Help me. PLEASE!!!!

Anonymous · Post by **Anonymous** » Mon Nov 08, 04 11:35 am

Hi everyone,

I have a (I beleive) fuelling problem with my car. I think I know what the problem MIGHT be but would appreciate a little help with diagnosis / cure.

The car (1970 Charger 440R/T) stalls within first mile of driving. I shall explain.

I drive my car about once a week. When I first get in her, I start her without problem, let her warm up and off we go. Within about 1 mile, if I slow down for a red light or something, she cuts out and wont start for about 5 mins. After that, she is trouble free, no matter how she is driven. I can even leave her oparked up for the rest of the day and the problem doesnt happen again.

Yesterday, I let her warm up to full running temp. Drove her out, and within a mile, I got a big bang that sounded like a backfire through exhaust valves and she cut out immediately. I coasted down a side road. Checked under bonnet, under car, had a twiddle with some bits, got back in her and she wound start - not even a cough. I left her for five mins and she started. Took her for a really long run and not a murmur from her. She behaved perfect.

I think this might be a fuel delivery prob, like a weak fuel pump or something but if that was the case, why does the probelm happen at the same sort of point all the time then go away.

Any help you could give would be appreciated.

Cheers

Clivey

Dave-R · Post by **Dave-R** » Mon Nov 08, 04 12:15 pm

Probably a combination of factors.

The not wanting to start when hot is probably heat boiling the fuel in the lines or in the carb or both.

If the carb is running too rich (what colour are your plugs?) that will make hot starting even worse. So will a weak ignition system.

Loud bangs are usually unburnt fuel/air getting into the exhaust manifold. Weak ignition or rich running carbs will do that too.

Anonymous · Post by **Anonymous** » Mon Nov 08, 04 1:14 pm

Hi Dave,
was hoping you would pick up on this

The car is deffinately NOT suffering from fuel evaporation problems. When she is hot hot hot, she starts first turn every time. This is just a cold running thing. The car has a new carb on it and new electronic ignition.

The problem, (now this will probably give the game away) has only come since the weather has turned cold and damp. The car was set up and serviced / tuned by RPM in summer. I never had the rpoblem then. It has new plugs, leads, dizzy cap, rotor etc. RPM said the new carb installation was done very well. So, knowing all this, do you reckon she needs a re-tune cos she might be running lean now air more dense at this time of year? I cant understand why the problem only happens if she is left to sit for a few days, then goes away once blatted about abit. When she is warm, she runs fine. Do you think it might be that when she is hot and the metal has expanded, some leaking seals are closing up, like carb to manifold or manifold to heads?

Dave-R · Post by **Dave-R** » Mon Nov 08, 04 1:25 pm

Ok now I see what you are saying.

No I would not expect you to have to re-tune the carb if it was set right to start with.

So this happens only once after standing for a week and then no matter how hot or cold the engine gets it does not happen again unless left to stand for a week? Yet it starts OK after standing for a week?

Mmmm.

When you say you warm her up before starting off do you mean you warm her right up to full operating temp? Or do you set off as soon as the engine sounds smoother.

If it is not fully warm and the carb set on the lean side then the choke might be coming off to quickly causing it to stall at lights etc.

Blue · Post by **Blue** » Mon Nov 08, 04 2:00 pm

I agree with Dave, most likely a choke problem, either coming off too fast or staying on for too long. Next time you take it out make sure the choke is fully open before you drive it and see if you still have the problem.

Anonymous · Post by **Anonymous** » Mon Nov 08, 04 2:07 pm

Hi Dave, yep I think we are getting close.

I let her stand for a week. When I start her, she turns over for quite a while but doesnt idle too well. From memory its well below 1000rpm. If i dont tickle the throttle she will stall (and keep stalling) straight away. With the exception of yesterday, I wait till she idles a little smoother (dont wait till she is at full running temp) and then go, and she stalls shortly after. I thought I had it at full running temp yesterday, but maybe not.

One thing I have done recently is had a newly recored rad fitted. The rad is now supposed to be 25% more efficient. Logically, I spose this means longer to warm up. I may be clutching at straws but my probs may have started when the rad was fitted.

