KB7SKV

Help please... I've searched every instance of spark issues and not starting I can find, and tried everything. Here's the problem... 91 N/A 'vert bone stock. No spark when cranking, one spark occasionally just as I let off the key. All sensors, CAS, ECU tests I can do check out ok according to the book and what I've found here on the board. I've been TOLD the ECU was recently sent in for testing and given a clean bill of health, all the input voltages appear 'normal' again according to the service manual. I also tried turning the key to 'on' (run position) and 'jumping' the starter to crank it and got no spark... I'm lost. Any suggestions?

HAILERS

I've no clue. I've seen a couple of threads like this never answered.

Usually you get a meter and put the key to ON, engine off. Then see if there is batt voltage on the two wires going to the Lead coil. Usually it is there. IF not, then the Engine fuse is bad or Main Relay isn't pulling in for unknown reasons. This is after you made sure the EGI fuses were good in the engine bay and the Engine fuse good in the interior.

Then if you know what end is up........key to ON, engine OFF (that part should be pretty easy for you {humor}). Then pull the CAS out of the engine. Spin the bottom gear on the CAS with your fingers. You should be able to hear the sparkplugs snapping and the primary fuel injectors clickity click. Or pull the LEAD spark plugs off and lay 'em near the left strut tower and watch the spark as you spin the CAS bottom gear. Doing things this way save on engine wear and battery wear (does not discharge the batt as when you use the starter to do this). Also removes a lot of the Load off the battery so as to keep the batt charge up.

Only do this is you KNOW how to install a CAS and KNOW that when you do, that the timing will be within five degrees of what you'd see with a timing light.

Stare at the tach needle. Turn the key to ON. The needle should make a tiny bump as the key is put to ON. This more than less proves the ECU is causing spark, at least at the Trail coil assy.

LIke I say, I've seen a couple of posts like yours and darn if anything I wrote ever fixed 'em.

Handful

iTrader: (1)

How are you checking for spark?

KB7SKV

Hailers; Been all over the elec. sys. with a meter and so far everything 'checks out'. I've done the CAS check (removed & spun by hand), heard fuel flowing (sounded like a fuel pump) but no clickity click, and no spark, I will double check the tach needle for a bump when I turn the key on, was watching for it to move when cranking before. I will post my results...

Handful; I was using an inductive timing light, but I don't trust it, so I just pulled a leading plug wire and put it on a sparkplug grounded to the drivers side shock tower.

AGreen

iTrader: (11)

I'd bet it's the ecu based on the fact that you get one spark when letting go of the key. There's a short pulse you get when moving the key from start to run, which could trigger the igniter on the coils, giving it the one spark. See if you can get a friend with a good ecu and try the cas spin test with the key on.

KB7SKV

OK, I just went out and watched for the tach 'bump', it is there... every time I turn the key from ACC to ON (RUN) it bumps a tiny bit. that is the first time I've noticed it move at all. SO... am I to gather from your suggestions that I probably need to replace the CAS? I hadn't thought of the fuel injectors operating when I turn the CAS manually, makes sense tho. Like I said before, all that happens when I turn it (with the key on) is a 'whirring' sound much like I get with the key on and the fuel pump 'test connector' shorted. I consider myself a fairly accomplished mechanic, just not experienced in the rotary world. Your continued assistance is deeply appreciated.

KB7SKV

I'd LOVE to try that, but cant find anyone in my area with a '7, much less a 2nd gen s5 vert. BY THE WAY, it doesn't do it EVERY time, just kinda randomly but it's always right when I release the key from the start position.

AGreen

iTrader: (11)

If an s4 CAS will work with an s5 (pretty sure it does) you can have mine for $10 shipped. Only bad part is that its connector was chopped by the guy I bought the engine from. I ended up buying a complete one because I couldn't get JUST the plug.

KB7SKV

Thanks all, I'm 99% sure I've nailed the problem down as the CAS!! I went and did the key-on, CAS-out, spin by hand method again, and got thinking about it a little (it wasn't firing the plugs)... I removed the cover from the CAS and kinda looked around a little, didn't see anything OBVIOUSLY wrong, thought I'd try something a little more massive than the little '****' on the upper sensor to see if they weren't getting a strong enough pulse from the '****'... I was right!! I used a fair sized screwdriver and when I pass it infront of the upper sensor in the CAS low and behold, the injectors snap, and the plug sparks!! I am now almost certain that the CAS is just bad regardless of the 'test' the service manual suggests will determine condition (it fell in the middle of the range recommended by the manual). I have 'ordered' a CAS from another member and will probably get it sometime this week and be able to confirm my suspissions!!! I will post results as soon as I have them. THANKS AGAIN TO ALL WHO POSTED SUGGESTIONS!!!!!! Ray.

KB7SKV

Well, a fellow RX7 lover happened by the house while I was out workin on the car, and offered to loan me a known good CAS, I jumped at the offer, dropped it in, hit the key and VAROOOOOOM!!!! it's running!! wont Idle, and smokes like a freight train, but I'll work that out later, atleast it runs. Probably didn't crank more than 2seconds before it caught and ran straight to ~3k, little bit later it dropped down to almost an idle and woulda died if I didn't catch it. Thanks again to all who posted help... I'll keep everybody up on how the rest of the project goes!