misfire?

[manny]

problem: when i rev the 2.3 in my mustang upto to about 6000 rpm for a couple of times then she developes a miss. when i shut her off and let sit for a few minutes she starts right up and runs smooth.could it be the lifters? should i be running anti pump up lifters?

[SilverHorseRacing]

Possibly lifters, also possible it's the valve springs, although the miss probably would stick around at higher revs only.

Why are you revving so high? Your motor stops pulling around 5200~5400, unless you've been playing with parts since last I saw you!

Anyway, you're still running the distributor, might be getting spark scatter, or could be a few other things. Any codes in the computer?
Revving under load or just making noise in the garage?
Fully warm or cold, or doesn't matter?
Vacuum leaks anywhere?


------------------
-Marcello Canitano
www.SilverHorseRacing.com (http://www.SilverHorseRacing.com)

[manny]

1. no codes in computer
2. under load during the race
3.no vacuum leaks
4. motor revs very easily with the 4:10 gears
5. missed once during first qualifier then put in new set of plugs for partice and when i took the revs back up there she began to miss again.during the cool down lap at a much lower rpm the miss started to go away, by the time i got in the pit lane she was running fine.?
6. new springs in head.

[Kazoo]

From our experience, stock valve springs and lifter pedestals are good to better than 6500 RPM...so I doubt that is the source of your miss. Assuming you don't have any obvious secondary ignition problems (burned/broken wires, bad plugs, etc.) Since Marcello mentioned that you are running a distributor: I would take a look at the ignition module as they can break-down over time and become tempermental.

Which ignition box are you running? TFI (small module on side of distributor) or Big Old Ford Box? (just curious)...

either way, if you have a spare module, change it out and see what happens...it appears as if heat is a contributing factor and those definitely are sensitive to temperature.
Good Luck.

Dave F.

[manny]

i have the TFI model. if the module was going bad would it also effect the use of the MSD box?

[SilverHorseRacing]

I don't think the TFI would affect the MSD, but I have seen TFI's "going south" but still functioning. So trying a different TFI isn't a bad idea. Also, yank the MSD and see if it fixes the problem.... I've seen more than my share of those too give people fits.

There's a reason NASCAR teams have a backup box on board

<-- Who's happy to report that crank triggers don't have this problem (but others of their own...)



------------------
-Marcello Canitano
www.SilverHorseRacing.com (http://www.SilverHorseRacing.com)

[Kazoo]

Manny,
I'm not trying to be a jerk, but why are you using an MSD box? Did you have a problem that you fixed, or hoped to fix with the box?

FWIW, the TFI system always worked perfectly for us (we used it for 3 or 4 seasons), with never a sign of the ignition being insufficient. The only ignition woes we ever had were a result of alternator failure.
Good luck.

Dave

[Mike Graves]

I recently found out that you have to use suppression type wires when you use an MSD box to keep EMI from messin' with the MSD box. Just a thought, disregard this if you already know that.

[manny]

no i'm not running the box. tried it on the car in my garage and it never ran right.i'm just using the blaster coil with FMS 9mm wires with motorcraft plugs and a cap and rotor with brass fittings.i know the TFI module is the one that came with the car,maybe to old? and marcello maybe not 6000 rpm maybe more like 5500 rpm but who know's , i'm still using the stock tach.i'm getting better though, had it down to 3:01 times on the long course. nothing like seat time.any special brand TFI module to get or stay away from?

[Kazoo]

>any special brand TFI module to get or stay >away from?

Can't really tell you. Hell, most of them are probably made in the same factory and have different company stickers put on them, but personally I think we had one Motorcraft and a spare Standard Ignition unit. I'd just stay away from the bargain brands, but like I said...they're all probably made in the same factory overseas anyway. Good luck.

[manny]

thank you very much KAZOO and you too MARCELLO. just want to be ready for the feb race at sebring.

[Rabbit07]

One way to verify a bad TFI is to use a Timming Light. They will on occasion scatter timming when they start to fail. Rev it up and watch if timming is jummping around. It should stay fairly steady. Also can check with Lab Scope if you have one. Keep in mind that the Hall-effect in the distributor can also fail causing similar condition. You can save yourself from future TFI failures buy relocating it away from the engine heat and vibration. I learned that from a Ford engineer. You just have to make a harness from the Hall-effect to the module.

Good Luck.