[aposak]

I'm new to the forum, and new to diesels in general. Thanks for the helpful threads on maintenance and repair!

I've muddled through the injector buzz test on my '95 F-250. They all sound different. 4 of them are loud, 1 is medium loud, 2 are quiet, and one doesn't make any noise. I'm not sure what I should expect to hear, but I'm sure at least one needs to be replaced. Would it benefit me to replace all at the same time? I've seen listings for rebuilt on eBay for $99/ea; are any of those places reputable, or do they cause trouble down the line? Is there any other maintenance I should do while I have the valve covers off, anything I should check, or any tips/tricks on installing the injectors?

Thanks in advance!

-Andy

 

[rockets10510]

you could buy a set of rebuilt stage1 injectors from diyinjectors.com (think thats the site) for around 600 i believe and while your under there i would replace the glow plugs

anthony

 

[Excavator]

A buzz test does not mean injector itself is bad just because it buzzed different. The buzz test sends signal to IDM which sends signal to wire harness up to valve cover gasket connector too under valve cover harness and then to injector solenoid and back to IDM. The weakest link here is the under valve cover harness, not the injector. The buzz test realy only test the electical side of the injector operation, not the mechanical. You also need to do a CC test. Does the engine have a slight miss? What are the symptoms you have

 

[aposak]

Does the engine have a slight miss? What are the symptoms you have

Has been tough to start since I've owned it (bought last year when gas neared $4/gal for unleaded), but was told that's just the nature of the beast. When it started, sounded like it was only running on 4-5cyl, but would smooth out and run well once it warmed up. It would also die at idle randomly, but fire right back up. It died on me for good while going down the highway late last fall... traced that to a bad CPS (black plastic, IIRC, replaced with a grey plastic one). Wouldn't start after that. No smoke from the exhaust, or fuel smell at all. Checked and replaced all glow plugs, just to be sure it wasn't the plugs, relay, wiring harnesses, or valve cover gaskets. Friend looked it over and said fuel pressure and HPOP oil pressure are good, but I haven't checked them myself for lack of a tool to do it. Also don't think he knows much about diesels, though he's a really great guy. Fuel filter looks newer, and whatever water may collect in there leaks out through the drain valve.

CPS is getting the correct voltage from the engine computer, and it's returning a signal on the oscilloscope. Tach reads while cranking, so this shows the same thing.

I have access to a bunch of general purpose electrical test equipment, and can really dig into the electronics. I have a good general mechanical knowledge, too. Haven't really dug into the problem too much, as it's been too cold for me to want to be outside most of the winter. So.... that's about all I know. Truck has about 220k, and doesn't have a 5th wheel hitch in it.

 

[Excavator]

What you need to do is have the engine scanned for codes using a Powerstroke friendly scanner such as Autoenginuity. With those miles that you speak of, it is possible to have worn poppet valves in a few injectors. If that is the case then that is the cold start problem and smooth out when oil gets hot. This can be checked with valve covers off and engine cold.I would first get the engine scanned to eliminate other area's

 

[aposak]

What you need to do is have the engine scanned for codes using a Powerstroke friendly scanner such as Autoenginuity. ...... I would first get the engine scanned to eliminate other area's

Friend hooked up some sort of scanner he borrowed from work (he's a oil and brake changer at a shop). It had the CPS flag thrown in memory, but that's all. I've read about Key-On-Engine-Off tests and other tests while the engine is running for other Fords with gas engines. Not sure if they're for diesels as well. What should I ask for? It's a pricey tow for me to get to a shop anywhere, which is why I'm trying to do work myself.

 

[Excavator]

If you have valve covers off, you can inspect the oil spouts for oil spitting out while running. All injectors should spit out at the same rate. If any are not or any are dumping oil out then that is suspect injector. Check this stone cold and then hot as it makes a difference if worn poppet valves. Now another thing you can do is while engine is idling you can unplug one injector connector at a time and any that does not cause a miss is already missing. You could also just have a loose poppet screw on a injector

 

[aposak]

I've tried cranking with the valve covers off (engine cold, it's still not firing at this point), and didn't see any oil spouting from anywhere. Will pull valve covers and check again. I know it has to have high pressure oil AND an electrical signal to fire the injectors. Could be an oil delivery problem?

