driften16

iTrader: (1)

i have a 88 na with a rb header,intake,no cats,5th and 6th ports open,all egr,air suction valves removed,new silicone vacuum hoes all grounds cleaned ,throttle body mod.
it happened yesterday all of a sudden driving down the road the car started running like **** felt like it was misfiring, backfiring loss of all power(what little it has) at every light it would stall.next morning i figure it would be fine...nope. drove to work stopped at a light and tried to keep it running but it died..but this time it wouldnt start so i started to push the car off the road got to the hill hopped in and the car ran again.finaly got it to work and now it wont even turn over..it turned over twice and i needed to keep the pedal to the floor for it to stay around 2k but missing and backfiring alot.
i haver checked everything so far
replaced the plugs
replaced fuel filter
checked for vaccum leaks
did the unflooding procedure 3 times
i have spark, good spark
the wires are new
tps is spot on
idk what else it could be can anyone help?

satch

iTrader: (1)

How about checking the fuel pressure. Should be about 70 psi before the fuel filter when dead headed and close to 30 after the filter when the fuel pressure gauge is teed in.

RotaryEvolution

iTrader: (30)

do a compression test as well as check the fuel pressure, however i'm not sure why the fuel filter would drop 40psi of pressure.. it should be ~32psi throughout the pressure line, ~90psi with the return line pinched and have no leaks.

satch

iTrader: (1)

When I said before the filter I meant that this would be if the gauge was dead headed as opposed to teed in. I just worded it incorrectly.

RotaryEvolution

iTrader: (30)

ah ok

driften16

iTrader: (1)

checked the pressure we have correct pressure .and just to make sure i took off the the pressure line and ran a sperate bottle with a regulated 32-40psi whiler cranking. and we have good on both rotors. i think its more of a electrical problem than mechanical.any idea on what componet i should check?

satch

iTrader: (1)

You stated "it now won't even turn over then it turned over twice." Which is it now? And when you say not turning over does this mean the starter is not cranking?

driften16

iTrader: (1)

it cranks and takes about 10 seconds to start then it goes to 2k and drops down quick unless you hold the throttle to the ground but then when you let go it backfires. then if you let it die and try to start it it doenst start

joeylyrech

iTrader: (11)

compression?

satch

iTrader: (1)

Go to the Circuit Opening relay found under the dash and to the right of the steering column. The plug is white but the relay is yellow and has five wires. On the bottom row there will be a solid Black wire, bottom left, and a Brown wire, bottom right. Jumper these two wires as it will bypass the AFM (fuel switch) to a degree and see if the car can start and stay running.

Post #166 https://www.rx7club.com/2nd-generation-specific-1986-1992-17/86-tii-swap-wont-start-but-really-wants-887302/page7/

driften16

iTrader: (1)

ok i will check these when i get back to work monday. anyone else have any suggestions? i checked compression it is good

zoomy942

iTrader: (2)

on my 88, i had to adjust the throttel cable behind the TB. someone had loosened it so much nothing would work that i adjusted.

just a thought for ya

driften16

iTrader: (1)

ok i tried the afm bypass and the car started so i figured it was the afm...nope the car is still borked i checked the throttle cable and that is fine.. anyone else have this problem before?

driften16

iTrader: (1)

bump..

satch

iTrader: (1)

Next time the car dies, leave the key untouched to the on position and check the Black/Yellow wire at the leading coil for battery voltage as it should be present. If you still have the jumper at the Circuit Opening relay in place then also check the Blue wire in that relay for battery voltage after the car dies out and the key not touched and left in the on position.

Have you done anything to the car in the days leading up to it having these problems?


You can bypass the Main relay to check to see if it is the culprit. To do so unplug the 4 wire plug to the relay and jumper the Black/Green wire to the Black/Yellow wire and jumper the White/Blue wire to the Black/White wire. This will remove the relay and its ground from the equation and in doing so will supply the coils, injectors, engine sensors and the ECU with constant voltage. Do not leave these wires jumpered for an extended period of time as your battery will drain down.

driften16

iTrader: (1)

thanks ill trie that ...and no the car has been driven daily for the past 2 months .it just happend out of nowhere

zoomy942

iTrader: (2)

trust Satch. he's a genius.

driften16

iTrader: (1)

kinda of a nub question where is the main relay? is it called that?

Black Knight RX7 FC3S

iTrader: (7)

the main relay is under the trailing coils

driften16

iTrader: (1)

ok i jumped the main relay and it still didnt start....i checked the wire at the leading coils and i had voltage... same with the blue wire

Black Knight RX7 FC3S

iTrader: (7)

I had a similiar problem last year with my gxl.
Turns out the plug for the coolant thermo sensor came out.
The car was hard to start, backfired at idle when you give gas. Until the engine warmed up everything was normal. A bad thermo switch will give you way more gas then normal at a cold start, once it warms up, it leans out. Though, I dont think that would make your car shut off while you are driving.

forgot to say that the thermo sensor is located on the back of the water pump housing.

driften16

iTrader: (1)

you know i was thinking that in the begining because the plug came unclipped while driving and after it was warm it would rev past 4k ill check into it

durtled

maybe ur timing is messed up if its not that

driften16

iTrader: (1)

that crossed my mind too but is it common for these cars to skip timing like that?

driften16

iTrader: (1)

bump!!!