'04 4.7 has no mojo

Just picked up my "new" truck yesterday. It rode and handled much better than I expected (35x12.50r20 mud tires) but it had no power. I would expect the 4.7 to be weaker than the hemi, but this was silly. It literally drove like a loaded semi... I couldn't get above 70 on the flats and it would lose speed on the little hills we have here. I tried dropping to fourth gear, didn't help. It's like it hits a wall at 70 and just stops pulling. Is the 4.7 just that weak, or is something wrong? I had a '92 F-150 with the 5.0 and it had no problem getting over 70. So I can't think the 4.7 is that much weaker.

I had thought that maybe, since the truck was owned by a teen previously, there was some sort of limiter installed/programmed to keep him out of trouble. Or maybe the MDS has gone haywire?

It might need a tune up. But FYI the 4.7 is a commuter motor not a work horse. I had a 4.7 in a 12 1500 4x4 and I hated that truck and couldn’t wait to get rid of it.
There are some performance threads here about that motor.
But mods for the 4.7 are super expensive.
Like I said a tune up is where I’d start at.
The most critical thing on these motors is over heating.
If it overheats the heads and radiator are the culprit. When ya do the tuneup a good plus is to change the Tstat to a 180* that’ll help keep it cooler.



- The Blue Mule

35" mud tires will weaken the Hemi also.
A regear is the only way to regain the proper gear ratio your truck was designed around which will also restore performance and gas mileage.

The gearing is definitely an issue. My wife used the speedo on her nav app while we were cruising around today and the truck's speedo is off by around 15%, which seems about right for the difference in tire size. But I wouldn't expect that to make a huge difference at highway speeds.

Is the 4.7 really that limp? I wasn't expecting to do burnouts and race Demons, but I would have thought it would at least keep up with the old 5.0 Ford I used to own. I don't mind that it has the same 0-60 time as a locomotive, I'd just like to be able to maintain the speed limit.

I definitely plan to do a tune-up soon. I'm not sure about mods right now. I had originally planned to return it to stock. But I think it's been lifted. Swapping the suspension out would cost more than tweaking what I've got. Except maybe for gearing. So I might just fix what the PO screwed up and go from there.

I think that might be overly optimistic.

SouthernGorilla said:

Is the 4.7 just that weak, or is something wrong? I had a '92 F-150 with the 5.0 and it had no problem getting over 70. So I can't think the 4.7 is that much weaker.
I had thought that maybe, since the truck was owned by a teen previously, there was some sort of limiter installed/programmed to keep him out of trouble. Or maybe the MDS has gone haywire?

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It's that weak lol. Only 230-240hp (depending on where you look, and running out of steam at 4800rpm) and 300 ft/bs way up at 3200rpm. Small bore, longer stroke small displacement. Basically analogous to the 318 2bbl back in the day as the pedestrian V8 (minus the 318's indestructibility). 4.7's don't have MDS, that's why they get almost as bad mileage as a pre-MDS hemi lol. The only limiter that would be factory installed (I don't think you can even push the speed limiter down that far in the PCM) is the 105mph governor based on tire speed rating.

McBroom said:

I had a 4.7 in a 12 1500 4x4 and I hated that truck and couldn’t wait to get rid of it.

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And you had the better 310hp version lol (though still had the ****** RFE)

SouthernGorilla said:

The gearing is definitely an issue. My wife used the speedo on her nav app while we were cruising around today and the truck's speedo is off by around 15%, which seems about right for the difference in tire size. But I wouldn't expect that to make a huge difference at highway speeds.

Is the 4.7 really that limp? I wasn't expecting to do burnouts and race Demons, but I would have thought it would at least keep up with the old 5.0 Ford I used to own. I don't mind that it has the same 0-60 time as a locomotive, I'd just like to be able to maintain the speed limit.

I definitely plan to do a tune-up soon. I'm not sure about mods right now. I had originally planned to return it to stock. But I think it's been lifted. Swapping the suspension out would cost more than tweaking what I've got. Except maybe for gearing. So I might just fix what the PO screwed up and go from there.

