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91 rx7 will only start from carb cleaner?

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Old 07-08-16, 12:58 PM
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91 rx7 will only start from carb cleaner?

Hey guys I'm new here, ive done a lot of searching and just cant seem to find anything to help me. I bought this car from a kid or didn't know what he had. the seals are good in the motor, it has compression and oil is new (he said it was just rebuilt but hasn't ran since then).
Things ive checked:
-replaced blown egi fuse
-replaced plugs
-verified coils are getting fire
-plugs are getting fuel

sprayed carb cleaner in the intake and it started for about 5 seconds and immediately died. I'm not sure what to look at now, any and all help is appreciated.

Thanks David
Old 07-08-16, 04:07 PM
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If it starts with carb cleaner or starting fluid then you have a fuel delivery problem.
Old 07-08-16, 07:10 PM
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do you have the AFM hooked up to the harness?..and is it piped in to the Throttle body without any vacuum leaks?
Old 07-09-16, 10:36 AM
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what would be something i need to check. the plugs are getting fuel.

thanks.

Originally Posted by KansasCityREPU
If it starts with carb cleaner or starting fluid then you have a fuel delivery problem.

Last edited by David Jones; 07-09-16 at 11:03 AM.
Old 07-09-16, 10:37 AM
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yea the maf is hooked up and plugged in, i havnt found any vacuum leaks anywhere.

thanks.

Originally Posted by misterstyx69
do you have the AFM hooked up to the harness?..and is it piped in to the Throttle body without any vacuum leaks?

Last edited by David Jones; 07-09-16 at 10:53 AM.
Old 07-09-16, 11:14 AM
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You say you have compression but the engine has been rebuilt? What are the compression #'s? If it is a fresh rebuild it may not be broken in yet. I'd try oil in the plug holes, and jump the fuel check connector and see if it stays running
Old 07-09-16, 11:23 AM
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im not sure the numbers my dad stopped by and checked and said it was good but didnt know anything about rotaries. ive put oil in the bottom plugs should i do it in the top to? Also how do i jump the the fuel check connector?

thanks David

Originally Posted by lduley
You say you have compression but the engine has been rebuilt? What are the compression #'s? If it is a fresh rebuild it may not be broken in yet. I'd try oil in the plug holes, and jump the fuel check connector and see if it stays running
Old 07-09-16, 01:49 PM
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There's a Yellow plug part of the emission harness which runs between the passenger strut tower and the engine (harness feeds the pressure/boost sensor). The plug is shrouded in a Black rubber boot and the plug has two wires (wires are Black and Brown). Jumper the two wires together. When done the Blue wire of the circuit opening relay has power (this Blue wire powers the fuel pump thus no power no pump, have power have pump). The relay is also Yellow (and Black). Located under the dash to the right of the steering column. Has 5 wires on two rows (3 on top and 2 on bottom,top right positioned wire is the Blue wire).
Old 07-09-16, 03:21 PM
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Ok so i tried jumping the yellow plug and got nothing. While it was turing over it almost cought but wouldnt fire. i de flooded it, put atf in the plug holes, and nothing. Then my buddy said he moved the (i know its not a distributer) but i cant think of the name, so i put it back to where it was and still nothing. i dont have a timing light or anything. Thanks for all the help so far guys. Is there a way to time it without a timing light by chance? or is it prob my fuel issue. after i tried starting it i checked the plugs and they are wet.
Originally Posted by satch
There's a Yellow plug part of the emission harness which runs between the passenger strut tower and the engine (harness feeds the pressure/boost sensor). The plug is shrouded in a Black rubber boot and the plug has two wires (wires are Black and Brown). Jumper the two wires together. When done the Blue wire of the circuit opening relay has power (this Blue wire powers the fuel pump thus no power no pump, have power have pump). The relay is also Yellow (and Black). Located under the dash to the right of the steering column. Has 5 wires on two rows (3 on top and 2 on bottom,top right positioned wire is the Blue wire).
Old 07-09-16, 03:33 PM
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if the plugs are wet then you are getting fuel.
If the AFM is not plugged in it can't get signal to the ECU to give fuel so make sure it is plugged in.
You know the plugs are sparking obviously as the car will fire with starter fluid,so it has to be fuel related and that is in the pump,the delivery OR the AFM is not giving the Ecu signal to give fuel.
Old 07-09-16, 03:50 PM
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when you say afm. are you talking about the Mass air flow sensor? If not im not sure what your talking about or where its located.

thanks david

Originally Posted by misterstyx69
if the plugs are wet then you are getting fuel.
If the AFM is not plugged in it can't get signal to the ECU to give fuel so make sure it is plugged in.
You know the plugs are sparking obviously as the car will fire with starter fluid,so it has to be fuel related and that is in the pump,the delivery OR the AFM is not giving the Ecu signal to give fuel.
Old 07-09-16, 04:02 PM
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Yes, he is. Under the air box.

