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Gas Starvation Problem Revisited

TAC

Well-known member
Joined
Feb 18, 2002
Messages
252
Location
Bothell, WA
Corvette
1987 Yellow Callaway TT Convertible & 2003 MY Z06
You all remember the story...I have gas starvation that shows up when the tank is just under 1/2 full. The car bucks and snorts when getting into the gass pedal. Today it did it while only 1/4 empty. I was going slightly uphill at 30 or so and goosed it a little and about hit the dash when the engine bucked on me. The problem happened going uphill and downhill and around a corner. I went to a gas station and put in 6 1/2 gallons and went back out. Surprise, surprise, the problem is still there.

I'm thinking more that this is a fuel filter problem, not a problem with the fuel pump or pickup. Does this sound right to you? I haven't had a chance to open up the top of the tank and look in yet but I'm thinking I should just change the filter again. Keep in mind the car sat for 10 years so even though I replaced the fuel filter last year it may have become plugged again. Also, I have heard some people say this year car has 2 gas filters. If so, I know only one got replaced.

Does this sound like a fuel filter problem and if so, does the '87 vette have 1 or two gas filters? I know where the main one is...under the body necessitating removal of the x-brace. Where is the second one, if it exists? TIA
 
There is a filter (a very fine mesh screen actually) attached to the foot of the in-tank fuel pump. If the pump is original it may be failing, or the screen may be plugging off. I replaced my pump recently and the filter/screen was black. It's normally a metalic or light bronze in color.

I can't remember, your injectors checked out ok?

_ken :w
 
Yes...injectors were removed and cleaned last spring. They were slightly clogged then but all tested fine when cleaned. Even the extra two up front.
 
Whoa, I just realized I was dealing with a Callaway owner! Oops! :eek: I might be over-stepping my bounds if I try to go any further with this. Hopefully Stan or someone will see it before long and chime in. ;)

_ken :w
 
Tim - Sounds like a very frustrating problem. Unfortunately, I don't really have any suggestions beyond the pump or the filter either. Just one other thought - have you checked the entire fuel line from the tank to the fuel rail for crimps or damage?

I'm also trying to remember the last time you posted this. Didn't someone suggest that you check the internal bladder in the fuel tank? I seem to remember something about them possibly coming dislodged and causing a similar problem.
 
Familiar Problem

Hi TAC,

Have you been using octane boosters in your car?

Even if the answer is no, it seems that your problem maybe in your tank. The bladder lining could be coming loose. This is not uncommon for C4s. It has shown up more when octane boosters are used. This seems to activate the separation process.

You can checked by how many gallons you put in on a total fill up. Check your gauge first. Then added the gas until its tops off. If you are at 1/2 tank, then you should put in around 9 or 10 gallons. If you are showing less at the pump then you may have a bladder problem. Simply, looking into the tank may not show the signs you are looking forward with regards to the bladder coming loose.

David F may have a few more ideas.

Good luck.....................
 
No, I have not been using gas boosters at all. I stick with 92 grade Chevron gas and ONCE put in a bottle of Techron in when I was experiencing minor fluttering.

The gas guage seems to be really close to accurate. When I was 1 bar under 1/2 I managed to get in 11 1/2 gallons. Last night I had driven 80 miles or so of mostly highway driving and was right on 1/4 down. I squeezed 6 1/2 gallons into it...which is about right since when I filled it previously I didn't top off at all. I topped it off this time since I wanted the tank absolutely full. The problem continues even with the tank full. This really reminds me of the time my Subaru would lose all power going up a hill and would sputter and kick. Problem was the fuel filter.

I guess I'll just have to get in there and see if anything looks amiss. It doesn't sound like the bladder is loose since I still have pretty good capacity. I once managed to get 18 or so gallons in it. I'll just replace the inline filter and have a good look at the screen around the pickup to see if anything looks amiss. I guess there could be other issues to cause this like maybe bad ECM or something but I'll wait until I fix the easy stuff first before moving on.
 
Try this!!!

On the drivers side of the Pleum, there are two small value lines. One is for the Tach and the other is for the boost control. The lines are colored black and toward the rear on the left side of the motor. I suggest that you clean out both lines and the pleum channels. A good tooth pick will help here. I cannot remember which line is which. A clog or a small blockage may cause the problem you are having too.

If you find that things are clear here, email David F directly at: dfulcher5@juno.com

Check the following before you contact David:

1. The rpm that the problem is occuring at
2. The amount of boost as indicated on the HG gauge

Post me or cc me in on what takes place.
 
Excuse my ignorance but what is a value line?
 
TAC said:
Excuse my ignorance but what is a value line?

I guess we're both ignorant because that one has me stumped too. I would have guessed it was vacuum line except for the fact that I'm not aware of the tach needing vacuum. The Callaway Microfueler does use two inputs: 1) engine rpm 2) vacuum... or under boost actually manifold pressure. I'm not sure if that's what Stan is eluding to.

Stan - You're going to have to explain this one further. Now you've got me interested too.

I do know that a Pleum is a Plenum or at least I think it is. ;)
 
Your right!

My spelling sometimes is awful but my typing is even worse.

You do understand where I am making reference too. I spoke with David and he said that you need to check all your plugs and wires too.

Since you had your injectors clean, this may not be a problem area. Also check your cap/rotor too.

David said that after you review all of this to call him at 770-393-0560 ext 2208 before 11:30am or after 3:00pm any day.

Stan
 
FUEL STARVATION

Hi

We had the same problem on our 89 CALLAWAY.The
problem was quite simple.The fuel pump with time
moved down and the filter got squashed on the bed
leaving it 2-3 mm of space to suck.The car would go
up to +/- 3000 rpm and then just cut. I think it is better
to start there, it will take you 30 min.

Goodluck
Nico
 

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