Mazda RX-7 Starting in the 1970s, the uniquely powered RX-7 helped put Mazda on the performance car map.

86 RX7 - sat for 7 years - Dies under acceleration

  #1  
Old 07-16-2011, 11:25 AM
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Default 86 RX7 - sat for 7 years - Dies under acceleration

I found a 86 RX7 that has sat for 7 years. Usual fuel problems have addressed them. Under no load - the engine rev's freely. under a load the engine dies under moderate throttle usage or under a load. Restarts fine.

Additionally it seems that the more electrical devices running / load on the system - worse it gets. Put on a new alternator (old one was hilarious - let out a black POOF then car died.)

I have read about the pulsation dampener and fuel regulators and will replace them - sure they are not happy and am ultrasonically cleaning the injectors - Fuel system has been blown out - cleaned & new pump & tank / chassis filters.

Sounds to me like a elect problem. MAF or brain?
 
  #2  
Old 07-17-2011, 12:19 AM
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sounds like a fuel issue to me. i would see where you stand after the cleaning. most of the problems that you get with electronics on the old rotaries will show themselves at idle.
 
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Old 08-05-2011, 07:01 PM
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What year is the car? It could be the OMP putting the car in limp mode, make sure your oil metering pump is working fine. I also would try the MAF as well.

The pulsation dampener is a spendy fix, just replace it with a banjo bolt. There are threads out there on other sites I know of that list the exact part number you need from Summit Racing.

I did it on my car a while back, works fine. Streetported 13b, series 4 block.
 
  #4  
Old 08-05-2011, 07:13 PM
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Originally Posted by Draelren
What year is the car? It could be the OMP putting the car in limp mode, make sure your oil metering pump is working fine. I also would try the MAF as well.

The pulsation dampener is a spendy fix, just replace it with a banjo bolt. There are threads out there on other sites I know of that list the exact part number you need from Summit Racing.

I did it on my car a while back, works fine. Streetported 13b, series 4 block.
It is in his heading, 86 model. Has nothing to do with the OMP.
 
  #5  
Old 08-09-2011, 09:18 PM
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Default Running... but still with issues.

Well I am driving the car now and it has improved to the point that it will run up through "half throttle acceleration" but under wide open throttle it will brurble at 3500 and continue to do so as the revs rise (or until I simply shift up). The engine pulls hard to that point - the exhaust is clean - no smoke - abnormal operation - just flattens out. Under half throttle it will pull high revs cleanly. I will have to check on the "banjo bolt" fix sounds simple enough.

Beyond that it is a blast to drive with a very tight suspension & steering. Only thing holding it back from being perfect... is the water temp gauge is not working - (sending unit is on the bottom left hand of the rad?). I removed the two connecting wires & put 12v to them & the gauge didn't move. I didn't check the switch for continuity to find the fault. Is this common? and if there is also a link to the aux. electric fan - which works as it runs the cold engine start sequence so I know it is ok...

Thanks for all of your help.
 
Attached Thumbnails 86 RX7 - sat for 7 years - Dies under acceleration-58532_114536181936761_114535885270124_102890_1977897_n.jpg  
  #6  
Old 08-10-2011, 05:03 AM
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Originally Posted by bgdesign
Well I am driving the car now and it has improved to the point that it will run up through "half throttle acceleration" but under wide open throttle it will brurble at 3500 and continue to do so as the revs rise (or until I simply shift up). The engine pulls hard to that point - the exhaust is clean - no smoke - abnormal operation - just flattens out. Under half throttle it will pull high revs cleanly. I will have to check on the "banjo bolt" fix sounds simple enough.

Beyond that it is a blast to drive with a very tight suspension & steering. Only thing holding it back from being perfect... is the water temp gauge is not working - (sending unit is on the bottom left hand of the rad?). I removed the two connecting wires & put 12v to them & the gauge didn't move. I didn't check the switch for continuity to find the fault. Is this common? and if there is also a link to the aux. electric fan - which works as it runs the cold engine start sequence so I know it is ok...

Thanks for all of your help.
I haven't worked on an RX-7 for years and decades, but I'm about 99% certain the temperature sensor for the gauge is screwed into the engine and not the radiator.
 
  #7  
Old 08-10-2011, 02:30 PM
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It is by the oil press sending unit.
 
  #8  
Old 08-11-2011, 09:03 PM
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Thanks Trini -

On a lighter note... THING HEALED ITSELF!!! - At my wife's urging... I put cans of "Sea Foam" in the tank at my 1st & second fill ups. Today - it's a miracle! It ran up through the rpms wide open throttle - no sweat. Around 6500 there was a simple "beep" tone emitting inside the car... is that the metering pump pressure alarm? he car has plenty of oil & it's clean. Only happens at higher RPM.
 
  #9  
Old 08-12-2011, 11:14 AM
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Might be the redline buzzer. That is kinda low for it to come on though.
 
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