tbarrfow

my 1988 FC Convertible will not start.

only mods it has is the cats removed and an exhaust.



i have replaced fuel filter, fuel pump sock, and AFM but it isnt getting any fuel.

all i can think of thats left is the ECU and injectors. what kind of tests should i run?


the fuel pump gets 12 volts on crank and keeps 12 volts but the car dies.

also i can run the car on starter fluid. but as soon as it all burns off the car dies out.



also sometimes it does seem to get fuel because i did flood the engine once. :/

so any ideas or input??

also have a video of trying to start it:

<iframe width="560" height="315" src="http://www.youtube.com/embed/_OsOiFmvRqY" frameborder="0" allowfullscreen></iframe>

Aaron Cake

iTrader: (1)

If the fuel pump is getting 12V, but not supplying fuel, then the pump is bad.

tbarrfow

fuel is getting all the way to the primary rail atleast. when i put the new line on i got distracted and left it just on the edge of the flare and when i went to turn the motor over it blew off and fuel went everywhere. so fuel pump is pumping fuel to atleast that point.

i was recommended by a friend that the ECU may not be grounded properly and the injectors arent firing. what kind of possibility is that?

unless someone comes up with other stuff for me to try before i leave work, im just going to buy the UIM gasket and injector o-rings and pull the manifold and noid light the injector harness and test the injectors.

am i taking the right path here?

tbarrfow

also heres a link to the video since it didnt embed right.

http://www.youtube.com/embed/_OsOiFmvRqY

projexladen

Check the following highly informative link for proper grounding:

http://www.aaroncake.net/RX-7/grounding.htm

Aaron did a great job on it.

If you're getting fuel to the rail, but not into the engine, sounds like you're on the right track. Maybe someone else with more experience will chime in here...

tbarrfow

thanks for the link and thanks Aaron Cake for the write up. very thorough and easy for me to follow.

had my granddad go look at the car for me and the ground that goes from the bell housing to the firewall is broken. so i will definitely change that one and i will pull the manifold and check the ECU ground.

satch

iTrader: (1)

Test for fuel flow coming out of the return line as this will help rule out the Pulsation Damper and the FPR as possible causes. It would also help if you could measure the fuel pressure. Have you also tested for spark? The B/Y wire at either coil should have voltage w/key to on. Have you tested for fuel flow w/the fuel check connector jumpered? This will help to determine if the Circuit Opening Relay is functioning properly and this relay powers the fuel pump, but it uses different signals to pump fuel w/the key to start then it does w/key to on and engine running. You know you have fuel delivery to the engine w/key to start but not w/key to on, which requires the jumper.

tbarrfow

yes i have tested it with the jumper so i know that relay is at least functioning enough.

when i pulled the pump to change the sock and test it there was fuel in the return line.

im getting spark tested that with the fuel pump unplugged and turned the engine over. ill check the voltage to those wires when i get home from work around 6pm CST.

i havent measured fuel pressure tho. dont have the stuff to test it at the moment.


believe it or not i searched for days before buying the car doing research and have had the laptop in the driveway constantly looking up potential problems and fixes and had friends searching on phones. so not a typical noob.

satch

iTrader: (1)

And did you try starting the car w/the fuel check jumpered or did you jumper the connector just to see if the pump would run w/key to on?

tbarrfow

I tried starting it that way aswell.

tbarrfow

also something i just noticed i left out.

i can get the car to start on starter fluid. then it dies out.

satch

iTrader: (1)

You need to measure the fuel pressure at the return line. Most auto supply shops will rent one to you for a minor charge. If you able to measure the pressure then "T" the gauge in line.

tbarrfow

so i need to measure in the return line? not the feed. right? i thought that the feed would be what i was concerned with.

but alright ill try and stop by there and rent one and get results for you guys.

satch

iTrader: (1)

You could have a good pressure reading going into the engine but not necessarily coming out as the Pulsation Damper and FPR are after the send line but before the return line. You could measure the pressure going in as this would give you a heads up related to the items that come before the pressure gauge but this ignores the fuel rails and their associated components.

tbarrfow

i got you. i will get you both measurements.

want me to check anything else?


also what are good numbers for those? 35psi?

satch

iTrader: (1)

Generally between 30 to 40 psi would be normal.

tbarrfow

if im checking the return line i will need to stop the fuel somehow right? becasue the return dumps in the tank wouldnt that make pressure build nearly nonexistent?

satch

iTrader: (1)

You would be capturing the pressure as it leaves the engine before reaching the tank so anything thereafter should be irrelevant. When I refer to the return line I am talking about the return line (fuel line closest to the fire wall) that comes off of the secondary rail and this reading is taken inline so there aren't any obstructions.

tbarrfow

Went to the store they didn't have that tester so I went home to test the other stuff.

1st grounds all seem ok. Except for the one from bellhousing to firewall. And I forgot to grab supplies to make new one. :/

2nd I tested the +12 to the coils the T coils have +12 and produce a strong spark. The L coils have +12 but do not produce a spark. :/ I feel stupid because thinking back I didn't test them because I got sidetracked. So now I'm 99% sure that coil is bad. Unless there is another test for me to do to make sure its the coils.

That's all I got for today because my daughter came outside and wanted me to.cone inside and play with her and she comes before the rx7 everytime.

satch

iTrader: (1)

The car relies more on the lead coil to start than the trailing coil. The igniter within the coil requires a ground and the coil needs to be properly bolted to the fender for a ground to be made otherwise it will not fire, so check this aspect.

tbarrfow

ok i will try that now.

will give you results in <20 minutes.

tbarrfow

well nevermind sorry.

didnt realize my little girl was asleep and i dont want to wake her up.

but in the mean time i did take my DMM and check resistance across the coil posts and i got <500ohms. which doesnt sound right. also there is a 2 pin connector and then a single female connector. does that female connector go to anything it wasnt hooked up in the car. i can take a pic if needed.

satch

iTrader: (1)

The single bullet type connector if for diagnostic purposes such as connecting to a tach. The two wire plug is for the B/Y wire that powers the coil plus the G/Y wire that is the trigger signal from the ECU. And the coil resistance should be between .2 and 1 ohm.

tbarrfow

oh ok well it was closer to 500 but im not sure if i checked it properly honestly. tomorrow i will put it back on the car make sure its grounded good and test spark again just to be safe.

satch

iTrader: (1)

If you're sold on the trailing being okay then you could compare the results of the two to each other.