1989 Ford 460 E 350 not running, need help

[RVKamper]

1989 Class-C 25-foot Ford E350 RV gasser with 79K miles (first-year fuel injection).
Question: Upon start-up while preparing for a trip in Feb. 2022 there was a loud noise like something broke, clattered, and/or something in the bottom end.
Upon subsequent start-ups, it does not repeat the noise, but now what I get is after revving up the motor, as it settles to idle, there is a rattling (almost like a baby noise of the initial noise), seems like noise is from the bottom end except I cannot pinpoint where. it is when I rev the motor in neutral that it settles. And other than the rattle that settles, it seems “normal”. As far as the behavior when driving, it slowly, gradually loses power until I’m creeping along in the shoulder, then the tow truck. My thinking tells me if it was a catastrophic failure in the engine, as was my first thought, then it wouldn’t run at all. My home made other demands on my time this weekend (can you say garbage disposal?), so I have not gotten under the rig yet.
In the Fall of 2021 the RV would not pass smog. The goal was to get the vehicle to pass smog, which it did, but it was also in need of a tune-up. Some work done by the shop, some I did myself. Took one trip after tune-up with good performance, but now this problem. I am able to back the vehicle out of the driveway and drive (slowly) on my residential street and put it back in the driveway, but I cannot get on the highway. A mechanic friend suggests it might be either the heat riser (does the FI engine even still have a heat riser??), or the Cat, but neither of those make sense to me. Please advise. TY.

Work done to this point.
Tune-up (fluids, sparks, wires, distributor cap, rotor, belts, hoses)
Map sensor checks ok
Battery ok
PCV valve ok
Fuel pressure regulator replaced
Catalytic converter checked out ok
O2 sensor replaced
Fuel filter replaced
Fan clutch replaced (3 years ago)
Fuel pump replaced (Twice!!)

[30sweeds]

My old 88 had the exact same situation and noise. (88 was actually 1st year for F.I.) It was the cat.One sign to look for is evidence of heat on exhaust before the cat...like a blue tint.

[heyobie]

It could also be a fuel issue. You can drive it but can't get up to speed.
i have a 1988 FI 450.Mine has 2 fuel pumps. One in the fuel tank. Low pressure. Then one on the frame. High pressure.

[RVKamper]

Thank you Ernie, and thanks all. I’ve got some things to check. I’ll che k back in and let you know how it goes.

[Krusty]

I would investigate the catalytic converter further. It sounds similar to an issue I had with my truck. It ran fine with good power most of the time, and intermittently the power would drop right down. It turns out that one of the catalyst "pucks" in the converter had broken in half, and the halves would rattle around in there until one of them became lodged sideways in the outlet of the converter, causing a severe restriction. It would break itself free after a bit, and power would be restored. Not sure you would be able to locate this blockage with a pressure test as it is intermittent. I cut my converter in half and knocked the guts out and welded it back up. Been fine since.

[Chum_lee]

opnspaces wrote:
It sounds like a plugged cat to me. With a willing helper start the truck and in neutral rev the engine a few times. Have the helper stand in the back stick their open palm by the exhaust and feel the strength of the exhaust coming out while you rev it. Then go for a drive and when it slows down pull into a parking lot and have them feel the exhaust again.

When it loses power will it still rev in neutral?
Does power level temporarily go back to normal after it gets towed home?

Pull the cat and see if it's plugged or rattles. If it's welded on then maybe talk to a local muffler shop guy have them cut the cat out and see if it's plugged. If not plugged they can weld it right back in.

I agree with the above.

Chum lee

[Grit_dog]

opnspaces wrote:
It sounds like a plugged cat to me. With a willing helper start the truck and in neutral rev the engine a few times. Have the helper stand in the back stick their open palm by the exhaust and feel the strength of the exhaust coming out while you rev it. Then go for a drive and when it slows down pull into a parking lot and have them feel the exhaust again.

When it loses power will it still rev in neutral?
Does power level temporarily go back to normal after it gets towed home?

Pull the cat and see if it's plugged or rattles. If it;s welded on then maybe talk to a local muffler shop guy have them cut the cat out and see if it's plugged. If not plugged they can weld it right back in.

I'm believing this is the most likely issue and where I'd start as well.
If you can even reasonably verify you think there is a restriction, (if there's not, it'll only cost you a $20 band clamp to repair the self inflicted damage I'm about to suggest) I'd cut the exhaust pipe off just ahead of the cat, in a spot you can clamp it back together, move the cat aside a bit, tie it up or whatever and take a run with it.
Hope you go the garbage disposal fixed! Its always something aint it??

[Grit_dog]

klutchdust wrote:
Have experienced fuel lines that collapsed and restricted fuel flow. They would rest and open up again then suction would collapse them. again.

Kinda doesn't explain the bang clatter, whatever noise. Although fuel system could be an issue.

[klutchdust]

Have experienced fuel lines that collapsed and restricted fuel flow. They would rest and open up again then suction would collapse them. again.

[opnspaces]

It sounds like a plugged cat to me. With a willing helper start the truck and in neutral rev the engine a few times. Have the helper stand in the back stick their open palm by the exhaust and feel the strength of the exhaust coming out while you rev it. Then go for a drive and when it slows down pull into a parking lot and have them feel the exhaust again.

When it loses power will it still rev in neutral?
Does power level temporarily go back to normal after it gets towed home?

Pull the cat and see if it's plugged or rattles. If it;s welded on then maybe talk to a local muffler shop guy have them cut the cat out and see if it's plugged. If not plugged they can weld it right back in.

[Gjac]

RVKamper wrote:
You are all great, thank you for the input. To expand on the second paragraph as someone suggested, it is when I rev the motor in neutral that it settles. And other than the rattle that settles, it seems “normal”. As far as the behavior when driving, it slowly, gradually loses power until I’m creeping along in the shoulder, then the tow truck. My thinking tells me if it was a catastrophic failure in the engine, as was my first thought, then it wouldn’t run at all. My home made other demands on my time this weekend (can you say garbage disposal?), so I have not gotten under the rig yet.

If I understand your post correctly, it starts fine runs fine for a while then gradually loses power until the engine dies? How long does it run fine for at hiway speeds? Hours or just until engine comes up to temperature? When was the last time the in tank fuel pump was replaced? How many miles ago?

[time2roll]

I would start with a compression check and possibly want to recheck the ignition timing to see if the timing chain jumped a tooth.

[ernie1]

At one time I also had a 1989 Ford E350 with 460 engine and FI. I also had the very same identical symptoms and the problem was the two(yes two) oxygen sensors had failed and the catalytic converter was glowing red while running hard and it was plugged up. All of this heat caused the AC high side hose to pop loose and the propane tank pressure relief valve to periodically let loose with a long violent whoosh! Along with not having much power for the engine, I was getting 4 1/2 mpg. Oh, also, the fastest the vehicle could go was 45 mph.

[RVKamper]

You are all great, thank you for the input. To expand on the second paragraph as someone suggested, it is when I rev the motor in neutral that it settles. And other than the rattle that settles, it seems “normal”. As far as the behavior when driving, it slowly, gradually loses power until I’m creeping along in the shoulder, then the tow truck. My thinking tells me if it was a catastrophic failure in the engine, as was my first thought, then it wouldn’t run at all. My home made other demands on my time this weekend (can you say garbage disposal?), so I have not gotten under the rig yet.

[Tom_Anderson]

If the catalytic converter is broken inside, it can rattle, and it can plug up the exhaust, which would cause a lack of power.