Intake manifold holes, and starting problems- need opinions.

[MadMac]

Apologies for yet another - it doesn’t start - post.

My old 1985 6.9 project truck has had increasing starting problems since the tanks were replaced (not convinced these are the issue…), but in the last several weeks (6 months from takes install) has become unstartable without help from starting fluid - a very bad thing. When I climbed into the engine bay to inspect the fuel input / return lines today, I discovered holes in the intake manifold. I was trying to get resistance readings from the glow plugs, and found them (zero in tested cases), photos are included of the holes - the #1 cyl is 1/8th and the #3 and #5 cyls are 1/4 and 3/8 respectively. No others were obvious, I did not work through the remainder thoroughly.

The obvious to me is - these engines do not care where the “air” comes from. Fuel, certainly. Compression - absolutely. The timing of all three is required. But nothing compared to the complexity of gasoline engines. What is perplexing is - once started, it runs just fine. Power, work - even restarting - work just fine. It does not stall, miss or anything else I can hear/feel.

I suspect this is a two factor problem. The engine started easily until recently, but declined - particularly when other work was done around the engine (air conditioning covered to R-134) (yes, I suspect leaks). Yet the smallest amount of ether starts the engine, making you suspect compression related to starter speed - but the batteries are good, two years old - and are refreshed with a battery tender - they are fully charged (I checked). 

I checked pressure at the fuel filter valve cold both after 120 seconds of starting (with pauses) and the next day at the first 1 sec of starting. Both have high volume fuel from the shrader valve on the fuel filter. So, draw, lift pump, etc - fuel intake is not the problem. There is a marine F/W separator, which does not have water, and has plenty of fuel with pressure.

Aside from the holes in the intake, I’m at a loss for the lack of starting. Once it runs - it runs (is this just the natural durability of the engine???). Could not find related links to starting problems in the archives - but I am happy to chase whatever the community suggests. Thank you all in advance…

Ladies, Gentlemen too - I’m at a loss on what to do next, and humbly ask for any thoughts and advice.

 

[IDIBRONCO]

The only place that needs the be sealed on these intakes is where it attaches to the heads themselves. That's in between each pair of intake bolts. I'm pretty sure that these holes are designed to be drains in case you have a return cap on an injector leaking. I think that they just go through to let fluid drain onto the intake gasket and in no way affect the starting.
What you have is fuel drain back. This simply means that when the engine is shut off, for some reason, the fuel in your fuel system drains back to the tank. It sometimes is related to and often confused with air intrusion. Since your truck runs just fine after it starts, you do not have air intrusion, which happens when air gets drawn into your fuel system before the injector pump. The lift pump on the side of the engine is designed to have a one way valve inside to prevent the fuel from draining back toward the tank when the pump isn't pumping. These can and do fail. If/when they do, this will allow fuel to drain back after the engine is shut off. I'm not saying that this is exactly what your problem is. I'm just suggesting one possibility. The solution to this to install an aftermarket one way valve in the rubber fuel line before the lift pump.

 

[Big Bart]

Since you do not feel it’s how long you crank. Rather just adding a little starter fluid gets it running. To me sounds like glow plugs, so a cold start issue. Rather than a lack of fuel issue which is solved cranking for 30 seconds 3 times gets it started.

Does your wait to start light come on? If so for at least 5 seconds or more? You said you tested some glow plugs that had no resistance, that is a sign they are burned up and not working.

I would pull all the glow plugs and test on the bench. If 3 or more are bad replace them all. (Have no resistance.) Only use official Motorcraft GP’s As other brands ballon and can break off when extracting them. I would also do a compression test while they are out. Make sure your compression is over 300psi on every cylinder.

I would also replace the glow plug timer. If these stick on they kill all the glow plugs. So cheap insurance to replace it.

Put the GP’s back in and then test the #1 and #2 glow plug to make sure they are getting power and for more than 5 seconds with the engine cold. (Insure both wiring harnesses are working.)

