Hi everyone!

I've got an interesting one for you today! on my '91 E250 Club Wagon 7.3

So late last year I had a miss fire and shake at idle, witch I determined it wasn't injector related, upon removing valve covers and pressing down on the rocker arms push rod side, I found I had 3 bad lifters that weren't holding pressure.


So I replaced all lifters, put everything back together, still had a slight miss, found a bad - 1 month old injector on #6. replaced it with another brand new one. Engine ran like brand new for 10 min idling.

I shut it down to finish putting everything back together, start it back up, miss fire is back and dry lifter tick.

After cursing every word I know, I said the hell with it, drove it like that for a lil over a month before storing it for winter.



Now I have everything opened up again (intake not off yet), I have both valve covers off and all my lifters have pressure in them? Engine been sitting for 3+ weeks now.

And it's got dry lifter noise when it runs, worst at idle. When a lifter gets noisy isn't it because it's not pumping up or holding pressure?

What else can this be? Any other way of finding out witch one went bad when all of them are holding pressure? It is miss firing, you hear it through the exhaust and has a very noticeable miss if you put your hand in front of the tail pipe.


Long shot but could my new IP be causing the miss and putting extra pressure on a lifter making it noisy?

I'm totally stomped here, and believe me, its no walk in the park getting this deep into an IDI that's in a fully loaded van...

 

Not to be a smart *** but have you checked the oil level? The fact that it's worst at idle indicates either fuel related​ or the lifter isn't being supplied enough. Of course if it's full it could be a wore out oil pump, probably worth hooking up a gauge if you don't have one already. What brand are the lifters?

 

Oil is always full, this thing never burnt a single drop of oil, I change it every 3-4k miles, I use Valvoline premium blue 15W40 with a Motorcraft FL1995 PSD filter.

I forgot to mention this is a Ford Reman engine, that now has 219,000km (136k miles).

Lifters are EngineTech brand from Rockauto.

 

I would say add two quarts of that lucas oil stabilizer to add some viscosity/oil pressure to rule out that it is the lifters. What's the oil pressure like? Not sure if you have a mechanical gauge or not. My 6.9 does 50psi cold at idle and 25 once warmed up, about 50 once your running down the road.

If it's indeed not the lifters I would take the injectors and have them tested just to be sure before buying an ip. Most shops will test them for next to nothing. Most companies "new" injectors are a joke, they set the pressure between 1400-2100 and call it a day. A brand new set of eight I had were all over the place and one was locked and wasn't fueling at all.

As a last step before changing the ip I would do a compression test before to rule out a dead hole in a cylinder. I believe the glowplug hole thread size is m10x1.0, also be sure the tester is rated for at least 500psi and has a liquid filled gauge

If you had a spare ip laying around it would really come in handy about right now.

Hope you get it figured out and I'll always be a major fan of your YouTube videos haha

 

IP and injectors are already all new from last year, a few months before I started having all these issues, injectors were all tested before install, they weren't all 100% matching pressures, but close enough anyways.

I do have a real oil psi gauge and warmed up it sits right around 30psi of pressure so it's not low on oil pressure.


I'm gonna do a compression check this weekend, and if I can't find anything wrong there, I'm gonna take the valley pan out, and valve covers off, re-install all the fuel system, and get it running with no valley pan or valve covers and just observe it running see if I can't see anything wrong.

 

I got some compression numbers!


front of engine
----^----
310 300
300 290
300 300
410 310


Are those good numbers? Seems a tad low to me, however, no blow by and no oil consumption at all in this engine.

Any taughts on that one cylinder at 410psi vs. all the others around 300?

 

I don't know what the readings should be and don't want to look it up but my thought is that the 410 psi cylinder is where the problem is, ... but WHY?

Carbon build-up? Or, leaking injector? <--fuel leaking in that tends to seal the rings which increases compression when you test it?

 

That engine is worn out. You've only got one good cylinder, and that would likely account for any rough idle as that one fires strong. On a fresh build it'll be well over 400 psi.

If it still fires and all are worn close to each other it's good enough so long as it's good enough for you and blow by isn't too bad. I don't know spec off the top of my head but I'd wager too much under 300 psi and it won't fire, which could account for your miss on that one at 290.