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If you have anything less than 3.92's with a lift and larger tires that 4.7 is gonna struggle even more. Your old 302 was a larger bore short stroke engine with better low end grunt (and a little more displacement, 302 vs 287). As long as everything is in good running condition (doesn't need a tune up, etc) then you can always tune it, though gears would probably net you the best results. The factory trans tuning isn't doing you any favors here either, as it is programmed to get you into 5th gear as fast as physically possible (CAFE standards). There are things you can do, but as mentioned they aren't exactly cheap/easy. The later 4.7 heads with cams can be retrofitted, as well as the intake manifold, though you either have to figure out how to fire both coils or just ignore the second set. There is also an intake adapter to mount the Eaton blower from an early 00's cobra mustang if you're feeling especially froggy. The 4.7 was one of those engines both the factory and aftermarket largely ignored. Airram.com will be one of your best friends should you decide to attempt to mess with it.

That was informative, if less than inspiring. I've been looking around and learned pretty quickly that you are right, the 4.7 has almost no aftermarket support at all. And what is available is ludicrously expensive... AirRam wants $600 for a later OEM manifold that would add 20 HP. And that manifold still requires a $260 throttle body adapter plate. $900 for 20 HP? I could add a 100-shot of nitrous for less than that.

Mine is the 5M, so I'm the transmission programmer. Dropping out of OD doesn't seem to make a difference in the pulling power. Revving a bit higher doesn't do much either. It pulls decently in 1st and 2nd, but loses it by 3rd and 4th.

I'd be all over a blower kit. But I'd also be all over a 5.9 Magnum stroked out to 408 or so if I was confident it would pass that annoying sniffer test. There's no visual emission test, so I could even put an old, carb'd LA under the hood if I could sort the emissions.

SouthernGorilla said:

That was informative, if less than inspiring. I've been looking around and learned pretty quickly that you are right, the 4.7 has almost no aftermarket support at all. And what is available is ludicrously expensive... AirRam wants $600 for a later OEM manifold that would add 20 HP. And that manifold still requires a $260 throttle body adapter plate. $900 for 20 HP? I could add a 100-shot of nitrous for less than that.

Mine is the 5M, so I'm the transmission programmer. Dropping out of OD doesn't seem to make a difference in the pulling power. Revving a bit higher doesn't do much either. It pulls decently in 1st and 2nd, but loses it by 3rd and 4th.

I'd be all over a blower kit. But I'd also be all over a 5.9 Magnum stroked out to 408 or so if I was confident it would pass that annoying sniffer test. There's no visual emission test, so I could even put an old, carb'd LA under the hood if I could sort the emissions.

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That's for a new manifold, me I would look for a used one and only if doing a cams upgrade to go with it. Mileage must be abysmal in that thing with just a 5sp; the RFE has two OD's at least for highway speeds. What gears do you have? If you don't know, go here: https://fcacommunity.force.com/RAM/s/equipment-listing enter your VIN and see what pops up.
Putting a 360/408 in would be a physical bolt in but you would actually have an easier time bolting a hemi in (similar computer controls) if you wanted all your electronics to play nice. Same thing with an LA, these trucks are rolling computer networks; you don't play within those confines you'll find many things don't function correctly. Also HIGHLY unlikely you could get a carbureted engine to pass 2004 spec emissions lol.

I always thought it would be fun to mess with a 4.7 just to see what I could do with it. I'd start with 08 heads and cam along with 08 intake manifold. With the right tuning it should at least get close to the 310hp mark of the factory version. Maybe custom cams to take advantage of those better heads. Putting a blower on one I think is only worth it if you can build a stout enough short block to make it worth it; dunno if anyone sells or even makes forged internals for those things.

Sounds like the 4.7 is a natural dog, but you could have a partially plugged cat that would suck some power. I'd give it a tune up, dump some injector cleaner in the tank and check the cat out before I put a ton of $$ into gears, cams a blower and nitrous... Although all that does sound fun.

I definitely plan to take care of the basics before getting creative. I learned on the way to work this morning that it wakes up a bit above 4,000. But that's not where I want it to live.

MPG is not as bad as I'd expected. I haven't measured it but I've managed around 150 miles on half a tank or so.

Based on the gps speedo on my wife's phone, my speedo is off by around 15%. So I'm betting the gearing is stock. New gears might fix everything.

I don't plan to go overboard with this. I bought the truck as a daily, not a project. Every dollar I throw at this is a dollar I can't throw at my actual project. While I really enjoy dreaming about engine swaps and superchargers that is extremely unlikely. I'll be perfectly content if I can get it to keep up with traffic uphill in 5th.

Gears have nothing to do with the speedo being off, that is tire height. Fix the tire height in the PCM and it will read right (assuming you don't have stock size tires?).

