Vapor lock Vapor lock. 1979 Ford

[gongzhen2015]

Hi, 

Summer again and want to get some attention on my car's vapor lock problem.

So last year summer, after I was on the highway for a hour, the first minute i drive off th highway the engine run really rough and dies. Andthen, for the first hr i crank my battery all the way from full to none, it still wont start. (Back at that time i have no idea what is vapor lock) I guess this must be Vapor lock. After about 2 hr, i am able to restart it. 

 

So for this year, I already done the following thing to prevent the vapor lock from happening:

1. Add a carter fuel pump, fuel pressure in engine compartment reads 5.5psi. Mechanical fuel pump i just left it there, i didn't run the fuel pass the mechanical fuel pump. 

2. Cut and throw the original carb bowl vent/col something canister away, i let the fuel bowl vent to the air.

3. I add a 3 port style fuel filter, and connect the third port to the original vapor line.

4. Instead of the original steel fuel line running between A/c compressor and engine (Really Really hot), I run a new rubber fuel line avoid getting close to any heat source. 

5. Shielded all the fuel line/filter

6. Add a electric radiator fan.

7. The shroud was missing, so i get another one( Last year the water temp was very high. Got a new radiator this year).

 

Are there any other thing I can do to prevent it? Just test run it in hot idle for 2 hrs, no vapor lock. Drive for 1 hr no vapor lock. but today the weather is not that hot.

 

Besides that, my A/C solenoid kicker is kinda gumm up, which it can only hold the position but it cannot push the position, where to find them? What's their name?

 

And, is 5.5psi good for the stock 302 and MC 2150?

[Jon37]

1. Are you sure it's vapor lock?  Could it be that the coil is overheating?  (Next time you head out on a hot day, carry a big of ice along.  If the truck again stalls, use the ice to cool down the coil and see if the truck starts again.)

 

2. Do you have sufficient fiber spacers between the carburetor and the manifold?  In my car I now have 4 gaskets, a metal heat deflector, and 4 more gaskets, all insulating the carb from the manifold.  The other day I drove 2 hours in low-90's temperatures, and had no vapor lock, even sitting with the engine idling, waiting for a light.  Whenever I'd turn the car off, it would re-start with no problems.  I'm running 10% ethanol gasoline, and have only a mechanical pump.

 

3. If your truck has an exhaust damper make sure it rotates and isn't stuck, and that the thermostatic spring is working. 

 

(I'm not acquainted with anything newer than 1937 so maybe none of this information pertains to a '79 Ford truck!)

 

Best of luck.  You may have solved the problem but if not, keep trying.  I'm sure your truck will run perfectly, before long!

[Graham Man]

Check your ignition control module?  pick up a spare anyway, I never leave home without one, they hate heat (sounds like it is out of gas) starts right up after it cools down the first couple times...

 

 

https://www.youtube.com/watch?v=vkGpMaF9NMs   video of how to change one in a Thunderbird

 

I have a 1980 Ford Truck, same problem....

[gongzhen2015]

2 hours ago, Jon37 said:

1. Are you sure it's vapor lock?  Could it be that the coil is overheating?  (Next time you head out on a hot day, carry a big of ice along.  If the truck again stalls, use the ice to cool down the coil and see if the truck starts again.)

 

2. Do you have sufficient fiber spacers between the carburetor and the manifold?  In my car I now have 4 gaskets, a metal heat deflector, and 4 more gaskets, all insulating the carb from the manifold.  The other day I drove 2 hours in low-90's temperatures, and had no vapor lock, even sitting with the engine idling, waiting for a light.  Whenever I'd turn the car off, it would re-start with no problems.  I'm running 10% ethanol gasoline, and have only a mechanical pump.

 

3. If your truck has an exhaust damper make sure it rotates and isn't stuck, and that the thermostatic spring is working. 

 

(I'm not acquainted with anything newer than 1937 so maybe none of this information pertains to a '79 Ford truck!)

 

Best of luck.  You may have solved the problem but if not, keep trying.  I'm sure your truck will run perfectly, before long!

Honestly, i was not pretty pretty sure it is vapor lock. But it did normally run really rough when idle at redlight.. I have to give some gas to stable the rpm otherwise it really looks its gonna stall. 

 

There is a EGR valve there, which i think it should be space enough?? Not so sure. 

 

And for the ignition coil. I just replaced one. Just in case if it is this coil. Plus, ignition coil can get really hot and eventually give up and work again when temps lower??

32 minutes ago, Graham Man said:

Check your ignition control module?  pick up a spare anyway, I never leave home without one, they hate heat (sounds like it is out of gas) starts right up after it cools down the first couple times...

 

 

https://www.youtube.com/watch?v=vkGpMaF9NMs   video of how to change one in a Thunderbird

 

I have a 1980 Ford Truck, same problem....

