Exhaust strangling 4k

[1goodidea]

If you run a 4k on the standard exhuast on a kp60 starlet that originally had a 2k would it affect how it runs? ie not idle very well?

[pervert]

It shouldn't do, I would imagine the exhaust diameter would be the same, but I could well be wrong...

[1goodidea]

It shouldn't do, I would imagine the exhaust diameter would be the same, but I could well be wrong...

yeh well thats what i thought!

but i'm trying to get to the bottom of my idle problem its very ruff, as if the motor has lumpy cams but i no that it doesn't

[pervert]

Is it running on all 4 cylinders?

[1goodidea]

it seems like it's not firing everytime on every cylinder

anythought on what could be causing it?

[Virtual Genocide]

Hi

Get yourself a timing light to find out if its running on all cylinders. The 2k exhaust should be ok, top end I imagine will be quite poor however. I would suspect your idle problems will be electrical or fuel related.

Any more questions just ask

Phil

[_will_]

Have you tried adjusting the idle speed and mixture? There are a couple of screws on the side of the carb which you can fiddle with to smooth out/speed up the idle.

The problem could also be a vacuum leak in one of the lines somewhere.

[1goodidea]

Have you tried adjusting the idle speed and mixture? There are a couple of screws on the side of the carb which you can fiddle with to smooth out/speed up the idle.

The problem could also be a vacuum leak in one of the lines somewhere.

yip tried playing round with this!

don't think its firing consistantly on every cylinder, how will a timing light determine whether it is or not?

[phat5k]

2K exhaust works fine! there all th same! but stock is gutles! id say u have an eletrical fault. checked ur plugs? leads? distributor?

[RS13]

I put a 4K into a 2K starlet, I found that the 2K exhaust was a single pipe from the manifold, whereas the 4K had twin pipes from the manifold, going into 1 pipe under the firewall. And oddly enough, I had a lot better performance using the 2K carb on the 4K.

[phat5k]

wen my 4k was put in2 my 2k starlet it had extractors on it! so opvoisly im nt gona kno much bout th manifolds, but my 2k exhaust managed to rip of th extractors at th join! an it wasnt dodgy welding eather! so id say get rid of th 2k exhuast if u wanna go fast!

and RS13 did u eva thnk of cleaning ur 4k carb??

[RS13]

The 2K carb had a larger secondary, over the 4K carb. Why? I have no idea.

[TygerTung]

We put a 4K in my friends KP60 which originally had a 2K. Went fine

[ee904age]

don't think its firing consistantly on every cylinder, how will a timing light determine whether it is or not?

Timing lights work off the signal going through the lead, so if you hook the light up to one lead at a time it will tell you which (if any) has no power.

[1goodidea]

don't think its firing consistantly on every cylinder, how will a timing light determine whether it is or not?

Timing lights work off the signal going through the lead, so if you hook the light up to one lead at a time it will tell you which (if any) has no power.

what i wanted to hear! i thought you could only do the timing off the 1st cylinder?

should the timing light flash consistantly if it's firing properly as when we tried to adjust the timing the light would flash consistantly and then stop then flash consistantly again like what i would assume a miss is

[Virtual Genocide]

Correct, the light should constantly flash.

I'd start by lifting off the distrubutor cap and looking to see that all the parts are nice and clean and free from "burn marks" on the contacting points, then if you think you're up to it pull of the rotor and cover to check the points. Might also be a good idea to put a multi meter on each end of the HT leads to see how many ohms of resistance there is and pull the spark plugs out to make sure they look ok aswell.

Another possibility is the carburettor, you could could try spraying it with some carb cleaner or running a fuel cleaner in you tank. Check your air fliter they can get very clogged up with dirt/dust.

Phil

[1goodidea]

Correct, the light should constantly flash.

I'd start by lifting off the distrubutor cap and looking to see that all the parts are nice and clean and free from "burn marks" on the contacting points, then if you think you're up to it pull of the rotor and cover to check the points. Might also be a good idea to put a multi meter on each end of the HT leads to see how many ohms of resistance there is and pull the spark plugs out to make sure they look ok aswell.

Another possibility is the carburettor, you could could try spraying it with some carb cleaner or running a fuel cleaner in you tank. Check your air fliter they can get very clogged up with dirt/dust.

Phil

Thanks
Yip i've had plugs out cleaned and checked the gap, i replaced rotor, dizzy cap and leads with the leads off my 2k which worked mint and still no change

[RS13]

Is it a 4K-U? If it is, it may be that you have a leak in one of the many, many vacuum lines around the motor. I did in my KE70, I removed most of the vacuum lines and bits and pieces, took a while to block the right hoses, but now she idles as smooth as a swedish supermodels' ass! I did it because it sounded like it was running on 3 at idle, but when revved, it seemed to run on 4.

[1goodidea]

Is it a 4K-U? If it is, it may be that you have a leak in one of the many, many vacuum lines around the motor. I did in my KE70, I removed most of the vacuum lines and bits and pieces, took a while to block the right hoses, but now she idles as smooth as a swedish supermodels' ass! I did it because it sounded like it was running on 3 at idle, but when revved, it seemed to run on 4.

Yip thats the symtoms exactly!

I'm not sure if it's a 4K-U? how do i tell, it was out of a 1986 Dx corolla wagon.

what is the valve/(connection where a vacum line could attach) that is on the intake manifold close to the 1st cylinder or front of the car? i blocked it and the car blew so much smoke it wasn't funny!

the thing is it was running badly before i put the 4k carb and manifold on

[RS13]

Vacuum lines EVERYWHERE! Also, the 4K-U has a little pipe that goes from the exhaust manifold, around the front of the motor, to a little valve that looks like a UFO, then into the airbox. Also, on the waterpump/thermostat, there are 2 little rods sticking out, with 2 vacuum hoses each on them, going to the carb. Me, I ripped it all off, blocked what had to be blocked.. idles awesome now. Chances are, you've got a leak somewhere, or one of the vacuum valves might be knackered.