Ok, I'm serious about this one

"DC3 LS, will be perpetually replacing cars until the end of time" (dc3ls-) 11/01/2017 at 13:51 • Filed to: None

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So it’s an 89 Galant that’s misfiring. My question is, is the fuel system on these hard to diagnosis? I’ve heard a lot of these early fuel injection systems were a pain in the ass, but I don’t have much experience with pre 90's FI.

The owner thinks it’s a HG, but I don’t really know how that’d cause a misfire. I’d think it would be an ignition or fuel issue. Or even a bad exhaust/vacuum leak.

Link

crowmolly > DC3 LS, will be perpetually replacing cars until the end of time 11/01/2017 at 13:57

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Before doing a single thing with the EFI system I’d start with the triforce of neglect :

Spark plugs

Fuel filter

Air filter

My money is on the plugs being off/dirty.

Edit: CL says “has new cap/rotor and plugs”. Start there IMO. Somebody may have done something as simple as not checking plug gap.

CalzoneGolem > DC3 LS, will be perpetually replacing cars until the end of time 11/01/2017 at 13:57

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Too much coolant in the cylinder causes the gas to not ignite / ignite poorly.

DC3 LS, will be perpetually replacing cars until the end of time > CalzoneGolem 11/01/2017 at 13:59

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He did say it’s not loosing coolant. Plus I’d imagine just watching the exhaust when it does it would confirm or deny that.

CalzoneGolem > DC3 LS, will be perpetually replacing cars until the end of time 11/01/2017 at 14:01

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Yeah I mean that’s just an explanation of how a bad HG could cause a misfire.

I hoon, therefore I am > DC3 LS, will be perpetually replacing cars until the end of time 11/01/2017 at 14:11

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Man, that thing is clean. Here’s what I would do:

Compression test, and preferably a leakdown test

Fuel pressure test at idle and under load (you can rent a gauge and run it outside the hood).

Inspect plug wires. It says new cap/rotor and plugs, but I’d ask for receipts.

Visually inspect vacuum lines for cracks.

AMGtech - now with more recalls! > DC3 LS, will be perpetually replacing cars until the end of time 11/01/2017 at 15:18

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Could also cause low compression, low enough to misfire. It also doesn’t take much coolant to extinguish a spark, not necessarily enough to notice coolant loss.

DC3 LS, will be perpetually replacing cars until the end of time > AMGtech - now with more recalls! 11/01/2017 at 15:31

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Yeah, If I wind up checking it out I’ll make sure to get a compression/leakdown test on it.

Die-Trying > DC3 LS, will be perpetually replacing cars until the end of time 11/01/2017 at 15:56

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NOOO, not always enough to watch the exhaust...... get a dye tester. those are worth their weight in something valuable. you can find a head gasket on its way out with it when nothing else gives any indication

also......... HOLD OUT FOR ANOTHER INTEGRA