bwiencek

Background: I bought this 1989 with a rod knock and went through and built a basic 355 for it with a small cam and the typical mods (long tubes, exhaust, roller rockers, ported intake, cam/springs/locks/retainers/seals, etc.)

Now I fired it up and ran it and it seemed to settle into an idle fairly well after getting a little heat in the engine - when I go to drive it it bucks and runs crappy 1/2 the time - so I checked the fuel pressure and it's 22 PSI with the engine running - vacuum unplugged or connected - doesn't matter so I started thinking - either I've got a bad pump or regulator - there is no fuel at the regulator nipple so I don't think that's it so I'm thinking of replacing the pump, strainer, and filter to see if it helps - but before I pick it up (they have to order it - will be in tomorrow AM) I had a question for those here that might know

I stared thinking - could I have hooked up the fuel supply/return lines backwards at the front of the engine connecting to the fuel rail? Is that even possible to do (haven't checked - just had the thought!) If it's even possible to put them in backwards what would be the symptoms?

dan_t

The hard fuel lines at the front have different size threads.

bwiencek

That's what I was hoping - guess I'll be replacing the pump, strainer and fuel filter then...

AGENT 86

Before you start spending, diagnose where the problem is.


http://members.shaw.ca/corvette86/Fu...mDiagnosis.pdf

383vett

I've got #6 braided steel lines going to the fuel rail fittings. I did switch mine around once. Zero fuel pressure, car wouldn't start.

bwiencek

That's what I was thinking - the restriction and pressure would be on the "return" side of the regulator then enter the fuel rail where it would immediately have a high volume zero restriction path back to the tank...

Going to change the fuel filter this weekend and see what happens...

nutz4c4

You might want to have a look at the Pulsator..

bwiencek

Where is it and what's it's function??

Is it that circular thing on the feed line? I looked at that and thought it was some sort of 'buffer' to keep the fuel pressure from bouncing when an injector is opened (kind of like an air buffer in water pipes)?


EDIT: A quick search found references to it being in the tank and to replace it with a short piece of rubber hose and a couple of clamps. Anyone know the size of the hose so I can grab a piece that's EFI pressure rated before tearing into the tank? (5/16"??)

nutz4c4

5/16 Fuel Injection hose. Its purpose is to stop fuel line hammering. Never noticed any difference with or with out in my car.

bwiencek

Thanks - that what I was thinking it was - going to grab some hose this morning and if time permits I'll swap it this evening... I know on the newer stuff that I've had to do fuel pumps in that piece isn't there in the tank - either they figured out that it's really not needed or it causes more problems than it's worth...

bwiencek

Well you find something out about an old car each time you go to fix something....

Turns out they had put a new pump in, eliminated the 'pulsator' with a short piece of fuel line but used cheap low pressure line and it disintegrated and split up the side - I'm really suprised it even made enough pressure to run! Fixed the line with good EFI rated line ($6.50/foot - WOW that's gone up) and turned the key on to prime it - 45 PSI on the gauge in about a second, held 40 PSI for the 5 minutes I was watching it. Took it for a drive and it actually ran well enough to get around without me worrying about it stalling/bucking/backfiring!

I also discovered the hood prop bracket was on backwards and the hood strut had been popping off and hitting the alternator - flipped that around too and now the strut doesn't pop off occasionally - wonder how much more I'll find as I keep fixing things on it!

Tony A.

Any references on how this short piece is oriented/placed in the tank? What does it connect to? I have nothing in the way of a reference.

bwiencek

It's obvious once you pull the pump assembly out of the tank (which is the easiest one to access that I've done yet!) - it's between the pump itself and the hard fuel line on the assembly. The pulsator looks like a little rectangular 'box' that goes between the two and is just held in place by the pump. I was going to buy a new one and do it and the pump but like most said you really don't need it and for a couple bucks you can replace it with EFI rated hose and a pair of clamps. I don't have any pics to share - so maybe someone else has pics of the entire assembly they can show you.