1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

Blown fuel pump?

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Old 03-11-05, 01:18 AM
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Blown fuel pump?

well my rx7 was started up for the first time with its new rb exhaust.... Anyways i remember before storing it for the winter in the top end it was studdering like it was starving of fuel. Now after i fired the car up it stalled after about 30 seconds no matter how much gas it was given... Anyways I checked my plugs and they were dry so I went straight to the fuel lines to check them, my to carb line had no fuel in it... Is my fuel pump shot? I turned the ignition on and no fuel flowed out, the fuel filter is very new, so I assume its not the problem. Is there any wire I could have accidently disconnected that would cause this? Note that I have been paint prepping the car, redid the battery cables and more mini mods.... Thanks!
Old 03-11-05, 01:29 AM
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Fuel pump

Well it sounds like it was giving you an indication of a problem before you stored it. If there is no fuel coming out of the line to the carb then you need to make sure there is power back to the pump. I don't think you disturbed anything duriong your paint prep. The fuel pump cut relay may be bad but i suspect failed pump. rx7doctor
Old 03-11-05, 01:34 AM
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ok thanks for the advice, ill test it tomorrow and most likly will end up buying a Carter pump and a holley pressure regulator, I was reading other threads and this sounded like a good combo...
Old 03-11-05, 01:39 AM
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Talking pump

Good choice on pump, but please make sure it is the problem first. Don't want to see you spend money on something you dont need. Besides you could buy something from me, lol. Well past my bedtime and my polygrip for my dentures are
failing and keep dropping onto the keyboard making me do typo errors, lol. rx7doctor
Old 03-11-05, 03:46 AM
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Yeh be sure it isn't something else - I've changed two pumps on my GSLs only to find it didn't fix the problems. Once it was a bad trailing ignitor, cutting off power to the pump. This is easily checked either by checking or replacing the ignitor (are you having any funny business with the tach?) or by running a hot wire from your rear compartment light through the driver's side storage compartment to the fuel pump line, which is right there under the compartment. Then check to see if the cars runs and you are getting fuel. If so, replace the rear ignitor.

I still haven't figured out the second problem, but it seems to be related to crapping up the fuel filter since it goes away for a week or two after I replace it. I've gone through four filters now (and I switched pumps once, which didn't fix it). The problem pops up when I'm cruising at 80 for extended periods of time, usually when going up a hill or passing a long line of semis. It starts coughing and sputtering and loosing power. The temporary fix is to simply disengage the clutch, turn the key off for about 3 or 4 seconds, then turn it back on and let out the clutch. After that it will run fine again sometimes for 20 miles, sometimes for a couple of days. Changing the filter (which really doesn't look that bad but usually has a little water in it) makes the problem go away again for a few weeks, but so far it keeps coming back - I'll be putting a fresh one in this weekend. Strange problem, but not the fuel pump.

Ray
Old 03-11-05, 08:55 AM
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^^^ Thanks ray green right there you shot it in the head, yes I just swapped my ignitors and it ran perfectly... I guess i knew the tach didnt work i didnt expect it to cut the power to the fuel pump. Thanks again!
Old 03-11-05, 10:19 AM
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One way to avoid the trailing ignition messing with your fuel pump is to bypass the fuel pump relay. Instead of the relay, I have a switch, which gives me total control on whether the fuel pump operates or not.
Old 03-11-05, 03:08 PM
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Originally Posted by ray green
I still haven't figured out the second problem, but it seems to be related to crapping up the fuel filter since it goes away for a week or two after I replace it. I've gone through four filters now (and I switched pumps once, which didn't fix it). The problem pops up when I'm cruising at 80 for extended periods of time, usually when going up a hill or passing a long line of semis. It starts coughing and sputtering and loosing power. The temporary fix is to simply disengage the clutch, turn the key off for about 3 or 4 seconds, then turn it back on and let out the clutch. After that it will run fine again sometimes for 20 miles, sometimes for a couple of days. Changing the filter (which really doesn't look that bad but usually has a little water in it) makes the problem go away again for a few weeks, but so far it keeps coming back - I'll be putting a fresh one in this weekend. Strange problem, but not the fuel pump.

Ray
Odd... my first instinct was to say rust in the fuel tank, but you said the filters are fairly clear?

I'd still probably get your gastank looked at tho....
Old 03-11-05, 03:12 PM
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fuel tank

Check the screen in the fuel tank or just blow compressed air into the fuel system to blow any debri that might be intere.
Old 03-11-05, 04:57 PM
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Good advice doctor, but if the problem is rust in the tank, then getting it professionally cleaned and re-coated in a must....
Old 03-11-05, 05:05 PM
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like I said im 99% sure its from my ignitors being swapped, ill buy a new used set as soon as I can...
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