98 Mustang GT....Black soot in tail pipes/car running rough

[sanitarium16]

My car was perfect up until a few weeks ago. My car is modified with the following: Mac CAI, FRPP 70mm Throttle Body, BBK Intake Plenum, FRPP PI Intake Manifold, Mac Off-road h-pipe,Flowmaster super 40 catback, Trans-go shift kit, Diablosport predator tuner premium fuel tune.
I have my rear o2 sensors shut off via the predator tuners so i am not throwing any codes or CEL. All 02 sensors were replaced with Bosch last year and the car has brand new plugs, wires, MAF sensor,IAC,cleaned the EGR Valve, cleaned throttle body and new fuel filter. Using the diagnostics feature of my diablo predator i am able to read multiple things. My tail pipes are black with soot and have always been since i put on the off road h pipe. My 02 sensor readings fluctuate from 0.1 to 0.7. I was told this is normal. My MAF voltage is .76 idle. My idle is jumpy....goes from 620,650,700 and fluxuates in between there. There is no pinging or detonating going on that i can hear and i fill up on 93. Do i have to buy a new h-pipe with high flow cats in order to fix this problem? Another note is that my spark advance is jumping around too. 17 to 18 to 19 at idle. I have it raised a little (8% throughout entire rpm range) but i have always had it on this setting. Another thing to mention.....there are no vaccum leaks...sorry for the long post but im trying to be as detailed as possible.

 

[punisher]

Timing jumping around is normal. Does your "tuner" have a readout for fuel trims? Verify fuel pressure. Idle will jump around until the idle strategy is reset, expecially after cleaning the IAC and throttle body.

Hard to speculate without some other readings (trims/crosscounts/fuel pressure), mainly fuel trims.

 

[boxcartommie22]

sounds like throttle position sensor

 

[sanitarium16]

Tps is reading .097 volts.
Here are some other readings in the "gas fuel" selection. not sure what they all mean

31.84V CAS GRND
2.26V FLI V
2.7V FRP V
5.0V FTPV
3.6-3.7MS FUELPW1
3.6-3.7MS FUELPW2
2.69V IAT V
.94V EGR VALVE
2.32V EFTA
100% FP

 

[mechtech]

Do you have a cloth/oiled air filter?
The Maf wire may be contaminated by that oil, and need cleaning.
Use a spray made for this, or brake cleaner that doesn't leave a residue. Spray it on a mirror and let dry to make sure.

 

[Buford T. Justice]

I have the exact same car. My car was running rough a few months ago. A mechanic friend of mine took off a piece on the top of the engine (in front of where the Mustang logo is) and sprayed it out with a cleaner and put it back on. Car runs great.

 

[sanitarium16]

You mean the intake plenum or throttle body? I cleaned the MAF and the throttle body. The plenum is fairly new.

 

[Chris142]

Ford used to have many problems with the fuel pressure regulators. The rubber inside would fail and dump gas into the vacuum line.

Something to ck if your car has the same part.

 

[brianl703]

Usually you can pull the vacuum line off and check for gas, or smell for gas inside the vacuum line fitting on the regulator. The one that was on my 1988 Mustang had a very slight leak (I smelled a slight odor of gas in the vacuum fitting). I decided to replace it since it was only $12 for a new one and it's pretty easy to replace.

 

[sanitarium16]

Where is it located?

 

[sanitarium16]

Ok, i found the fuel pressure regulator and i smelled the vacuum line fitting. The fitting smells like gas A LITTLE BIT....not a stong odor....There is no gas leaking either.

 

[sanitarium16]

Also my PROFILE IGNITION PICKUP Keeps reading ON AND OFF constantly using the diagnostics reader fuction in the diablosport predator. What does this mean?

 

[sanitarium16]

anyone?

 

[punisher]

The PIP signal on an EDIS system (post '94) is generated by the PCM based on data from the crank sensor,there really is no actual PIP signal like on older TFI. '91 to '94 vehicles had a seperate EDIS module, '95 up have it incorperated into the PCM. The SPOUT (Spark Output)signal is what controls timing. I have no clue as to what your "Diablosport" means when it reports a constant on and off signal when referring to the PIP.

If you can get us some fuel trim readings or some relevent data (fuel pressure) that will help. As an example, if your fuel trims are rich at idle and go lean at cruise, then you likely have a MAF problem, or rich at idle and OK under acceleration- possible fuel regulator concern. It is a bit hard to diagnose a system with all of these aftermarket parts and changes as there is no telling how well they play together. If you have the correct/relevent info/data, diagnosis is a lot simpler.