 

[Excavator]

Here is what you need to keep in mind.
The PCM computer will not let the injectors fire unless the cranking voltage is 10.5 volts or higher. If your batts are weak or starter weak and you crank it over the injectors will not get the signal to fire and no oil will discharge from injectors. So that is first place to look at. Might want to have a charger on there for a while and while cranking check voltage with good volt meter to check cranking voltage. If voltage is above 10.5 and no oil discharge fro oil spouts, then check the HPOP res. There is alan plug on top and you remove the plug and add engine oil with in 1/2 inch from top. Also the crankcase oil has to be above low mark. This is where a scanner comes in handy as we can monitor the ICP pressure while cranking and see where fault is

 

[aposak]

HPOP oil level

Here is what you need to keep in mind.
The PCM computer will not let the injectors fire unless the cranking voltage is 10.5 volts or higher. If your batts are weak or starter weak and you crank it over the injectors will not get the signal to fire and no oil will discharge from injectors. So that is first place to look at. Might want to have a charger on there for a while and while cranking check voltage with good volt meter to check cranking voltage. If voltage is above 10.5 and no oil discharge fro oil spouts, then check the HPOP res. There is alan plug on top and you remove the plug and add engine oil with in 1/2 inch from top. Also the crankcase oil has to be above low mark. This is where a scanner comes in handy as we can monitor the ICP pressure while cranking and see where fault is

Thank you for the tips. I pulled both batteries and had them checked at the auto parts store. One was bad, so it was replaced. The other was fairly new, so I put it back in. I think the replacement is a 1200CCA battery... the biggest beast they had. It cranks a lot faster now. I can tell the difference. Still can't tell if the voltage stays above 10.2V while cranking. I'm working alone and can't crank and measure at the same time. I have the batteries on a charger when I'm not playing with it to keep them up.

The engine oil level is 3/4 full; as I've driven many an older vehicle, I'm programmed to check it at every fillup and top it off. The HPOP reservior, however, was empty the first time I checked it (with friend a few months ago). I added some oil to prime it, screwed the cover back on, and thought it was good. I checked it again, since you mentioned it, and it was empty again, though the truck hasn't been run. I fill it up, crank it over a few times, and it's empty again.

There has to be some way that this HPOP reservior thing gets refilled, either through a pickup in the oil pan, a low pressure pump, or directly from the engine lubrication oil pump. Any ideas? Thanks again for all the help. It'll be satisfying to get to the bottom of this.

 

[Excavator]

If the HPOP is not staying full it will not run. You should check your oil psi gauge on dash and see if it builds up pressure when cranking. The oil is picked up from the oil pan from low oil pressure pump which is behind the harmonic balance or damper some call it. It pumps engine oil uo to the HPOP and then builds up high psi for fuel system. If you have low oil psi then you could have a problem low oil psi pump or cracked stand pipe in pan. You could also have bad anti drain valve if HPIOP is draining out. The 95 years had problems with this

 

[aposak]

low pressure oil reading

If the HPOP is not staying full it will not run. You should check your oil psi gauge on dash and see if it builds up pressure when cranking. The oil is picked up from the oil pan from low oil pressure pump which is behind the harmonic balance or damper some call it. It pumps engine oil up to the HPOP and then builds up high psi for fuel system. If you have low oil psi then you could have a problem low oil psi pump or cracked stand pipe in pan. You could also have bad anti drain valve if HPOP is draining out. The 95 years had problems with this

As I recall, the oil pressure gauge seemed to be reading something while cranking. All of the dummy lights/ indicators seemed normal (except the ABS light is on, but I think that's a bad wheel spin sensor). What's a good oil pressure measure on the gauge? I'll check it again tonight or this weekend. Is the anti-drain valve located in the pan or the HPOP assembly, or somewhere else entirely?

 

[Excavator]

Is the oil draining by itself over night or is it draing as fast as you crank it over. If it holds over night and only drains while cranking over than you may just have injector with blown o rings or leaking IPR.
Here is old thread about the years that have valve in HPOP. Read through to understand the difference in years

http://www.thedieselstop.com/forums/f28/hpop-reservoir-not-holding-fluid-158082/