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8613b 02-25-2009 06:11 PM

ok this is going to be a very complicated thing so just bear with me for a second.

i have an 86 rx7 n/a. right now the fuel pumpis not turning on. the the circuit opening relay is not working. because it is not getting a ground form the brown wire. i jumped it with a ground so that the pump would turn on but the car still does not start. it just floods the engine. now i tested the afm and it seems to be fine from what the shop manual says so now im stuck with a constant ground it floods with it just wired normally it does not even turn on. here is the wire diagrahm for what im talking about

http://www.cochran-racing.com/FSM/s4...NG_DIAGRAM.pdf

the relay im talking about is on page 30 its marked f-08 and the brown wire is not getting a signal what should i check next it is so close to starting and i just want to finally drive it

j9fd3s 02-25-2009 07:10 PM

interesting. ok the fuel pump circuit works like this....



ecu sees rpm then it switches the circuit opening relay by grounding pin 2J (2A is the reference voltage), if the afm is not fully closed, this energizes the circuit opening relay which runs the pump



the ecu needs to have i think only 2 things before it'll switch on the fuel pump, it needs 12v power, and an rpm signal from the crank angle sensor. i'm going from memory but the ecu power is battery -> underhood fuse box -> main relay -> ecu. there may also be a fuse in the dash fusebox, but i'm not sure. rpm comes right from the CAS to the ecu.



do you have spark? if yes, than the ecu is getting power and rpm.....

8613b 02-25-2009 09:22 PM


Originally Posted by j9fd3s' post='917353' date='Feb 25 2009, 06:10 PM
interesting. ok the fuel pump circuit works like this....



ecu sees rpm then it switches the circuit opening relay by grounding pin 2J (2A is the reference voltage), if the afm is not fully closed, this energizes the circuit opening relay which runs the pump



the ecu needs to have i think only 2 things before it'll switch on the fuel pump, it needs 12v power, and an rpm signal from the crank angle sensor. i'm going from memory but the ecu power is battery -> underhood fuse box -> main relay -> ecu. there may also be a fuse in the dash fusebox, but i'm not sure. rpm comes right from the CAS to the ecu.



do you have spark? if yes, than the ecu is getting power and rpm.....

yeah man i have spark so i know the ecu and cas are working im starting to think the afm is not good. i really dont know what else to look at here. its trying to start but then never does and just ends up flooding

jaguarx7 02-25-2009 09:32 PM

How old are the spark plugs? Perhaps they need to be changed. What about the compression?

8613b 02-25-2009 10:00 PM


Originally Posted by jaguarx7' post='917368' date='Feb 25 2009, 07:32 PM
How old are the spark plugs? Perhaps they need to be changed. What about the compression?

compression is good and plugs are new, that is what is baffling me. its got compression,spark, and fuel maybe the timing is off but i dont have a timing gun and i dont know how to check timing without it running. at this point i really wish it had pistons. this is my first rx7 and i just want to drive it

RicerJ 02-26-2009 12:20 AM

ok im not 100% but if there are timing marks then you should have some idea of if its right

8613b 02-26-2009 11:43 PM

i dont know but im about done with this car i think im just going to sell it and get another honda/acura. those things were at least easy and cheap to work on. plus im moving to a place with no garage so that kinda sucks trying to deal with this while trying to move

RicerJ 02-27-2009 12:01 AM

dont give up on it just because of a problem keep it and then if you get a major headache of it then sell lol like i did when i sold my 87 crx si

j9fd3s 02-27-2009 02:11 PM


Originally Posted by 8613b' post='917373' date='Feb 25 2009, 08:00 PM
compression is good and plugs are new, that is what is baffling me. its got compression,spark, and fuel maybe the timing is off but i dont have a timing gun and i dont know how to check timing without it running. at this point i really wish it had pistons. this is my first rx7 and i just want to drive it



timing is simple, if you take the cover off of the crank angle sensor, there are 2 sets of teeth, one set has like 30, the other has 2. if you look at the cas cover, there is a little plastic do-dah, take this out. reinstall the the cover, rotate engine to the leading timing mark, one of the 2 big cas teeth should be right about centered in the cas cover hole.



the fuel pump switch in the afm is easy to check too, if you pull the airbox out of the car, just holding it the 2 terminals should be open, if you push on the afm flap, they should have continuity.

smitty 03-01-2009 06:01 PM

Make sure the flapper in the afm moves when cranking the engine. I have seen several that had gunk on the shafts and they wouldn't move

when cranking so no fuel. If this is the case just clean and some light lube.

Dave


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