Back firing, missing, spluttering V8

TX3VIL · 11-07-2009, 05:02 PM

I've recently done some modifications to my engine, G&D CAI and Difillipo headers and have since noticed that the car's behaving pretty badly. I think it's mostly when it's cold. It seems to missfire a bit and today i went to put the boot in and there was a huge backfire. Sometimes when i'm cruising and give it some it sounds nice and smooth right through the revs, pull up at the next set of lights and go to give it again and it farts and carrys on a bit right through the same revs. It jerks and lunges forward and i cant seem to get a smooth launch from it.

I'm thinking my problem might be in the electrical circuit somewhere. How do i check to see what's causing it?

crakrz · 11-07-2009, 05:27 PM

Possibly a cracked plug when the headers were being fitted?

CFOUR · 11-07-2009, 05:37 PM

Burnt lead, bad/no tune or bad fuel.

FC:LTD · 11-07-2009, 11:13 PM

Mine was doing a similar thing after having extractors fitted . In my case it was number 4 lead heat protector arcing onto the head . Wait until its dark start the car and have a look to see if any leads are arcing .

FC:LTD · 12-07-2009, 10:52 PM

Any luk?

TX3VIL · 13-07-2009, 12:54 PM

Lots of luck i think. I didn't get time over the weekend to have a look, but i popped the bonnet first thing this morning and you were right about the lead. Cylinder 4 on the drivers side was arcing against the header.

What have u done to fix the problem. I'm going to get some new leads today and maybe new plugs while i'm at it, since it's got high K's and haven't been changed since i bought it. Are there any insulation shields i can use, some guy at work seems to think that's all i'd need to do.

Thanks for your diagnostics, much appreciated.

RG · 13-07-2009, 01:00 PM

How many k's?

Are they the original coil packs too?

lofty · 13-07-2009, 01:44 PM

This might help: http://www.fordforums.com.au/showpos...2&postcount=16 The last part, about the grease.

TX3VIL · 13-07-2009, 02:38 PM

The coilpacks say motorcraft something on them but i assume they're the originals as the car was more or less completely standard when i got it. There's about 290xxx k's on the clock as it stands.

RG · 13-07-2009, 02:47 PM

Quote:

Originally Posted by TX3VIL

The coilpacks say motorcraft something on them but i assume they're the originals as the car was more or less completely standard when i got it. There's about 290xxx k's on the clock as it stands.

Considering the standard mortorcraft coil packs generally last only 80-100k I dare say that they need replacing. Don't go with the originals from Ford as you'll pay through the nose for them. MSD make a direct replacement (part # MSD8241) that can be had for $140ea.

TX3VIL · 13-07-2009, 07:35 PM

I was trying to chase up some MSD leads, as most people here have recommended them in other posts but couldn't find anyone that was selling them. Trust me i looked. Rocket Industries said that they dont stock them anymore. I've managed to get onto a guy that ordered me a set of premium Eagle leads that are as good as the MSD leads so pretty happy with that. They come with insulated sleeves and nifty little 4 3 and 2 hole clamps that will bolt to the head/rocker cover somewhere. cant wait til he gets them in, car's still running like a bucket of .

Once all that's done i'll look into changing the coils, if it's still playing up, but i honestly dont think the coils are the problem, in fact i can almost guarantee it. one of my leads has a hole melted through it from my extractors and that's not even the lead that's arcing on the header. Long story short, if u get headers installed and they do a good job, dont take it for granted that they haven't stuffed anything else up.

RG · 13-07-2009, 09:10 PM

Quote:

Originally Posted by TX3VIL

I was trying to chase up some MSD leads, as most people here have recommended them in other posts but couldn't find anyone that was selling them. Trust me i looked. Rocket Industries said that they dont stock them anymore. I've managed to get onto a guy that ordered me a set of premium Eagle leads that are as good as the MSD leads so pretty happy with that. They come with insulated sleeves and nifty little 4 3 and 2 hole clamps that will bolt to the head/rocker cover somewhere. cant wait til he gets them in, car's still running like a bucket of .

Once all that's done i'll look into changing the coils, if it's still playing up, but i honestly dont think the coils are the problem, in fact i can almost guarantee it. one of my leads has a hole melted through it from my extractors and that's not even the lead that's arcing on the header. Long story short, if u get headers installed and they do a good job, dont take it for granted that they haven't stuffed anything else up.

Have you paid for the Eagle leads yet? If not cancel the order.

TX3VIL · 13-07-2009, 11:49 PM

Already paid for, what's wrong with them? I can't really go back on it now. From what i've heard eagle make as good a lead as MSD. I would have got the MSD's tho if i could have found them just for the record. My bad, i guess i'll let u know if they're any good or not.

These are what i'm getting just for reference... http://www.eagleproducts.com.au/prod...eliminator.php

Give me your honest opinion of them, good or bad, either way it's a step up from what i have now.

AuV8Fairlane · 14-07-2009, 05:21 AM

Hey guys, just thought i'd add i too had the same problem when chasing the MSD ignition leads. Rocket Industries didn't have any to suit the AU v8 so I ended up getting the MSD Super Conductor wire set Part No. 31199. These have the pre made lengths (8.5mm) with spark plug boots but doesn't have the clip type coil pack boot ends. I ended up getting the etco connectors and rubber boots through a mechanic friend of mine and i cut and crimped the leads to exactly the right lengths. Worked perfectly the pack comes with the crimp tool as well.

RG · 14-07-2009, 06:45 AM

Quote:

Originally Posted by TX3VIL

Already paid for, what's wrong with them? I can't really go back on it now. From what i've heard eagle make as good a lead as MSD. I would have got the MSD's tho if i could have found them just for the record. My bad, i guess i'll let u know if they're any good or not.

These are what i'm getting just for reference... http://www.eagleproducts.com.au/prod...eliminator.php

Give me your honest opinion of them, good or bad, either way it's a step up from what i have now.

I got the same spiel as you about the eagle leads and how good they are. Got them home opened the box and they sure looked the part. They were only on there 20k before they deteriorated and they were never much chop even when new. Sorry to be the one to say it but IMO for the money you pay the eagle leads are a bit crap. This was on my 347 though so a stockish 302 they may be ok with.

The only place that I know of the get MSD leads for the AU V8 is from Dave (forum member BOTTLEDUP) at A1. He can make you up a set and send them out for a good price.

TX3VIL · 14-07-2009, 05:08 PM

Thanks for the advice RG, i'll keep it in mind. Hopefully i dont run into the same problems. I'm moving to perth in a month or so, so if i do run into any drama's with them later in the piece i'll probably drop in and see him for a chat. I might have msg'd him about them if i had read his post a bit earlier

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Trace 347c · 24-07-2009, 11:17 PM

Hi guys, i have a similar problem. I have an au2 xr8, stroked to 347c, chiptorque did the comp. Car was running great for 2 years then started missing. Have replaced plugs, leads and coils and problem still remains. Car seems to be running rich and rough, and stalling as soon as i put it in drive. Any ideas ?