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240 LH 2.4 Spark Issue

I'm pretty sure that if the center of the rotor lines up with the notch on the housing at TDC, it's OK. Even if the drive gear is off a tooth, you'd need to rotate the housing by a tooth's worth to align the notch. At some point, you can't rotate the housing enough to get it to align. (It's the rotor position relative to the housing&cap that matters for proper spark distribution.)

Here's a picture of a LH2.4 disti with the alignment block. You can use the shinny place to center your bolt without the block. (click for full size)


Can you also check your distributor cap and make sure the spring-loaded carbon center shaft is still intact (sticks out maybe 1/4" when new)?
 
I'm pretty sure that if the center of the rotor lines up with the notch on the housing at TDC, it's OK. Even if the drive gear is off a tooth, you'd need to rotate the housing by a tooth's worth to align the notch. At some point, you can't rotate the housing enough to get it to align. (It's the rotor position relative to the housing&cap that matters for proper spark distribution.)

Here's a picture of a LH2.4 disti with the alignment block. You can use the shinny place to center your bolt without the block. (click for full size)


Can you also check your distributor cap and make sure the spring-loaded carbon center shaft is still intact (sticks out maybe 1/4" when new)?

The (new) cap I just tested on my 245 and works great, so that's ruled out I suppose. I also just double checked TDC with the crank and cam position and aligned the distributor appropriately, but sadly still a bunch of backfiring madness!!!
 
Pull the upper timing cover and get a strong light and make sure the notch in the washer lines up with the block casting.

2011-06-05_234001_42381501.gif



B230TM-Crank1.jpg
 
Pull the upper timing cover and get a strong light and make sure the notch in the washer lines up with the block casting.

2011-06-05_234001_42381501.gif



B230TM-Crank1.jpg

And take pictures so you can reference them later! I wish I would have taken more photos during my troubleshooting, so I could look back and say "I already did that!"
 
No need the remove the crank pulley to inspect. Just look from above as I mentioned. Upper cover off.

It really can't hurt to pull the covers, line the marks on the pulleys all up and make sure the dist is dropped in correctly.
 
No need the remove the crank pulley to inspect. Just look from above as I mentioned. Upper cover off.

It really can't hurt to pull the covers, line the marks on the pulleys all up and make sure the dist is dropped in correctly.

Well, sadly everything still lines up perfectly with the correct indicators. I took pictures of everything, how do I upload them to double confirm? I've tried making a folder, but TB won't let me. Thanks!
 
<a href="https://imgur.com/FeoJHtw"><img src="https://i.imgur.com/FeoJHtwm.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/gQhJtS1"><img src="https://i.imgur.com/gQhJtS1m.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/YmSfWMV"><img src="https://i.imgur.com/YmSfWMVm.jpg" title="source: imgur.com" /></a>

<a href="https://imgur.com/4OnQcuy"><img src="https://i.imgur.com/4OnQcuym.jpg" title="source: imgur.com" /></a>

Thanks, ZVOLV!
 
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... the car starts and runs on two cylinders with a weak spark ... When I crank the car with the coil wire unplugged I get full bright spark grounding over and over. The timing has been reset multiple times and has been confirmed by timing light to be dead on, but still only spark on cylinders one and three.
It sure sounds like everything is fine to the end of the coil wire, but goes bad somewhere between there and the spark plugs. How exactly are you testing to find the weak spark? Plug in a spare set of spark plugs and compare sparks, or something else???

Have you checked for diag codes yet? (Checking both ECU and EZK would be good.)

Are you using a LH2.4 distributor or an older distributor (I'm not sure it would matter though)?

And that rotor doesn't look so fresh or new.... Might help to do a good cleaning of the inside of the cap, rotor, shaft and dust shield if there's any oil film or grease buildup.

If you grab the rotor when installed and twist gently, does it move at all?
 
It sure sounds like everything is fine to the end of the coil wire, but goes bad somewhere between there and the spark plugs. How exactly are you testing to find the weak spark? Plug in a spare set of spark plugs and compare sparks, or something else???

Have you checked for diag codes yet? (Checking both ECU and EZK would be good.)

Are you using a LH2.4 distributor or an older distributor (I'm not sure it would matter though)?

And that rotor doesn't look so fresh or new.... Might help to do a good cleaning of the inside of the cap, rotor, shaft and dust shield if there's any oil film or grease buildup.

If you grab the rotor when installed and twist gently, does it move at all?

