Running really poor when cold LONG SORRY

[Anonymous]

So we have all been through this with me before, sometimes my engine runs like a dream and sometimes I can hardly keep it running.

I have posted lots of topics on this, we have been over many things, but I am thinking I am back to square one on this now that I have sealed up the intake and exhaust for sure. I should start back at the beginning.

So over the weekend I installed FSPP gaskets on the 2v intake and headers... I spent a lot of time making sure things were clean, surfaces mated fine, bolts were tight and everything is sealed up nicely. I know I was partly successful because the car runs much better, at least when it is warm and dry. The rpm range from 2-3K is usable now, shifts are smoother and the power curve feels better. Not 100% yet, because I know I am all in on the timing too fast, I need to get the distributor re-curved or replaced with one that better suites my setup.

Here is what caused me major trouble today.

It is cold and rainy here in ATL... temp is 33 degrees and raining lightly. Now for me the cold has been bad on things but nothing compared to the rain.
When the temps are low, I can close the choke and get her to warm up at around 1600 rpms, you can watch the temp needle, what happens is it warms up and then when the therm opens the temps drop and it warms up again, at some point it holds a steady temp. (This has always been normal with this car, there is a point at first where the engine internally gets warm but the coolant that flows in the first time cools the engine back down.)
When this happens the rpms can sometimes drop down to 1000 or 900 or so with the choke untouched. If I open the choke the car dies, the engine is very rough when this happens. If I shut the car off and let it sit for a few minutes then close the choke part way and it will fire up nice and smooth. runs a normal cycle, it only seems to die once and a while during that first drop in temp. And always runs fine if you let it sit and warm up without running.

Now this all gets MUCH MUCH worse when it rains. Today right from the first moment, you close the choke and does not want to run, it idles really poorly, very rough, no position of the choke makes any difference, closed it will not fire, open it fires then dies, halfway where she normally loves to warm up it runs rough and dies. I popped the hood and pulled the aircleaner, opened the choke and got in, fired it up and held the throttle for a few moments just to get things moving, then it finally idled but was not happy at all. I am pretty certain this is not a great way to run a cold engine but it seems the only way to keep it up in the high rpms, because with the choke where it would otherwise idle at 1600 only gives me an idle of 900? no matter where you put the choke?



My first reaction is to give the car a proper tune up this weekend, I changed those manifold gaskets, and did a halfway tune on it, checking the vacume and setting the rpm at 800... but I am sure it could use a new set of plugs, and some timing and carb setting... seems like it is a little lean right now.

But I am not sure why the wet weather effects this, it can be 32 degrees and raining or 19 degrees and dry and it runs better at 19...?
I am also wondering if it is not running too cold... I am not getting the best readings with the thermostat I am running, I am going to buy a mechanical therm at Autozone and see what my real temps are. I will start there and maybe next time it is cold and rainy I will hook a vac gauge and timing light and tach to the engine and get some readings of what is happening when the car is like this.


I also get a squeal when I do hold the throttle, I thought my squeal was a bad powermaster alternator I replaced three weeks ago, I used to get this same thing with the bad alternator, but I replaced that and the squeal and this symptom stopped for a while, but it was also warmer here lately... but today it squealed again? maybe I have a loose alternator belt? could be when I changed the gaskets I did not get it tight enough? because I also was reading 11 volts when this whole idle problem was occuring?

I am also wondering if I did not get a bum Holley, and maybe this 350 is just not the right carb, I am thinking about going up to the 500 and see what happens...

could it be this 2v intake when cold I am flooding the engine with fuel puddling? I am just trying to figure this out, winter is almost over for me, and I am starting to wonder how this will be when things heat up?

man sorry this is long, but you know me things are never easy.


Thanks Guys...


Jimbo

 

[Anonymous]

Are you running heated water through the intake...that should level out the playing field the carb is on.

 

[Anonymous]

No, because back when I was tracking down the intake leak and the smoking issue I sealed that off, maybe it is time to open it back up.

I know I was burning oil and not coolant...

I will try that right now! see if that helps.

 

[Anonymous]

your carb/intake might be icing from lack of heat so the water heat should help

 

[CougarT]

Consider that as your engine warms up it dries off and runs better. How old are your plug wires? how well do your plug wires seal into the distributor and onto the plugs? how old is the coil? how well insulated are the wires into/out of your dizzy?
Dielectric silicon and new wires/coil worked wonders for me a few years ago on my Civic.

 

[Anonymous]

The wires are about six months old, running engine time, they are really about a year and a half old, sat for 9 months while the engine was rebuilt. They are MSD Helicore 8mm wires, running a year old DSII dizzy, with new cap and rotor, and all wires are coated with grease and sealed nicely.
but that is never to say something may be bad in there?

The coil is a Petronix Ignitor coil, about three years old, ran on all of the engines and setups I have had, I have thought about changing them all to new but I have some money in those sets and they are not that old.

 

[Mustangaroo]

Jimbo,
How's your Holley power valve, if your engine has been having trouble and if it has back fired up thru the Carb it can blow the power Valve and give you some strange side effects because of the blown power valve! Just a thougt? Also do you have any idea if your running lean or rich? Good luck!

