Hard start only when warmed up

[irowiki]

So I'm doing phone troubleshooting. Pokey (84 Auto) starts perfectly when cold.

When turned off and allowed to sit more than 5 minutes, she's real hard to start, takes about 5-10 seconds of cranking and some degree of gas pedal to get her to start.

If she's been sitting for 15-45 minutes, it takes a minute or so of cranking before she'll start. If she cools down overnight, she fires right back up just fine.

It is 30-50 degrees in colorado where he lives, so I'm not sure this is a vapor lock issue. Car runs perfectly fine down the road, has good power.

Any ideas? I am replacing the fuel pump because the spare I had was really stiff (almost impossible to test by hand) and I want to eliminate it as a possibility.

edit: wow, he just called me and said he got 28 MPG driving her hard! Way better then we ever got.

[dlb]

the AAP is the first thing i think of but i would check all of the temp-related vacuum stuff too. could be a marginal electrical component too: plugs, wires, cap, rotor, some other internal distributor part since they tend to act up once warm. i would lean more towards that if it also had issues while driving when warm but maybe it's still something i would check.

[irowiki]

Brand new plugs/wires/cap/rotor, brand new AAP. Once it starts, it runs fine, except for wanting to randomly die at idle.

The TVSV had a crack in the N port for the AAP but we glued it while waiting for me to bring another one down.

[marlinh]

Did you have a look to see what the choke is doing when it won't start? Maybe it's something simple...

[Mark]

I'd try disconnecting the vacuum line to the EGR modulator. The EGR system is only activated at idle when the engine is warm. There could be a vacuum leak in the modulator causing issues at warm idle. I had this happen to me before, but it was never severe enough to prevent the car from running.

[Petros]

Mine acts this way to, in fact all of the ones I have owned have acted this way. I think it is vapor lock. it still could be vapor lock even in winter, that fuel pump and fuel line rests right on top of the exhaust manifold. when running you get supply of fresh and cool fuel from fuel tank and it keeps the pump and line cool, when you stop it the fuel line and pump sit there and take in heat from the head and manifold right under it. the ethanol mix (10 to 15 percent) will vaporize in the pump and line right over the exhaust manifold and make it difficult to deliver fresh fuel until it is pumped out. If it sits for more than about 30 to 40 min (including overnight), it cools enough so the ethanol bubbles go away and it starts. Hi altitudes exacerbates this problem because the atmospheric pressure is lower.

I notice that if I restart it right away (within about 30 sec.) it is no problem when hot, but after 5 to 10 min (like at a fuel stop) than I have to crank it for 30 sec or more to get it to start. but if it sits for more than about 30 to 40 min (like going shopping), than again it starts no problem.

the ethanol fuel mixture is the only thing I think that would cause this, it does not affect modern cars because the fuel injection puts 20 psi or more on the fuel system, vs. our car: about 4 psi.

If you can find a gas station that still sells ethanol free fuel, you might give that a try. There are a few still out there, the gasoline costs a little more, but your fuel economy will be better and it will run smoother, so it compensates for the higher costs.

[irowiki]

Meant to update this earlier. Replaced TVSV, verified all vacuum routing. I tried starting it when it was "warm" and it cranked to life after feathering the throttle and cranking for a few seconds. But he still can't get it to start right when warm and sitting for a bit.

It's also not starting properly when it is really cold...I have a feeling the carb I swapped to it may not be completely up to snuff, and I'm running out of good carbs!

[Gottolovem]

I have one with your name on it in your corner of my property

[irowiki]

Yeah, I'm trying to avoid the rabbit hole of having you ship random individual parts unless it is an emergency!

[drege]

Mines doing it too after various ignition replacement parts and carb tinkering.
When I got it it ran perfect, came to find out there was a blown out TSVT line, idle was off, timing off, old wires- now it does this stuff.
Though unlike you, mine starts perfectly cold; two pumps of the pedal, idles up to 2200 or so, then automaticaly drops down to base idle - but the damn thing just don't want to start warm, pretty much have to floor the gas pedal.
Might benefit from more tweaking under the air cleaner, maybe a fuel filter - I dunno.

[irowiki]

We took pokey out for black friday and noticed no problems. But the starting problems still persist. But only for him. So we disconnected the EGR vacuum lines and it is still doing it.

Example: He'll drive 20 minutes, stop at burger king to meet a friend for 1 hour 20 minutes, come back out and the car only starts after over a minute of cranking. Blows all sorts of gas smoke after it starts.

Drive to gas station after, off for 5 minutes, starts right back up. He's at 5,000 feet. All my other tercels work fine at 5,000 feet (that's what farmington is at)

I'm convinced he must be doing something wrong, or something is wrong with that carb. (Peter, this is the carb you sold me that Turtcel had tested, it worked mostly okay on my 1st gen (wiring problems) and it seemed to work fine when we swapped it onto this car, the only thing I can think of is something gummed up from sitting so long)


He'd rather do the weber though then deal with the carb, so he's going to go pick up a fuel pressure regulator at some point.

[Petros]

do you think it is possible the fuel is draining out of the float bowl during long stops? or does it start fine when fully cold?

[irowiki]

I thought of that too. Fires right up when cold, like say overnight.

[irowiki]

Update: Turns out part of the problem was a bad alternator that killed the battery resulting in much slower engine cranking. So it starts up easier when warm now, but still not ideal.