This is the controll module. yes, i just replace one of this in the car. I checked the original one installed in the car, it was all rusted and manufactured in 1978. Guess that one maybe toooooo old?? But will this thing give up when so hot?  Back in last year, i didn't check for if there is spark, cuz i was so struggled on the side of the road and know nothing about it..

However, when I was working on it this year, i got it replaced with new plug and everything. The original one looks pretty rusted . 

 

Plus, i also replaced all brake line, alternator, alternator wire, voltage regulartor... And starter solenoid. 

I have to say, this starter solenoid was the first thing failed on my car which make me think the starter need to replaced. And for 1 year, i already replaced 3 of them..... 

[gongzhen2015]

55 minutes ago, Graham Man said:

Check your ignition control module?  pick up a spare anyway, I never leave home without one, they hate heat (sounds like it is out of gas) starts right up after it cools down the first couple times...

 

 

https://www.youtube.com/watch?v=vkGpMaF9NMs   video of how to change one in a Thunderbird

 

I have a 1980 Ford Truck, same problem....

ok so i did some research. Sounds like this thing like to die when hot.... so, what to do ro make them cool? 

[gongzhen2015]

Any one have any idea how to apply Dielectric grease/ Heatsink compund on those ignition module?

[Matt Harwood]

1 minute ago, gongzhen2015 said:

Any one have any idea how to apply Dielectric grease/ Heatsink compund on those ignition module?

 

Smear it on the back before you install it.

[padgett]

Rubber fuel lines near an engine scare me. Had a similar problem on a Camaro and bent a steel line away from any heat. I also run engines at 180-190F and that helps.

[gongzhen2015]

18 minutes ago, padgett said:

Rubber fuel lines near an engine scare me. Had a similar problem on a Camaro and bent a steel line away from any heat. I also run engines at 180-190F and that helps.

i  know that. however i route the fuel line all the way away from the engine, and double shielded with nylon and chrome silver heat disspate wrap.. Test run it in park for 3 hr and so far so good. 

52 minutes ago, Matt Harwood said:

 

Smear it on the back before you install it.

Just got a question. So the back of my ICM , only the case is aluminum or metal, the place where those wire came from was covered by some black glue? So i need to only apply grease on the metal body, to help it transport those heat to the fender?

[TerryB]

You can buy, and maybe that is the goo you see, heat transferring compounds to apply to the back of the module to get to transfer it’s heat to the metal it’s mounted to.  At one time it was known as thermal heat sink compound when I was using it on high powered transistors.

 

And if I had read the previous posts I would have seen it’s been mentioned.

Edited August 20, 2020 by TerryB (see edit history)

[Graham Man]

The white dielectric grease is for the connections, so they don't corrode.  On the trucks they bolt to the plastic fender liner (not much heat transfer).   I just plug in the spare when it dies, drive home and install it properly.  We had a 1979 Ford tow truck, it ate the modules about once every two years, but the truck spent a lot of time idling (hours).  A spare is cheap insurance I think they are about $30 for an aftermarket unit.  I always carry a spare.

[padgett]

Thermal grease is mainly for CPU heatsinks. Is in two flavors: grease which can slide, and cement for holding something in place.

[gongzhen2015]

Hey guys.

Wonder will a vapor locked car able to squirt some fuel in the carburetor when slam on the acc pedal?

I just remembered last year when i think it is "vapor lock", it can still shot some fuel to the carburetor.. by the acc pump i think. 

 

A little more thing, what should the water temp be for those ford 302 motor? 

Plus, i found a un attaced wire coming from the same plug connect to the ignintion coil, that it is a red wire which output constant 12V when after i turn my key.. Sort of like a , ummm Switch power wire.  What is it for? Choke?

[Graham Man]

OK we need to know the model of this Ford so we can help more.  Vapor lock is the fuel vaporizes from heat, so the carburetor would normally be dry.

 

If you have 50/50 antifreeze and it is not boiling over you are good.

 

Depending on the model Ford you have the extra wire could be for anything, find a wiring diagram for your car/truck and it will tell you.

 

If you want your car/truck to turn over faster and be more reliable purchase an NOS Motorcraft starter solenoid.  They are no longer available from Ford, but they should be, the aftermarket ones are junk.

 

 

I have been driving 1979/80 Fords for over 30 years, my money is/was on the ignition control unit. 

[gongzhen2015]

14 minutes ago, Graham Man said:

OK we need to know the model of this Ford so we can help more.  Vapor lock is the fuel vaporizes from heat, so the carburetor would normally be dry.

 

If you have 50/50 antifreeze and it is not boiling over you are good.

 

Depending on the model Ford you have the extra wire could be for anything, find a wiring diagram for your car/truck and it will tell you.

 

If you want your car/truck to turn over faster and be more reliable purchase an NOS Motorcraft starter solenoid.  They are no longer available from Ford, but they should be, the aftermarket ones are junk.

