[JohnnyK]

Ok, now I'm getting discouraged.. replaced the thermostat on a whim.. On a 5.0, that involves removing the upper intake manifold.. Also installed the 5.0 EFI heater lines.. None of this should have made a difference as the coolant doesn't have a chance to heat up yet.. Installed upper intake. No vacuum lines are left unplugged... Have a coolant leak from somewhere (hose, hopefully) but that seems like a small concern now.

Within 3-4 seconds, literally, the headers started smoking.. Touched them, instant burns (Although not major.. May seem stupid to you, but the headers don't get that hot that fast, even if it is just high temp paint).. And it's been brought up to temperature a few times before, so it's not the paint just cooking for the first time..

When I first started it, it dropped to about 500rpm or so for a few seconds, then went up to about 1200-1300.. That's not normal for it.. Shouldn't be any vacuum leaks. Even replaced some of the vacuum caps that looked bad. Also I did remove and reinstall the throttle cable bracket, but it seems to be closed properly. Timing hasn't changed from the marks I have on my distributor and my engine..

Any ideas?! I can't really think of anything, nor at this point can I think of how to diagnose without doing some damage.. Also had the valve cover off to install the heater lines, but both headers seem to be too hot too fast, not just the one (Although it, passenger side, seems worse)..

Thanks guys.

 

[drummingrocks]

Did anything change on the timing? Have you verified the timing with a light?

 

[chrisruh]

Could you have possibly bumped the TPS sensor on the throttle body? Not sure if it would cause extreme heat but it would cause the car to idle abnormally if it was moved out of position... I know you said no air leaks, but could plenum gasket be damaged (leaking in between runners). Check the spark plugs for lean fuel condition.
I would at least start with that if you haven't already. Hope you get it figured out, good luck....

 

[JohnnyK]

Timing definitely not changed.. Could have bumped it I suppose, but this thing seems to be running lean (I assume).. Don't see how the plenum gasket could be damaged, but perhaps it is a good idea for me to start with that.. Would a tiny air leak there cause this problem? As I said, I'm too worried to run it for any longer to do tests that way.

 

[JohnnyK]

Well I can't physically SEE anything amiss.. I was hoping for a missing vacuum line or something.. Any way to check for vacuum leaks without firing? I logically can't think of any, but.

 

[BornInAFord]

Johnny, sounds like a vacuum leak is making the car run way lean and thus heating up the headers like you described. Since both exhaust sides are getting hot, I would think that it is involving the upper or the throttle body after the mass air sensor or some place common to all the cylinders. Any way you can get the car running long enough to spray carb cleaner around the junctions?

Good luck with it. You are soooo close.
Daniel

 

[JohnnyK]

Well I'm close in the sense I'm sure I can get it running nicely, but far in the sense it'll be a long time until it's on the road.. But I appreciate the encouragement.. haha

I agree with your diagnosis.. It definitely seems like the RH side is heating up more, but the lh seems to be heating up more than usual.. 4 seconds definitely doesn't not seem correct.. used to run much better before this little heater tube incident.. I COULD get the car running, but I don't want to toast the valves or anything.. I guess I'll pull the upper tomorrow and see if anything seemed amiss on dissassembly? Seems the best way to start at least? Vacuum leak would cause this severe of exhaust heat though (before I dive in)?

 

[Rick Williams]

Based on what was done I'm pretty sure you did what I did once. When re-installing the upper intake I somehow folded the gasket. I didn't know this when I did it but I had a huge opening along one side of the upper to lower interface. Air entering here is downstream of the sensors so the system doesn't know that all that air is getting through until the O-2 sensors give haywire feedback. That's why your idle jumped around. The A9L is trying to figure out how to compensate. I'd take the upper off again just to inspect. If nothing else, you eliminate one source of the problem if everything is OK.