Post #2 in the link supplied.

https://www.rx7club.com/2nd-generati...thread-868482/

And there are times when a rebuilt has to be pulled started to get it going the first time.

Last edited by satch; 07-09-16 at 04:16 PM.
Old 07-09-16, 04:27 PM
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Ok yea the maf is hooked up and everything, i was wondering if pull starting it would too, i havnt tried it yet, i guess thats my next try. thanks for the timing thread. And thanks for getting back to quickly with replies guys.

Originally Posted by satch
Yes, he is. Under the air box.

Post #2 in the link supplied.

https://www.rx7club.com/2nd-generati...thread-868482/

And there are times when a rebuilt has to be pulled started to get it going the first time.
Old 07-09-16, 04:35 PM
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Also, make sure the leading plugs are firing as they play a more relevant role than the trailing plugs.
Old 07-10-16, 01:32 PM
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i havnt been able to pull start it yet, but planning on doing that tonight, as far as the leading plugs firing. when the old plugs were in i couldnt get a spark from the leading plugs. then i put the new plugs in and tried with carb cleaner and it started for a sec. would it still start that way with the lead plugs not firing or are they good now since it started for a second?

thanks

Originally Posted by satch
Also, make sure the leading plugs are firing as they play a more relevant role than the trailing plugs.
Old 07-10-16, 02:58 PM
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The trailing could have made the car start. You can just check the lead plugs. Pull the plug wires from the lead coil. Place the plug wires right next to the coil bores. Turn the key to start and there should be sparks coming from both lead coil bores.

The plug wires could be problematic. Also, the coil needs to be bolted to the fender to ground properly or it won't work. And you could unbolt the coil and clean up the mating surface between the coil bracket and the fender (sanding helps).

Pull starting is going to offer little help if the lead coil does not fire. The car can run on just the trailing, but it will be rough. Since the engine has been rebuilt it could be hard to start even if the lead coil worked, but since you say it currently does not then you need to address that issue first.

Last edited by satch; 07-10-16 at 03:20 PM.
Old 07-10-16, 03:44 PM
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Ok I'll check them again. I'm noticing the trailing plugs arnt getting wet from fuel like the leading plugs. Is that also a reason?

Thanks

Originally Posted by satch
The trailing could have made the car start. You can just check the lead plugs. Pull the plug wires from the lead coil. Place the plug wires right next to the coil bores. Turn the key to start and there should be sparks coming from both lead coil bores.

The plug wires could be problematic. Also, the coil needs to be bolted to the fender to ground properly or it won't work. And you could unbolt the coil and clean up the mating surface between the coil bracket and the fender (sanding helps).

Pull starting is going to offer little help if the lead coil does not fire. The car can run on just the trailing, but it will be rough. Since the engine has been rebuilt it could be hard to start even if the lead coil worked, but since you say it currently does not then you need to address that issue first.
Old 07-10-16, 03:54 PM
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A wet plug could foul the plug and prevent it from working. Some will dry the plug off w/a hair dryer etc.
Old 07-12-16, 02:00 PM
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91 rx7 will only start from carb cleaner?

Originally Posted by David Jones
Ok so i tried jumping the yellow plug and got nothing. While it was turing over it almost cought but wouldnt fire. i de flooded it, put atf in the plug holes, and nothing. Then my buddy said he moved the (i know its not a distributer) but i cant think of the name, so i put it back to where it was and still nothing. i dont have a timing light or anything. Thanks for all the help so far guys. Is there a way to time it without a timing light by chance? or is it prob my fuel issue. after i tried starting it i checked the plugs and they are wet.
The part you are referring to the the Crank Angle Sensor, CAS for short. It is the most vital sensor in that EVERYTHING is referenced from it, especially ignition timing. If it is not timed properly, ignition events will be off as well. The method I was shown by Lynn Hanover to "stab the CAS" in place is to get one of the front rotor's apex seals halfway between the plug holes (this is TDC), align the marks on the CAS body, then shove it in. Be aware that it will turn slightly due to helical-cut gears. If you're close, it will run but not very well.

As for fuel delivery, check that you're getting proper voltage at the pump connector. Left side of hatch area. No juice=no fuel
Old 07-24-16, 02:22 PM
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hey guys i know its been awhile since an update. Found out the lead coil pack is bad as well as the upper injectors are clogged. I was finally able to spend some time on the car lastnight. Thanks for all the help from everyone!

thanks David
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