2001 Ford Escape: exhaust manifold heats & glows red

Maintenance/Repairs
21

Honda, you are correct that lean operation causes excess heat, not rich operation. And it doesn;t take much. Rich operation only causes carbon. When you use a bellows in a fireplace, it doesn’t get suddenly hotter because you added more fuel, it gets suddenly hotter because you’ve added oxygen. It should be noted that an EGR system cools the combustion temperature by displacing a bit of the oxygen with inert exhaust gas, whose oxygen atoms are already bound up with hydrogen and carbon.

As has already been pointed out, a plugged exhaust can also allow the manifold to go cherry.

Excess spark advance can also cause a cherry exhaust. My guess is that when Bing crossed the wires he introduced this condition. But I’m not seeing preignition in the OP’s description, so I’m inclined not to suggest that.

Regarding the question of which timing condition causes excess heat, it’s advanced timing. Retarded timing causes combustion while the fuel in the cylinder is decompressing, creating less heat than combustion during compression does.

EDIT: I just realized that retarded ignition will send lots of still-burning and unburned fuel into the exhaust, so in essence it WILL heat up the exhaust manifold… and on this engine that may include the cat converter.

Which brings up the added possibility of a valve timing problem…

22

???

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I’ve never had this problem myself. So I’m just offering an educated guess here. That said, it seems like if unburned gasoline – gas that is supposed to have been burned in the combustion chamber – made its way into the exhaust manifold, it could ignite there, and cause the exhaust manifold to get hot.

It seems like you’d hear a sound from it igniting in the exhaust manifold. And the OP hasn’t said there’s any unusual sounds from the exhaust, right? hmmm … also there would have to be some air in the exhaust stream. With the OP saying there’s a lean code, that means there is some extra air in the exhaust.

So it could be the case there is incomplete combustion going on in one or more of the cylinders, and that is causing the unburned gas and O2 to reach the exhaust manifold and igniting there. That might explain it.

OP, is there any signs of the engine misfiring? Maybe something went askew with the coil, plugs, or wire replacements, and one or more of the cylinders isn’t firing, or is firing, but at the wrong time. Check all that out again, make sure the correct wires are hooked to the correct cylinders.

I remember one time years ago my dad was about to go to work, and when he got in his truck, the truck – which previously ran like a top – it sounded like an old rattletrap, would barely idle. Coughing, gasping, hick-upping, and the like. Low idle rpm. Turns out some neighborhood teenagers had played a practical joke, switched his spark plug wires around.

So double check all the high voltage related wires are connected to where they are supposed to go and have good solid connections.

If that doesn’t pan out, probably time to visit a pro. They’ll have a fancy ignition diagnostic machine that will probably determine what’s happening here in short order.

24

I’m still thinking on this. Have you considered purchasing a vacuum gauge to see what’s going on with that motor; assuming it will idle enough on its own to use the gauge.
Gauges are cheap, easy to use, will last a lifetime, and will tell you a lot about what an engine is doing.

I might point out that vacuum leaks can occur in places where they’re not readily visible; say inside the brake booster, a cracked vacuum resevoir, or even inside the dashboard as the climate control uses vacuum controls. The odds of the latter being bad enough to glow a manifold are not very high so I’m just using that as an example.
A smoke test could be performed but I have no idea what that would cost in your neck of the woods.

The suggestions I’ve made about the EGR, retarded timing, and so on are long shots. The usual suspects are clogged cats, too lean or rich, or severe misfires.

25

@GeorgeSanJose, excess fuel in the exhaust pipe due to running rich cannot ignite in the exhaust because of a lack of oxygen. I was taught back in the days of carbs, and it was always better to run rich than lean. Rich would cost a bit of gas. Lean would cost an engine.

26

I noticed a crack in the vacuum line to the ERG valve, I’m replacing it tomorrow. Also I took the vacuum line of the brake booster and there’s no leak there the booster is holding sir

27

Are you testing each vacuum operated device with a hand held vacuum pump?

28

Bob, you responded to my post with question marks. What part(s) of the post do you have questions about? I’d be happy to explain everything I wrote.

29

Thank you MTB… You confirmed for me that I had the information rattling round inside my coconut still in the correct place.

I keep venturing on the net …only to read how much people do NOT know about this situation. I have read 4 times today that Retarded timing will cause a glowing manifold… But I have been thinking about this all day and cannot come up with the reason why this may be true… I dont think it is actually.

The condition that I fear has happened on this engine is a retarded condition in timing…Both Valve and ignition simultaneously as they are inextricably linked by design.

