Finally started working on issue

My 95 SC has an issue with the ignition seemingly to completely cut off when I get in to higher RPM's. Such as initial launch at the track and generally above 4500 RPM WOT in first gear.

The RPM's shut up fine until about 4500 or higher and it seems like the entire engine shuts off, Tach immediately drops off, and lose all power. In a split second it fires back up again and everything seems OK.

Can also get it to do it if I am cruising slowly in 2nd or 3rd gear, (35-40MPH)then nail the throttle it downshifts into 1st gear and as soon as RPM's go above 4500 or so, (could be more, but it happens so fast) the ignition seems to shut off completely, complete loss of RPM's on the stock gauge, no power and when I left off the gas or the RPM's quickly fall off the engine fires back up and I can press the gas again, just not WOT. Very strange issue I have never seen before.

Not sure if it would be a DIS Module, Cam Sensor, Crank Sensor or what?

Has anyone else had this issue before and if so what fixed it?

Thanks for the help.

Smitty

Make sure all your rev limiters are set to 7000rpm and then set your minimum PIP to -0-. If that fixes it then reduce the limiters down to where you want them to be (probably 6500rpm).

Ok Got it

XR7 Dave said:

Make sure all your rev limiters are set to 7000rpm and then set your minimum PIP to -0-. If that fixes it then reduce the limiters down to where you want them to be (probably 6500rpm).

Click to expand...

Thanks Dave I will look at it this weekend hopefully!

Hope it is that simple.

Smitty

I had a similar issue about ten years ago. Turned out to be the little reservoir in the gas tank that the fuel pump sets down in broke loose from the tank and wasn't holding any fuel under hard acceleration. It was OK with a full to half tank but anything less than a half tank it would do pretty much what your describing.
About five years ago I had a different problem with the car randomly loosing all power for a split second all the sudden but that would happen at any speed like just cruising down the road. That turned out to be the power steering pulley making contact with the bare spot it wore on the intercooler fan wiring causing a temporary short. One day I realized that when my intercooler fan wasn't on, (switch in car) it never happened and I quickly found the problem.

Which One?

XR7 Dave said:

Make sure all your rev limiters are set to 7000rpm and then set your minimum PIP to -0-. If that fixes it then reduce the limiters down to where you want them to be (probably 6500rpm).

Click to expand...

TIPMAX Spark - Tip-in Maximum Advance 0.0 Deg BTDC
TIPINC Spark - Tip Adv Per PIP 0.3 Deg BTDC
TIP_MIN_SPK Spark - Min Spark Retard For Tip In 50.00 Deg BTDC
SPUCLP Spark - Maximum Advance 50 Deg BTDC
SPLCLP Spark - Minimum Advance 0 Deg BTDC
SPK_MUL Spark - Global Multiplier 1.00 Multiplier
SPK_ADD Spark - Global Spark Adder 0.00 Deg BTDC
NTIP Spark - Tip-in Maximum RPM 5000 RPM
LUGTIM Spark - Spark / Fuel Lug Time Limit 2.000 Sec
LUGSW Spark - Lugging Timer Switch Enabled Switch
KACRAT Spark - Tip-In TP 0.1875 Volts
ECTIP Spark - Spark Tip In Min ECT 180 DegF
DEGPIP Spark - Ignition Degrees Per PIP 120.00 Deg

Dave, in reference to setting Min PIP to -0-, which one are you referring to?

Smitty

Also Rev Limiters?

XR7 Dave said:

Make sure all your rev limiters are set to 7000rpm and then set your minimum PIP to -0-. If that fixes it then reduce the limiters down to where you want them to be (probably 6500rpm).

Click to expand...

Is there any other place to find rev limiters than this table here?

UNRPMH RPM - Underspeed RPM Hysteresis 350 RPM
TCNDBR RPM - RPM Filtered Time Constant 27.000 Sec
TCN RPM - RPM Time Constant 1.200 Sec
TCDESN RPM - Desired Idle RPM Time Constant 3.300 Sec
NLMTNEULO_0 RPM - Rev Limit #4 On 7000 RPM
NLMTNEUHI_0 RPM - Rev Limit #3 On 7000 RPM
NLMTLO_2 RPM - Top gear stage 2 rev limit 7000 RPM
NLMTLO_1 RPM - Mid gear stage 2 rev limit 7000 RPM
NLMTLO_0 RPM - Low gear Stage 2 rev limit 7000 RPM
NLMTHI_2 RPM - Top gear stage 3 rev limit 7000 RPM
NLMTHI_1 RPM - Mid gear stage 3 rev limit 7000 RPM
NLMTHI_0 RPM - Low gear stage 3 rev limit 7000 RPM
BZZTM_ALT RPM - Buzz RPM Time Alternative 60.0 Sec
BZZRPM_ALT RPM - Buzz RPM Alternative 704.0 RPM

Thank again, Smitty

Your limiters are up there, but the PIP setting your looking for is not in the list you have up. The scalar your looking for is called MNPIP6, and the lower the number the higher reving the motor can go. It will be located under System.

