96 GT Starting/Running issues

[reevesracing]

I have a 96 GT 5-Speed which is basically stock. It has the following add-ons and features:

• PATS w/ keyless entry
• BBK CAI
• Accel Coilpacks
• BBK Off-Road mid pipes
• Steeda MIL eliminators
• Flowmaster turn down exhaust
• King Cobra clutch kit

I have three issues going on with my car, and I have spent the last month racking my brain and emptying my pocketbook trying to resolve them without any luck. Hopefully someone here may have run into the same issues and can help.

Problem #1

I have an issue with trying to get the car to start after sitting unused for more than 24 hours. It can take up to 10 minutes before I can finally get the car to fire off and run. After that, it starts without any problems, and continues that way as long as it is started at least once within 24 hours.

I have changed the fuel filter and the fuel pressure regulator and checked the initial fuel pressure (After sitting more than 24 hours), and it checks out OK. Also, it stays constant during startup and while running. Also, while working with Problem #2, I changed out the IAC and TPS with no effect on the issue.

I have connected my laptop to the car using Proscan 5.0, and can only see that the right bank was registering that it was running rich. Because of this, I would occasionally get a misfire on at least one cylinder on the right bank. I then replaced the original coilpacks with Accel coil packs and replaced the plugs with Motorcraft Platinums. The plug wires tested out fine, and were fairly new when I bought the car. The car idled a little smoother after that, but the problems did not go away and there was no change on the scan.

I have also checked all of the grounds under the hood, and all are good.

Problem #2

Along with Problem #1, I have an issue when attempting to get up to speed. If I hammer down on the throttle or give it a little more throttle to get up to highway speed, it acts as if it is running in "limp" mode. It is very hesitant to get up to speed, and sounds almost as if it is hetting a rev limiter at full throttle and low RPMS. At very light acceleration, it will come up to speed fine but when you go over an overpass, it has a problem.

Problem #3

The battery on the car dies after sitting for more than 48 hours. There is no radio in the car, and I even removed all of the bulbs from the car to ensure that nothing could drain it. The battery is brand new, and has been tested good. Also, with a jump start, the system comes back and will start up and run. The alternator is obviously working because after running the car for 5-10 minutes it will start back up without needing a jump start. The charge also lasts overnight, and the car will start back up in the morning. The only thing that is active on the car is the anti-theft overnight.

I have a sneaking suspicion that all three of these problems are related, but I can't put my finger on what is causing any of these issues and my pocketbook is running out of ideas as well. I am getting frustrated wasting good money on troubleshooting this problem when it could be better spent modding the car.

Please help me Obi Wan....You are my only hope!

Thanks in advance!

--Brian

 

[POWER302]

I just got a 96 Gt Auto w/ 157,000 miles that does the same exact thing. I am in the process of trying to fix it as well.

It has a miss when you give it throttle past a certain point, if you use very light throttle it will run fine, but over a certain point it will start sputtering..

When I scanned my car it said that bank #2 was lean... Im actually in the middle of pulling plugs out to see how white they are... I've only got 6 out and replaced so far "came in to take a break and check out stangnet" and they all look to be on the lean side from both banks..

Other things I have done.. I replaced the 02 sensor for the bank that read lean, I cleaned the element in the mass air sensor, I swapped on the 30,000 mile coil packs from my cobra "before I read the codes".... None of those helped...

What i have found while replacing the plugs, is a wire that wasnt connected to anything. It is a black wire on the rear of the drivers side injector wiring harness. It has a rubber 90 degree elbow that looks like it should be pushed over a bolt head.. It looks Just like the signal wire that would go to a starter solinoid on a fox body... Im pretty new to the 4.6s, so I'll probably reference the 5.0 cars alot....haha... ANyway it wasnt attached to anything. I would assume its some sort of ground ford the injector harness but I can see where it was originally attached...

Well, Im gonna keep workin on it. If I figure somethin out I'll chime back in..