HemiLonestar said:

Gears have nothing to do with the speedo being off, that is tire height. Fix the tire height in the PCM and it will read right (assuming you don't have stock size tires?).

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So it senses wheel speed directly rather than off the trans tailshaft? I didn't know that.

SouthernGorilla said:

So it senses wheel speed directly rather than off the trans tailshaft? I didn't know that.

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Been doing that for a long time now lol, in conjunction with electronic speedometers. There's a tone wheel on the ring gear (does double duty for ABS as well). You can put whatever gears that'll fit in the case and as long as the tone wheel is bolted to it, it'll read the same. Changing overall tire diameter (height) throws that off and needs the pinion factor (revs/mile) in the computer either changed or or tire diameter restored to stock.

HemiLonestar said:

Been doing that for a long time now lol, in conjunction with electronic speedometers. There's a tone wheel on the ring gear (does double duty for ABS as well). You can put whatever gears that'll fit in the case and as long as the tone wheel is bolted to it, it'll read the same. Changing overall tire diameter (height) throws that off and needs the pinion factor (revs/mile) in the computer either changed or or tire diameter restored to stock.

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Easy enough. Except that means I either pay $150 for a calibrator I may never use again or pay a dealer $150 to do it. Guess I see why it was never done. But I'm betting that fixing it would help performance and mileage a bit. It can't be good having the ecm reading the wrong speed. That upfront expense would probably pay for itself.

SouthernGorilla said:

Easy enough. Except that means I either pay $150 for a calibrator I may never use again or pay a dealer $150 to do it. Guess I see why it was never done. But I'm betting that fixing it would help performance and mileage a bit. It can't be good having the ecm reading the wrong speed. That upfront expense would probably pay for itself.

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Get a Superchips tuner (a used unmarried 3865 if you can find one). You'll be able to fix the pinion factor, load a performance tune (every little bit helps) and it doubles as a code reader.

HemiLonestar said:

Get a Superchips tuner (a used unmarried 3865 if you can find one). You'll be able to fix the pinion factor, load a performance tune (every little bit helps) and it doubles as a code reader.

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That is probably the way I'm going to go first. Superchips seems to be the most recommended. Will that clear codes too?

While I'm thinking about it, any recommendations on tune-up parts? I'm planning to change the plugs, oil, air filter, the usual. Should I think about the coils or anything else as well? Any brands to look for or stay away from? It's always the little details that take the most time to sort out when you switch to an unfamiliar make/model. The last Ram I owned had points ignition.

SouthernGorilla said:

That is probably the way I'm going to go first. Superchips seems to be the most recommended. Will that clear codes too?

While I'm thinking about it, any recommendations on tune-up parts? I'm planning to change the plugs, oil, air filter, the usual. Should I think about the coils or anything else as well? Any brands to look for or stay away from? It's always the little details that take the most time to sort out when you switch to an unfamiliar make/model. The last Ram I owned had points ignition.

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The normal codes yes. Weirdo codes like ABS, BUS comms, air bag, etc is won't.
OEM or equivalent plugs. Oil & air filter personal preference. Don't worry about the coils unless you're getting an active misfire code. If it's running well I highly recommend either a thermostat change or make damn sure your cooling system is up to *****. Also a good idea to switch to synthetic oil. These engines were known for getting sludged, partially because alot of them weren't gotten hot enough to burn the condensation out. Try to avoid short trips or at least let it warm up before you do. Kind of a catch-22 because you need to get it hot enough to burn the gunk off but get it just a bit too hot and you're in dropping valve seat territory (especially if they're the original heads).

I had a 4.7 (2002 IIRC) and yes it was a dog with stock sized tires(never got the gear ration). I had bought it used with only 12K miles on it. It was an auto and every lil incline it would drop out of OD. The only fix I did was put on a FM delta 50 muffler. This allowed it to breath. Only downshifted on extreme hills and mileage went up 2-3 (mostly likely because it was in OD more). Also it got a lil more spunkier.

HemiLonestar said:

Try to avoid short trips or at least let it warm up before you do. Kind of a catch-22 because you need to get it hot enough to burn the gunk off but get it just a bit too hot and you're in dropping valve seat territory (especially if they're the original heads).

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My commute is 24 miles each way, plenty of time for it to heat up. I'm thinking about flushing the engine when I do the oil change. Thinking harder now that I know they are sludge magnets. Might flush the rad too. Haven't seen any heat issues yet, but who knows what condition everything is in.