Yet another issue??? |
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mlachance112785
Senior Member Joined: 31-May-2012 Location: Dighton, MA Status: Offline Points: 343 |
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Posted: 30-August-2012 at 6:52PM |
Fix one thing, something else breaks. Confident in saying that's how it always is, and I know I'm not the only one with this problem.
So, the real issue. 77 XR7/C6: Maybe a little over a month ago, I was driving. Accelerated, and the car started to stutter. Sounded and seemed like it wanted to stall. Couldn't accelerate. A/F gauge went way lean. After a few seconds, it went away, then did it again briefly. Then fine after that. Car now does this periodically. Temperature doesn't seem to cause or cure this. I recently swapped out an Edelbrock 600, for a rebuilt Edelbrock 800. Also put a fuel filter between the fuel pump and the car, whereas the old filter was before the pump. Still, the same issue. Spark plugs were replaces within the last 2 months I'd say. Gas cap is fine. Also running an open element air cleaner with a 14x3 or 16x3 K&N filter, with clutch fan. Minus the shroud. It got eaten by the fan. After trying to secure it 2 other times, I gave up. Going to go with the Mark VIII fan within the next few weeks. *This motor has been fed 89 octane since Psquare did the motor swap a couple years ago. Anyone ever experience something like this? Fuel boiling before going into the carb? Icing? Bad fuel pump? Any help would be greatly appreciated. |
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77 Cougar XR7 460/C6
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aquartlow
Senior Member Joined: 19-December-2011 Location: Summerfield, Fl Status: Offline Points: 2270 |
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Reading that the A/F gauge gives a ratio that the engine is going/running lean shows you are losing fuel volume or fuel pressure. SInce you have done other things to rectify the problem, I would check the filter "sock" that is on the fuel sending unit inside the fuel tank. You could also plumb in a fuel pressure gauge between the pump and carb, 6.5-8 psi is your target pressure, you also may want to check flow of the pump. To check flow you will need to let the engine run a minute(to fill the fuel bowls) or so then disconnect the fuel line into the carb and using a plastic bottle of some sort(16 ounces or larger) plumb a rubber line to the bottle from the fuel line that goes into the carb, have someone start the engine while you watch the flow of fuel into the bottle, it should take less than 15-20 seconds to fill a 16oz bottle with a reasonably good fuel pump. If the pump fails at either pressure or volume, it's time for a new/different pump and or investigate if there is a problem with the fuel tubing itself from the tank to the pump(good time to blow through the fuel line's tubing when you remove the sending unit to check the "sock", disconnect the fuel line tubing to the pump first though and see what comes out by using a clean bucket). Another point of interest is the fuel tank's vent that is on top of the tank, if the vent is blocked by corrosion or other methods(mud dawber wasps) it will decrease the abilty for fuel to flow, thus losing flow and pressure at the carb. I hope this helps, Todd
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Yeah, It's a Hybrid...It burns gas and tires. No matter how good she looks, somebody, somewhere, is tired of her sh*t. Beauty is skin deep, ugliness goes clear to the bone. |
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Robbdtme
Senior Member Joined: 06-June-2012 Location: Central WI Status: Offline Points: 765 |
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Not to sound simple but I have seen this and it will cause your problem. Recheck the inline fuel filter flow direction. If it is in backwards it will not flow properly.
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Johnny cash Special 74-75-76 freak. 77 XR7. 78 LTD II sport looks pretty but poop 302 in it.
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mlachance112785
Senior Member Joined: 31-May-2012 Location: Dighton, MA Status: Offline Points: 343 |
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Thanks for that info Todd. Good place to start.
Also, I'm sure the fuel filter is not backwards. |
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77 Cougar XR7 460/C6
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mlachance112785
Senior Member Joined: 31-May-2012 Location: Dighton, MA Status: Offline Points: 343 |
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Welp, gas pedal is no longer "stiff". Doh. I need to learn that not every nut/bolt needs to be tightened to 1209209410 ft/lbs. Also, being a noob to carbs didn't help a whole lot. Thanks to Paul for the help.
As for the fuel/stuttering issue, the gas cap is fine. I took off the thick (insulating?) carb gasket, and replaced it with the one that came with the rebuild kit I bought. Also moved the feed, filter, and hose higher off the intake. Hopefully this helps. Sucks that this isn't a consistent issue, so I won't know if this fixed the problem. I guess I'll know for sure if it never does this again. I'll check back in tomorrow night. |
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77 Cougar XR7 460/C6
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Kit Sullivan
Member Joined: 23-October-2008 Location: Florida Status: Offline Points: 112 |
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Same gremlin on my 460...spent a ton of time and effort chasing it and replacing "questionable" parts. Turned out to be a loose ground cable on the bottom of the engine.
Rookie mistake on my part, I should have discovered that immediately. |
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"I'm too old to grow up now!"
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GranTorinoSport
Admin Group Admin of "The Org" Joined: 20-May-2003 Location: Seattle Status: Offline Points: 2287 |
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For my pickup with and edelbrock 600, some compressed air in the idle screw ports did the trick. Somehow dirt got in there, and caused it to idle terribly. This was a Psquare suggestion, and it was dead on.
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Scott Eklund
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