Spit and sputter only after 4000 RPM

4dStang

4dStang

Banned
Oct 23, 2002
718
1
0
Near St Louis, Missouri
#1
The car idles and runs great until I hit 4K RPM.

I am questioning the firing order. Can anyone provide it. I have checked the timing, plugs, added new wires and cleaned the cap and rotor. I just don't know the firing order.

I want to go to the track this weekend but my car keeps sputtering when I take off and get the RPM's up past 4000-5000. Any other ideas?


CB
 
#2
http://www.tracksideguide.com/Tech/firingorder.htm (This has visuals too)
That should be for 5.0 HO's... also heres an exerpt from this website http://www.coolcats.net/tech/advanced/ho_swap.html lists the HO order below:

FINAL NOTES

- The firing order will now be 1-3-7-2-6-5-4-8 (HO pattern).

- Stock timing is still 10 degrees BTDC. Once the car is running correctly, you can get some added power if you bump up the timing to 12 or 14 degrees. Try 1-degree increments at a time since every engine responds differently, but back off if you hear any detonation (pinging). Also remember that if you do advance the timing, premium unleaded gasoline (93 octane or higher) is REQUIRED.
 
#3
I have changed the timing anywhere from 10 degrees in increments to 14 degrees and it has no effect. In fact, I keep the timing gun and wrench in my car because it is not running right. I have a complete Mallory dizzy, ignition box and coil I am going to install in a few weeks but I am not sure if that is the problem because it idles purrrrfect. The cap, rotor wires and plugs are great, infact, the wires are new Mallory 8mm Stainless so I am not so worried about that. It just seems like ignition, but can my mass air be a problem here? Just learning here. Appreciate ANY help.


Chris
 
#6
The plugs are white. I do have a pressure gauge on the rail but it does not help me while driving at 4K rpm. I am soon going to 24# inj and GT 40 heads, cobra intake and all the other stuff to go along but maybe now would be a good time to change out that intank pump to a 170 or 255 walbro. Aye?

Maybe I should take the mustang to a tune shop in St Louis here if it still occurs after a fuel pump change. I kinda wanted to wait until after the ignition change but now that there is talk of a possible LEAN problem, mmmmmm, I may make other plans.

Guess I'm not racing midnight madness on Saturday. :(
 
#8
Primed, I think yor relay is shot. Thats my guess for the pump staying on.

More:
I was driving home from work trying to find the start of the rough spot in the rpms and it always seems to start right around 4600 rpm and contine to the top. If I drive the car to 4500 rpm every time, it runs great, any higher on the rpm and it dogs like it is choking.

All this started after I put on my headers, and pro chamber about a week ago. I already had flow 2 chambers. I can't help but think that some how, the exhaust change had something to do with it. I know cars run open headers all the time, but can the effects of much improved flow change the intake rate in the fuel delivery with this being a computer controlled car? I mean, what if my 02 sensors are out? Could this mess it up that bad. I unplugged the ck eng light.
 
#10
I definitely don't think your exhaust is the culpret, although anything is possible with these cars. What MAF are you running, and what TB are you running. You definitely want to bump to a 75mm pro-m maf with your set-up when you go for the fuel pump and injectors. I have a set of fairly new 24lb injectors, and a 76mm C&L maf, and T-rex 190 pump. was thinking 400 for all 3. I havent gotten my 42lb injectors and 255 pump yet, but I would sell them to you if you are interested.
 
#11
High speed miss when warm is usually a failing TFI module. If you don't have a spare to swap, find some canned circuit chiller or canned air and spray it down so that it gets good and cold. Then go for a test drive & see how it works.
 
#12
Where is the TFI module? I have never heard of that. I have heard of a TPS, but not a TPI. Maybe that's what you mean?

I am about two months away from doing a full top engine H/C/I swap with a 70 mm TB and a 75 mm mass. I already have the 24# injectors. I am just getting the cash together for the Mass and TB. Unless someone has a good used one :rlaugh: .


I am hoping after the top enging change and full ignition change, I will be running stronger in the 5000 rpm range. I am trying to spend more time at the track and not having that advantage sucks. I may just buy a new TB for now. I am going to swap out the TPS for fun, I have a spare.
 
#13
TFI (Thick Film Ignition) module is in the wiring harness. It works with the magnetic pickup inside the distributor and the computer to make the spark. It is the electronic switch that turns power on & off to the ignition coil.

The location is different in the 94-95 model from the location on the distributor on the 93 and earlier models. Make a post in the 94-95 specific forum and someone there can help you.
 
#14
"TFI (Thick Film Ignition) module is in the wiring harness. It works with the magnetic pickup inside the distributor and the computer to make the spark. It is the electronic switch that turns power on & off to the ignition coil."

The location is different in the 94-95 model from the location on the distributor on the 93 and earlier models. Make a post in the 94-95 specific forum and someone there can help you.



You mean the HALL effect pickup sensor? The one located in the dizzy under the rotor? That is all I can think of that you are talking about. I have changed that out before too. I really don't think that could be the problem. I think that sensor is on or off. Unlike a TPS that can have variable voltage.
 
#15
Mine did exactly the same thing and it was the TFI module on the distributor. On this picture you can barely see it, but it is the thing that the wiring harness plugs into.
488195_30_full.jpg

But like was said Earlier, I dont know if it is in the same spot on the 94-95's :shrug:
 
#16
4dStang said:
"TFI (Thick Film Ignition) module is in the wiring harness. It works with the magnetic pickup inside the distributor and the computer to make the spark. It is the electronic switch that turns power on & off to the ignition coil."

The location is different in the 94-95 model from the location on the distributor on the 93 and earlier models. Make a post in the 94-95 specific forum and someone there can help you.



You mean the HALL effect pickup sensor? The one located in the dizzy under the rotor? That is all I can think of that you are talking about. I have changed that out before too. I really don't think that could be the problem. I think that sensor is on or off. Unlike a TPS that can have variable voltage.
Click to expand...

The hall effect sensor is the same as the magnetic pickup inside the distirbutor. The TFI module is an electronic switch or amplifer that controls the flow of currrent to the coil, much like the points did in older cars. The computer uses the data from the hall effect sensor to tell the TFI module when to switch the current on and off to the coil.
 
#17
OHHHHHHHHHHHH. You mean the ignition module. I have a spare in the car. I changed that out about 10K miles ago. I have found that in my experience with those, they work or they don't. So I always carry a spare.

The 94-95 is right under the maf on the firewall.
 
#18
4dStang said:
OHHHHHHHHHHHH. You mean the ignition module. I have a spare in the car. I changed that out about 10K miles ago. I have found that in my experience with those, they work or they don't. So I always carry a spare.

The 94-95 is right under the maf on the firewall.
Click to expand...
I would put the spare on, just becuase its only 10k miles old doesn't mean its still good. I have gone through 3 in the last 20k miles. :bang:
 
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