chasing down a misfire.

[FoeSho]

Ok, here is my plan of attack for this weekend on my 93 SHO 5 MTX:

1) Install Felpro Valve cover set ( with grommets )

2) Install new upper to lower intake gaskets.

3) replace any cracked Vacuum lines ( just in case the old stuff is brittle )

4) Install (6) autolite 3924 Plugs gapped at .045

5) Install my Magnacore Spark Plug Wires

Anything else that I should pick up? and or do?

 

[Ishodu]

You should check valve lash while your in there.

 

[FoeSho]

ah ther ya go.. I knew I was missing something. Whats the best procedure for doing that?

 

[Black '93]

go visit phoenixshoproject.com and look under the upper 60k service in the maintenance section

 

[sdpatt]

Got CHECK ENGINE light? If not, the cause of the misfire is going to be the plugs or the plug wires 99.9% of the time.

 

[FoeSho]

I have a light but my scantool says its two codes stored, both for O2 sensors.

 

[SHOtimer]

Then, why not replace the o2's? I just did mine - huge difference in power and smoothness. Make sure you get the Bosch. I'd suggest Motorcraft plugs and wires though.....

Doug

 

[FoeSho]

I have seen write ups and such on Motorcraft vs AC delco VS performance aftermarket wires, the Mototcraft had the highest resistance ( BAD) and over 60% of the motorcraft wires had arc thru right out of the box. No thanks, motorcraft wires are junk. Magnacore on the otherhand is a 9mm wire that has a lifetime guarantee.

I want to replace the O2's when I replace the Y pipe. The Y pipe on ther doesn't leak or anything, but its been "modified" and looks jerry rigged at best.

 

[FoeSho]

alright I took the DIS off and found that the DIS connector closest to the firewall has a huge crack in it and someoen tried to repair it with silicone. Could this cause my intermitant misfire?

 

[projectSHO89]

motorcraft wires are junk.

You can't be serious.... I've installed many sets of these that are still running. Never had a failure out of the box.

alright I took the DIS off and found that the DIS connector closest to the firewall has a huge crack in it and someoen tried to repair it with silicone. Could this cause my intermitant misfire?

Yes. If it's broken, check for a failed subframe mount that allows the engine corner to drop and the DIS module to contact the roll restrictor strut. Perhaps it was a previous owner who did have this failure and you're stuck with the aftermath.

Steve

 

[FoeSho]

You can't be serious.... I've installed many sets of these that are still running. Never had a failure out of the box.



Yes. If it's broken, check for a failed subframe mount that allows the engine corner to drop and the DIS module to contact the roll restrictor strut. Perhaps it was a previous owner who did have this failure and you're stuck with the aftermath.

Steve

Yes Motorcraft Wires are junk, magazines tests have also confirmed this. You may have been one of the lucky ones. If you have installed many sets, this makes me wonder why unless you are refering to different cars? A good set of spark plug wires will outlast the SHO, and if Motorcraft wires are so good why do they need to be replaced in the first place?

I will check that roll resitrictor to DIS clearance and see whats going on. Thanks for the good info!

 

[projectSHO89]

magazines tests have also confirmed this.

I didn't just fall of a turnip truck when it comes to either SHOs or othe Fords.....

Magazines get paid to sell ads, which may include wire vendors.

The MC wires on these vehicles have been used by many other's besides myself and your assessment is one of a kind among those here who have done these things for years. You're welcome to your own opinion, but before you knock something, at least have a level of specific experience instead of relying on a magazine article or review.

Steve

 

[FoeSho]

I do have specific Experience as well. I owned an 89 SHO 3 years ago that had bad motorcraft wires. I replaced them with Motorcraft wires and they arced all over the place brand new out of the package. I bought a set of AC delco wires to replace them and all was well.

I also owned a drag mustang ( only ran 10.80's but it was mine! ) and went through the same crap. I built the motor from scratch and used brand new Ford Motorsport wires. Same problem, arcing. I replace them with MSD wires and all is well.

So you see I too did not fall off the turnip truck yesterday. In fact I have a rich racing history as well as rasing in a family of Mechanics. :type:

 

[revhardSHO]

The average life of stock motor craft wires (at least in my experience with 7-8 SHOs with original wires) seems to be 80K - 130K. Impressive, considering these wires are getting upwards of 15 years old. The quality and fitmet are far from "junk". Infact, they are one of the best wire sets available.

I have also had some experience with aftermarket wires, and it seems people have far more reliability / fitment problems with these than stock.

My personal preference is the $42.00 A/C Delco set that is made to OEM specs and even includes the plastic wrap, like from the factory. So far I have put 50,000 miles on a set and they are perfect. OEM fitment and design, no *** flashy colors or odd fitting caps. Funny how are are knocking motorcraft yet using a wire set designed after OEM specs.

 

[alorenz]

Got CHECK ENGINE light? If not, the cause of the misfire is going to be the plugs or the plug wires 99.9% of the time.

I'd like to second this. This advice about a year ago saved me plenty of time and frustration on both my SHOs. New plug wires and they both ran fine. I used the AC Delco wires due to them being over $100 cheaper than the Motorcraft ones.