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740 possible spark problem?

Have you pulled the LH error codes under hood? Lots of info there with online docs to guide you once you know what LH knows. Does the car rev up and just sound OK at 2K rpm? Or won’t idle and won’t make any rpm?
 
Sorry, forgot to put that in the last post with the recap. No codes on sockets 2 or 6. Both read 1-1-1.

It will idle, at around 2-300 rpm. And it will rev in park or neutral but it feels and sounds like it is being choked. You have to really give it throttle and hold it for a second for the engine speed to start rising.

After a while of running or cranking the plugs get to wet with gas and the car wont fire.
 
I didn't see that you have checked the timing belt and that the cam and crankshaft are in proper timing alignment? Just one tooth off and it can run like you describe.

Also if you are LH2.4 then you have a 3 bar fuel pressure regulator. The pressure should be more like 45psi or so.

Put a spark plug in the end of the plug wire and ground the body of the plug to a good ground and observe the spark. If there isn't any or it's weak. You'll need to move back in the system. You can check the ignitor signal by back probing connectors with a meter to see if you are getting the pulses there. Just like an injector. How is the crankshaft speed sensor?
 
I haven't cheked cam timing or anything since it was running and driving perfectly fine until the last 2 miles of my 30 mile trip. Belt is tight and I don't think it would have slipped. I'll definitely have a look tonight though...can't hurt to check

It does seem the fpr is a little low. I have the original 3bar at home that came off with the old fuel rail way back when. I'll throw that on there and measure it.

I'll definitely check the spark tonight.

Crankshaft speed sensor; I pulled off a junkyard car because it looked to be in almost perfect condition. I'll pull it to make sure the magnet is clean, the sheath is intact and looks good.

Ya know...timing would very well explain everything. Let's hope it's a few teeth off.
 
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Also, do you still run the IAC? I learned the hard way..... when the TPS connector plug disassembles (inside the rubber boot) and your ECU does not see the TPS closed input, the IAC does not run. I cheated my car into running for years with the throttle stop screw. HOWEVER, the PWM IAC valve will set your idle perfectly, but it must see the input "closed" switch from the TPS.
 
Didn't do much last night because of family things, but ran out there just now and the tps clicks when opened...in a few hours I'll check out the timing.
 
Didn't do much last night because of family things, but ran out there just now and the tps clicks when opened...in a few hours I'll check out the timing.

Clicking confirms the switch is making; however only peeling back the rubber boot will confirm if your ECU is getting the input! Check that all wires are connected to the TPS male terminals
 
Check the TPS and other stuff with the LED onboard diagnostic box. Fairly easy.
Most people only know the fault reading.
even more interesting are the other functions
2 times at 3sec and it will flash. on port 2 it is easy to check the TPS.

have a search in the word wide net.

good luck, Kay
 
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ill have a look tomorrow when it isn't pitch black.

Checked timing today and it is still in time, didn't slip.

Checked spark on each output on the coil pack and saw no spark on 2 of them and very weak spark on the other 2. I guess that is why it runs like garbage. I guess time to work my way down the system.
 
Check power to the coils, check for voltage drop while cranking between the coil and B+.

Check for good ground at the igniter (power-stage).

Test fire the coil by grounding negative side?
 
Okay so I'm definitely a noob when it comes to working with a meter....which is why I've put it off for this long.

Coil pack has 3 connectors going into it. The middle is 12v constant which I measured 11.0 volts. 9.5 volts while cranking. The other two come from the igniter and I assume fire the coils. They both show 0.0 volts with key on and while cranking, but I know one set has to have some voltage going to it because the car runs. Just on 2 cylinders..

My brother gave me his miatas igniter from his working wasted spark setup and it has no change.

The two wires coming from the wasted spark board to the igniter, IB1 and IB2, gradually increase while cranking and within 3 or 4 cranks shows 1.5 volts.

I'm not positive that I have a good ground by just looking at it...I know you use ohms but I'm not sure how you measure that one..

Also not sure on how to ground the coil pack to test fire as the only wires go to the battery positive and the igniter.

Electrical problems are my worst fear because I have no experience besides wiring up the wasted spark board
 
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Spark only on cylinders 2 and 3... So either IB1 or IB2 is not giving power to one side of the coil pack

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There is voltage going to the igniter on both connections for the coil pack, only 1.5 volts though and idk if that is sufficient...

If it is okay for it to have 1.5 volts to the igniter, and i switched igniters with a known working one, does this mean there is a failure point in between the igniter and coil pack for that one bank of coils?

Since there is only one ground from the igniter and one bank of coils are working, i assume that means the ground is okay and there is a problem elsewhere
 
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TPS tests good.
Swapped fprs, pressure is a tad higher but no change in how it runs
rewired igniter to coilpack and still no spark on cylinders 1 and 4. Wtf.

Before I go ripping apart my wasted spark setup....why would I have the same voltage coming from the ezk to the igniter on both outputs. But going from the igniter to the coil pack I have nothing. Really I couldn't get a reading from either output going to the coil pack, but there is "enough" spark to run the engine on cylinders 2 and 3
 
Thanks for all the help! I tend to panic when things go wrong...but it can only be so many things. I posted in the ezk thread as well.
 
TPS tests good.
Swapped fprs, pressure is a tad higher but no change in how it runs
rewired igniter to coilpack and still no spark on cylinders 1 and 4. Wtf.

Before I go ripping apart my wasted spark setup....why would I have the same voltage coming from the ezk to the igniter on both outputs. But going from the igniter to the coil pack I have nothing. Really I couldn't get a reading from either output going to the coil pack, but there is "enough" spark to run the engine on cylinders 2 and 3

You really don't have power coming from the WS system in your EZK.... those are "logic signals". Google TTL, transistor type logic. I would doubt there is any issue with your WS chip; while I'm no EE, you would probably need an oscilloscope to see the square wave pulse train coming to your power stage. In my mind, your most likely suspect is either the PS itself, or your wiring between it and the coil pack. If the WS chip is delivering proper 1-4 spark control to your PS, then the failure is downstream.

What do your connections look like at both ends of your harness? Unwrap your black tape and post some pics......ignition wiring is nothing to half a$$ construct. :nod:
 
Lol as am I no expert either...and don't have access or the knowledge to use an oscilliscope.

That's disheartening to hear as I've swapped a working powerstage/igniter from my brother's running setup.

As of last night I clipped the solders, coming from the PS going to the coil, and just twisted them together to see if the car would run better. (Thinking a solder joint cracked somewhere causing bad connection)

The connector I have going thru the ezk
<a href='http://i.imgur.com/AWIftNz' title=''><img src='http://i.imgur.com/AWIftNzl.jpg' alt='' title='Hosted by imgur.com' /></a>
Is my next target. It is of pretty cheap quality but all of the solders are holding tight. I'm planning to reflow them and see if things change.
 
It's running on all 4!! Crimped on some relay connector butts that I had and pushed them onto the coil pack. Fired instantly and runs smooth! I didn't let it run long because I now need to go back thru and resolder everything I cut and twisted together.....

But it's running!! I'm estatic right now!
 
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