4AC Problems....

[Rallystanza]

Hey guys,

I have been having some issues of late with the old 4ac in the sprinter. Problems aside from the fact that the engine is not being used as a boat anchor as yet...

Basically I have checked the tune and points gap and leads and what not but the car has problems when accelerating.
When car is stationary and idling, if you stab the throttle, it just seems to konk out and lose all running signs, then when you let the throttle go it comes back up to idle...

So when i need to take of in 1st, i have to be very gentle on the accelerato until the car is moving. Once moving i can gas it to my hearts content without an issue....if i gas it at low revs in a higher gear it does get a little stutter to it....sometimes.

Any ideas?

Thanks,

Jeremy

[myne]

Check the carby for a rubber boot over a vertically mounted pin that's pressed on by a tab on one of the linkages.
That squirts a bit of extra fuel when you accellerate. It could be flooding, or not working at all.

[roadsailing]

if you want to eliminate the dizzy as a cause, i have the one from my old 4AC, was working fine when i pulled the engine out and the pints gap might even still be right.

might be around your area in the next few days so i'll leave it in the boot of my car.

[mrshin]

Better yet, I've actually got an old 4AC that some clown has adapted a Weber to. If you have a sense of humour, that is...

[slide86]

I agree with MYNE.
sounds like the accelerator pump (part described) has a split seal. this would stop the extra fuel from being put into the motor on take off, causing the engine to die until the throttle butterfly is opened far enought to allow the primary port to add the fuel to the system.

you can buy a carby rebuild kit, which will include the parts to fix the accel. pump, for not too much and then go ahead and just change the accelerator pump boot.

you should be able to do it with out removing the carby. as the pump is on the top of the carby.

[Rallystanza]

Ok here is how its evolved today...

I changed the carby to another standard carby which i know was working fine....

Did not change a thing.

I then proceeded to change to coil and the problem was resolved instantly...did not have a fault at all and was running better than ever...

But i took the car for a 10 minute drive and all was fine...car rested and then i drove it for another 20 mins when about half way through the drive the problem started to occur again...


I think possibly the coil resistor is at fault??

Any ideas now?

Thanks for the very good help so far though guys,

Jeremy

[mrshin]

Ahfff, point ignition! Put in some new points and a new condensor, and swap everything else for stuff that you should have lying around, assuming you have an adequate junk collection.

[andurils_sheath]

Perfect excuse to shell out for a 4age conversion. lol.

But back to the topic, sounds like your opening the butterflies quickly and its leaning out so i think its a fuel delivery issue, strange you say about the coil though.

So i got nfi. Bizzare.

[slide86]

there goes my theory on the accelerator pump. ah well.

next up, did you replace the ballast resistor thats usually with the coil. its like a white long thing that feeds the power (+) side of the coil.

they usually get really hot, it runs fine when its cool and then after driving it gets hot the ballast resistor could get a small open circuit and temporarly open the (+) circuit to the coil.

thats why it may work fine for short periods.
try changing the resistor. it should be on teh side of the coil, or very close to it. WHITE, THIN looking thing with a spring looking thing wound inside.

sorry bout the ghey description, its late. hope you get it going!

[c2888]

If you want more spark, find a ae82 fourack dizzy (you spin me right round baby right round like a record baby right round round round) they are electric, piss off them points, i hate points

Time to get a 4age in it already, even ya missus has one

dan

[bathurst-91]

Its the dizzy, replace it.

Same thing happened to leigh on the way back from Melbourne. Exactly as youve described it. Its a heat issue affecting it. Which isnt to say that its a set in stone problem, but yeah try replace it and see how you go.

[Rallystanza]

Okay Guys.

MrShin- Done that already mate and yes i have an adequate junk collection..under the bonnet of my sprinter, otherwise known as a 4AC...

Other people.....I am shelling out for a very nice turbo 4AGE...if you read my o-ringing HG post you will see what the engine is about....Hence the reason to not spend any money on this shit.

Slide86- I am thinking exactly the same thing....went back to the car last night after about 15 mins and it had cooled slightly and no more problems....I am going to bypass it tonight when it starts to happen again and see if it stops... if so i will replace the ballast resistor.

Bathurst- I also have a spare dizzy sitting there and that will be tried out next, then a fuel pup, which i also have lying around...

Lets hope the ballast resistor is teh problem.

Thanks for the help,

Jeremy

[cri_ag]

check the main lead coming off the coil, my 4ac does the same thing often and ill i do is take the lead off, clean of the surface rust that has accumulated on the contacts (dont ask me how, must get water in there somehow) and shes apples. i have to do this about every 2 months. not that worried though as im in the same boat as you (4agte swap).

[pro-16t]

Better yet, I've actually got an old 4AC that some clown has adapted a Weber to. If you have a sense of humour, that is...

You got the weber i'll take it off your hands?

[mrshin]

Yes, I do... PM me if you're interested.