Intermittent miss...

Boydster

5 Year Member

Apr 10, 2011

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Maryville, Tenn

Jan 10, 2012

#21

• Jan 10, 2012

• #21

No.11 said:

could it possibly be a weak fuel pump causing it? have you checked fuel pressure?

Click to expand...

Thanks, No 11. Fuel pump has been in there for quite a few years, but I have an adjustable regulator and it's set at 40 with vac removed and plugged. I would think a weak pump would make it run bad all the time and not be causing a hard miss.

Know how a V8 will run all-around rough when a cylinder is totally dead? It's not a miss like that... it's a hard miss like the timing is way off. Just sitting in the driveway and idling, you can hear / see / feel it skip a beat every once in a while (no rhyme, reason or fixed tempo to it) and if revved to about 2000 rpm, the engine is like Rrrrrrrrr Rrrrrrrrrrrrrrrr Rrrrrr Rrrrrrrrrrrr Rrrrrrrrrrrrr Rrrrrrrr Rrrrrrrrrrrrrrrrrrrrrrrrrrr Rrr Rrrr Rrrrrrrr Rrrrrrrrrrrrr.... wow, that made me feel stupid doing engine noises on a forum. Maybe I should do a video.

 

Noobz347

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#22

• Jan 10, 2012

• #22

Boydster said:

Maybe I should do a video.

Click to expand...

Ok, but the video should be of you mimicking the noise so that we don't miss what you're talking about.

 

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Boydster

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#23

• Jan 10, 2012

• #23

hahaha.... not gonna happen, man. I dont have enuf trophy points to get away with that.

 

Noobz347

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#24

• Jan 10, 2012

• #24

Boydster said:

hahaha.... not gonna happen, man. I dont have enuf trophy points to get away with that.

Click to expand...

... and this is the VERY reason why.

 

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Boydster

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Jan 12, 2012

#25

• Jan 12, 2012

• #25

Checked the shielding of the ignition wiring today. From the open end of it near the TFI / spout connector to battery neg... .5 ohm. No problem there...

Computer will be here tomorrow. I'm not real confident that this'll fix it, but I'm starting to hit a dead end...

 

Noobz347

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#26

• Jan 12, 2012

• #26

Worn gear on the dizzy. That been checked? How about a stretched (old) timing chain?

 

Boydster

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#27

• Jan 12, 2012

• #27

Noobz347 said:

Worn gear on the dizzy. That been checked? How about a stretched (old) timing chain?

Click to expand...

New MSD Pro Billet dizzy, new Ford timing chain during the rebuild. Gear on dizzy looked fine when I pulled it to change the PIP.

 

Noobz347

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#28

• Jan 12, 2012

• #28

Boydster said:

New MSD Pro Billet dizzy

Click to expand...

SCORE!!!!! You got the OEM dizzy??? Swap it in and see if that clears it up!

 

Boydster

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Jan 13, 2012

#29

• Jan 13, 2012

• #29

No, I don't have the OEM. Tore it apart to make a pre-oiler.

If the A9p doesn't do it today, I'll try a new dizzy next. Although since I already replaced all the electronics in it, I don't know what in the MSD could be causing this... misalignment between the cap and rotor? And why would it be intermittent?

Not questioning your help, Noobz, just wondering why. I'm an aircraft mechanic... it's in my nature.

At least I have another angle to attack...

 

Noobz347

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#30

• Jan 13, 2012

• #30

Boydster said:

No, I don't have the OEM. Tore it apart to make a pre-oiler.

If the A9p doesn't do it today, I'll try a new dizzy next. Although since I already replaced all the electronics in it, I don't know what in the MSD could be causing this... misalignment between the cap and rotor? And why would it be intermittent?

Not questioning your help, Noobz, just wondering why. I'm an aircraft mechanic... it's in my nature.

At least I have another angle to attack...

Click to expand...

I'm not sure why either and I wouldn't head out and dump money into the possibility either. After market distributors for Fox's seem to be problematic. The MSD (whether earned or not) seems to be the poster child. Personally, I've never owned one. I've always used the OEM dizzy but check here: http://www.stangnet.com/mustang-for...let-distributors-garbage.851499/#post-8564097

For troubleshooting purposes, I would see if I could get my hands on an OEM dizzy.

