Wow, this is a weird one.

Went to start the car after the rebuild today; starts, runs one one rotor.

Compression test shows 3 even bounces on both rotors. Both bounce to around the 80-90 psi mark (bear in mind these are new housings and seals and havent been run in yet) Cumulative pressure just over 95ish psi.

Ok, all 4 leads produce a spark of sorts when held with a spark plug to an earth.

All 4 spark plugs are tested and working.

The rear housing plugs both show signs of ignition - i.e blackening, dry.

The front housing plugs come out completely and totally clean and soaking wet after running the car for a minute or two. The leading stinks of fuel. Didnt sniff the trailing. In any case - there are no signs of ignition.

Swapped the front plug for the rear plug. The plug in the rear rotor (the old "clean" Front plug) now shows signs of compression. The front rotor plug is now being washed off of soot, is soaking wet and stinks of fuel.

Swapped the leads over (l1 to l2 and l2 to l1) still same situation, no ignition on front rotor.

Swapped the leads for a set of proven ones off my car, still no ignition on front rotor.

Swapped the leading coilpack from my car (proven working) and used leads off my car. Still no ignition on front rotor.


I dont understand it, i've swapped everything (leads, plugs, coil) and the problem still doesnt follow any item (swap plugs, coil, leads - no difference)

What the hell is going on? has anybody seen this before? As i say, compression test is good, ignition components are known good, spark plugs are brand new and tested working - but front rotor still will not fire. Car does not seem to be losing coolant either. Both plugs do produce a spark when held on an earth and front rotor is definately getting fuel.

 

please help me!


I just tried a new ignitor too - no luck, still 1 rotor - front one not firing.

 

Have you gone through the wiring harness for the ignition system?

 

what do you mean gone through it?

The leading coil is a common coil. One plug is firing off it, the other isnt.

not sure what else there is to check? the wire is plugged in, one plug works - i figure its not the wiring?

 

Injector stuck wide open on front rotor?

 

Hmmm, could be - it does STINK of fuel constantly. Maybe ill try switching it out with another i have...

I did have them cleaned recently though - they didnt find a problem with them :S

Man this sucks ***. This car should run great!

 

I also just found my knock sensor was unplugged. Plugged it back in, reset ECU - still same deal.

What the hell gives man?!

 

anyone?!

 

https://www.rx7club.com/showthread.php?p=6132496

Make sure the injectors are doing what they ought to be.

One good start is to make a circuit from the main relay to the ecu pin and use a 9V battery to click-test each injector. Then if one doesn't seem right try what is described in that thread.

Dave

 

swaped the injectors round from front to rear rotors. I swapped all 4 injectors as i couldnt rule out a secondary hadnt stuck open or something (even though id had all 4 cleaned and the report came out good)

Upon removing my front rotor secondary injector, i could see the bottom o-ring had somehow become pinched? in any case, it wasnt in a good shape. I replaced it; put the car back together, started her up and she seems happy on both rotors now. I havent driven the car yet as currently it has no IC, intake elbow, lots of the rats nest is disconnected, it has no Y pipe, crossover pipe etc. Ill update in a few hours once its all back together.

But man oh man that was a horrible problem!!!!! took me days and days of swapping and dismantling and re-building to diagnose. I guess what was happening was the front rotor seal in the fuel rail wasnt sealing, and the fuel was being forced into the rotor without being metered by the injector.

 

Glad you found it and got it straightened out. I ended up screwing with my leaking injectors for a long time too.

Dave

 

Ok, car now firing on one rotor again - but this time its the REAR rotor that isnt firing. Since i swapped the injectors over, i figure it has to be a freaky injector. Either a stuck shut primary or more than likely stuck open either injector.

im gonna switch em out, have to source a spare primary first though.

 

Okay, ive figured this one out now i think.

i had a stuck open injector. This flooded the engine which fouled the plugs. This then made the whole car not start at all.

I unflooded it, replaced the leading plugs and it started right up. I then put one of the old plugs back in (the fouled ones) and ran it for a bit. Then i put the second one in and ran it for a bit.

It now seems to run and start superbly and moves under its own power.