hard hot start, smells gassy for few minutes after start

[85stanggt]

Basically, it starts ok cold, but after it's warmed up and turned off for anything more than a few minutes, restarting it is hard. It will turn over but just die unless I give it some gas.

Also, for the first few minutes, the exhaust smells strongly of gas and the idle runs low and a bit rough. Revving the engine will not stabilize the idle or de-stunckify the exhaust. It seems to run much better at idle and all once you start driving it.

What's causing this problem? A carb issue or maybe an emissions thing?

[10SEC86GT]

Sounds like a carb issue. Probably leaking some gas into the engine causing it to flood thus causing the hard start and the gas smell.

[85stanggt]

Where could it be leaking from, because I don't see anything...? I tend to think it is carb related, because these issues only occured after I rebuilt this carb and put it on the car. The carb before this one started fine, but didn't idle smoothly and really had serious, dangerous issues in the cold.

[grtskydog]

Most likely fuel percolating in the bowls...called heat-soaking. When you shut off the car, the engine heat is no longer moving with the airflow through the compartment. It's just basically cooking the carb and boiling the fuel in the bowls. Get yourself a heat shield and one of those thicker insulated gaskets.

[85stanggt]

It has the heat shield and a pretty thick gasket on it. I think it must just be a slow leak down of fuel after the car is turned off. Where could it leak from where you couldn't see it with the carb on the car? Power valve? The bowl itself isn't leaking I don't think...

[grtskydog]

You could check your PV and needle/seats. Those things would manifest themselves while it's running...regardless of whether it's cool or hot, though.

Also check that your choke is opening up all the way when it warms up.

[wilsmoku]

it could be an internal leak and make sure that the gaskets are the right ones holley has several that will work but some of the passages are diffrent also check the float settings and check for a vac leak while its running spray some wd40 round the base and round the intake if the motor speeds up u found the leak and the hard starting could be a timing thing check the simple stuff first

[85stanggt]

Just to clarify, the car runs great. And idles fine after a drive. It's just when starting it and letting it idle after it's been off for more than a couple minutes.

Timing is set properly. Bowl levels are good. Power valve seems to be working properly. There are no vacuum leaks and no obvious fuel leaks, although the thick gasket between the carb base plate and heat shield seems to be "browning." It originally was black. Is this getting wet with fuel?

Any leak that would be happening isn't great enough to affect the car with the engine on after it has been run and the excess fuel blown out, but would have to accumulate enough to make it run rough after starting for a couple minutes, even after revving the engine.

Odd thing I noticed today: vapor or smoke of some sort coming out of the bowl vent after the engine is revved and let back down to idle. It will very lightly "puff, puff, puff" a whitish looking plume at idle after revving lightly at 1500-2000 rpm or "bliping" the throttle.

[Ltngdrvr]

Everything you describe is what it would do in a heat soak condition. Heat sheild and thick gasket or not, that is almost for sure what is happening. The crappy gas these days is even more susceptable to it than it used to be. That 10% alcohol content in gas these days just causes more and more problems.

The vapor you see coming out of the carb vents is just that, fuel vapor, and being able to see it so readily is again attributable to the crappy gasohol.

[85stanggt]

The vapor was only coming out of the primary bowl vent, but yeah, the gas must suck.

So why is the carb getting so hot with the gasket and heat shield in place?

Did they make different heat shields? Is there anything I could otherwise do?

[JACook]

It's important to use high quality carb gaskets, and install the gaskets and
shield in the correct order. From the intake manifold up-

----- Carburetor -----
---- FelPro 60058 ----
----- Heat Shield -----
---- FelPro 60616 ----
----- EGR Spacer -----
---- FelPro 60625 ----
--- Intake Manifold ---

This is exactly what's under the stock carb on my '85, and I get no percolation
problems on hot days, even with underdrive pulleys, and the ethanol-laced
swill they pump here in SoCal.

One other thing I'd suggest is to take a good look at your cooling system. If
the engine is running a bit hot, you'll be much more susceptible to percolation.
My '85 has a good 3-row HD radiator core, and a good fan clutch. Like most
other things, fan clutch quality matters. A lot. Motorcraft YB-295, or step
up to the SSP fan clutch. Don't settle for the cheap McParts junk.

[Ltngdrvr]

Might even go so far as to block off the exhaust heat passage in the manifold, of course that will do away with the exhaust flow to the egr too.

Heck, while you're at it, rip the stock intake off and throw a stealth or air gap on it...