 

[POWER302]

"ITS FIXED" Update, I finished changing the plugs, and I found a stud that was grounded and pushed the black wire on to it... The car runs perfect now... I couldnt be happier right now, I got the car on a real good deal with this problem, and just expected it to have a blown head gasket or something....

Try and look for the wire I am talking about maybe it worked its way loose on your car also..

 

[reevesracing]

Can you post a pic of where you found this wire?

I will try to search around it this afternoon for it if the weather holds up.

 

[reevesracing]

Is there anyone else who may have ideas on these issues?

 

[LaserRed01GT]

The wire power302 is talking about is the injector harness ground lead. It attaches to a threaded ground stud right on top of the EGR valve.

View attachment 402013

I suspect though, that this is not the problem that is causing your battery to drain so quickly reevesracing.

It sounds like a fuel pump power/ground problem to me actually. Have you tried cycling the key on and off a few times before starting the car after it has sat for a while? You said you checked the fuel pressure, did you check it with a mechanical gauge on the Schrader valve? What was the pressure with the KO/EO?

 

[reevesracing]

I never turn the engine over for more than 6 seconds, and then turn it off (To prevent burning out the starter solenoid and also excessively draining the battery). So, technically I do cycle the key. I typically turn the key on, and wait a few seconds before starting the car (Because of the PATS system).

I know for sure that the injector ground is connected and OK.

The fuel pressure was 38 PSIG, and hold that when initialized and while running. And yes, I use a mechanical gauge on the schraeder valve located on the fuel rail on the left bank at the front of the car.

 

[LaserRed01GT]

I never turn the engine over for more than 6 seconds, and then turn it off (To prevent burning out the starter solenoid and also excessively draining the battery). So, technically I do cycle the key. I typically turn the key on, and wait a few seconds before starting the car (Because of the PATS system).

I know for sure that the injector ground is connected and OK.

The fuel pressure was 38 PSIG, and hold that when initialized and while running. And yes, I use a mechanical gauge on the schraeder valve located on the fuel rail on the left bank at the front of the car.

If the fuel presure did not increase over 38 PSI once the motor was running that's not good. 38 PSI is low. I obviously can't say for sure whether or not your fuel pressure is directly related to a power or ground problem, but you likely have a problem with the fuel pump regardless.

Do you have a way to monitor or datalog the fuel pump duty cycle with a scanner?

 

[reevesracing]

Yeah, I have ProScan, and it does datalogging.

I will check the FP again when I get home, to make sure I gave the correct gauge reading.

 

[POWER302]

The wire power302 is talking about is the injector harness ground lead. It attaches to a threaded ground stud right on top of the EGR valve.

View attachment 401957

I suspect though, that this is not the problem that is causing your battery to drain so quickly reevesracing.

It sounds like a fuel pump power/ground problem to me actually. Have you tried cycling the key on and off a few times before starting the car after it has sat for a while? You said you checked the fuel pressure, did you check it with a mechanical gauge on the Schrader valve? What was the pressure with the KO/EO?

Actually that line running to the top of the EGR is a vacuum line.. The wire Im talkin about is further back in the wiring harness... Ijust pushed it over the closest grounded stud I coukd find..

 

[LaserRed01GT]

Actually that line running to the top of the EGR is a vacuum line.. The wire Im talkin about is further back in the wiring harness... Ijust pushed it over the closest grounded stud I coukd find..

You're absolutely right. I even had that picture labeled wrong.

This is the one, for those who are searching it's located right by the #8 cylinder:
View attachment 401955

 

[reevesracing]

UPDATE:

I changed out the MAF with a new one, and the starting problem seems to be better. It took less than a minute to start (From being dead for several days) and the throttle response was much better.

However, under load it still is a dog. This time, it backfired under WOT which leads to a timing or PCM issue.....

Any ideas?

 

[LaserRed01GT]

Why did you change the MAF?

Did you get a chance to datalog or look for codes yet? You really need to look towards your fuel system with your FP being that low and not increasing under load at all.

