Fuel Problem Just Not Finding Same Symptoms

[440Music]

First Posted Question:

1984 5.7 Crossfire
4/3 Transmission
40,600 Miles

I thought I had put my car away for the winter but as luck would have it here in Chicago we are(were) having a warm winter so I took it out one more time. I had filled the tank added Staybil and an octane booster. Started right up (5 to 8 seconds) and ran great till I got to the Interstate and on acceleration was fine till I hit about 40 MPH and that's when it got sluggish. I never got to highway speeds and it quit on me twice trying to make the next exit about 4 miles.

I've read about 30 post and trying to find symptoms similar to mine but nothing. I know it's the fuel system but not sure if I need to change the filters, sock, or pump but maybe I should do it all just to be sure.

History of car, new 1984, 1997 transferred to original owners son, son traded it in on a 2011 in 10-2010 and sat at the dealer till 4-2011 when I purchased it. I don't think this car ever saw a drop of rain and was a sunny weekend drive.

Looking for suggestion on where to start looking for solutions and which I should do first. Should I start with the fuel tank sock? Filters? or Pump? Yes I will test pressure prior to doing any work but as far as I can tell the pressure looks OK.

Tommy :cool

 

[ßill]

Does it idle ok? When was the fuel filter changed? If it idles smooth or you don't know when the filter was changed then I'm leaning toward the filter as the culprit.
Good luck

 

[John Robinson]

Time & Storage

Here are some suggestions of things to check

In line fuel filter

Fuel pump pick up filter

The fill up gas has water in it.

Do a fuel pump pressure test

The problem with low mileage cars is what happens while in storage. For example your car before you bought it averaged less than 125 miles a month of running time. That means it spent a lot of time just sitting with what ever fuel it had in the tank and then it was run with bad fuel for short times. Until you bought it the running gear when run was not brought to full temperature. This is a picture of a car that like yours was very low mileage. As you can see the fuel pump is badly contaminated. Once you get these little things corrected you will have a pristine fun to drive car. And of course don't be afraid to ask questions.

 

[440Music]

Does it idle ok? When was the fuel filter changed? If it idles smooth or you don't know when the filter was changed then I'm leaning toward the filter as the culprit.
Good luck

Idle is good and seems to be OK when I accelerate with no load.

The Octane Boost and Staybil should have taken care of water in the system, at least that is part of their claim.

Will change filters on Saturday and report back the results.

Thanks, I kind of knew the answers just wanted some advice on where to start rather then chasing symptoms without direction.

Tommy :cool

 

[John Robinson]

I agree the stabil should have taken care of water but I have seen severe cases of water in the fuel. I had a friend who blew his engine up a block away from the gas pump and we found a gallon of water in the tank when we drained it. If there is a lot of water in the gas a little can of stabil will not treat it all. Yes you did all the right things for storage but I still believe the past is the problem.

 

[thearborbarber]

The octane booster has been known to plug injectors and foul spark plugs. An individual with with a LS1 Camaro had problems with the octane booster. You may want to pull the intake cover off and watch the spray pattern of the injectors. It should be a nice fine coned shape spray. Also see what the plugs look like.

Where did that "miss" come from?!?:* Time to cool things off a bit more

 

[440Music]

Interesting article and very informative, I'll take a look at the plugs and run the gas out the best I can. I wonder if the boast and Sta-bil combination is causing the problem? Since I can't get the car to run faster then 40 MPH( about 2200 RPM) I'll have to drive around the neighborhood in first gear. Good thing there's a gas station at the entrance of the neighborhood.

Tommy :cool

 

[boomdriver]

Theres a good chance the additives caused the problems but not as you think...
they may have loosened crud and gunk that was stuck to the tank, sock and allowed it to travel to the filter where it now plugs and limits the flow. If its burping, stumbling as you give it gas...then its almost certainly a filter/flow problem.
Change the filter, drive. If that did not help then look in the tank at a pump & sock.

