Very erratic skipping

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Very erratic skipping

Unread postby 88351stang » Sat Sep 21, 2019 1:37 pm

Not sure if I put this under the correct forum, but not sure if it is a hardware issue or something has happened to the tune.

My car has started a very erratic skipping issue. At idle and normal driving, everything seems fine...as long as I keep it under 3000 RPM. I can rev it up to 3K even sitting still and can start to pick up a random miss. Even putting a timing light on it, I can see the miss with it at around 3K.

A little above 4K, it is almost like it hits a rev limiter. Datalog shows it is commanding the right timing, but my STFT goes to +12.5 around the same time this happens. I am just at a loss.

TFI module and distributor have been checked by MSD and checks good. I have verified eec ground (external and internal). Fuel pressure checks good at idle, but I don't really have a way to check it running down the road, but I really think this is in the ignition system.

Any help or next checks to do would be greatly appreciated.
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T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby decipha » Sat Sep 21, 2019 1:47 pm

msd distributor would be my first guess. I would upgrade to a stock distributor and see if it goes away.
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Re: Very erratic skipping

Unread postby 88351stang » Sat Sep 21, 2019 2:54 pm

Ok, I'll try that.

Are msd distributors really that unreliable?
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Vehicle Information: 88 Mustang GT
A9P ECU
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351W
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X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby decipha » Sat Sep 21, 2019 4:17 pm

yes but more so they throw spark around so cylinder to cylinder is very inconsistent. Thats why stock distributors always make more power than aftermarket ones. More details in the pre tune info write up.
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91 4r70w - Skarlett
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94 5spd Rionda
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06 Chrysler 300 AWD - Sharifa

Re: Very erratic skipping

Unread postby 88351stang » Sat Sep 21, 2019 6:28 pm

Well, I'll be damn. Swapping the distributor back to a stock one worked.

Guess I should have read through all that.

Thanks decipha
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Vehicle Information: 88 Mustang GT
A9P ECU
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X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby decipha » Sat Sep 21, 2019 6:45 pm

yep no prob thats what the pre tune info is there for
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91 4r70w - Skarlett
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94 5spd Rionda
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07 GMC 2500HD 6L - Veranafer
06 Chrysler 300 AWD - Sharifa

Re: Very erratic skipping

Unread postby dleach1407 » Sun Sep 22, 2019 8:55 am

The only part I run on my car from MSD is their ignition box. You know what their name stands for right? "My Spark Disappeared" and truthfully that has been my experience. Their distributors and coils are garbage. I know a bunch of people who have had the same issues as you using an MSD distributor. After 2 different extremely low mileage MSD Blaster coils failed on me, I wont buy another MSD product.. In fact, when the ignition box fails, I plan on going with a different brand. I keep a spare ford TFI, ford coil, and rebuilt (using motorcraft sensors) ford distributor in my trunk for emergencies.
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T5 with an XTD clutch that somehow holds my power
80lb Dekas, Stock lines and rails 340LPH in tank
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76mm On3 turbo, HP hotside, Custom coldside
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27degrees total timing.
Vehicle 2 Information: 1957 Ford F100
Mustang II front suspension -done
C-notched rear frame - done
Luxury ECU using RZASA - have
Fuel injected explorer 302 - have
4r70W -have

Lots of stuff planned including air bags and twin 55mm turbos.

Re: Very erratic skipping

Unread postby 88351stang » Fri Sep 27, 2019 6:46 pm

That one definitely surprised me. I bought it through late model restoration. when I called them to return it, the tech guy I spoke with told me the same thing. I asked about the box and he said it shouldn't be an issue for what it's worth.

Thanks for the suggestion. I will definitely throw a spare of the coil in the car though just in case.
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Posts: 69
Joined: Tue Oct 22, 2013 11:59 am
Name: Danny Prichard
Vehicle Information: 88 Mustang GT
A9P ECU
BE/EA
351W
10:1 compression
X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby dleach1407 » Sat Sep 28, 2019 5:20 am

The first time someone told me MSD distributors for SBFs are junk, I kind of blew it off but after working on so many turbo Mustangs it became obvious We found a lot of cars that would start having ignition issues around 4k. The thing that makes me laugh is 99% of the time, MSD will test and return their distributors saying there is nothing wrong but as you already proved, there is clearly something wrong with the MSD unit. Thats the worst part, you just cant trust them, obviously they dont have a way to accurately test them or they just dont test them period. I have heard good things about those hot forged distributors but have no real world experience.
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Posts: 223
Joined: Fri Sep 07, 2018 10:13 pm
Vehicle Information: 1995 Mustang T5 CBAZA/T4M2 Moates QH BE or TpRT
331 10.2:1 compression, TFS 11r 190 56cc heads
HPX MAF 3.25 OD tube with SaxonPC air straightener
F303 Cam, 1.6 Miller Mid-Lift rockers
T5 with an XTD clutch that somehow holds my power
80lb Dekas, Stock lines and rails 340LPH in tank
Minor upgraded T5 with counter gear stiffening plate
76mm On3 turbo, HP hotside, Custom coldside
560WHP and 606TQ 8lbs tapering to 6 91 octane
27degrees total timing.
Vehicle 2 Information: 1957 Ford F100
Mustang II front suspension -done
C-notched rear frame - done
Luxury ECU using RZASA - have
Fuel injected explorer 302 - have
4r70W -have

Lots of stuff planned including air bags and twin 55mm turbos.

