borisf

Good day All,

I am not getting a spark on my leading coils/plugs, only on my trailings.
I have since replaced/added the following to the ignition system:

- Lower Mileage Coils
- HKS Twin Power+ Harness
- New Coil Harness
- Sake Bomb/MSD Super conductor wires
- Brand new NGK Plugs (9's for both trailing and leading).
- Coil Relocation kit (driverside firewall).
- Pettit Racing Starter Booster



Now, with the car on a jump pack, it will crank and try to turn over, but only for a second. Every now and then, it'll after fire pretty loud, or occasionally let out a flame.

The Car is definitely get fuel. So i pulled the plugs after about 30 tries of trying to crank it, and the Leading Plugs are completely spotless. Mind you, the plugs in the car now are 100% brand new. the Trailing ones looked much blacker, as it appears they are trying to the brunt of the work.

I got the car going, but it was running really rough and stalling out.

I searched and got some answers on Crank Angle Sensor, however my harness looks OK there.

I checked the Fuses, and they all look good. I replaced a lot of stuff on the ignition side, however I am still getting this nonsense.

Anyone run into something similar? It wants to crank over...but just doesnt have that spark needed from the leading plugs.

And yes, I checked to make sure the wires weren't switched around....

Looking for any and all help!


Thanks!

IRPerformance

iTrader: (41)

Did you check for spark on the leadings?

Valkyrie

Unplug the fuel pump and the plug wires, then put the leading coil on one of the trailing's harness plugs. Put a spare plug into the wire and hold it with rubber gloves against an exposed metal part of the body (like the bolts on the shock tower). Crank and see if it sparks.

If not, the coil is bad.

If it does, you probably have a wiring problem (or a bad ignitor).

If you don't have anyone to help you do this, you can use locking pliers (to hold the plug in place) and a smartphone on a tripod to record a video of it.

I would probably remove the Twin Power for the time being. Recheck that all the wires and plugs are in the right place.

borisf

Ok so I did this test as you had advised. L1 has a strong spark, L2 doesn't. It's there but it's much weaker.

I had a spare set of coils so I swapped the leading and same results. L1 is still just as strong, L2 was weak.

Could it be wiring that's not generating enough spark for L2? Or do I have 2 bad coils with the same symptoms?

The twin power is not hooked up ( as you had advised).

If the spark is getting there, then the igniter should be ok then?

Thanks a bunch man.

borisf

Hi Ihor

I did check the leading spark as per Valkyries test procedure above and it did work, but like mentioned, L2 was weaker.

Any thoughts?

Valkyrie

I'm not sure. It might be normal for one of them to work fine while the other is weak, since each trailing coil only has to fire half as much with half as much spark as the leading.

Maybe try hooking up a trailing coil to your leading plug and seeing if the spark is strong? I wouldn't think that would hurt your trailing coil.

If it doesn't spark, you've probably got a wiring problem or a bad igniter.

Just to be thorough, check your grounds; especially the big fat one that hooks to the engine block. Make sure they're all clean and tight.

Also make sure your plug wires are all in spec (resistance per meter).

borisf

Valkyrie, Thank you for taking the time to help me out with this.

Last night, when I was testing, it really started to bug me why they made the two lead plug connections on the same coil, but separate ones for the Trailings. Kind of seems backwards to me, but then again, I'm still learning about these damn things.

We tested all of the coils, and all of them work. The trailings have strong spark, and L1 has a strong spark, just not L2. I would think that because we are getting spark, then the ignitor should be okay? I did do some reading on this before, and from my understand the igniter is just a switch.... so I'm thinking we are OK there. I am curious if the two bolts on the igniter both have to be grounded to the body. I had the ignitor bolted up to the relocation bracket that was bolted to the car, so now i'm second guessing if that could be my issue when everything is hooked up.

Regarding wires, I had 3 different sets that I used for this car already.
1. OEM NGK's
2. Magnacore Race
3. MSD Super conductor (Sakebomb Garage specials with OEM Coil Pinning).

All 3 had the same result.

Also, the cranks did seem a bit quicker with the twin power not hooked up when doing the tests yesterday. I don't know if I was just tired or what, but it almost seemed like the car cranked much faster without it hooked up. On the HKS site, they specify that the Twin power works wonders from Low RPM -> High RPM (obviously) to combat ignition break up, but I wonder if it actually does anything for startup...

Anyways, I am going to try using putting everything back, keep the igniter grounded to the body instead of through a bracket. no Twin power. See where that gets me.

Valkyrie

The igniter does need to be grounded. According to the electrical diagram. I think.

FWIW, a car WILL still on just one rotor. My car actually had the coils installed in the wrong order and the car still started (but it wouldn't rev well). "Zenki" (91 to 95) FD's have the coils laid out differently then "chuuki" (96-98) FDs and "kouki" (99-02) FDs.

Again, make sure that the two trailing coils aren't reversed. The leading plugs don't matter since they run on a wasted spark (it fires at the same time).

It might be a good idea to remove the starting booster, although I have no idea how that works or what it does. When diagnosing problems, mods are the enemy.

On another note, if one of your plugs is in a bright area and one is in a dark area, the latter will appear stronger.

I actually went as far as using slow-mo video to confirm the leading plugs were firing before the trailing plugs to make sure the wiring hadn't been crossed.

IRPerformance

iTrader: (41)

Could also have a bad igniter (pretty rare) or the body wiring harness is damaged somewhere. The wires to the ignition run under the fenders. Too big of a gap between the crank angle sensors and trigger wheel could do it too. Measure per the fsm and shim if necessary.

borisf

Yeah, no doubt on it being grounded. Its grounded through the bracket (I guess), because the bracket is mounted in the same position as where the igniter was. The Igniter is bolted to the bracket. I will see if it makes a difference if the Igniter is bolted direct to the body or through the bracket. its a relatively quick swap.

