maybe when the injector got stuck open on me a while back it burnt a valve or something and its leaking gas which is why it stinks and since it then would be just dripping raw fuel into the exhaust read lean since a o2 cant read liquid?

grasping for straws, might just be the tune. cant wait to get my ebl p4

 

You cap the regulator vacuum hose and cap the manifold nipple. Those Blm's are too high. Are you sure you don't have a vacuum leak somewhere? Are you actually smelling gasoline? If you smell gas,then I would suspect a leaking injector.

 

Blm's that high mean it's sensing lean so it is dumping tons of fuel in. If you haven't had your car "tuned" then your Blm's should be below 128

 

How is your o2 sensor?

 

Well here is the thing. When i had an injection get stuck open on me back in April it melted the cat. So Im just hoping it didnr burn an exhaust valve. And with the headers on just about impossible to do a compression test.

I really don't think i got a vacuum leak. Iv used card cleaner and a smoke machine.

The thing that dont make sense is raising the fuel pressure so it runs at 41 line on 51 line off didn't do anything.

I do have some black soot in my tailpipes but who don't without a cat.

But if i had a burnt valve wouldn't it run **** in upper rpms? WOT if will do a consistent 5.7 to 6.1 sec 0 to 60. Im not bragging with the mods done thought would be better but maybe a tune will help.

I think my o2 is fine seems to match my wide band rich lean.

 

Quick question. What is "blms"?

 

Long term fuel trim in 1991

 

check your cts too,a bad one cab produce overly rich readings and black soot in your exhaust. have u tested for a leaky injector yet?

 

cts is good. i had an injection fail earlier in the year. at that point they were tested and ok


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