Fraser

Thanks!

fturner said:

Your limiters are up there, but the PIP setting your looking for is not in the list you have up. The scalar your looking for is called MNPIP6, and the lower the number the higher reving the motor can go. It will be located under System.

Fraser

Click to expand...

Thanks Fraser, I appreciate the quick response. hey can you think of any other reason my SC will not rev above 4000 rpms under WOT conditions?

Right at 4000 RPM's I lose all power and tach signal drops to 0 until it the rpms drops a little then it all comes back like normal until I try and go to WOT again and it does it again!

Pretty stumped on this one.

Thanks for the help.

Smitty

Quik95SC said:

Thanks Fraser, I appreictae the quick response. hey can you think of any other reason my SC will not rev above 4000 rpms under WOT conditions?

Click to expand...

So you tried all of this:

XR7 Dave said:

Make sure all your rev limiters are set to 7000rpm and then set your minimum PIP to -0-. If that fixes it then reduce the limiters down to where you want them to be (probably 6500rpm).

Click to expand...

And the problem persists. Or you haven't yet tried those changes?

Yes

Mike8675309 said:

So you tried all of this:


And the problem persists. Or you haven't yet tried those changes?

Click to expand...

I just found the MNPIP6 that Fraser mentioned and it was set to 1232. I dropped it down to 0 as Dave suggested and will go out in a few minutes to reflash the QH and see if that fixes it.

If it does not fix it, any other ideas?

Frustrating when you have a low 12 second car and the best it has ever done is a 13.42. I am ready for this thing to be fixed.


Thanks again for the help.
Smitty

New info hope it helps!

I have attached a short data log of 3 quick burst I did in WOT. Notice the highlighted areas how they look very strange and erratic.

All Rev limiters have been set to 6500 and the MNPIP6 has been set to 0 as suggested above.

Spark jumps all over the place, RPM goes nuts, not sure what happens or what the cause is. I have deleted all the non important stuff in the log so it may look funny, I just save the WOT burst to shorten it up.

Anyone have any idea what would cause this erratic behavior. Or perhaps where to look for a wiring problem perhaps? Really Stummped on this one.

CAM sensor is brand new FYI.

Thanks,
Smitty

You have electrical issues, it's not in the tune.

You have a rich commanded AFR + steady high PW on the injectors yet the HEGO and WB both indicate lean. Since the WB is not powered by the EEC yet both read the same, I tend to believe that you have either a very lean condition (not supported by the PW command) or a complete loss of ignition which will also read as lean since pure 02 will be read at the sensors.

If you are sure that you don't have a mechanical ignition problem (plugs/wires) then it has to be electronic. Suspect EDIS, cam sensor, crank sensor or wiring issues. I assume the car throws no codes?

You are correct sir.

XR7 Dave said:

You have electrical issues, it's not in the tune.

You have a rich commanded AFR + steady high PW on the injectors yet the HEGO and WB both indicate lean. Since the WB is not powered by the EEC yet both read the same, I tend to believe that you have either a very lean condition (not supported by the PW command) or a complete loss of ignition which will also read as lean since pure 02 will be read at the sensors.

If you are sure that you don't have a mechanical ignition problem (plugs/wires) then it has to be electronic. Suspect EDIS, cam sensor, crank sensor or wiring issues. I assume the car throws no codes?

Click to expand...

Yes sir there are no codes, when this happens. Although, it did through a very quick CEL today when I did it, but I stayed in the gas this time to see if it would go past the 4000 rpm barrior. It immediately went out when I removed foot from gas and slowed down.

Yes it does seem I have a complete loss of ignition when it happens.

Even a with a bad plug or wire or similar would it cause a complete lack of ignition?

Cam sensor was replaced 2 days ago, so I am also looking at EDIS or wiring issues.

Will swap out the EDIS from the wifes 94 SC and see if that cures the problem if so then I know what I have to get, if not I get to keep looking.

Oh there were 2 scalars that had 4000 rpm as the rev limit, so I was hoping I had founf the issue, but changing them to 6500 didn't help obviously.

The MNPIP6 was set at 1232, is this normal or was that way off? It is now set at 0 for that Datalog.

Thanks,
Smitty

Electrical it's a B

I have a tach that drops to Zero every time I stomp the peddle. I had already ordered a new tach when I talked to a Ford Mechanic. He said, "When a tach drops to zero, it is almost always the tach." I had already had a tach coming. When I replaced it, I still was not very convinced. But you know what? The tach is very acurate now. The transmission has not done it's hunting for a gear thing either. As for the rest of the problems they still exist. The only thing I have yet to replace before I take it to a professional is the MAF. I am still attempting the figure out the wiring and my haunch is that the tranny has a problem or the secondary junction block under the center of the dash on the driver's side. I have had the dash out and the harness looks good but I did not check them with meters at that pt. If you want to know more check the the string that starts with "rev the engine and the tach drops to zero." Somehow I bet if one of finds it it will help the other.

This sounds like the problem that has been plaguing mine since the shootout. Is it hard to start when it's warmed up like mine was? I replaced my DIS module and it seems to have cleared up but haven't been able to give it enough testing to be sure, so far so good.