Losing performance after about 10-15 minutes
 

Have just fitted a new carburettor, and checked the manifolds for leaks etc. All appears good, no leaks and car runs beautifully. I have stripped distributor and redone timing and again appears to run at idle and speed with no problems.

So, after idling correctly and running properly up and down local hills, I then find I lose power after about 10-15 minutes. It is as though it is is running too lean and when pushed may backfire. It loses power to the point it may stop altogether but will start and run immediately after albeit with no power. Fuel feed appears OK and after it cools down, performance returns.

Suspected issues could be:

- Bad distributor capacitor
- Bad high tension coil or lead
- Something I haven't thought of but which is temperature affected...

Any ideas???? I am running out of them.

Thanks, Peter

Re: Losing performance after about 10-15 minutes
 

Your suspicion of the capacitor and coil are spot on. I do not subscribe to the "throw parts at it until it's fixed" method of troubleshooting but in this case, there really isn't a more efficient way to diagnose either of the two components. R&R the cheapest item first.

Re: Losing performance after about 10-15 minutes
 

Just for the heck of it, when it starts acting up just crack open the fuel cap and see if that helps.

Re: Losing performance after about 10-15 minutes
 

My gas cap vent was plugged and car had the same symptoms. Wayne

Re: Losing performance after about 10-15 minutes
 

Somewhat refreshing to see the word losing spelt/spelled correctly for a change.

Re: Losing performance after about 10-15 minutes
 

When your car acts up, do you leave it running at an idle and feel the temp of the coil. Is it hot. Had almost the same problem, coil got hot wouldn't run. Cooled down ran fine. Replaced coil, problem gone.

Re: Losing performance after about 10-15 minutes
 

Going by the thread title I thought this was going to be spam for E.D., too funny.

Re: Losing performance after about 10-15 minutes
 

At my age any loss of performance is concerning...

Oh, and losing power is the spelling as defined by the Queen's English (Aussie, Aussie Aussie !!!!)

Thanks for the help guys....

PeterBo

Re: Losing performance after about 10-15 minutes
 

"Losing" is the correct spelling on this side of the pond, too :-)

Re: Losing performance after about 10-15 minutes
 

True story: How about the biker guy who had "Born to Loose" tattooed on his arm? I wonder if he meant he was born "to lose" or that he was born "too loose"? Maybe the tattoo "artist" didn't know the difference? How many people would know the difference in spelling? Or would care to point it out to the biker? :)
Pooch - Don't get me started on the always-to-be-seen misapplications of loose/lose, they're/their/there, its/it's (there is NO SUCH WORD as a possessive pronoun! That is spelled "its" without an apostrophe, just as "his" and "hers" have none.), whose/who's, then/than in the comparative, and so on. These "gotcha's!" are why the English language can be difficult for foreign speakers to learn. Heck! We have very little grammar to master. So, we gotta' do SOMETHING to make English difficult to learn! I know! Let's have multiple spellings of words that sound the same, but have different meanings! That'll fix those foreigners trying to learn our language! :)
Did you know that because of phonetic spelling, the simple word "fish" can be spelled 76 different ways? Jeez! No wonder little Bobby and Jane can't spell!
Marshall

Re: Losing performance after about 10-15 minutes
 

Dad takes those special blue pills, they turn the top of his head red.:eek:.. Don't tell anyone:D

SA sonnoutt

Re: Losing performance after about 10-15 minutes
 

HA, SA Kid,
Don't need those pills, eat your heart out!:D
Dad

Re: Losing performance after about 10-15 minutes
 

Hmm I would try the coil as its easy to get to and cheap but I helped repair an A that was doing what you described:

Stone cold it would start and run beautifully but after 5-10 minutes it would start to cough and occasional backfire and slowly loose power till it eventually died. Would not restart or cough till it cooled down.

We did the whole electrical system, carb, etc nothing changed. Ended up doing a leak down test after we got it hot and it shutdown on its own. Leak down test is where you supply a regulated 10 lbs of air to each cylinder at TDC on compression stroke and see where the air leaks out. You must remove the radiator cap, oil fill cap, and all 4 plugs. In theory it shouldn't leak out anywhere but after a few seconds it will blow by the rings and you will hear air escaping thru the oil fill - thats normal unless its immediate then you got stuck/broken rings. If it escapes thru the carb you have an intake valve not sealing, thru the muffler its exhaust valve not sealing, if it sounds like its coming from the neighboring cyl then the headgasket is blown between them. Repeat on each cyl turning each one to TDC. BE AWARE THE AIR CAN HAVE ENOUGH OOMPH TO MOVE THE CAR! so dont do it with your legs between the bumper and the garage wall...parking brake and blocks are a must with car in gear.

In our case it was not sealing from cyl to water jacket so when we applied air it was like old faithful out of the radiator neck! New headgasket, decked head, and no more problems. It must have only decided to leak when things got hot and resealed when things cooled down a bit.

So like I said IF a different coil fixes it then yay your back in business for only a little $ and repair time. BUT be aware it could be the headgasket - the leak down test doesnt take much time to do at all and really tells you the health of the engine.

Re: Losing performance after about 10-15 minutes
 

Why?

Re: Losing performance after about 10-15 minutes
 

I confused my neighbour the other day by trying to explain English spelling and pronunciation using just four words, red; read; read; reed. I didn't have the strength to try to explain plough; tough; thought or go onto bough; bow; bow; beau.

Re: Losing performance after about 10-15 minutes
 

I would go for changing the condensor. I had a similar problem and, that is what it was.

Re: Losing performance after about 10-15 minutes
 

Cornishman -
You are right/wright/rite about that! :)
Marshall
By the way, Cornishman, I have always been impressed by your command of the English language, which I am guessing by your location is a second language to you. Articulate, the correct words chosen and properly spelled, and very, very few grammar errors, certainly no more than the rest of us make. Are you native French or an American/Englishman living in France? I suspect that because of the "Cornish" part of your Fordbarn name, you are from Great Britain? I wish I were as fluent in my chosen foreign languages of German and Russian as you are in English!

Re: Losing performance after about 10-15 minutes
 

How did it run before you changed carb, and worked on dist. Did you check the spark when it was not running right. If so what color was it.

Re: Losing performance after about 10-15 minutes
 

Re: Losing performance after about 10-15 minutes
 

Capital letter with an "a". ;) A capitol with an "o" is a building and is generally where a state's legislature holds its sessions. Iowa's capitol is in the capital city of Des Moines. 'See why English is so hard for foreigners to learn???
I know, I know: Everybody likes a little *ss, but nobody likes a smart*ss. :)
Marshall