Three sensors that can fail and give intermittent starting problems are the Barometric Pressure sensor, the Engine Oil Temperature sensor and the Air Intake Temperature sensor. I believe each of these have a “fail safe” setting if they totally fail but if they short to ground or somehow stick partway open you will get bad input to the PCM and the engine will be difficult to start. You could unplug these sensors one at a time to see if the truck starts on the failsafe input.
Sorry but I can't find my sensor location chart right off...

"Easy stuff first"

 

Wow, lots of good tips in these last few posts.


Latest update:


I found a friend of a neighbor's friend (really reaching here) who used to be a Navistar tech. He borrowed some kind of scanner from somewhere and came over and gave my truck a buzz test.




And it started right up. In the morning. After sitting for, I dunno, a week? With new but pretty drawn-down batteries, and it was about 30 degrees.

He was very nonchalant about all my issues, he was sure it was the injectors sticking and said this had happened to him a few times before. First words out of his mouth were "If you let the oil go too long the injectors will stick, especially if it is cold out."


Since then (last Thursday I think) I have put about 300 miles on it, started it about a dozen times (once when it had been sitting all night at temps in the high teens and low twenties).

Bang. Starts instantly every time. I even put one of the old batteries back in (put the new one in my backhoe), and that was before the really cold morning start.


I have also changed the oil again (so, about 320 miles or so on that last change) on his advice. I usually change at a little over 3k, this last time before my problems I let it go to almost 4k. Won't be doin' that again...


Other tidbits from our conversation:

He said a multimeter WILL NOT read the voltage at VCs (except for glow plugs). Give Stroker a prize.

He said an ODBII scanner will not pick up any IH/Navistar-specific sensor faults on the '96.

He didn't know why I couldn't find voltage at the IDM harness, I will chalk that up to my own error.

After I told him about my Expressway Ford experience he said all dealers are the spawn of satan (no, wait, I said that).

He also said you could start the truck w/ ether and explained how to do so (kudos to the Duck for that advice then), and said that, absent a buzz test, ether was a good way to help un-stick injectors, his theory being the rapid rpm change when the ether ignites somehow frees them up ("don't do this on newer trucks unless you disconnect the intake heater or you will lose your eyebrows.")


So his opinion was that it was dirty oil causing the problem. Period. When I explained I had changed it he said probably enough dirt remained to make them stick, he said cold, thick oil was even more likely to make them stick. Now that I think about it, most (but not all) of the failed-starts were when the truck was cold, or not warm, anyway, and had been sitting.


At least one particpant to this thread also thought it was dirty oil, so props to whoever that was (way back on page 1 or 2 I think). So far it looks like that really was the problem. Page 1 of the thread says dirty oil, page 5 says "buzz test." Appears we have two co-winners of the "start NMRanchers PSD" contest.

So, I feel a little humbled by this, if indeed this is the true source of my problem (I'm not 100% convinced yet).

At least it wasn't the batteries or GPs.





Hopefully this will be my last post to this thread (pending any unanswered questions you guys have etc.)

 

NMRancher,

Major congrats in order (even if you didn't really 'fix' it) Been reading since the beginning, and 2 days ago my truck doing the EXACT same thing. Although she still hasn't started, alas. Did you ever test HPOP pressure?

Can anybody tell me CLEARLY just how to put together a gauge?

And how did he suggest using the ether? Did he mention wd40? Been thinking I may resort to it. Has anyone ruined their PSD using juice?

And another question on my first post... actually make that 3...
Where are the Baro sensor?
EOT sensor?
AIT sensor?

I'm 50 miles to the parts store and no INT'l dealer boohoo and

I ain't leavin' my ranch till she's fixed.

Thanks for keeping us updated; your determination has got me about to go out into the cold and FIX MY TRUCK, dammit.

Danny

 

NMRancher'
First congrats on getting the truck started. I'm a little skeptical of the dirty oil theory at 4K on the oil. I've read of a case at 8K where the anti-foaming agent in the oil depleted and caused problems with the HPO (high pressure oil) system. If I can ask, what brand and type of oil you used that gave the problem at 4K and did you replace the oil filter at the same time?

dannyo,
First welcome to FTE (first post). Second I would recommend starting your own thread with your questions because this one is so long and you might get lost and poorly assisted. I would also suggest you go to the "user cp" area and fill in your signature with year , model truck, etc so we can see what you have. Anyone moving their mouse pointer over the "signature" in the upper right hand corner of each post can then see what you have and better assist you.

