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engine chugging and missing


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Something is seriously wrong with my car. Since adding the blower, I've been fighting misfiring. Since recognizing it, I've been running LucasOil octane booster and Chevron premium exclusively. This has helped a lot. However, for the past several days, I've noticed that in 4th and 5th gear, regardless of RPM, the engine has started chugging violently and I can hear the exhaust popping out the back, even when at very slight throttle in those gears.

 

The car accelerates fine out of 1st and 2nd with all the power in the world and no missing. 3rd is kind of hit or miss. For the most part, the engine is fine there too, unless I'm going uphill, then I notice it starting to bog. Today, I went up a very large hill on HWY 50 for the first time and I honestly didn't think the car was going to make it. So at an incline, the problem is much, much worse.

 

Since adding the high flow fuel rails, I never got around to re-installing my fuel pressure gauge sending unit. So tonight, since I'm selling the new rails anyway, I decided to pull them back off and install my OEM rails along with the fuel pressure sender. I checked the injectors for any debris and found none. I checked all of my vacuum lines and they're fine. I do notice, however, that the fuel pressure gauge is jumping around more than I remember it doing in the past. At idle, I'm never above 30psi. At WOT, it's hitting 40psi. What I don't get is that the car seems totally normal out of the hole. As the speed increases and I jam through the gears, the problem presents itself and then gets dramatically worse.

 

Any suggestion?

 

Ken

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I forgot to mention that since the engine started having this trouble, I pulled 2* of timing off of my global spark parameter. Aside from that, I haven't touched the VMP tune at all. Justin at VMP has had zero advice on any of this thus far.

 

Ken

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Don't know what the problem could be Ken...but I experienced the same thing on my stock SGT yesterday when I cranked it up to head to a cruise in over in Midland...Hit the starter, it fired, but was chugging like a freight train, popping, almost backfiring...I hit the throttle, and it reved up to 3K and sat there for a few seconds then fell down to just under 1k...blipped the throttle a few more times, and she seemed normal...no problems on the trip to Midland or back home...It's done that a time or two in the past, we just had a cold front come through yesterday...maybe it doesn't like the cooler weather, I dont know...hope it doesn't keep happening, can't be good for the motor...

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Don't know what the problem could be Ken...but I experienced the same thing on my stock SGT yesterday when I cranked it up to head to a cruise in over in Midland...Hit the starter, it fired, but was chugging like a freight train, popping, almost backfiring...I hit the throttle, and it reved up to 3K and sat there for a few seconds then fell down to just under 1k...blipped the throttle a few more times, and she seemed normal...no problems on the trip to Midland or back home...It's done that a time or two in the past, we just had a cold front come through yesterday...maybe it doesn't like the cooler weather, I dont know...hope it doesn't keep happening, can't be good for the motor...

That doesn't sound good either. However, my issue is non-stop, regardless of temp or other conditions. I hope that was a fluke for your sake!

 

The more I ponder this deal, the more it seems like the GT500 fuel pumps I installed. If one of those pumps has failed for whatever reason and the other is still limping along, most of this would make sense. However, that still doesn't explain why the car is operating normally through the lower gears. :headscratch:

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I forgot to mention that since the engine started having this trouble, I pulled 2* of timing off of my global spark parameter. Aside from that, I haven't touched the VMP tune at all. Justin at VMP has had zero advice on any of this thus far.

 

Ken

I think you may have a coil or two that went tits up. Could be as simple as plugs.

Edited by LuckySnake
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Does California switch to Oxygenated Gas or an Ethanol mix in the winter months? Around here, I believe on October or November 1st, they switch to some blend and I've noticed my car sometimes runs like crap.

That's a very good question. But around here anyway, any station running the blend has to advertise it at the pump. So I steer clear of those guys at all costs.

 

I think you may have a coil or two that went tits up. Could be as simple as plugs.

I'm pulling the plugs now. I'll check back with a report on their condition. Thanks for the input.

 

Ken

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The driver's side coils are all wet with oil. The 2 holes closest to the front of the car on the driver's side have the most. The passenger side has none.

I'm digging for my air compressor nozzle so I can blow the crap out of them, before pulling the plugs.

 

This brings me to another question. WTH would cause this? Paxton requires the install of a cheesy PCV valve onto the pre-existing vent tube. Would a faulty PCV valve have anything to do with the oil that's collecting here? I've never had a drop of oil in the past. What is the negative effect of removing the PCV valve that Paxton included with my blower kit?

 

Ken

Edited by kahmann
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Is the Paxton PCV in addition to the one already installed or does it replace the stock one?

I can't imagine needing two.

The Paxton one is to be installed where the original PCV vent tube was installed, from the top of the driver's cam cover into the side of the intake manifold.

However, after pulling the Moroso air/oil separator can I had installed, I noticed that the hose going into the bottom of the can was kinked extremely tightly.

I imagine that this was restricting most if not all of the crankcase pressure. I'm pulling the can for good, till I can figure out a better way to mount it.

For now, though, I have a whole ton of crappy oil mess all over these FRPP zero degree plugs. I'll swap the original OEM plugs back in and hope the coils werent' damaged.

 

Ken

 

p.s. These plugs are only 3 months old.

 

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Edited by kahmann
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Ken,

Have you tried running a tank of gas without the octane booster? Seems like everybody who's had mis-firing problems has at one time has used octane booster and the plugs are usually orange or rust colored.