 

[Falcon62]

Know anybody close by with a known good Holley 350/500 you can try? That might save a lot of frustration and would isolate the carb as a problem source in a hurry.

Other than that, I don't know what else to suggest.

 

[strat1960s]

Hey Jimbo

I have pretty much the same problems with my car. I average 3 to 5 restarts just to get from my house to my shop at the Air Force Base. I am leaning towards a couple of things in my case as being the cause.
1. Possible vacuum problems with my Weber 38 DGAS carb.

2. May need to go up in idle jet size.

I am not flooding. The motor acts like it is flooding, but it is not. When it is cold, the motor bucks, RPMs fall to around 400 to 500 and then she dies, almost like the motor can't keep itself running.
Yesterday, in the afternoon, when it was in the upper 60s, the motor ran very well. I think it is a good thing I live in Arizona. I really wander how it is going to run when it is in the 100s??
I am thinking of pay the guy who does the DYNO work at our shop to come over to my house and help me figure this thing out.
If we come up with any possible solutions, I will email you to see if this may help you.

Ted

 

[Anonymous]

I have had a lot of deiseling, backfire through the carb... specially with the rpms up where they were when I had the vacume leak.

the power valve was replaced as were the jets back when I was varying the sizes, I ended up with the 6.5PV and 61jets on both sides.

I have several different valves here, but no other 6.5's

it seems to me like there is something sticking when it is cold, could it be a valve sticking? or maybe the power valve gets stuck? because when it sits for the few minutes after it boggs down, it runs fine then? seems like a little heat wait, then no more problem?

I am also running an unkown PCV valve, which I know can cause a lot of weird things too... I got a motorcraft valve - the right one for the 200... I am installing that now, and there is snow on the ground here in ATL this morning... guess we will see how it starts in the snow?

I will keep you posted.


Jimbo

 

[Anonymous]

I dont know what your problem is but I do remmember the guy who had my 250 2V for 10 years prior to me said that it did not like running without water going through the inlet manifold and improved when he allowed it to.
Also my 2V although it runs very smoothly it can be a trick to start and will stumble and die easily just after it fires when cold. I pull my manual choak on full and the moment it fires I push it in about a quarter leave it for a few seconds and then push it all the way in and just use the throttle. In about 30 seconds it will then idle by itself.
Any other way just doesnt seem to work for me.

 

[Anonymous]

lost compression? did you check you compression during the bad idles?

 

[MustangSix]

I've had cars that did not like damp weather. On one, it was a case of condensation inside the distributor cap. On another it was bad plug wires.

Both cars did the same thing - ran rough, needed lots of choke (rich mixture's easier to fire), backfired. Both cleared up when I got everything dry inside the distributor and wires. Try some wd 40 and a dry cloth inside the cap, cap adapter, rotor, and magnetick pickup. Also spray the wires and boots. That might make a difference.

 

[Anonymous]

I had similar problems, and found that although my choke plate was closing, the choke pull down linkage was not adjusted properly to engage the fast idle. I occasionally have a bit of cold weather problem now, but I think it is due to the electric choke warming up before the engine has warmed up.

 

[66200i6]

That sure sounds like an icing venturi. The next time you start it cold, inspect the base of the carb. You may even be able to see the frost that can form on the carb body. The transition and idle circuits depend on the sensing holes in the throat of the venturi. If these holes are iced over, those circuits are disabled.

Good luck, Ric.

 

[Anonymous]

Well my fix for this morning worked like a charm...

I fired it up cold, it idled rough but did run for about 5 minutes giving the engine time to build up some heat, then I went inside and let it sit for about 10 minutes... when I went back out and fired it up, ran like normal, no problems with the choke or the engine... melted and or dried up that moisture...

I will re-route the water lines through the carb base this weekend... and do a complete tune-up on the engine... temps are supposed to be in the 60's this weekend, man going from Snow and freezing to warm and sunny is making life fun and interesting...

Georgia winters suck because you can go from one extreme to the other in a day or less...



One more note: Is there some way I can test my wires to make sure they are OK?

I am going to go ahead and replace the petronix coil with a MSD unit in case there are any issues there, might as well get things together! the cheap and easy ones are best tried first.

J.

 

[Anonymous]

cant you test spark plug wires with windshield weasher fluid at dusk? something about rubbing wires with fluid, then starting it up. If thye are bad, you will see a spark of blue in the night...something...

 

[Anonymous]

I doubt the coil is a culprit. Years ago, I replaced a couple of them only to still have the problem. I think coils are pretty hearty critters. As far as checking the wires, I have identified some before while popping the hood when it is very dark out and I have been able to see some leakage around some of the wires.

 

[pedal2themetal45]

HI GUYS
I'm not sure of his motor set up but isn't 800 idle a little fast... which would cause the mixure screws to be adjusted wrong and causeing the iceing prob. persay the need to run the water thourgh the intake..
Just my .02
tim

 

[Anonymous]

Often, there is a tendency to raise idle speed in order to smooth out the idle. Problem is, that the higher throttle plate position starts to transition the carb out of its idle circuit and the idle is not really stable. Sometimes inadequate total timing advance at idle is the culprit.