 

[reevesracing]

http://www.stangnet.com/images/stories/docs/sn95_TSBs/98-23-10.pdf

This is why I changed out the MAF, and this did get rid of my rich condition. The inside of the MAF looked like it had been bathed in goo, so it was obviously fouled. Plus, one of the terminals on it had some corrosion, and it was just a helluvalot easier to buy a new one than attempt to clean it up.

I did not have time yet to check the FP today, but I will verify it tomorrow after work.

 

[reevesracing]

OK.

Downloaded a freebie application and was able to see that I DO have a bad O2 sensor. It is the reason why my system in in "Closed Loop" status, basically putting it in limp mode. For some reason the ProScan software did not report that issue.....

The sensor that is being reported bad is Bank 1, Sensor 2.

Does anyone know which one this is?

 

[COramprat]

Bank 1 sensor two is passenger side after the cats...if you still had them.

 

[LaserRed01GT]

http://www.stangnet.com/images/stories/docs/sn95_TSBs/98-23-10.pdf

This is why I changed out the MAF, and this did get rid of my rich condition. The inside of the MAF looked like it had been bathed in goo, so it was obviously fouled. Plus, one of the terminals on it had some corrosion, and it was just a helluvalot easier to buy a new one than attempt to clean it up.

I did not have time yet to check the FP today, but I will verify it tomorrow after work.

There was never anything actually wrong with the MAF sensors, Ford just released that TSB to satisfy customers who had never cleaned the MAF. But, if it was really that corroded, then replacing it was probably a smart idea.

Which "freebie" application did you use that told you that you had a bad 02 sensor? Bank 1 Sensor 2 is the passenger side O2 sensor after the cat and has nothing to do with your fuel trims (open or closed loop operation). The back 2 O2 sensors monitor the efficiency of the cats and that is all.

 

[reevesracing]

I used Scantool.net v1.13, which specifically told me that the Bank 1, Sensor 2 O2 sensor was bad. All that I was getting from Proscan was that the fuel system was in closed loop, but for some reason I could not get any readings from the O2 sensors.

With scantool.net, I was able to scroll through all the available scans and found the particular O2 channels it was reading, and could see that it was unable to receive any voltage readings from that particular O2 sensor, and it specifically stated that it was bad.

I will change out the O2 sensor Friday and see if that pulls it out of the closed loop. I will first remember to put the FP gauge on before I start the car to get the initial FP to see if it is 40 PSI or less. I still had a problem starting the car today, but it still took less time to start it than it did before. However, this time I could smell the extra fuel coming from the exhaust so it is running way too rich.

 

[reevesracing]

I just re-read your reply laser....

It is my understanding that the O2 sensors have a direct effect on closed loop operation, especially the post sensor because if it was not able to read anything coming past the cat, then it would put the system in limp mode to protect the engine from potential damaged caused by the increased backpressure.

Am I wrong?

 

[LaserRed01GT]

I just re-read your reply laser....

It is my understanding that the O2 sensors have a direct effect on closed loop operation, especially the post sensor because if it was not able to read anything coming past the cat, then it would put the system in limp mode to protect the engine from potential damaged caused by the increased backpressure.

Am I wrong?

The post cat O2 sensors are not used in any way to control fuel trim. In other words, the voltages they output is not used for the fuel trim strategy. Only the front two O2 sensors are used to control the fuel trims (closed loop).

If you are smelling fuel that obvious at startup, you may want to check/replace your ECT sensor that is on the front of the intake manifold opposite the thermostat. It is one of the main inputs used to control startup fuel strategies.

Proper input is required from the ECT, IAT, MAF and Crankshaft Position (CKP) sensors to activate the HO2S Monitor which heats the O2 sensors to about 500°C in about 8-10 seconds when the key is turned on. It sounds like the HO2S monitor is not preoperly being activated upon key on. Without the O2 sensor heated to at least 500°C, they will not properly switch and give the PCM proper feedback. This almost always results in an overly rich startup. Then when the normal exhaust gas heats the front O2 sensors, the fuel trims will be corrected short term.