P0175 plus Light pulsing vibration (also tickin)

ForeverDriven

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So I just bought a 1997 Mustang GT (After my 98 v6 got wrecked) and I've been going through minor problems here and there, which are mostly just rattles. However, on a drive home two or three days ago the check engine light came on and right around that same time, I noticed a small pulsing vibration when cruising in 5th. Scanned it, and it threw two P0175 codes.

I'm goin through the basic stuff like checking spark, switching the coil packs around (a friend suggested this, probably gonna look up that this is ok before I do it lol), crap like that. The car does have a tick in the engine so I'm really hoping a small piece of a valve didn't break off, but if I can't find the problem soon I think I'll have to take the valve cover off and look around there.

Any thoughts? Also, anybody know where you can get fuel injectors tested, like on one of those demo fuel rails? I've heard of leaky injectors.

Thanks,
Blake
 

ttocs

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the tick you describe, does it go directly with the rpms? Spark plug wires can make a mix of a tick/pop if they are shorting out. Try starting up at night and looking to see if you can see any arching, or just grab the wires and either it will go away or you will get shocked but electrons are really small!
 

white95

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Why not pull a plug and inspect it? Could be well worn and just too weak. That would cause a slight misfire and it could run rich. The tick could be a chain tensioner going out. How many miles on this 2V?
 
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ForeverDriven

ForeverDriven

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Why not pull a plug and inspect it? Could be well worn and just too weak. That would cause a slight misfire and it could run rich. The tick could be a chain tensioner going out. How many miles on this 2V?

Lil over 166K for miles on the girl, and I've heard of the tensioners goin out. Can I just go back in and tighten it back down or does it need to be completely replaced? How hard would that be?
 

white95

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Lil over 166K for miles on the girl, and I've heard of the tensioners goin out. Can I just go back in and tighten it back down or does it need to be completely replaced? How hard would that be?

You have to remove the accessories, the cam covers, the timing cover and the engine fan + coolant tank (just for extra room) to expose the timing system. If you commit to going this far, you should buy the timing kit and replace it all. It’s more of a pain in the ass than difficult. We can walk you through it if you run into issues.

upload_2019-12-23_22-35-38.jpeg
 
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ForeverDriven

ForeverDriven

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You have to remove the accessories, the cam covers, the timing cover and the engine fan + coolant tank (just for extra room) to expose the timing system. If you commit to going this far, you should buy the timing kit and replace it all. It’s more of a pain in the ass than difficult. We can walk you through it if you run into issues.

View attachment 2832

Ohhhhh that looks fun . I'll go through the easier possible solutions first, checking the injectors and such. I want to fix the misfire before I go into fixing the tick, but if I end up needing to remove the valve cover, I'll give the timing chain a tug. How tight should it be, relatively speaking?
 

white95

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You shouldn’t be able to move the chain at all as it goes around the cam gear. With everything apart you could push the chain inwards slightly but nothing loose, say, like a bicycle chain. If the tensioners are doing their jobs it shouldn’t be loose at all.

@lwarrior1016 - Sound about right?
 

96blak54

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Chasing a mis-spark on a modular with plug wires is nerve wracking!

Moisture in the plug holes, wires plug end boots to long, push the connection to the plug off, the wire itself to the coil packs, the coil packs are known to track spark from tower to tower, a crack in the coil pack not seen or only separates when it gets engine heat warm.

Also a leaky injector will produce that same feel. You could be chasing that problem down too with poor results. Best just to swap in another set.

Just as ttocs stated, you could go feeling around on the plug wires to find the short. Thats how i knew the #3 plug wire on my car was bad...iirc. Its been so long, i cant remember....it could have been the coil pack too. But either one, simply remove on wire at a time at either end. If their is a short, your body will feel it
 
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ForeverDriven

ForeverDriven

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Chasing a mis-spark on a modular with plug wires is nerve wracking!

Moisture in the plug holes, wires plug end boots to long, push the connection to the plug off, the wire itself to the coil packs, the coil packs are known to track spark from tower to tower, a crack in the coil pack not seen or only separates when it gets engine heat warm.

Also a leaky injector will produce that same feel. You could be chasing that problem down too with poor results. Best just to swap in another set.

Just as ttocs stated, you could go feeling around on the plug wires to find the short. Thats how i knew the #3 plug wire on my car was bad...iirc. Its been so long, i cant remember....it could have been the coil pack too. But either one, simply remove on wire at a time at either end. If their is a short, your body will feel it


I went and started checking the spark plugs, but holy crap are spark plugs on a modular engine hard to get out on the passenger side! I ended up only looking at the first two plugs, which both looked fine. The connection on one of them was a little dirty and I wiped it off, so I may have to go back and check the others but I feel like I'll have to take the throttle body off cause it's so tight. I should have also mentioned that it has fairly good looking Ford racing spark wires so I believe the wires should be OK along with the spark plugs, can't say anything about the coil pack though.

I noticed my PCV valve was almost out of it's hole, so I put it back in and put everything else back together. I also had to disconnect the battery cause of a separate ground wire I was able to just pull off so the engine light got reset, but the vibration was still there when it took it out after, and it would randomly vibrate hard at idle and the RPMs randomly dipped twice at stoplights.

So with the feeling-around method for shorts, do I have the engine running when I do that or? Also, do you think a compression test using the schrader valve would find a leaky injector?
 

07GtS197

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You could hook up a fuel pressure tester to the fuel rail and cycle the key. If it holds everything is ok, if it drops and keeps dropping it could be a leaky injector, fuel pump check valve or a leak somewhere else in the fuel system.


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