OK so background on the truck I've been fighting with it on and off for about a year now with different running issues and other problems the truck had a cab swap from previois owner and I've had to run down some electrical issues from said swap. The last few weeks its had an intermittent misfire under acceleration but seems to idle fine. Has some white smoke on coldstart but this has been the case since i bought the truck. No Cel on but I also don't have a way to pull codes as of right now. Had a chance to do a fuel pressure test tonight and the fuel pressure gauge was fluctuating really quickly between 40-60 and vibrates so badly on acceleration that you can't even see the needle. Could this be a sign of worn lift pump? Air in the fuel system? Any help is greatly appericated. Will try and get a video of the test up as soon as I can

 

here the video sorry about the quality it was getting dark and didn't have much time to mess with it.

 

Your fuel pressure seems to be fine. The jumping from 40-60 is from the mechanical fuel pump. To me it sounds like a miss at idle in your video. I would check the valve cover gaskets for burned pins/wiring, both the outside connections and the under valve cover connections.

 

I knew it would fluctuate from the mechanical fuel pump but that much? It seems to be running the same at idle since I bought so maybe its had this issue and has just gotten worse lol. Also I was under the impression that a faulty ucv harness would usually be accompanied by a Cel of some sort?

 

You have too much faith in the PCM.

There is no way for the PCM to know if you have faulty wiring to the injectors because there's no feedback from the injectors. The only 2 wires going to the injectors are to energize the solenoid.

You can pick up a faulty injector or bad wiring through a buzz test or a CCT, but it's not 100% effective because faulty wiring is usually intermittent.

Start by removing the IDM plug and doing your resistance checks. If you find a short (low resistance) or an open circuit (infinite resistance), then you disconnect the wiring at each of the valve cover plugs and do your resistance checks on each of the 5 independent wiring systems (Harness - IDM plug to valve cover plugs, and 4 under-valve-cover harnesses).

Here is the IDM plug resistance procedure: http://www.gbreman.com/techbulletin_103.html

Or, take the valve covers off and give all of the wires a thorough hand-over-hand inspection. Look for melted wires, melted plugs, check for bad/loose/corroded connections, etc.

 

Guess I have to remember I'm dealing with a 1995. I'm a tech at Toyota dealer ship and have seen codes for nearly everything on these new cars. I will start checking harness as soon as I can if I was to invest in an ae scanner a buzz test or ccv would at least point me towards the correct cylinder. I had the vc off a few weeks ago to put in all new glow plugs didn't pay close attention the harness but don't remember seeing any cut or burnt wires. Is there a definite injector test or is it just buzz test and if all wires check good then it has to be injectors?

 

You can do a buzz test and CCT with a $7 Android App called "Car Gauge Pro" and a $12 Bluetooth OBDII dongle.

I also recommend the $6 Android App called "Torque Pro" for reading all of your PCM values like pressures, temperatures, and whatnot.

Both of these used together are great for troubleshooting.

A CCT and buzz test may or may not identify a bad cylinder. If you fail either test on multiple cylinders, it could indicate bad wiring or a bad IDM. If it singles out a cylinder, it could still be wiring but it could also be injector O-rings or the injector itself. You can swap two injectors and see if the singled out cylinder follows or stays the same. Inspect the O-rings and injector cups when you have the injectors out.

 

Where can I find said obdII Bluetooth? Very interested in seeing how my phone could possibly be a scan tool lol

 

I've got torque but this car gauge pro sounds interesting.

 

https://www.ford-trucks.com/forums/1...werstroke.html

That thread talks about Torque Pro and the $12 dongle.

Car Gauge Pro is in the App store same as Torque Pro.

Car Gauge Pro has a reputation for being counter-intuitive:

1. Enable Bluetooth on your android.
2. Turn the key on.
3. Open Car Gauge Pro and click "Connect" at the bottom
4. Select the "OBDII" Bluetooth device and Ford - > Powertrain
5. Click either "scan for codes" or "don't scan", it doesn't matter
6. Click "10" once it finally connects to the vehicle. It's the only option
7. Click "diagnostics" and then "Self test"
select either Buzz Test or CCT and wait for the test to complete for the results.

Do the buzz test with the engine cold and not running. The CCT is with the engine running. You should probably try it cold and hot.

-Matt

 

Ordered a Bluetooth dongle should be here Friday which is my day off so should get some time to use it. So torque will not do a buzz or cct but car gauge pro will?

 

Correct. Have fun!

 

Interesting. This I'm going to try. Reps sent

 

When you buzz, pay attention to the volume of each buzz.

See here:

 

Received the Bluetooth dongle and performed a buzz test. Injectors #5 and #7 are very muffled compared to the rest. Next step going to Tear the valve cover off now to check connectors and re test