If that does not fix some other things to check.
1) Fuel supply issues.
2) IP timing advance is getting power and activating.
3) The timing on the engine is set correct.

 

[The_Josh_Bear]

Good job trouble shooting your fuel supply and battery situation for us, that helps narrow it down a bunch.

If it cold-started easily recently and is going downhill fast, and you have good fuel supply then you can only look to glowplugs and starter speed. The need for ether could be either one.

1. The starter should turn faster than you can count out loud. (Unless you're an auctioneer)
The IP's need a certain RPM to fire the injectors and too slow won't do it.

1a. Corroded battery cables are often the cause of poor starting. Most typically is the starter, then IP, then cables. But IP's don't suddenly become hard to start.

2. You can test 12v glow plugs with a test light, I can't remember if the early 6.9's are 6v or 12v GP's. But if 12v it needs to be an incandescent style and it should glow brightly. You'll know one is out or dying because the lamp doesn't light up or it's dim.

3. You say the fuel filter is full of fuel, so it shouldn't be fuel drainback/air intrusion. (In order for the fuel to drain back, something has to replace it, which would be air.)

4. Another thing easy to try is to double-heat the GP's. Run them for one cycle then wait a few seconds and do it again. If that helps then glow plugs are probably the culprit.

 

[MadMac]

The only place that needs the be sealed on these intakes is where it attaches to the heads themselves.
...
These can and do fail. If/when they do, this will allow fuel to drain back after the engine is shut off. I'm not saying that this is exactly what your problem is. I'm just suggesting one possibility. The solution to this to install an aftermarket one way valve in the rubber fuel line before the lift pump.

Thank you for the suggestions. The lift pump is relatively new, maybe better said as under 5000 miles. The old one - which ran - was hanging on by one bolt, leaking and I think actuated LT 50%... Also, I tested the pressure at the fuel filter schrader valve, both after 60 seconds of cranking, and *prior* to any cranking - both provide excellent fuel, though I didn't get a pressure gauge on it. More to DX there...

I believe your point about the fuel going back in the tanks is right, I've thought as much myself - because fuel does not leak from the truck - and the system is clearly pressurized when running. One of the mechanics who was working on it (see previous comments about my old hands...!!!) complained there was fuel in the valley pan - but didn't take any photos or video... and I seen nothing since.

Again - Thank you for the pointers, I'll keep chasing this.

 

[MadMac]

Since you do not feel it’s how long you crank. Rather just adding a little starter fluid gets it running. To me sounds like glow plugs, so a cold start issue. Rather than a lack of fuel issue which is solved cranking for 30 seconds 3 times gets it started.

Does your wait to start light come on? If so for at least 5 seconds or more? You said you tested some glow plugs that had no resistance, that is a sign they are burned up and not working.

I would pull all the glow plugs and test on the bench. If 3 or more are bad replace them all. (Have no resistance.) Only use official Motorcraft GP’s As other brands ballon and can break off when extracting them. I would also do a compression test while they are out. Make sure your compression is over 300psi on every cylinder.

I would also replace the glow plug timer. If these stick on they kill all the glow plugs. So cheap insurance to replace it.

Put the GP’s back in and then test the #1 and #2 glow plug to make sure they are getting power and for more than 5 seconds with the engine cold. (Insure both wiring harnesses are working.)

If that does not fix some other things to check.
1) Fuel supply issues.
2) IP timing advance is getting power and activating.
3) The timing on the engine is set correct.

I typically let the Glow Plugs cycle at least twice - so 10 to 15 seconds. This appears to be working, both b/c I can hear the solenoid (newer), and due to the cycle times being six, break, two, break etc... The controller is... less new but not old. Replaced at the same time with the GP harness, the return lines back to the central were also replaced in a similar timeframe.

I *had* a GP bypass on, and now I'm thinking how silly it was to revert it (Non-GP-aware drivers had to be able to drive the truck...) Easy enough to remediate... Lucky to have survived a "cheap set", so I have a spare used set of the right GPs - I'll just bench test them, and R&R existing. Rather - I'll add that to the "do" list.

