Lugging at speed/No power at WOT

[ratdude747]

Ah. I've never seen the races (in thew four that have happened since I moved here in April 2016)... always is on or near my birthday, and I don't drink so being around a lot of drunks with no other purpose isn't my forte (at least that's how the fireworks are, my wife makes me go to that part ). I've been all over Indiana my entire 27 years of life... this is where I'm likely settled... I'm moving to a new position at the same employer over winter shutdown, apparently I'm "good" enough that a department I work with a lot poached drafted me out of a position I half suck at into one that I, in theory, will kick epic ass in (I'm overqualified, but the pay is the same and the vacation rules are a hair better... and less hours too!). Anyway...

 

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Updates (been a month in the making, been uber busy at work and haven't had time to truely prove things out until now):

• Discovered that my thermostat was busted and not closing. Replaced it, but cracked the housing since bozo here hasn't done a horizontal thermostat in a shallow recess like this. Lost a week waiting on a new one; my wife has Amazon Prime though her parents, but the two day shipping only works if you actually remember to click the order button

• Used a socket extension to crudely confirm TDC... right on the money. Verified that base timing is still at the factory 10 degrees BTDC.

• Discovered that my hacked choke (no stove, just the stock electric) may be an issue when warm starting on a cool day. Had "fun" starting it coming out of lunch break a couple times last week (one time having a bunch of lube techs from the Valvoline next door insist on troubleshooting things... didn't know a carburetor from a can of pop . Anybody know of an electric choke that will fit a YFA that is meant to run without a stove or any vacuum stream?

• Checked compression tonight. Got dry test pressures of (cylinders 1-6) of 135, 140, 150, 135, 145, and 140. Yes I had all plugs pulled. Maybe I'm not interpreting this right, but seems like I have a tired engine on the edge of needing a rebuild? Edit- the engine was not at operating temp. Not stone cold (drove it home from work a few hours before), but not hot off the highway either.

The thermostat helped a bit with performance, but my fuel economy is still 13MPG or so.

 

Advice? Thoughts?

As preventative maintenance, I replaced the fuel mix solenoid with a NOS Motorcraft unit, and drove it on a long trip yesterday.Good news: runs well on the interstate. Held 70mph without too much trouble.Bad news: still shakes (the "lugging" from the start of the thread) in high torque situations. May be the uneven cylinder wear resulting in unbalanced torque? Also my fuel milage is still a pitiful 12-13mpg on the highway. Short of the cam timing being off (are the plastic timing gear rings known slip on the steel gear core?) or the meh compression, I'm running out of issues to fix.

[Gary Lewis]

As preventative maintenance, I replaced the fuel mix solenoid with a NOS Motorcraft unit, and drove it on a long trip yesterday.

Good news: runs well on the interstate. Held 70mph without too much trouble.

Bad news: still shakes (the "lugging" from the start of the thread) in high torque situations. May be the uneven cylinder wear resulting in unbalanced torque?

Also my fuel milage is still a pitiful 12-13mpg on the highway.

Short of the cam timing being off (are the plastic timing gear rings known slip on the steel gear core?) or the meh compression, I'm running out of issues to fix.

Sorry for the delayed response. But I think you are stumping us.

The compression isn't "bad", it just isn't "good". However, in my estimation a compression test doesn't tell much. A leak-down test will tell a lot more. (I just did a quick search in this thread to see if I've told you about leak-down tests and I didn't find anything to say I have. So if I have please kindly tell me so.)

I've had situations where the compression test say all was well but the engine shook badly. Turned out that I had burned valves on cylinders adjacent to each other in the firing order, and it cause the engine to miss quite a bit. So I'd recommend you do a leak-down test. Here's a good discussion of how it works: https://mobiloil.com/en/article/car-maintenance/car-maintenance-archive/how-to-do-a-leakdown-test.

Another issue I've seen is that some lobes on the cam were "flat", meaning they'd been damaged and weren't opening the valves as far as they were supposed to be opened. That's a lot harder to find as you have to pull the valve cover and use a dial indicator on each rocker arm to determine valve lift. But that's lots better than pulling the cam and miking each lobe.

As for the timing gears, even if the plastic falls off the gears don't usually slip or skip. So I doubt that's your problem as even the absence of the plastic will only retard the timing slightly, and probably not enough to do what you are experiencing.

[ratdude747]

Sorry for the delayed response. But I think you are stumping us.

The compression isn't "bad", it just isn't "good". However, in my estimation a compression test doesn't tell much. A leak-down test will tell a lot more. (I just did a quick search in this thread to see if I've told you about leak-down tests and I didn't find anything to say I have. So if I have please kindly tell me so.)

I've had situations where the compression test say all was well but the engine shook badly. Turned out that I had burned valves on cylinders adjacent to each other in the firing order, and it cause the engine to miss quite a bit. So I'd recommend you do a leak-down test. Here's a good discussion of how it works: https://mobiloil.com/en/article/car-maintenance/car-maintenance-archive/how-to-do-a-leakdown-test.

Another issue I've seen is that some lobes on the cam were "flat", meaning they'd been damaged and weren't opening the valves as far as they were supposed to be opened. That's a lot harder to find as you have to pull the valve cover and use a dial indicator on each rocker arm to determine valve lift. But that's lots better than pulling the cam and miking each lobe.

As for the timing gears, even if the plastic falls off the gears don't usually slip or skip. So I doubt that's your problem as even the absence of the plastic will only retard the timing slightly, and probably not enough to do what you are experiencing.

Ah.

Didn't do a leakdown as I don't have compressed air to do such with. My father inlaw does though... so maybe I'll drive her to Thanksgiving this year and do such while I'm up. Or pony up for a cheap air compressor...

Another option I just though of is to do a wet compression test... that would tell me rings or valves, right?

She needs a valve cover gasket badly... so getting a dial indicator and mag arm in there wouldn't be too bad.

[85lebaront2]

Sorry for the delayed response. But I think you are stumping us.

The compression isn't "bad", it just isn't "good". However, in my estimation a compression test doesn't tell much. A leak-down test will tell a lot more. (I just did a quick search in this thread to see if I've told you about leak-down tests and I didn't find anything to say I have. So if I have please kindly tell me so.)

I've had situations where the compression test say all was well but the engine shook badly. Turned out that I had burned valves on cylinders adjacent to each other in the firing order, and it cause the engine to miss quite a bit. So I'd recommend you do a leak-down test. Here's a good discussion of how it works: https://mobiloil.com/en/article/car-maintenance/car-maintenance-archive/how-to-do-a-leakdown-test.

Another issue I've seen is that some lobes on the cam were "flat", meaning they'd been damaged and weren't opening the valves as far as they were supposed to be opened. That's a lot harder to find as you have to pull the valve cover and use a dial indicator on each rocker arm to determine valve lift. But that's lots better than pulling the cam and miking each lobe.

As for the timing gears, even if the plastic falls off the gears don't usually slip or skip. So I doubt that's your problem as even the absence of the plastic will only retard the timing slightly, and probably not enough to do what you are experiencing.

Gary, I think I remember the 240/300 have an aluminum cam gear. I do know that just like the brand C in-lines, they are gear drive not chain driven. A missing tooth on those usually ends up being several and no more cam rotation.

FWIW, my second pickup was a 1977 F150, one of the chemists I worked with had a near twin, a 1977 F100, both trucks had the 300 and automatic. Mine had a 3.25 rear, I don't know what his had. I could consistently get 14 mpg in town and 17-18 highway, he was lucky to get 8-10 in town and maybe 12 highway. Difference, mine had a PCV valve and evaporative canister, his had EGR, and a catalytic converter. No feedback carbs in those days.

If his is an EEC-IV system, there should be a test connector underhood, and hopefully a working MIL light. If so there is a manual way to extract the codes if he doesn't access to a good older scan tool, parts store ones usually are all OBD-II units. The system may be in a "limp" mode due to something not being right. Quick check, after checking the timing with the SPOUT connector or jumper unplugged, reconnect it and see if the timing jumps to more advance, then rev the engine and see what the timing does.

One other item, O2 sensor, on these it is a one wire (no heater) and is in the exhaust manifold just above the exhaust pipe flange and can be a bear to change, possibly even will strip the threads upon removal. When was it last replaced?

[ratdude747]

Gary, I think I remember the 240/300 have an aluminum cam gear. I do know that just like the brand C in-lines, they are gear drive not chain driven. A missing tooth on those usually ends up being several and no more cam rotation.

FWIW, my second pickup was a 1977 F150, one of the chemists I worked with had a near twin, a 1977 F100, both trucks had the 300 and automatic. Mine had a 3.25 rear, I don't know what his had. I could consistently get 14 mpg in town and 17-18 highway, he was lucky to get 8-10 in town and maybe 12 highway. Difference, mine had a PCV valve and evaporative canister, his had EGR, and a catalytic converter. No feedback carbs in those days.

If his is an EEC-IV system, there should be a test connector underhood, and hopefully a working MIL light. If so there is a manual way to extract the codes if he doesn't access to a good older scan tool, parts store ones usually are all OBD-II units. The system may be in a "limp" mode due to something not being right. Quick check, after checking the timing with the SPOUT connector or jumper unplugged, reconnect it and see if the timing jumps to more advance, then rev the engine and see what the timing does.