 

[JohnnyK]

Ok, I'm at a loss.. First thing. Heater tubes, thermo.. No matter WHAT is up with them (Back heater hoses are kinked in a 180 temporarily) that would have no affect on this, correct.. I mean, 4 seconds.

PLEASE tell me I haven't screwed up my lower manifold somehow, would that account for this? I did flush with a hose through the upper rad hose.. Hopefully I didn't blow a gasket (Sealed the hose in there, with a t-shirt, but didn't go full blown with the hose).

Put upper on again with a new gasket (no problems with the old ones though).. Didn't attach throttle cable or bracket or anything so nothing is touching anything.

I am running with probably 3-4 gallons of fuel in there.. EFI.. Could that cause this problem? I mean, it's low, and not reading on the fuel gauge, but it seems coincidental to start happening right when I pulled the upper for the heater tubes.

Where should I go from here? Fuel pressure check for 3 seconds? Manifold vacuum check for 3 seconds?

 

[JohnnyK]

I went gung ho and let it run.. Fires up to 1400rpm.. stays there for a bit.. Then it stalled. Started it again.. Idle settled to 800-900.. Unfortunately without exhaust I can't tell if I'm hearing a knock or just the engine bouncing around.. Valve covers getting pretty hot after a minute. Frankly, I can't remember what is normal and what is not. The smoking stopped.. I Guess the paint had enough.. But I swear I never got any grease or anything on there. How long should it take for uncoated headers to be boiling hot (Blisters.. spit evaporates in a second).. Longer than 5 seconds?

 

[chrisruh]

this may sound like a dumb question, but have you checked to make sure you have oil pressure? Could just be one of those things that took a dump as you were repairing another part on the motor...

 

[JohnnyK]

Yessir.. Oil pressure is at 40-50 at idle (Err, at 1300, the 'new' idle.. )

 

[JohnnyK]

Any ideas before I go back to the car in a couple days? If FP is good, timing is still at 10 base or so, and manifold vacuum is good (What should I be shooting for on an EFI with a B cam), should I Just chock it up to "Headers are supposed to get that hot within a few seconds, even though I don't think they did before". I assume the vacuum will be the telltale if I have a vacuum leak? Or is there something else I can do?

 

[brianstrange]

On initial startups these cars run a bit rough. Also, headers will smoke upon initial burn in, or after sitting quite some time. Another factor is how close your o2 sensors are to the end of the header. Headers will "inhale" fresh air near the ends during idle. If you have an exhaust system, that won't be the case.

 

[MarkStang]

For what it is worth , my headers smoked in what seemed less than 4 seconds. They do not smoke any more. Having a lot of fan during this time is a good thing.

 

[JohnnyK]

Well just concerned because they never did that before.. And now all of a sudden they started to, after I messed with the intake.. Maybe I have really greasy hands or something..

 

[Rick Williams]

Here's another possibility if you're using the EFI harness from a donor. There are two connectors that tie the main harness to the intake sensors and injectors. One is black and one is white. These are notorious for failing and losing contact on one or more pins if you fiddle with them too much. In fact, at some point Ford added extension pigtails to give them more slack. Maybe when you took the intake off you lost a connection. Try jiggling them when the car is running and see if things change.

 

[brianstrange]

Here's another possibility if you're using the EFI harness from a donor. There are two connectors that tie the main harness to the intake sensors and injectors. One is black and one is white. These are notorious for failing and losing contact on one or more pins if you fiddle with them too much. In fact, at some point Ford added extension pigtails to give them more slack. Maybe when you took the intake off you lost a connection. Try jiggling them when the car is running and see if things change.

Very good point. I removed my bulkheads, but do remember that they had failure from what was thought to be not enough slack. I performed many of these recalls back in 87-88. I was told later that there was corrosion quickly building up in them and that was the real problem. Not sure which is correct.

 

[JohnnyK]

Yeah, thought it might have been the 'salt and pepper' shakers, no codes though, but i can squeeze the terminals closed a bit more I guess..