This happened somewhat quickly - several weeks - more importantly it degraded quickly after someone else's work. So after making certain the GP system is working, I'll re-seat all the return lines. Both the tanks and pickups are new - but not the fuel lines (kick self here...) so I'm going to push IP Advance and Engine Time down the priority list. FWIW - I dialed back the IP Advance slightly - 1/8th I think - to fix a previous grey smoke issue several years ago.

Thank you for your comments and suggestions! I will update.

 

[MadMac]

Good job trouble shooting your fuel supply and battery situation for us, that helps narrow it down a bunch.

If it cold-started easily recently and is going downhill fast, and you have good fuel supply then you can only look to glowplugs and starter speed. The need for ether could be either one.

1. The starter should turn faster than you can count out loud. (Unless you're an auctioneer)
The IP's need a certain RPM to fire the injectors and too slow won't do it.

1a. Corroded battery cables are often the cause of poor starting. Most typically is the starter, then IP, then cables. But IP's don't suddenly become hard to start.

2. You can test 12v glow plugs with a test light, I can't remember if the early 6.9's are 6v or 12v GP's. But if 12v it needs to be an incandescent style and it should glow brightly. You'll know one is out or dying because the lamp doesn't light up or it's dim.

3. You say the fuel filter is full of fuel, so it shouldn't be fuel drainback/air intrusion. (In order for the fuel to drain back, something has to replace it, which would be air.)

4. Another thing easy to try is to double-heat the GP's. Run them for one cycle then wait a few seconds and do it again. If that helps then glow plugs are probably the culprit.

Yes on the starter. "newish" - the 3rd one installed, I learned though lessons about letting them cool off... and getting good parts. When it was startin well - even cold it would start on 1/2 second of turn. Two cycles of GP and it would start with half throttle. Two year old good 800cca batteries - on a tender, they are fully charged. 90 seconds of 15/30 cranking (so six cycles) took them down about 15%. The Tender really makes the difference to trickle in that last part of the charge.

All the related Battery/Starter/Ground cables were replaced with a custom 4-0 harness. It made a huge difference in "starter spin rate". As much as it cost, and as difficult as they are to install - on my highly recommended list if you have a set of 35 year old aluminum versions...

GP's are 12v on these. I have the right meter, and will bench test. I have a spare used set of the right GPs, so I'll just wrangle 8 together and replace the existing ones. FWIW - my standard of practice for GPs is "two cycles".

Really appreciate yours and everyone else's help on my old Heffalump. ... ... Yes, the wife's Pilot is called "Wooozle"

 

[snicklas]

Since this seems to come up every so often... the plug voltage.

Both the 6.9 "dumb" and the 7.3 "smart" controller send B+ ~12 volts to the plugs.

What I have read is they are 6 volt RATED, non regulated plugs. This is so they would heat faster, so the WTS cycle was shorter. Remember, Ford was trying to bring Big Block Gasser owners over to diesel.. and on a 460, you can hop in and hit the key. If you have to sit there "forever" waiting on the WTS light, that could be a strike against them.

Unlike the 60g ones in the 6.2/6.5 GM engines that are 12 volt regulated. You can give them 12 volts and they heat to a point, then do to the design, stop heating and remain hot. You could put them on a switch and leave them on all the time without damage (as I have read members have by accident). But the 60g plugs take something like 30 seconds to heat and be ready for a start.

Not sure on the ZD1/ZD9's if you fed them 6 volts what would happen.... but it would take longer for them to heat... but not sure you could leave them on a long time without damage....

 

[The_Josh_Bear]

Yes on the starter. "newish" - the 3rd one installed, I learned though lessons about letting them cool off... and getting good parts. When it was startin well - even cold it would start on 1/2 second of turn. Two cycles of GP and it would start with half throttle. Two year old good 800cca batteries - on a tender, they are fully charged. 90 seconds of 15/30 cranking (so six cycles) took them down about 15%. The Tender really makes the difference to trickle in that last part of the charge.