[85stanggt]

It's important to use high quality carb gaskets, and install the gaskets and
shield in the correct order. From the intake manifold up-

----- Carburetor -----
---- FelPro 60058 ----
----- Heat Shield -----
---- FelPro 60616 ----
----- EGR Spacer -----
---- FelPro 60625 ----
--- Intake Manifold ---

This is exactly what's under the stock carb on my '85, and I get no percolation
problems on hot days, even with underdrive pulleys, and the ethanol-laced
swill they pump here in SoCal.

One other thing I'd suggest is to take a good look at your cooling system. If
the engine is running a bit hot, you'll be much more susceptible to percolation.
My '85 has a good 3-row HD radiator core, and a good fan clutch. Like most
other things, fan clutch quality matters. A lot. Motorcraft YB-295, or step
up to the SSP fan clutch. Don't settle for the cheap McParts junk.

So, I basically have gaskets where they should be (I don't remember if they're Felpro or what numbers). The carb to heat shield gasket is thick and gave me a problem mounting the carb to the intake because the studs were shorter than desired; the other two are thin. If they're not necessarily Felpro, but are in place, is that still a problem? (One other note about the thick gasket...it had plastic grommets where the studs go through...didn't think it would be a problem, but maybe it is affecting the "crushability" of the gasket and causing sealant problems...?)

I'm in NC right now at college, and even at night, when it's sub 50* the same starting thing happens, so it would make sense that the heat is soaking through.

The cooling system intrigues me. This summer I looked into that, because the stock temp gauge (I changed the sender a couple years ago) reads higher than middle (bottom of A; top of A, bottom of L with A/C on), but is always consistent. I just chalked it up to the sender being "off" a bit and the IVR, since my gauges all seem to read a tad high. The readings are noticeably higher with more amperage draw on the electrical system (headlights, blower, radio).

The radiator is a 3-row, no more than 5 years old; water pump is fairly new. The fan clutch, however, is original to the car. Last time I had it off, I cleaned sand, grease, and grime out from the thermal spring on the front of the clutch, and cleaned the whole body with simple green. Everything about it seems fine, the fan spins with resistance when moved by hand, and you can feel it pulling a decent amount of air through the radiator when the hood is up.

I took my infrared temp gauge and tested the temperature at the thermostat housing and it read 199*-200*, which I thought was a little high, but figured that it was coming right out of the engine, so not that bad. Does this sound like a problem?

I don't know what else to look at, except maybe internal carb problems. For example, when I rebuilt it and put it on the car, there was gas dripping out from holes in the baseplate between the two primary bores. The power valve wasn't nearly tight enough apparantly, and once I tightened it up it didn't leak anymore. Since then, I haven't seen any other leaks.

[85stanggt]

Bump.

The cooling system seems to be working. The only non-new part is the fan clutch, which is original to the car. It seems to be working though, as there is resistance to the fan when I spin it.

The temperature at the thermostat housing is 199*-200*. Is this ok?

There are gaskets in place at the levels they're supposed to be, but they may not be felpro and one is thick, while the rest are thin. I doubt that is a factor, but is it?

[NAVYCAT]

may be a clogged or a bad cat.? something is causing it to get hot like that.... to lean? pull a spark plug to see. the EGR valve sticking? chech the temp at the carb base/EGR area.

[85stanggt]

The cats aren't clogged, as the vacuum remains high with the engine revving. The EGR valve isn't sticking open at idle. I'll check the temp at the base of the carb. Does 200* at the thermostat housing sound right?

[JACook]

The gasket immediately beneath the carburetor is supposed to be about 1/8"
thick, and made from a heat-isolating material. This is one of the reasons I say
you need to use quality gaskets. Some cheap aftermarket gaskets have the
thickness, but they don't isolate so well. I'm a bit concerned when you say you
had trouble getting the nuts on the studs. If this is all stock stuff, that should
not have been an issue. On my '85, I've got about 3/16" of stud sticking up
above the carburetor nuts. Even if I had the thicker aftermarket nuts, I'd still
see some stud.

Although this does sound like heat soak, I would also check that the float valves
are sealing completely. I've seen quite a few of these that would leak just enough
to cause the problem you're having, but not enough to cause any driveability
issues. With the engine fully warmed up, shut it down and immediately remove
the sight plugs in both bowls. Let it sit for awhile, and make sure the fuel level
does not rise. Having the hood open and air cleaner off will prevent percolation
that might confuse things. If there is any rise in fuel level, pull the float valve
and check for debris. Also check the o-ring on it.

You -DID- use a genuine Holley kit when you rebuilt the carb, yes?

One other thing I would check is the flapper valve at the outlet of the driver
side header. If it's being held closed, you'll be routing hot exhaust under the
carb, which is fine when the engine is cold, but not such a good thing when it's
warm.