If what you say is the case, is there a reason why she should be lean? I mean, if she was ok a few months back, why probs now? Is this a cold air density related thing? If carb needs adjustment, would you mind giving me some pointers on what screws need turning? I will need to post a picture of my carb for you to see what I have (it says carter on the side but has Edelbrock sticker on it. RPM said it was an Edel carb n all)

Dave-R · Post by **Dave-R** » Mon Nov 08, 04 2:18 pm

Before you try to start the car from stone cold press the throttle all the way to the floor once or twice and then leave it alone. This puts the choke on (if it is working!)

Then turn the key and start the engine. You should not have to touch the throttle to start the engine.

You will find that when it starts it will soon start to idle quite fast. This is the 'fast idle position'. after a few seconds blip the throttle. If the choke is working correctly it will continue to idle faster than normal until the engine is quite warm.

Once the engine is warm enough blipping the throttle should bring you down to normal idle speed. If this is happening too quickly your choke needs adjusting.

Edelbrocks normally have an electric choke. If i remember right you loosen a screw and the casing of the electric choke rotates. One direction makes it stay on longer the other direction brings it off quicker.
It sounds to me like it needs to stay on longer because you say it idles below normal idle speed.

If you are driving an automatic your idle speed should be 800rpm.

Anonymous · Post by **Anonymous** » Mon Nov 08, 04 3:59 pm

Thanks chaps. What you say makes um heap o sense. Not sure what I am looking for on the carb for choke adjustment, but I will try the foot-to-the-floor thing next time I take her out.

Will let you know how I get on

Anonymous · Post by **Anonymous** » Mon Nov 08, 04 8:42 pm

ive got the answer Clive,dont leave her parked up,just drive her every day.Thats 1 tec problem solved. lol

Anonymous · Post by **Anonymous** » Tue Nov 09, 04 12:19 am

Wow

you guys are going to have such a field day when I get my car together!
I am going to need a ton of help!
Well I have Mick and Alistair close by, fingers crossed it will be a month or so till I crank the beast!
Glad to be in the MMA!

Anonymous · Post by **Anonymous** » Tue Nov 09, 04 12:04 pm

bigger rad should make NO DIFFERENCE to warmup time, because there should be no water going into that rad until the engine is at full operating temperature. (assuming you are a good boy and have a thermostat in your engine!)

Ivor · Post by **Ivor** » Tue Nov 09, 04 1:50 pm

Nobody gonna mention carb icing?

Sounds like classic symptoms to me...but then I'm only a humble wordsmith...

Anonymous · Post by **Anonymous** » Tue Nov 09, 04 2:10 pm

Hey guys, couple of quick comments. I had my thermostat removed, so rad is now a factor sadly.

Ivor, what sort of temperature will ice start forming in fuel? I assume its different to water?

Will,
will hook up soon and you can have a drive of my motor for making that comparrisson. See what you think

Dave-R · Post by **Dave-R** » Tue Nov 09, 04 2:23 pm

Ivor wrote:Nobody gonna mention carb icing?

Can carbs ice up after driving just a few hundred yards? I wouldn't have thought so. But maybe they can?
It's not that cold down South is it?

The one and only time I have had a carb ice up on me was on my way from Huntington to Peterborough. Nightmare journey in deep drifting snow, in the dark, lost etc. Car was my trusty MkII Escort 1600 and the carb was the twin choke weber. I was running on two cylinders at best at times. Had visions of being found days later frozen to death under a snow drift. I remember being seriously worried at times. Limped into Peterborough and the engine finally packed in just 15 feet from where I was staying.
Got up next morning and could find nothing wrong with it. I never had any trouble with it after that. Well I wouldn't have because I dropped the block out and replaced it with a less worn one from a Cortina!

Guy · Post by **Guy** » Tue Nov 09, 04 2:52 pm

Yes Dave carbs can ice up that quickly my old RS1800 was a nightmare in the winter mind you the fact the the bellmouths on the twin 50's were about 10mm off the inner wing didnt help. The first 2 miles were alway interesting but after that it was usually fine unless it was exceptionally cold.
As for Clivey I dont think the air temp has been cold enough to cause this problem, is the choke manual or electric ?

Just a thought when the fan went through the rad on your car I take it that it sprayed water every where and this problem has reared its head after you got the car back on the road have you checked all electrical conections and made sure that they are dry inc bulkhead conectors the way you discribe a backfire it sounds like the ignition is cutting out maybe something like damaged coil or am I just clutching at straws