 

Dmarstroker

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Jan 13, 2012

#31

• Jan 13, 2012

• #31

i am having similar issues to mine as well. I have an accell dizzy though. Ive replaced almost everything you listed. Gets frustrating real quick.

 

Boydster

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#32

• Jan 13, 2012

• #32

Dmarstroker said:

i am having similar issues to mine as well. I have an accell dizzy though. Ive replaced almost everything you listed. Gets frustrating real quick.

Click to expand...

Yeah, it does get frustrating. Stay tuned as I either figure this thing out or start parting out my car...

 

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Noobz347

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#33

• Jan 13, 2012

• #33

Boydster said:

Yeah, it does get frustrating. Stay tuned as I either figure this thing out or start parting out my car...

Click to expand...

Watch you start parting out the car and find a steel wool hair or something in some electronic part as you box it for shipping.

 

Boydster

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Jan 13, 2012

#34

• Jan 13, 2012

• #34

Noobz347 said:

Watch you start parting out the car and find a steel wool hair or something in some electronic part as you box it for shipping.

Click to expand...

It would kill me to part her out... I've owned it since new.

 

Noobz347

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#35

• Jan 13, 2012

• #35

Boydster said:

It would kill me to part her out... I've owned it since new.

Click to expand...

Yeah... I'll chock that up into the, "Not an option" column.

3 months ago, I'd have been able to drop a dizzy into a box and send it to you.

Might be worth putting an APB out to see if anyone has one to loan/sell for troubleshooting.

 

Boydster

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#36

• Jan 13, 2012

• #36

Noobz347 said:

Yeah... I'll chock that up into the, "Not an option" column.

3 months ago, I'd have been able to drop a dizzy into a box and send it to you.

Might be worth putting an APB out to see if anyone has one to loan/sell for troubleshooting.

Click to expand...

Thanks for the thought. I considered the APB idea myself... watch me work!

 

Boydster

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Jan 16, 2012

#37

• Jan 16, 2012

• #37

Rebuilt A9P installed, no help. Seems to run better overall, but still has the miss. Started instantly. Got a $10 bid in on a used Ford dizzy, auction closes tonight.

Does anyone think the MAF meter could cause this? I wouldn't think so. I'm running a used C&L 73 that I got off CList, has the correct 24 tube for my injectors, no related codes... just wondering out loud.

While I had the A9P out, I checked the ground and it's clean and tight. Comp pins were all in place and clean.

 

Noobz347

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#38

• Jan 16, 2012

• #38

Could just disconnect the MAF and see if you still have the miss.

 

txstang84

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Jan 16, 2012

#39

• Jan 16, 2012

• #39

Boydster said:

Rebuilt A9P installed, no help. Seems to run better overall, but still has the miss. Started instantly. Got a $10 bid in on a used Ford dizzy, auction closes tonight.

Does anyone think the MAF meter could cause this? I wouldn't think so. I'm running a used C&L 73 that I got off CList, has the correct 24 tube for my injectors, no related codes... just wondering out loud.

While I had the A9P out, I checked the ground and it's clean and tight. Comp pins were all in place and clean.

Click to expand...

just thinking out loud myself here, I had a 73mm C&L and I never had a days fuss with it. But, I guess if there's a dirty contact in the connector, it could do that nonsense...momentary glitch? The wires all shoot good right? Did you win that $10 dizzy?

Oh, noticed your an aircraft mechanic, same here...we have problems with oily cannon plugs on accessory drive gearboxes all the time...causes no engine rotation faults during startup pretty frequent. Gotta love lowest bidder parts...

 

Boydster

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#40

• Jan 16, 2012

• #40

But with the MAF disconnected, it'll run like crap, right?

Tx, what do ya work on? I'm on 757-200 and 767-300ER freighters right now. Been with Big Brown about 23 years now.

Yeah, oily plugs, especially on these modern engines with 2-channel FADEC...

The $10 dizzy still has an hour and a half to go...