Probably the first two questions that get asked on a no start problem are:
1. Does the tach move while cranking the engine? This indicates whether the CPS (CMP as Ford calls it)(camshaft position sensor) is working.
2. Is there smoke, and color smoke, coming from the exhaust while cranking? This typically determines if it's a fuel delivery problem or a glow plug problem.

Any additional info you can give on the problem will always help.

The baro sensor in inside the cab above the accelerator pedal.
The AIT (air intake temp) sensor is next to the air filter, inside the air filter housing if you still have the original housing on your truck.
The EOT (engine oil temp) sensor is behind the drivers side of the HPO reservoir.

 

No, I did not. But if I knew that my Fluke VM couldn't read the IDM voltage at the valve covers regardless, I'm sure my next thought would have been something wrong w/ my IPR. In fact, I'm still wondering about that component. A combination of dirty oil and a worn-out or perhaps less efficient IPR makes loads more sense to me than just the dirty oil. But I'm not speaking from experience....


No, but I don't see why you couldn't get a hp gauge out of Harbor Freight and plumb it in there. The hard part would likely be the fitting, i.e. where the high pressure sensor is. Screw a T fitting in there and install your gauge and, voilá! Problem is I'm betting the fitting in the head is some oddball thing not available in a Granberry catalog. Not an insurmountable problem, but could take some digging (been there w/ a '99 PSD fuel line, which are solid compared to our trucks' hoses, and have some PSD-only fitting). Or not.

Try it.

Loosen the clamp on the intake tract where the rubber boot goes on the air box, and pry the boot up to create an opening. Turn on the key, let GPs heat for 5 seconds. Crank the motor and squirt small amounts through the opening in the tract. Start small, increase until it fires. You don't want to kill your starter but go ahead and spin it enough times to give it 3 or 4 shots of ether.

I think if you soaked your air filter w/ ether, and then started the truck and let it run you could damage it.

I have to admit I don't understand this issue fully. Ether works and causes no harm on the vast majority of engines, but the 6.5 chevy just pre-knocks like a rod is going to shoot out the pan (don't try it), and I've always been told that it is verboten on the PSD. This guy showed up w/ the scanner in one hand and a can of ether in the other.



I hope somebody comes along to answer your other questions, I think they are good ones, and would myself like to know the answers.

 

Always use 15-40 Delo in everything, have the same oil in most of my stuff. I would never even bother changing the oil in anything w/out replacing the filter. Filter brand I had in there could've been anything but Motorcraft (see: spawn, satan). Whatever Car Quest carries (Purolator???).

And the more I think about it the more I agree w/ your comments about the oil etc. (wish I didn't....)

 

so let me get this right....

somebody comes over and scans your truck and now it starts??????

runs fine for a few days and then you change your oil???

for some reason i dont buy that....

well at least she runs now..

 

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I'm having a hard time w/ the oil also.Went w/ a buddy the other day to look at a used 7.3 Excursion,had 63,000 on it and the oil wasn't even on the stick. The last oil change info the guy could dig up was at 42,000!The thing ran great though.Didn't buy it for obvious reasons.

I was looking at my man. yesterday in the Hard Start/No Start Diagnostics and it said:

"The CMP and the IPV valve are the two most critical electronic sensors/acutators to inspect in a no start situation".

If your injectors were stuck ,was it open or closed?And all of them?Shouldn't you have gotten some smoke at the tailpipe?Just thinking out loud.

Brian

 

Why not?


- Truck would not start, I came to this forum
- Back on page one or two most of the usual suspects were covered, lift pump, oil change, batteries, CPS. So I changed the oil and batteries.
- Truck would start about 5% of the time after that.
- Jimmy does the Buzz Test and it starts. Before this there were at leats 2 dozen no-start attempts. Now going on 4 days and about 15 starts w/ no problems, of the 15 5 were cold, 2 were VERY cold.
- On his recommendation I change the oil again.