 

[440Music]

Just got around to changing the fuel filter and still the same problem. I've drained 70% of the fuel and added new but still have the same problem although it's a little better. I've replaced the spark plugs because I think it's the combination of StayBil and Octane Boost which is the culprit. I'll know more when I dilute the fuel a bit more. Next if the fuel isn't the problem I'll run a pressure test. Thanks for the advice.

 

[ßill]

This won’t help the rough running problem, but will not the alcohol (ethanol) in modern fuel eliminate the water problem?
You changed the filter, I’m guessing the one under the pass door? Did you also change the one in the tank? (Easy to do on a C4). Fuel pressure test will confirm or rule this out. Is your check engine light on? Do you have a scanner to check for codes and running conditions like Oxygen sensor and manifold vacuum?

 

[440Music]

Is your check engine light on?
Do you have a scanner to check for codes and running conditions like Oxygen sensor and manifold vacuum?
Did you also change the one in the tank?

No check engine light isn't on.
No scanner but I'm sure I can rent one from the local Auto Parts Store, I was going to rent the pressure tester. I did check the tank filter and it's dark but doesn't seem to be blocked. It was easy to pull until I dropped one of the screws and that took 10 minutes to find where it was hiding. lol

 

[boomdriver]

No check engine light isn't on.
No scanner but I'm sure I can rent one from the local Auto Parts Store, I was going to rent the pressure tester. I did check the tank filter and it's dark but doesn't seem to be blocked. It was easy to pull until I dropped one of the screws and that took 10 minutes to find where it was hiding. lol

You cannot tell with the tank screen. Once the material has pulled debris inside you can no longer see the trash and you cannot see thru the sock even when new and dry. Replace. Always. Also get a new tank gasket. Like it or not your old one is not going to seal around the rusted and warped tank edge.

get a new tank gasket and sock for about $12-$15 and that will assure you that everything inside the tank is in order....unless the pump itself is failing and that can be seen by the pressure.

Low fuel pressure or poor flow will result in backfiring, burping and stumbling that does NOT improve with speed or time. IT may go away for a short time until the filter gets completely blocked again. Each time you park and shut down the fuel flows backward and that pulls some trash out of the filter so it runs again after 15 minutes....then plugs again and burps and stumbles..

. However, the stumbling and backfiring and drop in pressure after some driving does indicate a plugged filter...or nearly plugged.

Because you have a CROSSFIRE you have to look at things differently and you really need a FSM for that yr. Nowhere near the same diagnostic proceedures as a TPI or Multiport EFI system. Your car only has 15 psi fuel pressure, so its very EASY to restrict or plug the system. Its common to install a higher pressure pump BUT do so with the advice of people that have done it so the low pressure hoses and lines/seals are not blown out causing a gas fire under the hood...:ugh


2 other things that can cause your symptoms....

low voltage. does the same thing. Higher RPM the worse it gets.

bad air metering.

Most likely its the fuel filter or pump...because there is no code stored, the only other thing that does not set a code is a major vac leak. Look carefully at everything to eliminate that possibility.

 

[440Music]

Solved and it wasn't a fuel problem the catalytic converter was full I guess that's why I didn't find the answer looking for a fuel problem.

In the process I changed the fuel filter, drained the gas tank, replaced spark plugs, wires, and cap & rotor but that all needed to be changed anyway. Now it time to start on upgrading the breaks and exhaust.

Thank you all for the help and advice.

Tommy TBones

PS if you all go to my web site(link below) and hit the contact button I'll set you up for a few songs for your help.

 

[Janice]

cat

Solved and it wasn't a fuel problem the catalytic converter was full I guess that's why I didn't find the answer looking for a fuel problem.

In the process I changed the fuel filter, drained the gas tank, replaced spark plugs, wires, and cap & rotor but that all needed to be changed anyway. Now it time to start on upgrading the breaks and exhaust.

Thank you all for the help and advice.

Tommy TBones

PS if you all go to my web site(link below) and hit the contact button I'll set you up for a few songs for your help.

Did you replace the cat or delete it?
If you simply gutted it then you might want to go ahead and delete the smog sys. as well. I really liked the sound and response i got after a complete smog delete with the empty cat as an H pipe. Cost of the delete was 0.00.
it also makes tuning the exhaust a little easier