Regarding a leaking injector, it there was oil in that 410 cylinder it would likely fire and make a heck of a scare while destroying your gauge. Do not test diesel compression "wet".

 

I couldn't find the low end limit for compression either but the 'normal' acceptable variation in cylinder compression between lowest and highest, stated in my 87 manuals for the 6.9L is 75%. That means going down from 410 psi (in number 8), would be 307 psi, or going up from 300 psi would be 400 psi. All it says is that a variance exceeding 75% implies improperly seated valve or worn or broken piston rings. It seems to me it would be blowing a lot of white smoke if that was the case.

He says it's running good otherwise so I wouldn't call the engine "Worn Out" yet, not as a whole, anyway.

The noise must be coming from the valve train and I'll post a page from my manual for diagnosing that, should be the same valve train except for the size of the valves. Quite a lot of things to look at.

I don't understand why one cylinder, #8 would be so much higher. Maybe it got better lubrication? It seems like the rear two cylinders on these engines 7 & 8 get pointed to more often than others when diagnosing problems, like IDI-John's glow plugs/controller problem awhile back AND the unmaintained CDRs leaking into the rear two cylinders.

Oh yeah, I read something related to the oil pump gasket leaking air into oil lines- maybe getting into the lifters. That's interesting. Maybe it's on the page I'm going to post.

Thanks for that safety warning. I was thinking of a comment I had read about a similar situation in gas engines and it made sense.

I have excellent problem solving skills, seriously but I am taking high doses of morphine 3 times per day for chronic pain and that really messes up my concentration, focus, attention span and mental stamina- (and almost never enough sleep). That's why my posts are often quite long and then I'm honestly too worn out with no concentration left to edit them to make them shorter.

I should use that statement as my signature line since it happens so often and then maybe more people would read my longer posts. I do have a few "brilliant moments" from time to time.

 

Two pages. The air leak I mentioned previously that could affect lifters would be at the oil pick-up tube gasket mentioned in second column on first page. You may have to enlarge these images to read them clearly. This is the best I can get from the scans on CD of the original manual and have file sizes small enough to upload.

 

I just re-read your original post. That does seem like it could be from an air leak at the oil pick-up tube! Bad gasket or a crack.

I would take it off and examine it very closely for cracks and replace the gasket.

I hope it's that simple!

 

I don't understand why my compression would be low in this motor, it's a Ford reman engine with low miles, has tons of power (alot more than any other of my IDI's), burns 0 oil, and has 0 blow by. Starts on half a turn of the starter! I'm thinking maybe a bad compression gauge to be honest, i've never used it before, brand new in box Napa one, but older one.


Anyways, I think I found the problem, when I removed the intake and valley pan, while observing everything inside, I turned over the motor, everything was operating normal down there, rocker arms all working properly.....but visually looking at the very last push rod, drivers side rear of motor, I noticed it looked odd, didn't sit very well on the lifter.

Looked out of place, sticking up abit more than all the others.

Upon removing that rocker set, found this:

Left rocker was the one with the pushrod that wasn't properly sitting in the lifter. It wore a really odd uneven ridge in the rocker. Right side one is normal no wear showing.



It's been "tapping" the valve quite a bit from the look of the valve as well, last one on right, hard to see in pic, but I can easily feel with my fingers the tip is flatten and has sharp edges all around. Guess there was a problematic lifter after all!




I haven't yet fired it up, it's all back together, minus the intake, I found some really horrible looking tall Orings that go at the back of the IP, the middle one that goes to the fuel filter, gotta find some and replace those before putting the intake back in and firing it up.

 

Its fixed!! I fired it up this morning, runs like a dream! Super smooth and healthy.

Can't believe it was that one new defective lifter, witch still held pressure when pressing down on it.



On a side note, I found my problem to my random loss of prime every now and then....the special thick orings that go in the hard line fittings, the center one behind the IP that runs up to the filter, that Oring was toast! Couldn't find anywhere that had those so I made one using return line hose, slipped it on and fits perfect!

 

They come in whats called an "injection pump install kit"
They are refered to as fuel line olives, rockauto stocks the kit,

More Information for DELPHI 7135275

If using a 6.9 you need two kits for all as the injection return uses one, if 7.3 the leftover one can go before the filter.

Stock up before they go MIA (: