Lugging at speed/No power at WOT

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Lugging at speed/No power at WOT

ratdude747
I'm at wits end with my 1984 F150 (bought a month ago as a project). It has a 300 with an AOD transmission. RWD, 3.16 Gears (Limited Slip, but needs new clutches), and factory sized tires. The issues are:

1. At highway speeds (over 55) it lugs when I try to mildly accelerate. Once I get a downshift, it does better... but in OD it can't handle anything more than 55 on flat land or hills. It also does this around 25mph as well.

2. This morning at least, It stalled several times when given heavy throttle from a stop.  Not the first time it's done this... but it's intermittent.

Information:

-Almost 100% stock. The only changes are rubber fuel between the pump and carb line with a clear filter (no OE steel lines or filter), and plugging off the choke stove lines at the carb (Rusted out, using the electric element by itself).

-EEC IV codes: Did a KOER test, got one for running lean, one for TPS. I did punch the gas when code 10 came up.

-Air/Fuel system: Found and fixed many vacuum leaks. Rebuilt the carb. Verified with a homemade smoke machine (party fogger) that there are no more leaks. Had a rough/bad idle, which I was able to fix by going richer on the idle screw. Replaced O2 sensor due to suspected issues (reported no switching). Vacuum is OK, mostly stable.

-Ignition: New plugs, wires, cap, rotor, and TFI module (PO had the wrong unit installed, which was also faulty). All were bad. Used Motorcraft copper plugs. Timing set to target, within 1 degree of 10 BTDC (Notched target on timing scale). Yes, I did unplug SPOUT when setting timing

-Mechanical: Haven't looked at mechanical timing yet. Engine has 102K on it. Uses some oil, but seems to be due to many oil leaks. Does have oil fog when vent tube unplugged... but not forceful blowby. Replaced a faulty PCV valve to correct oil flooding the air filter.

-Transmission: seems to be working. Fluid is old but not thick or gritty. Verified TV cable adjustment (0 slack/tension at idle) and correct TV cable travel/lever movement.

Otherwise, I'm out of ideas short of mechanical timing (AFAIK, it hasn't had a gear swap, so I'm doubting a gear timing issue?). No vacuum leaks (that I can find), and the carb is getting fuel it seems.

Suggestions on places to look next?
1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

Gary Lewis
Administrator
Wow!  What a thorough post, and a thorough approach to fixing it.  But, it didn't work.

I don't remember hearing of a 300 six getting out of time, but that is possible.  Still, unless someone else has seen the problem, it seems remote.

But you a code for the TPS and didn't mention fixing it.  Have you?  I've heard bad things about how the engines run when the TPS isn't right.

And it would seem the engine is NOT running correctly.  With those gears I would expect the 300 to handle 60 MPH and above quite well.  So, if the AOD linkage is spot-on, then it must be the engine.

But how does it do out of OD?  With those gears it should still do quite well on the highway w/the OD locked out.  Does it?
Gary, AKA "Gary fellow": Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI
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Re: Lugging at speed/No power at WOT

ratdude747
I haven't looked at the TPS since my (in hindsight, foolish) assumption is I'm doing the throttle stomp wrong... also because I'm having a heck of a time finding feedback carb info since 90% of "solutions" are to swap a DSII and 4 barrel. Is there a test procedure out there for such? The schematics I found here don't give resistor values for such (I don't think, will relook), so I'm flying blind (I feel dumb, I have an EET degree for crying out loud). And I really don't want to fire the parts cannon, especially on a $40 part. Suggestion?

Out of OD it does OK... I don't think it's OD related as much as it's RPM related. Seems like I have no bottom end. Which for a 300, makes no sense. Aren't these supposed to be torquey?

Timing: My fear/concern was it skipped a tooth due to a worn out timing gear (fiber fail). But as leaking and old as the timing gasket looks, I doubt anybody's been there... and I doubt helical gears "skip" like that without completely failing? I do know the base ignition timing was way off... too advanced. Like the PO timed it without disconnecting SPOUT.

Other note: this is a far cry from where it was when I bought it. When I bought it, it had no brakes and wouldn't idle or start consistently. With the exception of the O2 sensor (which was a hunch and a rockauto closeout), every move mentioned had positive impact. No idle was partialy carb tuning (I beefed the resetting of the idle screw during the carb rebuild), and a bunch of vacuum leaks. The intermittent no-start was all of the ignition issues. The brakes were a bad MC and booster... swapping those and bleeding the system took care of such. I've done other unrelated work (oil/coolant change, A/C seal replacement and recharge, etc.)... Not bad for a $750 truck with virtually no rust (other than the floor of the bed :( ).
1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

ArdWrknTrk
Administrator
TPS values are around here (somewhere)
I know I looked them up.

When you first mentioned 'sluggish, won't pull' I thought of Ron's month long escapade (which included timing gears and a carb rebuild) when it was a clogged Cat that I suggested within an hour of his OP.

But the intermittent part seems different.
Anyway, subscribed, to see what happens.
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
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Re: Lugging at speed/No power at WOT

ratdude747
Forgot to mention: I did an exhaust backpressure test while I had the O2 out. Less than 1PSI at idle or at ~2K RPM. Doubt it's a clogged Cat. The exhaust past the cats is garbage though (rusted out aftermarket looking bullcrap).

I'll look for TPS values... So much info here I probably missed it (and I thought I was spoiled with tech info over at the RangerStation- My other truck is a 1995 Ranger).

Intermittent: as in sometimes I'll let off the gas, try again, and it will pull a bit better. Sometimes, no change. Does seem to be running lean (other than meh gas milage, mixed driving has been around 13-14mpg, I read these can do better???).
1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

ArdWrknTrk
Administrator
Sure! Now you tell me...




Rangers are cool.  
Don't see many left up here, but when I was down in NC at my brother's, they were everywhere!
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
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Re: Lugging at speed/No power at WOT

ArdWrknTrk
Administrator
In reply to this post by ratdude747
David gets over 20 mpg when he baby's his 300.

But it is DSII.
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
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Re: Lugging at speed/No power at WOT

ArdWrknTrk
Administrator
In reply to this post by ratdude747
Cut the exhaust off after the cat and stick a turndown tip on it.

Those trucks don't really need anything more than the cat anyhow.
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
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Re: Lugging at speed/No power at WOT

ratdude747
In reply to this post by ArdWrknTrk
I've owned two 1995 Rangers... the first was my first Ford ever (I was raised a chevy guy, and traded a POS  durango for it). But something clicked, and I built it up into my dream truck (or as close as I could get), only for my wife to wreck it a couple winters ago. Found a nearly identical one 5 hours way, and made a road trip up there to fetch it and moved my mods over. It doesn't look too modded, but looks are deceiving. It's not Farm Truck, but it's not a bare bones POS either.

Picture of both trucks from my facebook page:



-----

I'll look around for TPS info and follow up with what (if anything) I find.
1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

ArdWrknTrk
Administrator
What river is that?

Where (about) do you live?
 Jim,
Lil'Red is a '87 F250 HD, 4.10's, 1356 4x4, Zf-5, 3G, PMGR, Saginaw PS, desmogged with an Edelbrock 1826 and Performer intake.
Too much other stuff to mention.
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Re: Lugging at speed/No power at WOT

ratdude747
Ohio River. I live in Madison, IN. That's the Madison-Milton Bridge- it carries 2 lanes of US 421 from Madison IN to Milton, KY.
1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

Gary Lewis
Administrator
It took me a while to find the TPS values, and I PUT THEM THERE.  

Anyway, they are on the TPS Values tab, oddly enough, here: Fuel Systems/Diagnostics.
Gary, AKA "Gary fellow": Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI
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Re: Lugging at speed/No power at WOT

grumpin
Could it be the AOD TV adjustment? I have never worked on one, but heard that messes something up.
Dane
1986 F250HD SC XLT Lariat 4x4 460 C6
1992 Bronco XLT 4x4 351W E4OD
1997 Mazda 626 LX 2.0L G25M-R
1998 Suburban LT K2500 454 4L80E
Oregon
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Re: Lugging at speed/No power at WOT

1986F150Six
"David gets over 20 mpg when he baby's his 300." [ArdWrknTrk]

Yes, that is true.

My son has a 1984 F150 with 4.9L engine and it still has functioning "feedback ignition and carburetion". It has a manual OD transmission and was "born" with 2.47 rear gears. It has returned 26+ mpg on the Interstate.

I have never heard of 3.16 rear gears. For 9" differential, there was a 2.70, 3.0 and 3.25 [I believe]. The 8.8" differential had 2.47, 3.08 and 3.55 [I believe].