 

Just a shot, maybe back the tune off to run 91 octane.

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Ken,

You guys are way more knowledgeable than I, but wondering about a couple of items:

- how is the oil getting into the coils, then fouling the plugs?

If the collection can kinked hose or a faulty Paxton PVC valve caused excessive crankcase pressure, then might there be damage to seals in the cam covers at each problem coil?

- seams odd that with several plugs fouled that your engine would run Ok in lower gears

Wonder if there is also an issue with inadequate fuel delivery at higher demand, like you mentioned earlier, where the computer may be sensing a lean condition and then significantly retarding the timing which would result in loss of power and poor running

 

Hate to ask, but have you checked the compression on the cylinders with the known bad plugs?

 

Hope that there is a reasonable soultion and please keep us posted

Larry

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Ken,

Have you tried running a tank of gas without the octane booster? Seems like everybody who's had mis-firing problems has at one time has used octane booster and the plugs are usually orange or rust colored.

 

Just a shot, maybe back the tune off to run 91 octane.

Hey Dave, you make a solid point. I'm done with the stuff personally. After seeing what 3 months of using this crap does to the plugs, I'll just leave the timing pulled and stick with 91.

 

Ken,

You guys are way more knowledgeable than I, but wondering about a couple of items:

- how is the oil getting into the coils, then fouling the plugs?

If the collection can kinked hose or a faulty Paxton PVC valve caused excessive crankcase pressure, then might there be damage to seals in the cam covers at each problem coil?

- seams odd that with several plugs fouled that your engine would run Ok in lower gears

Wonder if there is also an issue with inadequate fuel delivery at higher demand, like you mentioned earlier, where the computer may be sensing a lean condition and then significantly retarding the timing which would result in loss of power and poor running

 

Hate to ask, but have you checked the compression on the cylinders with the known bad plugs?

 

Hope that there is a reasonable soultion and please keep us posted

Larry

Hey Larry you make some good points. As for the oil getting to the coils, what I'm assuming is that because of the unreasonably high crankcase pressure, the oil is pushing through the threads, up into the bottom of the coils. The middle and tops of the coils are dry. The seats of the coils are damp with oil. Again, this is just an assumption. As for a compression check, this is the first day I've gotten my hands dirty, so I'm not there yet. Before this, I've been hoping it was something simple - tune, octane, etc, but I'm not so lucky. I hope I don't have to pursue this much further than where I'm at now, but we'll see.

I just finished dinner, so I'm getting back to the plug install now. I've got another bank to tighten down, then I'll fire her up for a spin around the block.

 

Ken

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OH NO!!! This doesn't sound good. Try replacing your fuel filter. I had a bad one on an old car and it had the same reactions you're having. +1 on getting the compression checked. Keep us posted.

I replaced my original filter just a couple months ago, otherwise I'd do it now for sure. Thanks for the input.

I'm headed out on the freeway to put the screws to this thing right now. Wish me luck...

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After running it up the freeway and back, I'm happy to say it's back to normal.

No misfiring, no chugging, no hesitation. I was surprised by how much power there was actually. I guess I didn't realize how badly it was neutered over the past month or so. The lack of power kind of crept up on me, enough so that I had it sideways down the freeway on-ramp just now.

 

Anyway, I ran it without the PCV valve. Instead, I plugged the original vent tube back in. I'll get an email into Paxton to find out how necessary that thing is. Either way, I need to get some spark plugs and probably a set of coils on order, just to be safe.

Thanks again for everyone's input. :shift:

 

Ken

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All I've heard is horror stories from people who have added octane booster...I'm never putting that stuff in my car...

Yeah, the octane booster is most definitely responsible for the heavy build up of rust colored gunk all over my brand new plugs.

That's the reason I won't be using it anymore. I need to find an excuse to expense 55 gallon drums of 100 octane at work! :lol:

 

Ken

 

p.s. You've got the finest looking model/color/wheel combo Mustang I've ever seen, by the way. ;)

Edited by kahmann
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This was way over my pay grade and automotive knowledge but an educational read. I am glad you got it back to normal, Ken and hope yours is ok too, motorjock. I did blow a valve on the front right valve cover right after I started driving the car after being overseas for almost a year and I think wrapping it up to redline very quickly blew the rubber gasket on that sensor on the valve cover - went kapuey - only reason I noticed is I was misting oil in the engine bay. My local Ford dealer fixed it all under warranty though. Scary stuff when your baby isn't running right.

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I just caught up w this thread...glad you seem to have it resolved Ken! I've rarely seen plugs that looked that bad. I was also going to mention also that I've read several threads which say stay away from the octane boosters and other additives on these cars - I don't go near that stuff.

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WOW, just catching this. What a scary read. Glad you were able to resolved the issue. I would have gone ape shit over this. Especially since I would not know what to do or even where to start. Lets see what Paxton responds with.

 

Frank

Edited by WildAzCat
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Cool Ken, That first plug in the pic did appear to be missing porcelin? Glad you got it ....Wrenches forever! my friend.

Yeah I dunno I'll have to take a closer look at it tonight. Either way, I'm not too happy about any of this!

I'm lucky to have gotten it resolved this time. I need to remember to make much more frequent and thorough inspections of this thing between services!

 

Ken

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