All the related Battery/Starter/Ground cables were replaced with a custom 4-0 harness. It made a huge difference in "starter spin rate". As much as it cost, and as difficult as they are to install - on my highly recommended list if you have a set of 35 year old aluminum versions...

GP's are 12v on these. I have the right meter, and will bench test. I have a spare used set of the right GPs, so I'll just wrangle 8 together and replace the existing ones. FWIW - my standard of practice for GPs is "two cycles".

Really appreciate yours and everyone else's help on my old Heffalump. ... ... Yes, the wife's Pilot is called "Wooozle"

Nice man, then you certainly have nothing left but GP's, or air intrusion. Since you got fuel out of the schraeder on the cold fuel test, should be GP's.

Honestly I think your truck should start on accident even without GP's if you're doing 6 starting cycles with a hot and fast starter. I know mine would since I got the Power Master starter on there. My OE cables(not aluminum, were some made that way?) were corroded but I just chopped off the bad parts and switched to marine terminals. Made it a hair shorter than I'd like but at the time saved me a bunch of money for a new harness.

Anyway no joke sometimes I turn the engine over without GP's just to see how long it takes, hehe. But that's usually in the summer, 70-90* outside after a 10+hour day of work. Since the powermaster install I think it's never taken more than 6-8 seconds with no GPs. I should try it in the cold for fun, see if it ever catches. Would be good to know for just incase. Of course thats what the ether can next to the back seat is for too.

Haha I like your vehicle names... my brother named our local network 100 Acre Wood almost 20 years ago and all the computers on it: Rabbit, Pigglet, Tigger, Pooh. Many years later my upstairs computer is still Pooh and my main box is Tigger. Just for funsies.

 

[MadMac]

@IDIBRONCO, @The_Josh_Bear, @Big Bart

Gentilemen burners... thank you...

Finally over to do some multimeter work this morning, spot checking the easy access in #1,3,4,8... 1 and 8 are dead. 3 & 4 - ~15.x ohms. So, this should confirm the problem.

Spot checked my old sets, and I have plenty showing ~1 ohm net. So - its the GPs, exacerbated by the damned controller (thank you @snicklas for the notes)

Saturday I defensively ordered a set of motorcrafts, I'll use them to reference set the three old sets I have...to make up some spares, and next weekend we'll get the work done. I'd forgotten how damned pricey these were - at $10-$12 each (yeah, in a hurry). Which means it is worth while to bench test them and save the ones still good (which will make DX even more difficult later.

For now, I have to make a run to the lumber yard so... slap my hand for the expediency method I'm about to use... unfortunately it is valley fog "wet cold" out... not much choice.

@The_Josh_Bear - one of my networks is... logically the same as your brother's. I have had to add some creatives such as "PoohBridge" and "PoohSticks" to the pool...

 

[Big Bart]

Sounds like you have diagnosed the no start issue back to the glow plug system so good for you. Keep in mind the block heater is another temporary way to get started if the glow plugs are not working.

Be sure after putting in the new glow plugs to check the wiring harness at #1 cyl and #2cyl to make sure you are getting power for at least 5 seconds. That will confirm the rest of the system is working. (At least at the time of the test.)

I would also while the GP’s are out, run a compression test for a baseline. Then if you have issues in the future a new compression test at that time will be more informative since you have a baseline.

 

[MadMac]

Quick update on this thread (well, not so quick...). After the fiasco with the GPs being wrong, am now in possession of two sets of what looks to be valid ZD1A's - the punched bag variety. Also taking the advice above - ordered a decent compression testing kit. It was already in the high 30's when I started the work last night, somewhat cold for my area. No shop for me...

The bad news is that the GP in cyl #2 sheared off and is frozen to the block. At least it is the easiest cyl to get to. Have not decided exactly what to do, but leaning towards a) trying to extract it using the drill/screw/pull method (doubtful), and b) pull the injector and drill it out with liberal use of the shop vac and a small neodymium magnet. If the end drops in the cup, then I'll have to find a shop to pull the heads off. Sucks - it is what it is. Half the GPs were sooty, two were marginally mushroomed. Seven GPs are stamped, the broken GP - has beru stenciled/printed on... grrr...

