no voltage to injectors
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Joined: Jul 2018
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From: MI
no voltage to injectors
car runs on ether, cleaned and checked injectors but not reading any voltage at injector plugs,I have heard you need some special tool to diagnose the problem ? I know nothing about rotary engines so I am in the dark
Last edited by bones007; Jul 22, 2018 at 07:26 PM.
EDIT: Just found out that yours is a 1987 NA, S4 NA just like mine was from the factory. Injector power comes from the Main Relay, bolted to the driver's side inner fender. It is very close to the Trailing Coil and has two connectors on it. Check for power there too. If you don't already have the Factory Service Manual, grab it from Foxed.ca - Mazda RX-7 Manuals
When my car wouldn't shut off for some reason (later determined to be a worn out ignition switch), I thought my Main Relay was not disengaging. Cracked it open, it looked okay but still had 20+ years on it. It is actually two SPST relays with a common coil, so there are six terminals total. So I hedged my bet and replaced it with two generic 40A relays for reliability and easier servicing. Plus, FC Main Relays are crazy expensive too. Last time I checked, even Rock Auto wanted almost $100 for another one :/
Last edited by Akagis_white_comet; Aug 3, 2018 at 10:06 PM.
Thread Starter
Junior Member
Joined: Jul 2018
Posts: 31
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From: MI
Well the injectors are now working, the relay was not energizing , now it is , I now get unburned material out of the exhaust pipe but car still wont run, I do not have any fancy mazda test equipment they claim you are suppose to use , but I did a compression check with a conventional tester and one chamber only has 60 lbs the other is just above 100. I assume there is not enough compression to fire the mixture? I know this car sat for well over 2 years , so I figure that the seals are all shot in the motor...
Sitting for two or three years isn’t an automatic death sentence on an otherwise healthy rotary. And there’s VERY little “fancy test equipment” really needed for your car. With unbalanced compression sometimes you can roll-start them when just cranking won’t do it. On the chance you did have a stuck seal getting it running and up to operating temp for a while might improve compression.
Thread Starter
Junior Member
Joined: Jul 2018
Posts: 31
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From: MI
Well I cleaned the plugs , and we push started it and it ran... about 2 minutes blowing smoke like crazy....taking your advice I tried to keep it running to see if seals would break loose... but then it just slowed down and stopped... cleaned the plugs again but this time we pulled it down the road and nothing .... occasional backfire and that was it... the plugs are full of oil when we take them out ... maybe getting too much? backfire tells me unburned gas in exhaust... could it be a timing issue ? not even sure how these things are timed but when it did run it had a miss to it , so compression or apex seal issue?
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