Thanks, bobxyz!

I'm using a couple different methods to test spark. First, I'm checking visually with the garage lights out to see the spark at the plug when they're removed, and it appears to be weak and intermittent. I've also hooked up the clamp on the timing light to wires, and it only detects a current through wires 1 and 3. I've also gone through three sets of new plugs, with no difference in the end result.

I had a MAF code, but when replaced and reset all I get on both terminals 2 and 6 is 111.

The distributor is an older one, but when I swapped in the LH 2.4 distributor from my 245 there was no change.

The rotor in the picture was one of the three or four I've tried, including a new one, however, I'll go clean everything now to make sure. And yes, the rotor does barely move when you try to move it side to side.

Thanks for the reply I really appreciate it!
 
Are you using the original K-Jet mechanical+vacuum advance distributor? Maybe with the advance mechanism "fixed" in place? If so, there's a chance that the rotor alignment is off. An easy test is to loosen the disti hold-down bolt and rotate the disti to the end of the slot and see if it makes a difference. Try both ways and see if there's any change in idle.

Otherwise, look at the lengths and fit of all the parts carefully -- coil wire fully seated into cap, plug wires fully seated on both ends, rotor in notch, carbon center post spring ok (and enough length left to reach the rotor), cap dropped into groove all the way, etc.
 
Are you using the original K-Jet mechanical+vacuum advance distributor? Maybe with the advance mechanism "fixed" in place? If so, there's a chance that the rotor alignment is off. An easy test is to loosen the disti hold-down bolt and rotate the disti to the end of the slot and see if it makes a difference. Try both ways and see if there's any change in idle.

Otherwise, look at the lengths and fit of all the parts carefully -- coil wire fully seated into cap, plug wires fully seated on both ends, rotor in notch, carbon center post spring ok (and enough length left to reach the rotor), cap dropped into groove all the way, etc.

There's no different with the distributor moved, and its all been swapped out, so that makes sense. I cleaned everything and checked all the wires and nothing changed. After all the cleaning and wire confirmations, I was greeted with the same good immediate startup, and then back to weird backfiring, and hesitation and bogging on throttle. I decided to let the car sit for a while with its strange issues, and things started to smooth out. Not only did the motor sound perfect and smooth, the exhaust no longer sounded like an FD RX-7 racecar. I thought maybe everything was perfect, but still, when more throttle is applied there is hesitation and backfiring. Could this be a fuel pump thing? The car is full of fresh premium so I know the gas is good, but hey PROGRESS.
 
Are you using the original K-Jet mechanical+vacuum advance distributor? Maybe with the advance mechanism "fixed" in place? If so, there's a chance that the rotor alignment is off. An easy test is to loosen the disti hold-down bolt and rotate the disti to the end of the slot and see if it makes a difference. Try both ways and see if there's any change in idle.

Otherwise, look at the lengths and fit of all the parts carefully -- coil wire fully seated into cap, plug wires fully seated on both ends, rotor in notch, carbon center post spring ok (and enough length left to reach the rotor), cap dropped into groove all the way, etc.

There's no different with the distributor moved, and its all been swapped out, so that makes sense. I cleaned everything and checked all the wires and nothing changed. After all the cleaning and wire confirmations, I was greeted with the same good immediate startup, and then back to weird backfiring, and hesitation and bogging on throttle. I decided to let the car sit for a while with its strange issues, and things started to smooth out. Not only did the motor sound perfect and smooth, the exhaust no longer sounded like an FD RX-7 racecar. I thought maybe everything was perfect, but still, when more throttle is applied there is hesitation and backfires. Could this be a fuel pump thing? The car is full of fresh premium so I know the gas is good, but hey PROGRESS.
 
Glad it's doing better. Next time you're at the salvage yard, find a spare set of plug wires, cap, rotor to throw in the trunk for luck -- the plug wires should measure around 1500 to 3000 ohms, or they're toast already.

When you converted to LH2.4, what _engine_ parts did you swap or alter? Where did the parts come from? Known good or salvage yard specials?
 
No need the remove the crank pulley to inspect. Just look from above as I mentioned. Upper cover off.

Yeah, that's true...one of my friend's 2.4 240's could not be timed(flywheel mounted incorrect by clutch shop), and his guru buddy got grumpy and pulled the crank pulley even tho I could see down in there. In any case, it shouldn't take more than a minute or two to loosen the crank bolt, once there's room to get in there
 
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