With my 3.08 gears and manual OD, @ 55 mph the engine is turning ~1530 RPMs. One cannot expect brisk acceleration at that point.

What is your idle speed and have you checked the vacuum @ that speed?

When the truck stalled several times, was the engine still not up to operating temp.? I ask because the choke will open more slowly since the heat choke has been disabled.
1986 F150 4.9L manual O.D. 3.08 Duraspark MSD ignition w/ no EGR
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Re: Lugging at speed/No power at WOT

ratdude747
The diff tag said 3L16... I'll check again. It's an 8.8.

No idea on idle speed. I have no tach. Seems to be around 1000 or less when warmed up.

The stalling was cold. Running late to work. The other issue (lugging down at low RPM) is at all temps.

----

TPS values don't match the chart but are close. Off the carb (plugged in, green wire backprobed) I'm getting 0.45V at 0 degrees, and 4.20V at 100 degrees. No skips or other weirdness in the middle of the range.

Close enough? Or reason to replace the sensor?

1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

Whisler
"Timing set to target, within 1 degree of 10 BTDC (Notched target on timing scale). Yes, I did unplug SPOUT when setting timing"

Please explain what you mean by "Notched target on timing scale"

I don't know 300s but I know that on my 351W the large notch on the balancer is not the timing target.

Just curious!
God Bless
Whisler

Frankenstein: 1989 F250 4X4, C-6, Hurst Pro-Matic 2 shifter, carbed '84 351W, Edelbrock manifold, Edlbrock AVS, DS2 ignition, 3G alternator, JBA shorty headers, no cats, dual exhaust with H pipe.
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Re: Lugging at speed/No power at WOT

ratdude747
Everything I read said that the large Notch on the block mounted gauge is the 10 degrees BTC to aim for. My crank pulley just has a line.

If it's not (and the round hole is the 10 degree target), then maybe I'm to blame. Will do more research (or if you know for sure on the 4.9, chime in!).

--------

Reinstalled the TPS. At hot idle position (not fast idle) I'm getting 0.9V. At WOT I'm getting 3.26V. Close, but not quite.

-------

Diff Tag. First Character is a "W", if anybody cares.

1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

Gary Lewis
Administrator
In reply to this post by ratdude747
ratdude747 wrote
TPS values don't match the chart but are close. Off the carb (plugged in, green wire backprobed) I'm getting 0.45V at 0 degrees, and 4.20V at 100 degrees. No skips or other weirdness in the middle of the range.

Close enough? Or reason to replace the sensor?
I don't think that's close enough, but let's see what other say.  Personally, with the problems you are having, I'd replace the TPS.

Here are the readings:

               Factory  Yours
0 degrees:  0v      .45v
100 deg      5v     4.20v

Gary, AKA "Gary fellow": Dad's: '81 F150 Ranger XLT 4x4: Down for restomod: Full-roller "stroked 351M" w/Trick Flow heads & intake, EEC-V SEFI/E4OD/3.50 gears w/Kevlar clutches
Blue: 2015 F150 Platinum 4x4 SuperCrew wearing Blue Jeans & sporting a 3.5L EB & Max Tow
Big Blue: 1985 F250HD 4x4: 460/ZF5/3.55's, D60 w/Ox locker in front & 10.25 Spicer/Trutrac in back, & EEC-V MAF/SEFI
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Re: Lugging at speed/No power at WOT

ratdude747
In reply to this post by ratdude747
I am an idiot.

I was looking at the wrong part of the diff tag all this time... Open 3.08 gears. DOH!

 
1984 F150: 300 L6, AOD, RWD. Stock everything but radio (for now).
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Re: Lugging at speed/No power at WOT

1986F150Six
Before replacing the TPS [probably needed, as Gary suggested], try to set the idle [warm engine with fully opened choke] to a slow steady speed [~650 RPMs]. Attach a rubber vacuum hose to an unused port [manifold vacuum] and with a vacuum gauge, adjust timing [spout disconnected] for the highest vacuum reading. This should approach 20" of Hg.

You can use the same method for adjusting the idle air/fuel mixture.

If the idle speed gets too high, lower with the idle speed screw and check everything again until you get a steady idle.

Reconnect the spout wire and see if the engine runs better.
1986 F150 4.9L manual O.D. 3.08 Duraspark MSD ignition w/ no EGR
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