That is how it happened and I'm not sure which part you have an issue with. If it is the dirty oil and intermittent nature of the problem then I agree w/ you. The only apparently material changes I have made are the one (then 2, then back to 1) new battery and the oil change. Seems strange to me also, but not to my new friend and PSD mentor Jimmy the Buzz Tester from Chapparal, NM.

But most of the non-starts were when it was cold, so maybe that is the only source of intermittent nature of this issue. Time will tell.

I haven't started it yet this morning, it is pretty warm, already in the high 40s....


Fired right up.








Are you still fixated on the Glow Plugs 97?? Do you work at Expressway Ford or something?

I'm a little insulted that you don't believe me when I tell you that THE GPR IS WORKING! REALLY! I SWEAR! JIMMY SWEARS! 7 GPs IN SPEC!!!!!!!!!!!

In all seriousness '97, I appreciate all your help, and we will see if this gremlin resurfaces. I would not be surprised.

 

I know exactly where you are coming from, my dad has a '99 and he regularly goes to 5k. I pointed this out to Jimmy, (BTW, my dad's GPR is fried, has been for months, I'm not sure how hard it is to start but he hasn't complained too much).

Anywho Jimmy explained that the newer PSDs have a different kind of injector, this is why they are quieter, they fire multiple pulses to mitigate the knocking, and, according to this former Navistar tech anyway, don't stick as easy, if at all, but don't last as long as the older-style injector. I know a guy w/ a '00 that replaced them at about 125k, but through the dealer, so maybe he just got fleeced. I've heard other folks complain about the cost of replacing injectors, but it occurs to me I haven't heard folks complain about the older models like mine in this regard.

CMP: Is this the cam sensor?? Remember, I replaced this early on.
IPV valve: What is that? If this is another term for the pressure regulator for the HPOP, I am considering replacing/rebuilding it, particularly if this problem resurfaces. I forgot to mention that after the buzz test, the tech unplugged the HPOP oil pressure sender to bump up the pressure (so he said). But I had already unplugged this sensor 2 or 3 times to no affect (trying to make it start and/or trying to get it to spit an ODBII code).

Once again, you are the man, thanks for the info. My impression is the injectors are stuck closed, but I didn't clarify that. I would imagine they are "normally closed" solenoids, and when the IDM lights them up they open (or sometimes they stick).

Never saw or smelt any smoke at the tailpipe (yes, I even stuck my nose in there, so I'm fairly certain it was not getting any fuel).


Thanks for your interest in my problem(s).

 

no actually i am in the U.S. NAVY.
dont work for any stealership. never have never will. please no offense taken here and hopefully you arent offended...
i am a grown up and can disagree on here and have no hurt feelings..

not stuck on the glowplugs by anymeans...........

i think this was checked/covered by you early on... the oil level in the cc and hpop??????

if it wasnt that i dont know what was...

did he tell you what your codes where???

i have never heard of a code that would not let the engine start until cleared......

and when i say i have never heard that is exactly what i mean.........

hopefully not coming across as never heard of that means it cant happen or desnt exist...

i know no more than the next guy here and am here to learn and help when i can...
thats why i ask you so many questions...... as this is a new problem for me..


and as far as the glow plugs....in my mind i could think of nothing else that was wrong with your truck thats why i said that so many times...

anyhow you got er running and thats all that matters..


ryan

fwiw the idm needs 9.6v to fire the injectors.............

 

Sorry, Ford calls the camshaft pos. sensor CMP.The other was a typo,I meant IPR, for injection press. reg. valve.

 

NWRancher,
A final thought on your problem. If it was an injector problem due to dirty oil, possibly the buzz test exercise them enough to free them up good. I would run some diesel fuel additive, PowerService DieselKleen gray bottle (available at Walmart) or Stanadyne (available at most truck stops or farm stores). They have injector lubricants in them that may help cure / prevent the problem. Possibly you're getting some "dry" (low sulphur) diesel fuel in your area. I use DieselKleen in my truck for this very reason. It's hopefully cheap insurance against injector problems or having to replace injectors (big $$$$).

 

Yeah, we did that on page one or two. I have checked it 2 or 3 times, always full.

Yes, but they all related to things I had jacked w/ (CPS, IPSensor, etc.) so he didn't pay much attention to them.

You are obviously very knowledgeable about these motors and I appreciate all the time you have taken to help. I would have parted that thing out by now if it weren't for this forum.

Thanks again.