The valve actuator has a pretty good spring in it, so it should be open when
there is no vacuum applied. First thing I'd do is crawl under there and disconnect
the vacuum line after the engine has been run up to operating temperature.
If the valve springs open, you've got a problem with your vacuum plumbing up
top. I would also check the valve when the engine is cold, that it moves freely
through it's entire range of motion. One of those Mityvac hand held pumps works
really well for this.

Also, if you've ever heard the flapper valve rattling, it's possible that the butterfly
has come loose from the shaft. If you suspect this has happened, you'll have
to pull the H-pipe down to check.

[85stanggt]

You -DID- use a genuine Holley kit when you rebuilt the carb, yes?

Yes. Without hesitation.

I'll check if the fuel level rises next time I drive the car.

The gasket immediately beneath the carburetor is supposed to be about 1/8" thick, and made from a heat-isolating material. This is one of the reasons I say you need to use quality gaskets. Some cheap aftermarket gaskets have the thickness, but they don't isolate so well. I'm a bit concerned when you say you had trouble getting the nuts on the studs. If this is all stock stuff, that should not have been an issue. On my '85, I've got about 3/16" of stud sticking up above the carburetor nuts. Even if I had the thicker aftermarket nuts, I'd still see some stud.

The gasket immediately under the carb is thick. Like between an 1/8" to 1/4" thick, but the others are the standard thin "paperish" gaskets. So, because of the thick gasket, it would make sense that I didn't have much stud left.

One other thing I would check is the flapper valve at the outlet of the driver side header. If it's being held closed, you'll be routing hot exhaust under the carb, which is fine when the engine is cold, but not such a good thing when it's warm.

I tested the valve a couple years ago and it seemed to work fine. I applied vacuum to the line and I could hear it squeak closed and flip back open when I released it. I suspect it is still working because I can hear a change in exhaust tone when it opens after the engine has warmed up enough to trip it. I'll check it again, though.

Also, if you've ever heard the flapper valve rattling, it's possible that the butterfly has come loose from the shaft. If you suspect this has happened, you'll have to pull the H-pipe down to check.

I have heard it rattling, but only when the car is restarted after cooling down for a bit, but not all the way. The engine warms up a little and then the vacuum holding it closed (partially closed?) dumps to atmosphere and it opens all the way. I always assumed it rattled because it was only partially closed and the exhaust was buffetting it, causing it to rattle. Is that not the case and my valve is messed up?

[85stanggt]

Bump.

I haven't been able to check the bowl levels yet. Probably sometime during the week after Monday's microbiology exam.

[85stanggt]

Well, I'm between classes, and had one other quick thing to ask, which is likely related to this problem...

The car is all warmed up and I turn it off for 30 seconds. When I restart it, it will catch at about 700 rpms and then will immediately fall to 250 for a second and rebound to 500. It will idle at 500 (sometimes smooth, sometimes not so much so) until I get driving and roll up to a stop, where it will then correctly be at 700. Revving the car after starting it while parked does not recorrect the idle.

Is this some sort of vacuum feedback or sensor issue confusing the emissions system? I'll keep looking at the carb, but this is a very consistent problem that I can't help but think is something emissions related (thermactor?).

Edit: what would happen if the smog pump air was routed to the heads on a warm start? Anything like this?

[JACook]

The car is all warmed up and I turn it off for 30 seconds. When I restart it, it will catch at about 700 rpms and then will immediately fall to 250 for a second and rebound to 500. It will idle at 500 (sometimes smooth, sometimes not so much so) until I get driving and roll up to a stop, where it will then correctly be at 700. Revving the car after starting it while parked does not recorrect the idle.

This suggests your fuel level is rising in the secondary bowl. You need to pull
that sight plug after shutdown. If the problem was in the primary bowl, you'd
see some improvement revving the engine. But revving the engine in neutral will
not pull any fuel out of the secondary bowl.

Edit: what would happen if the smog pump air was routed to the heads on a warm start? Anything like this?

Not likely.

[85stanggt]

Ok, so I did some testing today.

First, the bowl levels were a tad high, so I adjusted them down a little (don't know why this should be, as they were set fine last time I checked). I wasn't on the levelest of ground, but I set it to just barely trickling out the primary and a tad below the edge of the secondary. Glad I actually checked this stuff, because the fuel filter fitting was leaking under the air cleaner.

Second, after I adjusted the bowls and drove the car, I turned the car off and watched the bowls to see if they filled up. They did seem to fill a little, but really not much at all. There was only ever a slight trickle that didn't last too long.

