8 months ago my Granddaughter got an "00 Ranger 3.0 for her first vehicle. It now has 160K. 6 weeks ago the truck started bucking/stumbling on her so bad she was afraid to drive it. I sent her to a small shop with a good mechanic for diagnosis. They said it needed a valve job but couldn't do the work. To help out, I decided to pull the heads and send them out. I haven't done any engine work of note since the early 90's but previously done several major rebuilds with good success.

When I drove the truck to my place about 25 miles away, I noticed the stumbling occurred while maintaining a steady cruise. I found out that loading the engine smoothed it out as did coasting, so I would accelerate to 65ish and coast to about 45, then repeat.

At my shop, I pulled the heads, and they were promptly pronounced DOA at the machine shop due to numerous cracks and said the engine had probably been badly overheated. The relatively new water pump backs that possibility up. The machine shop located a used reman set with no repairs and I installed them. I also carefully and accurately installed a reman CMP and synchronizer. Now the vehicle won't start.

#1 cyl. has great spark and great compression (others not checked). Fuel at the Schrader valve is under very high pressure. My scanner gives me cranking rpms of 250ish to 400+ which I believe indicates the CKP is working. The scanners temp indication matched OAT.

I am not sure about timing chain condition. One way I tested it indicated a potential 12* to 15* slop. Without the benefit of a helper I tried to check it again by marking the CMP flag location at TDC, then hand turning the motor further, then backing it up to TDC. I thought that would leave the flag at a different point where I could then determine the degrees of slop. But, nay nay, the flag was exactly where it had been previously.https://www.ranger-forums.com/rf/for...:irked::irked:

 

Cracks in head and symptom was bucking?
Overheating yes, bucking reads like dirty MAF sensor or faulty coil pack

Compression of above 150 in one cylinder would mean timing chain is fine.

As you know there are 2 TDC's for a full revolution of the cam, and the CPS(cam position) sensor is timed with cam not crank.
So remove #1 spark plug and rotate engine until you start to get air being forced out #1 hole, start of compression stroke, continue turning crank until TDC mark is at 0deg.
Now setup the CPS/syncro

Check the coil pack, make sure it is plugged in.
Spark plug wiring is a bit odd on the coil
3 4
2 6
1 5
Front

The 5 6 4 always gets me

If you manually add fuel, i.e. starting fluid or gas in intake, does it start and then die?
That would confirm good spark and compression but no injectors/fuel.
That could indicate a PATS(passive anti-theft system) issue

 

Probable overheating was an event of a former owner as the truck has a replacement water pump. We've not experienced it. I agree that cracks in the head and bucking aren't related, but I was concerned about the constant repeat code throw of #5 misfire. In retrospect, I really don't think the shop did a diagnosis with any guages. But I figured 160K was justification for a look at the valves. Going that far, there was no way not to do the other head considering we want 6 more years out of this thing. Both heads had numerous cracks and # 5 cracked valve seat. I watched the magnaflux.

After numerous hours of research and numerous video's at the University of U2be, I could teach a class on CMP's and sycnh's. I'm not even sure that stuff was a concept in '76 when I got my degree as a power mechanics shop teacher (which I never pursued as a vocation).

I LOL at the 4-6-5 everytime I go thru it.

Did a compression test yesterday and found 90's across the board. I had a discussion with machine shop. He quickly remembered same problem from another and recommended loosen the valves for initial start and oil pressure build up in the lifters. I had operated the lifters in a hand press and pumped old oil out. I was told that oil soaking was no longer recommended--but I think that was bad advice. Maybe that advice does not account for pumping the lifters down.

Here comes an embarassing (or not) admission--I opened the valve covers and found 4 valves not operating. The push tubes were out of their seats. 4? All 4 were exhausts and exactly the same 2 on each side? I can't--and don't--believe I did that. How it happened, who knows? Jumped out at start attempt due to unpumped lifters?

I need to finish partial reassembly with valve covers off until start up is accomplished.

Also, I am no longer satisfied with fuel pressure. Subsequent tests at Schrader without a guage indicate pressure is half or less of the initial test. I will get a guage and have to work that out at the same time.

Well, time to get back out to my dungeon and oppressive heat. I'll update. Thank you for your time and $.02.

 

Well the truck is done and returned to my grateful Granddaughter.

I still am not believing that I could have installed 4 push tubes outside of their lifter cups. In my defense, it is extremely strange that all 4 were exhaust valves and all 4 were in a row in the firing sequence. I have got to believe they came out during initial start up attempt before the lifters were pumped. All the lifters had been drained and not oil soaked before installation. The fail to soak was based on probably incomplete info given to me from the machine shop.

RE: Fuel pressure--I made a Fuel Pressure tester out of a former a/c freon installer w/gauge. A couple of years back I had to buy one of those cheapo can of freon & installer kits while on a trip with a commercial vehicle. I took the hose and cut off the fitting that attached to vehicle. I bled the vehicle fuel pressure and removed the Schrader valve core. I fit the installers hose over the Schrader and clamped it with an appropriately sized clamp. It worked terrific. Operating the trigger allowed me to bleed off the pressure into a container.

 

Good work on finding that very odd occurrence, wasn't even on my radar, lol.

Lifers springs are usually tight enough so oil soaking is no longer needed, I still do it but just because I am old and have my "lifter soaking pan".