Cascade Crew

Xecris · Posted: Sun Mar 01, 2009 1:35 pm Post subject: Gas tank strainer?

Alright, new guy to boards here, have a problem that I've been poking at with a dull stick for a few weeks now.

I've been experiencing a high rpm starvation issue, that will eventually turn into a fuel starvation issue, period. After driving the car a while, it will hesitate, huff and puff. Sometimes, it will stall out, and will not restart for a bit of time (has spark, fuel will dribble out of fuel line). When I look at the filter before the carburetor, it will either have very little fuel in it, or be completely bone dry. I have tried 3 fuel pumps I have lying around, and even bought a new pump, with the same results. I have hardline going into the pump, and then to the carb, and they stay real cold to the touch, and are far from the headers. I am assuming vapor lock isn't an issue here. When I backblow the feed line from the tank, all my issues go away, atleast for a day or two.

So, I have dropped the tank the first time, saw that the strainer sock was completely plugged up with gunk. Put a new strainer in, worked great for a week or so, before I started getting a starvation issue again. I dropped the tank a second time Mad

, realized I put the strainer on too far up the pickup tube, and it was trying to suck through a tiny 3/8" section of the strainer. Cleaned the tank the best I could (really had no clue what I was doing, never cleaned one before. I sprayed the inside out with hose, used a little superclean(!) in there where I could reach with a soft brush, hosed it out a few more times, and left it to dry out 24hrs or so). Then I put a new strainer back on, but wired it open with safety wire so it could not collapse on me.

I am back to having a starvation issue.

This is on my '86 Camaro Coupe. There is no intank pump that I am sucking through. The motor is a decently built up 355, stock fuel pump (50 miles on it), Edelbrock performer intake, Edelbrock 1406 Carburetor with .098 main jet, .095 secondary jets. Believe the jets are stock to the carb. I also have a FPR set to 5.5psi, as I know Edlebrocks don't like much more. The last time I had the gas tank out, I plugged the ends on all the hard lines, and put them under pressure, to check with soapy water if any were leaking. I did not find any leaks between the front and rear of the car, nor in the pickup tube itself.

Is there a chance that there is just so much junk in the tank that I missed, that I plugged the strainer again? Am I better off running without the silly thing? Am I looking at the wrong end of the car? If I really stay off the throttle, the issue will usually take a very long time to show up. But if I am putting a heavy load on it, I'll have it in no time. I really don't want to drop the gas tank again (could you believe that, miss out on all the fun?), but will if the strainer really could be an issue. I will not do the hatch door in the cabin.

I am kinda at wits end here, have really tried everything I could think of. Everything under the hood is under 1000miles, with ignition/fuel stuff under 100miles. Any ideas? Confused

And wow, what a wall of text

90droptoproc · Posted: Sun Mar 01, 2009 5:47 pm Post subject:

is there still the stock EFI fuel filter inline on the main pressure line?

the one I mean is located just inboard of the drivers side rear wheel.

Xecris · Posted: Sun Mar 01, 2009 6:01 pm Post subject:

The car was originally a CCC Qjet 305, 5spd. I didn't recall seeing an inline filter, though, so went out and double checked. There is just one-piece hardline from the rubber connections to the tank, to the engine bay.

90droptoproc · Posted: Sun Mar 01, 2009 6:07 pm Post subject:

hmm, sorry I asumed it started out as a mpfi V6, that may be hangover induced Embarassed

any way to test the fpr?
and your running electric pump I assume, how is your wiring to it?

Xecris · Posted: Sun Mar 01, 2009 7:01 pm Post subject:

Sorry, guess I got carried away with the OP. I am running a new mechanical pump. Before I started working on the car again this winter, I had an MSD electric pump of some kind, and an AFPR with return. I had the same problem then, too, which prompted all the work I've been doing to it. I have a fuel pressure gauge, but need to find a 3/8" T adapter to read the pressure.

It isn't a hot/cold issue, either. When I took the car to parent's house (mine has not a garage), I got on it a little after it got up to ~ 160-170*, and it fell on it's face. Sad

I did notice, though, that the tiny section of rubber hose (new) between the hardline in the engine bay, to the hardline going to the fuel pump had collapsed almost flat, indicating a kink/blockage somewhere in the line before that? The fuel pump must have been really straining, because I can barely squeeze the line by hand.

Dewey316 · Posted: Sun Mar 01, 2009 7:14 pm Post subject:

I would drop the tank, and blow some compressed air down the line, you will know if you have blackage that way, or it might even shoot the blockage out under that air pressure. Just don't go blowing compressed air, into the fuel tank. Wink

Xecris · Posted: Sun Mar 01, 2009 7:29 pm Post subject:

The last time I had the tank down, I blew air from the front of the car back, and it didn't seem the least bit restricted. I then capped the line at the rear, and put it under a little pressure, sprayed soap the whole length of the line. It held pressure, didn't see any bubbles Confused

. It really is stumping me. I will probably be dropping the tank Tuesday after work (joy), unless I can get anything else to check. Thanks for all the interest so far though! Really can't wait to get this toy back on the road for good. The Hooker aerochamber sounds great when the car works Cool

Dewey316 · Posted: Sun Mar 01, 2009 7:32 pm Post subject:

The only other thing I am coming up with off the top of my head, is to check the condition of the rubber lines that connect the fuel tank to the chassis lines. Maybe that rubber line is collapsing, and causing the blockage.

OHHH... and, I'm not sure if you car has this. I had a problem with my car a couple years back. THe small rubber line that connected the fuel pickup to the lines coming out of the tank, had a very small crack in it, causing it to be unable to build pressure. You car may not have that though, since you don't have an intank pump. But it is worth a check.

Xecris · Posted: Sun Mar 01, 2009 7:37 pm Post subject:

There is no rubber in the tank on the pickup tube Sad

. All rubber on the fuel lines is new, BUT, I can definately double check to see if it is collapsing, or I may have twisted it putting it back on, Hadn't even thought about that one.

aaron_sK · Posted: Sun Mar 01, 2009 8:01 pm Post subject:

If you do pull the tank and find more junk in the sock, you might want to consider taking it to a local radiator shop and having it burned and cleaned out.

Xecris · Posted: Sun Mar 01, 2009 9:01 pm Post subject:

Oo, good idea on that, didn't know people did that. I will definately look into that.

rjmcgee · The Hammer Joined: 08 Jan 2004 Posts: 2328

Switch the fuel lines at the mechanical pump, pull fuel through the little return line and use the bigger line for the return. See if the problem goes away.

90droptoproc · Posted: Sun Mar 01, 2009 11:49 pm Post subject:

I'm glad some more people are looking now, I think I need to limit my drunk posting, sorry I missed so much outta your original posting, lol I read it over 3 times and still couldn't get everything outta it.
it deffinatly sounds like it is more junk in the tank to me though.
I don't know where your at exactly, but if you are close or have buisiness up here I think I have a spare tank laying around from a 90 or a 91

Dewey316 · Posted: Sun Mar 01, 2009 11:53 pm Post subject:

From an 86, upgrading ot a 91-92 tank would be a good move anyway. The late tanks have a little more baffling.

blue89 · Posted: Tue Mar 03, 2009 8:13 am Post subject:

i second that notion. I heard you can put the plastic 4th gen tanks in if you shorten the filler tube?

aaron_sK · Posted: Tue Mar 03, 2009 10:43 am Post subject:

blue89 · Posted: Tue Mar 03, 2009 12:17 pm Post subject:

You might try to run the engine from a plastic gas can. If it runs fine then you might replace your hardline.

Xecris · Posted: Fri Mar 06, 2009 7:22 pm Post subject:

Update!: I dropped the tank, but couldn't find a radiator shop near enough worth a drive. This time, though, the pickup filter look ok Confused

. So, I went out and picked up another one anyway, rinsed out the tank again, had my brother look at it (he teaches mechanics in the Marines, and is usually right about stuff), put it all back together. I fired the car up, and took it for a spin. I got two blocks before it started acting up on me. So, I started conjuring up all sorts of obscenities, thinking what the hell, etc.

It was at this point I did one of the most basic fuel line tests. I grabbed a hold of the rubber fuel line between the pump and the AFPR, which was pulsing a good bit (Like I believe it should feel, when it pumps fuel). Then, I looked at the clear filter I have between the AFPR and the carb. Here, fuel was barely trickling in. I rotated the AFPR to every setting, didn't make a difference. Finally, I bypassed it altogether, fuel pump to filter, filter to carb.

I instantly got a filter full of fuel, haven't had any cutting out/starvation issues in couple days of driving, and there is always fuel in the filter (it would run empty before, easily). I am kicking myself for not even thinking of the AFPR after the last time I dropped the tank, as I've had problems with the Spectre brand ones before. Is nice to drive the thing again!

Oh, and I can get the tank down in just about 45 minutes now, from first setting the car up on jacks. Thumbs up

Suppose next time, I'll be starting from the front of the car again.

BTW - I did try to run the car off of a plastic tank like suggested, and it worked like a charm. It was after I pulled the fuel lines from under the hood, though, so I wasn't running the afpr or filter. Guess I figured the problem was in the tank again. Thanks everyone

Dewey316 · Posted: Fri Mar 06, 2009 7:29 pm Post subject:

Glad to hear you figured it out, and can enjoy the car now!

mc6811 · Posted: Fri Mar 06, 2009 7:38 pm Post subject:

ok whats a AFPR (Automatic fuel pressure regulator)?
Still learning Wavey