Help - Engine question

[langlj00]

Just arrived at work, on the way the car gave a very large backfire on hard acceleration (slight loss in power as it happened), but then seemed fine. Treated it gently up the motorway (5 miles), no issues. But when I arrived at work it wouldn't hold an idle and eventually died, and pushed it the last 2ft into a parking space (very ungraceful).
So question - do I try and start it again when I go home (lunchtime) - or if I've bent a pushrod or dropped a valve - should I leave it alone and call the AA?
In two minds........ - Ross?

 

[CaptainK]

Possible vacuum leak? My Vette randomly on the rare occasion under initial hard acceleration (aka if I suddenly put my foot down) does a large backfire, hesitates for a bit and then resumes - mostly because I've backed off by then.
Though I'm not that technical, so you'll probably get more helpful answers when the technical people have woken up.

 

[James Vette]

Check your fuel hoses for leaks and check your choke is working properly.

 

[Roscobbc]

Mechanical fuel pump failure? - diaphram eroded by ethanol based fuel - still pumping some fuel in to the carb - perhaps enough to feed it under light throttle conditions - then it failed completely? - try that first

 

[62 C1]

If you managed to drive it another five miles it is probably okay to start. Was it making more noise than before the backfire afterwards? Have a look at your exhaust headers/manifold and check it hasn't come loose/blown the engine/header gasket or come loose at the exhaust/header connection. Problems here can cause hard acceleration backfires.

 

[langlj00]

Update, started fine at lunchtime. No issues, stopped at temporary lights on way home. Cut out. Will not start, awaiting AA !?!

 

[langlj00]

Check your fuel hoses for leaks and check your choke is working properly.

Thanks done

 

[langlj00]

Mechanical fuel pump failure? - diaphram eroded by ethanol based fuel - still pumping some fuel in to the carb - perhaps enough to feed it under light throttle conditions - then it failed completely? - try that first

Thanks I happen to have a new one at home, when I get there…..

 

[Roscobbc]

Thanks I happen to have a new one at home, when I get there…..

Spin engine over with carb gas connection removed (over a can) to check fuel delivery

 

[Forrest Gump]

Update, started fine at lunchtime. No issues, stopped at temporary lights on way home. Cut out. Will not start, awaiting AA !?!

I would check you still getting a spark at the plugs - Just to eliminate ignition failure

 

[langlj00]

Back home after 5 hours. And of course it started the moment it was finally pushed into the garage!

 

[Mad4slalom]

Back home after 5 hours. And of course it started the moment it was finally pushed into the garage!

Had similar on a 78 and turned out to be the coil breaking down when hot

 

[langlj00]

Had similar on a 78 and turned out to be the coil breaking down when hot

AA man thought similar, I’ve got a spare in the cupboard, plan to change that and the fuel pump just in case.
Thanks all.

 

[Roscobbc]

AA man thought similar, I’ve got a spare in the cupboard, plan to change that and the fuel pump just in case.
Thanks all.

Its good practise irrespectively

 

[Mad4slalom]

Its good practise irrespectively

Always little niggles with these cars, I seem to do one job and create two or three others.
Or an issue will present itself and then disappears again just after you have ordered the three things that you thought it could be!. A good way of accumulating a good stock of spares tho, ( most of which you will probably now never need again ) Hobby Cars!! Gotta love em !!

 

[langlj00]

Pulled the valve covers yesterday and checked the valve lash (easy way to check the valves and pushrods at the same time). All set correctly, so rotating assembly 'feels' good - which was my initial concern.
Coil has puked oil, so 99.9% that was the issue, I'll get that changed and leave the fuel pump for another day, (I don't really want to change 2 things - fix the problem and then not know which was the cause).
Thanks all, 5 hours waiting for a flat-bed in that heat was not the best use of a Friday, but never mind, lots of people pulled over for a chat!
J.

 

[Forrest Gump]

That ties in with the big backfire you had initially - lack of spark in the cylinder causing unburnt mixture to detonate in the exhaust.

 

[Mad4slalom]

Pulled the valve covers yesterday and checked the valve lash (easy way to check the valves and pushrods at the same time). All set correctly, so rotating assembly 'feels' good - which was my initial concern.
Coil has puked oil, so 99.9% that was the issue, I'll get that changed and leave the fuel pump for another day, (I don't really want to change 2 things - fix the problem and then not know which was the cause).
Thanks all, 5 hours waiting for a flat-bed in that heat was not the best use of a Friday, but never mind, lots of people pulled over for a chat!
J.

fingers crossed thats all it is the place where you waited for recovery will forever remind u of that day, I have two of them, affectionally known as “corvette hill” and “ corvette lay by “ I suspect many on here will have their own “special spots” too

 

[antijam]

fingers crossed thats all it is the place where you waited for recovery will forever remind u of that day, I have two of them, affectionally known as “corvette hill” and “ corvette lay by “ I suspect many on here will have their own “special spots” too

It'll be a brave man who says 'not yet'........

 

[CaptainK]

fingers crossed thats all it is the place where you waited for recovery will forever remind u of that day, I have two of them, affectionally known as “corvette hill” and “ corvette lay by “ I suspect many on here will have their own “special spots” too

My Corvette had a time where it just played up randomly and I couldn't get to the bottom of the issue. Consequently I ended up not just with a Corvette layby or Corvette hill, but ended up with Corvette Taunton.