Starting the car still has the same issues. But, here's the interesting thing: it starts, catches, and doesn't die as long as I give it a pump of the pedal before starting it (before, if sitting for more than a minute or so, it would start, and then just die unless I feathered the gas). It'll idle around 500 rpm and a little rough, but will smooth out once driven. I don't want to be too picky, but I'm just interested as to why the car would need extra gas to start when it's warm rather than want less.

Thanks for the help.

[85stanggt]

bump...for JACook

[JACook]

One explanation would be that things aren't quite as warm as we thought they
were. We started out looking at this as a heat soak problem, but I now believe
it was really just a leaky O-ring on the secondary float valve.

You didn't say, but did you check for a rising float level after shutoff -before-
you adjusted the floats down? Reason for doing that, as opposed to adjusting
first, is it's best to know what you're dealing with before you make any changes,
so you don't "accidentally" fix the real problem. It sounds like we went straight
to the adjustment. Which is probably OK, since things are getting better.

So, now we're left with another symptom that was being masked by the float
valve leak. I would start with a fresh mindset, and treat this as a different
problem. If the engine needs extra gas at startup, that suggests to me that
it's either not up to operating temperature, or perhaps there is a vacuum leak
that goes away once it's been run for a bit. Such as in the thermactor system.

I would start by testing everything that gets manifold vacuum, and make sure
there are no leaks. The thermactor dump valve, and thermactor diverter valve
have to be tested by disconnecting them from the TAB/TAD solenoids.

Make sure your evaporative purge valves aren't leaking. Those will be the 5/32"
hose connected to the front of the EGR spacer. Also make sure the bowl vent
solenoids are working.

One other thing- Make sure your thermostat is functional, and that it's the right
one. The '85 HO is sensitive to operating temperature.

When all this stuff is working right, your engine should warm start with just the
shortest bump of the starter, and your foot off the gas. (One of the things I've
always thought was cool about these older carb'd engines.) Cold starts should
need nothing more than a short stab of the pedal to set the choke, and again,
leave your foot off when you crank.

[85stanggt]

Hey thanks for your help. The cold start acts exactly as you say. I have the choke adjusted just right on this carb. The warms start used to do exactly what you say (and man I loved it) with the old E4ZE carb that was on it. I replaced that with this E5ZE back in spring of '07.

I replaced the thermostat about 4 years ago when I changed the intake gaskets. I replaced it with a Motorcraft 192* piece from Ford. It does open and let coolant circulate, but my stock gauge always seems to read high (although the old sender read low, so I think it's just the sender).

Apparantly, rereading my post, I did not check for bowl seepage before I adjusted the levels... Dumb, I know, and I don't know why I would have missed that, unless I just wasn't thinking. One thing I do remember is that gas would just flow out of the bowls if I took the sight plug out, which I believe was the reason why I adjusted the levels down, because there would have been no way for me to tell if they were rising after car was shut off if they were already too high. Of course, I could have just let the extra gas out and then looked at it...doink.

I do want to tell you that I used to give it a small squirt on start as I feathered the pedal before, and that always seemed helpful, but now it just seems consistent with one pedal pump to the floor (I haven't driven it that much, but after the adjustments, it seemed that way). I drove the car last night in 30* weather to the store, and when I came back out, I decided to test and see how it would start without touching the pedal (it was fully warmed up before I got there). It started, dove down to 250 rpms, and rebounded right back to 500 rpms once it quickly stabilized. This is much like what it would do in warmer weather, but only after having the engine off a *short* time. Much longer, and it would just die on the "rpm dive" after it starts. It was off this time long enough for me to expect it to die. I don't know if it was the cold or the adjustments.

I was thinking that it might be vacuum related with the thermactor system, as I get backfires out the exhaust occasionally when I let off the gas to shift (worse when the engine is cold; man, the other day it was popping if I got a little into it over 2k at all). The other thing that has me wondering is the idle mixture, because this summer, a friend who works at Ford told me that my car smelled like it was running "lean and mean" after start up. It's only until the engine heats up some and you drive it that the smell goes away (something with cats or idle mixture?).

And finally, I'm actually concerned about the o-rings, because the Holley kit I got from Summit (3-1346) had the wrong o-rings for the fuel transfer tube. They were too small and fuel was spraying everywhere when I started it for the first time. I called Holley and asked WTF?!? and the guy told me the o-rings expand in contact with fuel. I said BS because there's no way they're going to expand enough to seal this leak and just went to Advance Auto and bought some fuel o-rings. Long story short, I wonder if the needle and seat o-rings are acting the same way...? They came already on the assembly, so there's no way I put the wrong o-rings from the kit on them.

I'll have to test the thermactor components. I went through the vacuum system not long ago and tested every component, but things can break. I'll have to go through it again. I don't know why this didn't happen, though, with the E4ZE carb.