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Old 07-08-2018, 09:42 PM   #1
sideways242
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Question LH 2.4 Spark Issue

Hola Volvo Brethren,

First I'll explain the car and the setup to limit confusion. I've got a 1984 Volvo 242 with a rebuilt b230ft and t5. The car was running on the stock k jet system, but I preferred the thought of a smoother idle, diagnostics and the other pros of LH 2.4 so I swapped in a fresh harness. long story short the car starts and runs on two cylinders with a weak spark. I have checked (on my LH 2.4 245) or replaced the following components: ECU, EZK, CPS, Powerstage, Distributor, Rotor, Cap, Wires, Plugs, and all ground connections. 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. I am so lost and anything would help at this point in time.

Thanks!!!
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Old 07-08-2018, 10:12 PM   #2
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Have you checked that the distributor drive shaft is oriented correctly? If you take the cap off, there's a groove on the edge of the distributor body. The tip of the rotor should be ~centered over the groove when at TDC. The actual spark timing for LH2.4 is controlled by the EZK and CPS, but the distributor rotor still needs to point at the correct cylinder post when the spark fires.

Edit: one other thought, are you using a LH2.4 coil, with the original K-Jet ballast resistor bypassed? If the ballast resistor is still supplying the coil, it would result in low coil voltage when running (but full voltage when cranking).

Last edited by bobxyz; 07-08-2018 at 10:22 PM..
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Old 07-08-2018, 10:17 PM   #3
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This link has some points for putting a b230 ft into a 240, opposite I know, but it might help:

http://people.physics.anu.edu.au/~am...sion_hints.htm

You have probably already read this thread:

http://forums.turbobricks.com/showthread.php?t=18472

I wish you good luck and I hope that it is a simple fix to get it running right!
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Old 07-08-2018, 11:51 PM   #4
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Thanks so much, Ill read up on these! Appreciate it!
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Old 07-08-2018, 11:53 PM   #5
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Quote:
Originally Posted by bobxyz View Post
Have you checked that the distributor drive shaft is oriented correctly? If you take the cap off, there's a groove on the edge of the distributor body. The tip of the rotor should be ~centered over the groove when at TDC. The actual spark timing for LH2.4 is controlled by the EZK and CPS, but the distributor rotor still needs to point at the correct cylinder post when the spark fires.

Edit: one other thought, are you using a LH2.4 coil, with the original K-Jet ballast resistor bypassed? If the ballast resistor is still supplying the coil, it would result in low coil voltage when running (but full voltage when cranking).
I have the distributor all lined up with the pesky notch at TDC which is what I thought it would be at first, but no luck I have the full LH 2.4 harness, but is there still a ballast resistor I need to bypass? I haven't ever seen one but Ill double check to be sure. Thanks!
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Old 07-09-2018, 12:00 AM   #6
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The easy test is to measure the voltage on the coil with key on, but not running. You should see very close to full battery voltage. If the ballast resistor is still in the circuit, voltage will be much lower at coil. The ballast resistor, at least on my 85 k-jet, was on the fender roughly under the wiper motor. It's a ~3" long 1/2" x 1/2" white ceramic thing, with spade connectors on each end.
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Old 07-09-2018, 12:09 AM   #7
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The easy test is to measure the voltage on the coil with key on, but not running. You should see very close to full battery voltage. If the ballast resistor is still in the circuit, voltage will be much lower at coil. The ballast resistor, at least on my 85 k-jet, was on the fender roughly under the wiper motor. It's a ~3" long 1/2" x 1/2" white ceramic thing, with spade connectors on each end.
Yeah, no ballast resistor. I just went out to check and I have 11.85v with the key on.
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Old 07-09-2018, 02:47 PM   #8
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Did you put the flywheel on correctly?
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Old 07-09-2018, 04:26 PM   #9
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Did you put the flywheel on correctly?
I sure believe I did! The gap should be at the bottom of the starter hole at TDC yes? thanks for the reply!
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Old 07-09-2018, 04:53 PM   #10
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Did you have the dist pulled out? Is it timed correctly?
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Old 07-09-2018, 05:01 PM   #11
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Did you have the dist pulled out? Is it timed correctly?
Its confirmed to be 100% on time, and I've tried 3 different distributors out of other LH 2.4 cars and they all do the same thing. I was just reading another post of yours where you mentioned adding a switched 12v to the blue wire going to the coil? If I already have spark coming from the coil should I still do this? whats the benefit? Thanks!
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Old 07-09-2018, 06:43 PM   #12
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You need power to the coil key on. That's what the wire does.

Do you have steady spark coming out of the coil itself? A test light between coil negative and ground works great too.
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Old 07-09-2018, 06:45 PM   #13
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You need power to the coil key on. That's what the wire does.

Do you have steady spark coming out of the coil itself? A test light between coil negative and ground works great too.
Yes, a full spark coming from the coil which is the weird thing!
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Old 07-09-2018, 07:02 PM   #14
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If you have consistent steady spark from the coil, that really only leaves the dist timing or cap/rotor.
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Old 07-09-2018, 07:19 PM   #15
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Any diag codes from the EZK after trying to run?

[And just to cover the bases, re-check your plug wires. 1-3-4-2 as the distributor rotor moves in a clockwise direction as viewed from above.]
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Old 07-09-2018, 07:29 PM   #16
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Quote:
Originally Posted by ZVOLV View Post
If you have consistent steady spark from the coil, that really only leaves the dist timing or cap/rotor.
I've got the distributor aligned with the notch on the side at TDC. Honestly, at this point, it seems like distributor timing, but from everything I know, I'm doing it correctly!!!
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Old 07-09-2018, 07:30 PM   #17
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Quote:
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Any diag codes from the EZK after trying to run?

[And just to cover the bases, re-check your plug wires. 1-3-4-2 as the distributor rotor moves in a clockwise direction as viewed from above.]
I'll check codes now because all the wires check out great! Thanks!
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Old 07-09-2018, 07:46 PM   #18
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Is that little black plastic alignment piece still there? Aligning the rotor with the housin is great, but that assumes you have dropped the dist in correctly on the correct tooth. If you drop it in on the incorrect tooth it doesn't help lining up the rotor with that notch.
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Old 07-09-2018, 07:49 PM   #19
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Is that little black plastic alignment piece still there? Aligning the rotor with the housin is great, but that assumes you have dropped the dist in correctly on the correct tooth. If you drop it in on the incorrect tooth it doesn't help lining up the rotor with that notch.
Realllly? I've never even seen that piece, but I assume it would slot in where the bolt goes into the block?
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Old 07-09-2018, 08:17 PM   #20
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Is that little black plastic alignment piece still there? Aligning the rotor with the housin is great, but that assumes you have dropped the dist in correctly on the correct tooth. If you drop it in on the incorrect tooth it doesn't help lining up the rotor with that notch.
And would that matter if I'm getting spot-on timing with a timing light?
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Old 07-09-2018, 10:08 PM   #21
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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)?
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Old 07-09-2018, 11:36 PM   #22
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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!!!
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Old 07-10-2018, 12:33 AM   #23
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Are you timing the crank with the crank pulley or the SPROCKET?
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Old 07-10-2018, 03:08 AM   #24
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Are you timing the crank with the crank pulley or the SPROCKET?
the crank pulley...should I be using the sprocket?
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Old 07-10-2018, 04:48 AM   #25
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If I recall you need to pull the crank pulley off to be 100% sure the sprocket is aligned correct.

* He may be alluding to a slipping/slipped harmonic balancer *
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