The good news was the compression testing looked really good with only #7 being unlike the others at #400.5 PSI. That lower number could be my impatience showing - it was cold and my fingers hurt - so just not tightening the adapter enough. Tests were done on a warm engine (2 hours after a 20 min intown drive), using 10 seconds starter cranking each. Nearly killed myself getting to #4, turns out to be the high cyl.

#1 465.5 psi
#3 466.0
#5 480.0
#7 400.5

#8 461.5
#6 438.0
#4 494.0
#2 - No Test

So fellow burners... is this good, bad, or ugly?

A bit worried about the variability, but given anecdotal comments about desired compression in the forums, I'm thinking the engine internals are in good shape. OD reads 62K, obviously TMU. I've guessed at 160K given wear on the foot pedals, interior paint, seat, etc. it just didn't look like 260K miles. Given how badly the rest of the truck was cared for... I doubt these numbers are due to a well cared for engine - interested on others opinions on appropriate pressures for a 160K engine. Since the C6 is highly likely to have a shift kit (angry mule cold shifting) indicates its been out of the truck - leads me to thinking this engine has been rebuilt.

In other cringe-worthy thinking - To test the GP/Controller, I may well stick the broken GP back in #2, tape it off disconnected, put in new GPs and replace what is likely a still good controller. Guessing that even with one disconnected GP, it will start just fine. Risk is the tip breaks off... with the 50/50 chance of a catastrophe in #2. Cringe-worthy, no doubt. I'd best stick with the plan to just have shavings...

The rather cheap GP tip extraction kit arrives Monday, an expensive kit - on Friday. Given it will rain all week - I'll update next weekend - and thank you everyone for the good advice.

 

[Noiseydiesel]

I have briefly read your story and will offer you a bit of advice i ran across some time ago with the fuel return line routing. Somewhere along the line I read of a situation where the engine would start and die. It was found that the fuel return line coming off the filter housing should be raised up two inches. I did this and wrapped a zip tie around it in order to keep it bent up at the 2 inches.
I did this trick when I first got my toy and never have had any problems with stalling after start or prolonged cranking.

 

[Big Bart]

Some thoughts

Ford’s only guidance on compression was no two cylinders further than 20% different. You are right at 20%, so nothing to worry about. Personally if it was me and it was 380 not 400 I would still run it. You might find a second test on charged batteries comes back at 425psi. To your point a leaking test gp, lower batteries, hot starter, 8 vs 10 seconds all creat variance. So you are in good shape.

I have yet to have a stuck GP. So no pro on this. But I would not run it it as is, a rebuild is down time and very expensive. I would rather try to get that one out. Perhaps you can drill partially down and use an extractor. If not pull the head and fix it.

Some other ideas.
a) Put the piston at TDC.
b) If you need to drill through the GP tip, Pull the injector and use vacuum when drilling and compressed air to help blow out shavings. c) Put lots of grease on the drill bit to catch as much of the shavings as possible. Before drilling all the way through the tip blow out any shavings so they do not drop in.
d) Drill out the center of the bad glow plug.(The part that has the threads that you did get out of the hole, or a different glow plug.) You then can insert in the hollow glow plug in the hole and use as a drill bit guide. Prevent drilling up to, or on the GP threads.

BTW the 7.3 controller generally works with up to 3 bad/unplugged glow plugs, so yes it will work with one glow plug unplugged.

Lets us know how it goes.

 

[Jl elevatorman]

What you have is air leaking into the top of the fuel filter. This is happening for two reasons. The first is you must replace the O rings under the injector caps. Also a new return line set won't hurt either. secondly, you could have a leaky check in your fuel pump. If you are going to put a check valve in line with pump, it must be LOW PRESSURE. A sure fire work-around is to put an electric fuel pump around the lift pump and wire it to the glow plug circuit. If it's been sitting a while, let it cycle twice. Joe