HELP!!!! Running on 3cyl over 4000rpm

[newbien]

hello,

My TE72 is running a standard 3tc.....i have noticed a rather annoying problem with it...it runs fine on four cylinders when it idles and when it revs to 3500 its fine, but when i take it over 3500-4000rpm it runs on 3cyl maybe 2....you put your foot down at 3500 at it doesnt seem to gain revs or anything???

can anyone help here??

thank you

[joecoolmk2]

check your leads, sounds like they might be loose or broken.

see if you can find out which cylinders it is, if it's consistently the same ones.

[30psi 4agte]

may pay to have a look inside dizzy cap and pull out plugs and check em just for good measure!

[newbien]

thanks for the input... i have just put new Plugs, Point, Dizzy Cap, and Rotor Button in and it still has the same problem, i have also put new leads in and the problem remains...

[thechuckster]

timing is way out?

[joecoolmk2]

have you checked the wires on the coil? they could be loose/broken. other than that, you might have shitty fuel, it's been gettin around. it's unlikely but check anyhow.

[30psi 4agte]

Check that the wires to the coil are tight and in good cond.
Have a VERY good look at the coil for any hair line cracks.


Are you sure this is a ignition prob??????????


EDIT : BEATEN

[Smokey228]

how do u figure its cylinders not firing? could it be missing? checked timing?
could it be a lack of fuel at the higher demand? ie, does it do it worse under load? going up a hill, full throttle, 3400rpm?

ive had similar symtoms, but i brought them down to things like fuel, and timing etc.
lol, or once, a dissconnected coil pak peak hour traffic, under cover cop up my ass, no stopping lane and the bastard fell loose and unpluged itself. didnt tak elong to work out, but was a pain to get out and fix while i had this guy yelling at me wif sirens blazing... lol

[joecoolmk2]

it sounds like one but it could be fuel. you mightn't be getting enough fuel, maybe the diaphragm in your fuel pump has a hole or split.

[Dale]

Maybe the second venturii isn't opening up as it should and you aren't getting enough fuel? Not sure where they open up on those engines.. I think vacuum pulls them open

[joecoolmk2]

does it do this when your standing over it revving by hand, or just when driving?

[newbien]

i will get the timing checked etc...

yes it does do it when a rev it by hand in the bay...

could it be the carby just being and old buggered one???

[joecoolmk2]

i'd say the timing's out still.

have you looked down the carb when you rev it? does the secondary butterfly move?

[newbien]

im not too sure i didnt look at the butterfly...

....i have another carby waiting to go on, after its rebuilt so i might just leave it till then and get the timing chain replaced and tuned properly when its on....

Cheers for the help

[Toy_T-18]

i had this same problem in my TE72 i changed the timing several times and i also changed a timing chain and it was still happening! well befor i changed the points in the dizzy over the old points seemed to have a large whole in one side and a like mound on the other with was laking in contact so it was missing badly in high rev's, this also may not be the problem in ur case, it may be many things as the others have said! it definatly sounds like its an electrical problem! hope my dizzy problem can help u a little bit

Cheers Sean