 

 

I have been driving 1979/80 Fords for over 30 years, my money is/was on the ignition control unit. 

Its a 1979 Ford thunerbird with 302.

So i basically have the same starter solenoid, i only use the S terminal. Not so sure what is that I terminal for.

I could only find the 1977 thunderbird manual and it said nothing about that unattached wire, coming from the same connecter where ignition coil connectes to. 

 

yes, i sorta think the same thing. Vapor lock means no fuel in fuel bowl, so I shouldn't be able to get any fuel shot from the bowl. 

 

Could be a overheating ignition coil or ignition contro module.

 

Was trying to find some motorcraft parts but seems they do not exist anymore, just get a Tru-tech ignition module, Standard blue streak ignition module, and going to pick a Duralast ignition module up tomorrow. The ignition coil i currently have the Standard Blue streak one. Good quality?

 

And what i have before i think should be misfire. Car running really rough when at red light and pretend to stall. So i order a distributor cap and rotor kit to install tomorrow.

 

Will get a video about how the car running for a better diagnoises. All the shop nearby me know nothing about those old car, which they tune my carburetor by following the manual... 

[gongzhen2015]

oh yes, and for the compression.

Did one weeks ago, only 1 cylinder shows slightly low at 127psi, all other at 135psi. Not so sure what psi they should be? 

[Graham Man]

The ignition control units are OK the starter solenoids have big contactor points that burn out easily.  You can get NOS solenoid on ebay.

 

If you are having rough idle go to the basics, have you rebuilt the carburetor?  I use a sonic cleaner on mine, one good cleaning will change everything.

 

PS for a lot of us on this sight a 1979 is a new car

[carbking]

Our 1979 Ford Econoline shop truck rusted out the third time (thanks to Missouri poor drivers requiring salt and cinders in the winter) at 440,000 miles.

 

The cylinder head was never removed from the engine, and the engine still ran strong.

 

We were forced to change the ignition module 13 times in 440,000 miles. I carried TWO spares and tools with me at all times.

 

Also still have a 1979 turbo Cobra Mustang which I special ordered. It has always been garaged, never seen snow, rained on once (I couldn't get home in time), and currently has about 55,000 miles. Currently on the third ignition module.

 

Jon 

[gongzhen2015]

1 hour ago, Graham Man said:

The ignition control units are OK the starter solenoids have big contactor points that burn out easily.  You can get NOS solenoid on ebay.

 

If you are having rough idle go to the basics, have you rebuilt the carburetor?  I use a sonic cleaner on mine, one good cleaning will change everything.

 

PS for a lot of us on this sight a 1979 is a new car

The carburetor was a rebuild carb. For this year since i change the module, the rough idle problem seems to be fixed. For the NOS starter solenoid, did some search found nothing on ebay.. I just keep carry a spare part in trunk.

[gongzhen2015]

29 minutes ago, carbking said:

Our 1979 Ford Econoline shop truck rusted out the third time (thanks to Missouri poor drivers requiring salt and cinders in the winter) at 440,000 miles.

 

The cylinder head was never removed from the engine, and the engine still ran strong.

 

We were forced to change the ignition module 13 times in 440,000 miles. I carried TWO spares and tools with me at all times.

 

Also still have a 1979 turbo Cobra Mustang which I special ordered. It has always been garaged, never seen snow, rained on once (I couldn't get home in time), and currently has about 55,000 miles. Currently on the third ignition module.

 

Jon 

Good to know. So the heat is first priority thing to kill these module? Or vibration or what. Was thinking add a computer 12V fan on the control module to reduce the heat. 

 

Nice, i think these motor ran really strong. My T-bird have a llit over 100k mils which the compression result surprise me. 

[carbking]

The engine, when the ignition module was new, would often act like the distributor was at full advance when trying to do a hot start. Turn the key off, turn it back on, and would start normally. After 25,000~30,000 miles, the engine would start normally when hot, and once this happened, you knew within a few thousand miles, the ignition would die.

 

Also had a 1980 Mustang that did NOT have the issue.

 

Jon.

[ted sweet]

the nos solonode i get on ebay didnt work at all

[gongzhen2015]

Alright, found something interesting.

The spare wire I talked about comming from same connector which connect to the coil which output constant 12V, 

Is it something should connect to the I terminal on the starter solenoid?

When I got the car years ago, the starter relay dont have a "I" terminal. 

But, what is that I terminal do? 

[gongzhen2015]

ok. 

Finds out the purpose of the I terminal is to bypass the resistor wire.

So my mistery 12V wire from ignitoin coil connector is nonsense. 

But it do have a plug look pretty like it should connect to the choke. And the length of the wire serve that question.

However, why something should supply constant 12V to a choke doesn't matter before or after engine start..... Didn't those electric choke use only about 6 to 7 volts?