Re: Very erratic skipping

Unread postby 88351stang » Mon Oct 07, 2019 11:39 am

I think I am just going to stick with stock and run the msd box. Looking back at it, I kinda wished I would have just left well enough alone, but I hope the 6al box is ok from here on out.

And yes, I dont think they check them. I had traced every wire on my car including the eec trying to figure out what the hell was going on after they said the distributor was good.
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Posts: 69
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Vehicle Information: 88 Mustang GT
A9P ECU
BE/EA
351W
10:1 compression
X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby indy2000 » Tue Dec 31, 2019 8:16 am

dleach1407 wrote:The first time someone told me MSD distributors for SBFs are junk, I kind of blew it off but after working on so many turbo Mustangs it became obvious We found a lot of cars that would start having ignition issues around 4k. The thing that makes me laugh is 99% of the time, MSD will test and return their distributors saying there is nothing wrong but as you already proved, there is clearly something wrong with the MSD unit. Thats the worst part, you just cant trust them, obviously they dont have a way to accurately test them or they just dont test them period. I have heard good things about those hot forged distributors but have no real world experience.




MSD doesn't test their ignition systems with a ford commanded ignition system

that is why there is nothing wrong with them, until you put it on your ford system
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Re: Very erratic skipping

Unread postby lugbolt » Sun Jan 05, 2020 10:25 pm

All this talk about MSD and junk. My drag (bracket) car is mechanical injected (methanol) and using a MSD distributor and old school 6AL box. It runs fine, never had any noticeable ignition issues for the 20 something years it's been in use. Makes me wonder if there's anything "better" with such a simple non-ecu setup (and I like simple).
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Re: Very erratic skipping

Unread postby decipha » Thu Jan 09, 2020 10:32 am

the older msd stuff is fine and usually no one has a problem with it

the problem lies in the efi setups since MSD never made an efi distributor they just modified their existing non efi one which is wrong
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90 (4x 5spds) - Dante, Ruby, Daja, Ava
91 4r70w - Skarlett
92 (2x) 5spd & auto - Bianqa, Andrea
93 auto - Danika
94 5spd Rionda
95 auto Aisha
Vehicle 2 Information: Others:
00 Lincoln LS - Luanda
98 Camaro SS - Bounquisha
02 Harley F-150 - Sasasha
03 Marauder - DyShyKy
00 Explorer 5L - Bernyce
07 GMC 2500HD 6L - Veranafer
06 Chrysler 300 AWD - Sharifa

Re: Very erratic skipping

Unread postby 88351stang » Tue May 05, 2020 3:37 pm

Hey guys...bringing this back up since I have gotten rid of the MSD distributor. Great runs good now for the most part, but I am fighting what seems to be a TFI module issue. It just reminds me of how one starts acting when I have had them go bad in the past. Every so often I get a noticeable skip going down the road....at times it's worse than others and when its really acting up, the idle will hunt when I come to a stop. Get in it the next day and nothing misses a beat. I tried a new motorcraft module and the car wouldn't even start. I am at a loss with what to check, what to replace. Been trying to drive my car more lately as I rarely drive it, but this is getting very annoying.
88351stang
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Posts: 69
Joined: Tue Oct 22, 2013 11:59 am
Name: Danny Prichard
Vehicle Information: 88 Mustang GT
A9P ECU
BE/EA
351W
10:1 compression
X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby decipha » Wed May 06, 2020 1:02 am

make sue you are running the correct color module. If it wouldnt start you have problems.
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Vehicle Information: Supercoupin' x10
90 (4x 5spds) - Dante, Ruby, Daja, Ava
91 4r70w - Skarlett
92 (2x) 5spd & auto - Bianqa, Andrea
93 auto - Danika
94 5spd Rionda
95 auto Aisha
Vehicle 2 Information: Others:
00 Lincoln LS - Luanda
98 Camaro SS - Bounquisha
02 Harley F-150 - Sasasha
03 Marauder - DyShyKy
00 Explorer 5L - Bernyce
07 GMC 2500HD 6L - Veranafer
06 Chrysler 300 AWD - Sharifa

Re: Very erratic skipping

Unread postby 88351stang » Wed May 06, 2020 4:41 pm

Got the gray one....not black.

The thing is it started when I put the old one back on
88351stang
General Poster
 
Posts: 69
Joined: Tue Oct 22, 2013 11:59 am
Name: Danny Prichard
Vehicle Information: 88 Mustang GT
A9P ECU
BE/EA
351W
10:1 compression
X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster

Re: Very erratic skipping

Unread postby 88351stang » Tue Jun 30, 2020 3:24 pm

Just wanted to update this. Turned out to be the pick up inside the distributor. Replaced and no issues since.
88351stang
General Poster
 
Posts: 69
Joined: Tue Oct 22, 2013 11:59 am
Name: Danny Prichard
Vehicle Information: 88 Mustang GT
A9P ECU
BE/EA
351W
10:1 compression
X303 cam
GT-40 X305 heads
30 lb injectors Ford Racing
Pro-M 77 mm mass air
T-5 5 speed
exhaust - 3" pro chamber pipe; 2 1/2 " flowmaster


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