SO… what to do? I’d say perform a compression test on all cylinders to see what the values are One could also do a timing check… Put the engine at TDC and see where the cams line up…this way you can determine IF a timing change has taken place… If it has…we know the reason for both the manifold as well as the timing change itself. 196K on the original T chain is about all one can ask of the part in question…Chains last a long time but not indefinitely. They also stretch slowly over time so the degradation in performance is not so easy to detect because it happens super slowly.

Some Homework needs to be done to check the timing on this engine. Without that info…honestly…we are kinda lost. Do a compression test and also a TDC valve timing check. Its pretty essential here. If there is NO timing change…then we are back to a vacuum leak causing the lean condition.

Thats bout all I got… Thanks for the info confirm MtnBike…

Blackbird

30

Retarded timing causes the engine to have to struggle to run and it also indirectly richens the fuel/air mix.

My suggestion about timing is that it’s a grasp due to the vehicle being a distributorless ignition system. Any excessive timing retard would have to be a PCM gone way stupid.

I wonder about the possibility of a severely worn timing chain set causing this kind of problem. That could change the spark timing in relation to the camshaft position and which then gets into a weighty cam lobe duration and overlap discussion.

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What do you think the ECU uses as a timing mark? It ALL relys on the T chain keeping things in time. The sensor is on the cam sprocket one could be on the flywheel or crank as well…and when the relationship between the cam and crank are out of whack… you have timing problems. Basic basic…

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It’s my understanding that retarded timing overheats the manifold as well as the valves
because the fuel air mix gets a late start of combustion it also finishes late.
It’s still burning strongly and generating heat as it exits during the exhaust stroke.
Normally combustion is nearly finished by the time the exhaust valve starts to open.
And remember the exhaust valve starts to open a good bit before BDC.
There is still some burning going on (and sometimes air injection to help it along) but at a low rate.

A lean mixture burns more slowly so you get the same problem of excessive late burning.

A very rich mixture IIRC burns a bit slower but late burning is prevented when the oxygen runs out.

33

So then… If the T chain has stretched beyond the ability of the ECU to cope… It is both mechanically and electronically out of time.

These manifolds are pretty thin as well…

Hey…its something to check…hows that as a synopsis?

I am certain advanced timing will glow a manifold… I need to talk to my engine guru to fully understand how retarded timing will do the same. I see your point about the mixture still in process being pushed into the exhaust and that makes some sense…

the main point here is that the timing could very well be off on this engine…what happens after symptom wise i need to check on…but at any rate…if we have a timing issue…we have a problem.

Blackbird

34

“I am certain advanced timing will glow a manifold”

I have no doubt it can happen, especially if it causes misfiring.

35

Honda, I would argue that retarded ignition timing could cause a hot manifold by retarding the combustion process such that it would still be combusting as the exhaust valve opens. The paradox is that it causes cooler cylinders… some of the heat energy leaves the cylinder before the process is complete.

But my gut is telling me that the OP’s problem is much more basic, like a restricted exhaust or plugged cat converter, or perhaps a vacuum leak.

36

A very rich mixture IIRC burns a bit slower but late burning is prevented when the oxygen runs out.

Except it doesn’t run out due to air injection reaction systems designed to expend all unburned fuel that makes it to the exhaust stream. In the old days :slight_smile: it was injected right at the manifold making them glow on rich mixtures all the time. Newer systems have two stage A.I.R. systems that have both upstream and downstream injection. When cold, they inject upstream and as the engine warms, they switch to downstream (at the cat).

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I believe the OP addressed the exhaust concerns however…New Down Pipe and Front Cat removed rear Cat, etc… So they shouldn’t be in the mix as possible causes any longer.

Blackbird

38

Any issue with a timing chain and possible effect on timing, etc should show up on a vacuum gauge.

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Sure…agreed. Since this entire thing about the t chain stretching and timing being affected was my “Idea” I would simply go about checking the timing myself. If the vehicle were in front of me…I would have already run thru the procedure to quickly test my theory… because that is all it was…a theory…easily proven or disproven. Until then…this is a mystery. It wasnt meant to be discussed Ad-Nauseum it was meant as a possible reason for the symptoms… Next is to simply check it and move on if Im incorrect…which has been known to happen. RARE as that may be…:LOL it happens.

A mechanic has many ideas and theories when facing issues like this. In reality…he looks at the symptoms… posts a theory…and sets out to prove or disprove it. This usually takes a little time, but its part of the repair process. With all the time it has taken to write n read all this stuff…I would have been finished proving this theory many times over.

The OP…if able…simply needs to test this idea. If it holds water…the next steps are to follow thru with what he finds on the TDC/Valve timing test…

Blackbird

40

Light came on this morning P1409 Egr ? Replace the hose on it and took it for a test ride then the light came on . Seemed to be idling better and not stalling out but manifold still got red.