Surging & NQR running

[enthuzed]

So I took a risk & put some shit fuel in my car (old dirty fuel only really good for the mower) only to come unstuck...

On initial impression, I put more fuel in and drove it home on what felt like 3 cylinders (this car still runs the standard TBI). Checked the dizzy cap, and given it looked ordinary I swapped it.

The next time I took it out it still wasn't running properly then it proceeded to die - I ended up on a towtruck.

When I pulled the tank out and checked all the components, the fuel strainer had had been rubbing on the bottom of the tank & wore holes in it. (Have a solution for that now which I'll update in the "strainer solution" thread). In any case it was bye bye pump.

So I swapped in a used fuel pump, fitted a new in-tank strainer as mentioned and gave the tank a massive cleanout then reassembled.

When I started the car it would run then cut out after a few seconds, so I swapped in another fuel filter, a used one though because I didn't have a new one on hand.

Things I've noticed:
On a straight stretch of road, the car seems to surge, will accelerate fairly cleanly with heaps of acceleration but with small inputs or steady throttle it seems to surge.
With about a 1/3 of a tank, when turning hard left or right the pump doesn't seem to get fuel. This has never been an issue with this car before, even when showing empty it never did that.
This pump seems noisy. It doesn't have that little black (relay?) block that most of them do with their wiring.
There sounds like a strange sucking noise from the engine bay that I've never heard before.

Questions:
Has anyone ever experienced simply swapping a fuel filter (in engine bay) to resolve the issue of their car running like shit?
Could there be an air lock? I primed the pump a few times each time I pulled something apart on the fuel system (on & off with the key before turning over the engine)
So is the pump possibly faulty? I'm not so fussed about the noise as long as it isn't going to shit itself.
What are the specs for standard fuel flow?

[Alspos]

Sounds like you may have an air leak somewhere, that would explain the surge bit and perhaps the noise.

The black thing is a noise supressor, you can safely bypass it (at least I have)

[mackaman64]

the sucking noise is probley a vaccum hose that has come off
or split it probley happend when it coughed back through intake
try looking at all hoses

[enthuzed]

Thanks guys for the suggestions thus far. I'll check some hoses, etc.
What about the injectors? Could they be full of shit and cause the issues I've got?

[enthuzed]

Nothing obvious with the hoses. It's weird how it runs - the more I want to accelerate the more it farts & carries on. When it's cold it runs best but after 5 - 10 minutes it's bunnyhopping doing 40 or 50 km/h with only the smallest throttle opening. I've found that if I pull up, turn the ignition on & off repeatedly it will run a little better for a short time. Tonight I did the on /off repeatedly and it struggled to start & all I could smell was petrol. It's really starting to piss me off!
Help!!!

[Alspos]

Unplug the TPS and check it is reading properly. Multimeter across the pins and check you get a constantly changing resistance as you (or an accomplice) moves the go pedal.

I had once that was a bit dodgy, drilled a small hole in it and fed the contact cleaner nozzle into it and gave it a blast. Could help.

[vr4gone]

If you can, put a loop in your fuel return line using a cable tie to slow up the fuel on return to your tank. If you can't do that, use some vice grips but softly first. Try not to crimp the line completely. It sounds like a fuel pressure prob. I had the same symptoms with mine. Turned out to be the FPR.

[enthuzed]

I've used carby cleaner and sprayed heaps of it into the injector top hat, checked the injector spray pattern and the one I could see looks alright. I've checked the injector resistors & used contact cleaner on all connectors. It revs freely now but still dies under decent acceleration. I suspect the plugs so I'll swap them. After that I'll check the TPS and the fuel pressure reg. I reckon I'll have it sorted tomorrow. :)

[enthuzed]

Swapped the spark plugs though the ones in there looked pretty good. The TPS was checked and had to do things a little different than the info in the 4g63.pdf file in the Tech section of this site because what's in there refers to everything except Starions. Here's some more details about how to check it:
There are three green wires on it. I connected an alligator clip to the white striped one & touching on the red striped one it measured 6k ohm, opening the throttle it progressively went to zero when the throttle was fully open. Then touching on the black striped one it recorded some low figure and increased progressively until the throttle was wide open, at which point it measured about 6k ohm.
Checking this all over again on the working JA next to it, the resistance only went as high as 3.8 or 3.9 k ohms. What's important is that the resistance changes progressively in either direction depending on the sets of wires you use to test. I think I'll make a tech article out of this.
Swapped in another fuel pressure regulator and replaced the elbow piece below it. I'm yet to test drive it, I've got a proper hose clamp to use on the return line if the problem still exists & at that point I'd be swapping the fuel pump because it either is low on pressure or low on volume (flow).

[enthuzed]

Bloody hell! The plot thickens! Okay, so the hose clamp made it run worse not better. Could hardly drive it.
Swapped in a known good fuel pump, car behaved exactly the same! :WTF
Stupid thing is that it gets progressively worse. It drives best when cold & eventually becomes undrivable. By priming the pump it will sometimes come good, but as soon as some decent acceleration happens it starts to misfire and gets worse until 15 or 20km later it won't run. Curse & wait, curse & wait some more. If I prime the pump before it gets too bad I get to drive it a bit smoother further.
This plain sucks!
H E L P !

[palmystar]

i hate mystery problems like these. Great at doing your head in. have you tried things like unplugging the air flow meter or engine coolant temp sensor. If hose clamp made it run worse then it suggests it is running rich. Did you clamp it off completely or just restrict the flow? Does it make a difference if you pull the vacuum line off the fpr? there arn't any air leaks between afm and turbo?
Just some things i can think of to check atm.

[JA83]

coolant temp sensor

[enthuzed]

Some good suggestions guys but I get the idea it's a fuel pressure/ flow problem. Tonight when it stuttered almost to a halt I undid the fuel filler cap expecting to release some pressure. But none was detected. Took a leak, jumped back in the car and it drove properly again...for a while.
I think I'll be dropping the tank again... :(

[enthuzed]

Whilst this site was down I dropped the tank, checked the strainer and the assoc. pipes, blew through all the hoses on the tank, trimmed some that were starting to split on the ends & whilst at it I swapped the separator tank. It ran perfectly again & I rejoyced that it was finally sorted.
A couple of days later the symptoms re-occurred dammit, but certainly not as bad.
I'm thinking I'll have to blow through the lines on the car body up to the front of the car & to be sure get a new fuel filter. Might have another go at cleaning the injectors too. What a pain in the arse!

[Entaran]

Save yourself some time. Get some redline fuel system cleaner, dump the entire bottle in the tank, replace the fuel filter ~3 days later.

Sounds like you managed to pickup all the shit off the bottom of the tank and send it down the lines. At low fuel usage (light throttle) there's still enough "opening" to send enough fuel down, under heavier throttle when the pump really starts to well... pump, the blockages cause restrictions causing your car go to rich-lean-rich-lean.

Be stupidcareful, this blows piston rings. Ask me how I know (Just ordered a new set of Arias pistons for the vr4.)

Take the hardlines off and shove an aircompressor in one end then replace all the soft lines. It's cheap insurance. I blew enough shit out of my hardlines to coat part of the wall of my garage in black gunk. Oops.