The Starter booster I got as an aid to hit or miss starts. Link for it below. Basically its just a booster relay to pump more juice in the starter. I have my rad fans hooked up to kick on when the key is on the on position and it drains a good amount of voltage for startup.

I know the coils and plus aren't reversed, because I was sure that it was going to be one of those things that's a stupid install error that could cause all of this headache.
That's why I'm thinking there's something else that's really causing this troublesome behavior.

I'm going to take a look again at it today, I think i'm just going to take all of the ignition components out, and reinstall everything.

Thanks again for all your help Valkyrie.

borisf

Thank you Ihor for your suggestions. They are most helpful, and I truly appreciate you taking the time.

I will look for the wires under the fenders to see if there's any exposed wiring shorting anything out. Also, I have looked up a way to test the igniter to see if it is really bad. I hope its still good because these damn things are expensive!!

Regarding crank angle sensor, I have seen some threads and in particular this one has some interesting things on it, in regards to the exact same problem I am having. Weird that I couldn't find it before based on the keywords for the ignition problems. Good thing I printed out all 800 pages of the Factory Service Manual!

https://www.rx7club.com/3rd-generati...-923730/page2/


Thank you again Ihor. Hopefully this gets it sorted out, otherwise it's going to be a gruesome 2hr tow over to Metuchen from CT.

borisf

So I cleaned the crank angle sensors as they had some oily deposits and the connectors were a bit dirty. Lightly sanded the gunk off of the crank sensor wheel as well to maybe get a better connection as it had a good amount of grime on it.

No change in the car starting.

The car is still getting plenty of fuel, however it still doesn't seem like the spark is enough to get the car going.

When you cycle the key, power comes to the fuel pump instantly and then shuts off. When cranking, the pump is getting power (6-6.5 volts). but even so with that much the fuel is still being delivered as the the car is backfiring upon trying to start up.

With th the crank angle sensors, I can't imagine them failing as they are just magnets, but for shimming them, how would you gauge how far or close to the crank wheel it would need to be?

borisf

Shimmed the crank angle sensors.

The car starts up each time, but still runs rough (but maintains an Idle), and seems like its not getting any spark to the Leads.

Could I really have a bad coil since everything else works?!

I tested the two coils that I have, and both have the same results. What are the odds that both are garbage?

The good thing is, it starts each time... however, I dont like cranking it and having it run like complete ***.

Any more thoughts?

Valkyrie

Hmm... What do the L1 and L2 plugs look like now?

Clean them off, then switch up the plug cords, start the car, and see if the plug deposit results are backwards.

Didn't you already try changing the coil?

You should try taking videos of L1 and L2 sparking (in slow-mo if possible) so we can see what's happening. Use the same plug, cord, and grounding location for both videos.

90% of the time, replacing solid-state parts like the coils does NOT fix a problem... it's usually something else.

borisf

I hadn't looked after yesterday, but the last time I pulled them the trailings were black, and the leads were completely clean.

I'll see if I can get slow motion video.

Are you saying to put the T1/T2 wires over the Lead plugs? I had contemplated that the other day, but opted out.
I'll do that tonight and report. Thanks Valkyrie, you've been a big help.

Valkyrie

The "clean" plug should at least smell like fuel, and should probably be wet with it.

borisf

Yeah, it definitely reeks of it.


I am going back to where the car is kept to do some more work on it. Gonna test it out, swap the wires and see what we get.


There is definitely progress... but not enough!!!!!


AGHHHHH

Valkyrie

If you know for sure that one plug is weaker, I'd just consider buying a rebuilt coil just to eliminate it as possibility.

borisf

So, I ended up getting her fired up yesterday.


I started her up, and it was a little bit rough and then all of a sudden, magically, everything started working just fine!!!


I let it get up to operator temp, then shut it off. Started it back up about 4-5 times to see the consistency, and she starts right up.


Could it have been some old **** gas in there?


Consistency is key, so I'll be starting her up today again after work. Hopefully she starts right up again.

Valkyrie

I have no idea... maybe? Sometimes you mess around with something for long enough and it just suddenly starts working again. I'm still not sure what got my car running...

borisf

We'll see what happens tonight.


I can definitely say for a fact that shimming the CAS to the Crank Wheel definitely helped a whole lot.

borisf

And its back to being difficult. Starting up each time, but its breaking up... i think it may be possible that my leading coil pack is screwed up at this point;

ThunderSprinter

Working fine, then magically not working sounds like a wiring issue to me. I'd bust out a wiring diagram and get to tracing wires in the ignition system, or maybe jiggle the harness in different places with the engine running to see if something is coming in and out of contact or grounding out somewhere. Pay particular attention to the places you recently modded.

borisf

Ok, so a followup to all of this:

I got 2 New Crank Sensors for the car, cleaned up the connectors and plugged them in. Sanded off the Crank Wheel to get rid of the grime and now the car runs and drives great. There are a few other things to iron out, but its looking good.

I read everywhere that these crank sensors are pretty good and don't usually fail, but perhaps I got ones that failed over time. I maybe didn't have to do both, but I figured if one was getting to the point of not being able to crank the car over, then the other one would follow shortly thereafter.

Valkyrie

Well, you didn't mention the crank wheel was grimy....

In hindsight, that's probably why shimming helped. I bet you don't even need the shims now.

I wonder if it would have run fine with just cleaning the connectors and the wheel?