One other item, O2 sensor, on these it is a one wire (no heater) and is in the exhaust manifold just above the exhaust pipe flange and can be a bear to change, possibly even will strip the threads upon removal. When was it last replaced?

1984+ has a fiber cam gear. Mine was right at the start of such if it has the original gear.

It is EEC-IV, but no check engine light (Ford didn't introduce those until later in the 1980's). I haven't checked it for lately (*facepalm*)... probably has codes, historically has been giving codes for running lean. I do have a scan tool. Just been lazy and forgetful (out of sight, out of mind?). Given the fuel economy issues my interpretation of such lean codes is a partial misfire (no more vacuum leaks per a smoke test)... the plugs are sooty on one side and clean white on the other... sometimes lean, sometimes rich???

Already verified that I am getting timing advancement via SPOUT at idle (base timing set to 10 degrees BTDC, Spout at idle moves it to ~30 BTDC).

One wire O2 sensor, replaced a few months ago. Did a backpressure test around the same time (<1psi), so a plugged exhaust is ruled out.

[ArdWrknTrk]

1984+ has a fiber cam gear. Mine was right at the start of such if it has the original gear.

It is EEC-IV, but no check engine light (Ford didn't introduce those until later in the 1980's). I haven't checked it for lately (*facepalm*)... probably has codes, historically has been giving codes for running lean. I do have a scan tool. Just been lazy and forgetful (out of sight, out of mind?). Given the fuel economy issues my interpretation of such lean codes is a partial misfire (no more vacuum leaks per a smoke test)... the plugs are sooty on one side and clean white on the other... sometimes lean, sometimes rich???

Already verified that I am getting timing advancement via SPOUT at idle (base timing set to 10 degrees BTDC, Spout at idle moves it to ~30 BTDC).

One wire O2 sensor, replaced a few months ago. Did a backpressure test around the same time (<1psi), so a plugged exhaust is ruled out.

Back in July Ron said the same thing about backpressure tests, when I was the third reply to his thread.

Two months and a thousand dollars later, he finally unbolted his cat and figured it out, after changing the (incredibly loose) timing chain, farting with ignition timing, carb adjustments, checking valve openings, etc..

Don't be the guy who passes over the most simple diagnostics and heads down a rabbit hole.

[FuzzFace2]

Back in July Ron said the same thing about backpressure tests, when I was the third reply to his thread.

Two months and a thousand dollars later, he finally unbolted his cat and figured it out, after changing the (incredibly loose) timing chain, farting with ignition timing, carb adjustments, checking valve openings, etc..

Don't be the guy who passes over the most simple diagnostics and heads down a rabbit hole.

I was also thinking plugged exh. and only way to know is to drop it and test drive.

On the MPG are you sure the speedo is on the money for miles?

Also have to look at the winter blend fuel now as that will also give bad MPG.

Just my .02

Dave ----

 

[ratdude747]

Back in July Ron said the same thing about backpressure tests, when I was the third reply to his thread.

Two months and a thousand dollars later, he finally unbolted his cat and figured it out, after changing the (incredibly loose) timing chain, farting with ignition timing, carb adjustments, checking valve openings, etc..

Don't be the guy who passes over the most simple diagnostics and heads down a rabbit hole.

I was also thinking plugged exh. and only way to know is to drop it and test drive.

On the MPG are you sure the speedo is on the money for miles?

Also have to look at the winter blend fuel now as that will also give bad MPG.

Just my .02

Dave ----

AFAIK the odometer is accurate. Not by enough to make the difference.

The exhaust is a basket case... I'll drop the cat and see.

[ratdude747]

AFAIK the odometer is accurate. Not by enough to make the difference.

The exhaust is a basket case... I'll drop the cat and see.

Disconnected the cats from the manifold and drove it some.

No idea on MPG... didn't fuel it up and drive it far enough to tell.

Seemed to run/shake worse though... which is why I cut the test drive short and went back home. Pretty sure I heard it misfire a bit when I let off the gas (was cruising at 55mph) on one, but only one occasion.

Makes me think the cats are probably OK (everything past the cats is rotted junk) and maybe my head is toast... but opinions welcome here.

[Gary Lewis]

Disconnected the cats from the manifold and drove it some.

No idea on MPG... didn't fuel it up and drive it far enough to tell.

Seemed to run/shake worse though... which is why I cut the test drive short and went back home. Pretty sure I heard it misfire a bit when I let off the gas (was cruising at 55mph) on one, but only one occasion.

Makes me think the cats are probably OK (everything past the cats is rotted junk) and maybe my head is toast... but opinions welcome here.

Sounds like the cat(s) is good. Time for the leak-down test. Bad valves or a bad cam can certainly cause rough running. Been there and done both of those.