Lack Of Power - Ke70 4K Motor

[WA_TRD_83]

my super Rolla has hit its first stumbling block after a few weeks of reliable driving...

 

she's got a total lack of power - and I don't just mean cos its a 4KC motor

so wierd that it was running perfectly fine one day, and then went to drive to work the next day and this problem occured

 

basically coughing and spluttering and struggling to idle. I can put my foot flat to the floor and it just coughs an pops and backfires. Can't even get the car to move under load, it just stalls.

 

upon purchasing from the previous owner, I know the following things have been claimed to be replaced within the past 12 months (and they still look in good condition):

- coil

- leads

- new mechanical fuel pump

- battery

 

last weekend

I replaced fuel filter, distributor condensor, and sprayed a hell of a lot of carbie cleaner in.

Still seems to be getting fuel in the carby, so seems to be more an ignition/spark issue.

checked coil, still sparking

 

this weekend

new spark plugs

new dizzy cap

new rotor

(new points not in stock - now on order)

 

All vaccuum lines appear to be connected and in good condition, nothing dried out or cracked that I could see.

 

so far STILL no joy in fixing my problem. :bash:

 

any suggestions on things to check/test would be helpful

:hmm:

 

cheers

Damo

[Evan G]

check for vac leaks! check all the manifold/carby bolts for tightness.

[WA_TRD_83]

 

All vaccuum lines appear to be connected and in good condition, nothing dried out or cracked that I could see.

 

so far STILL no joy in fixing my problem. :bash:

 

any suggestions on things to check/test would be helpful

:hmm:

 

cheers

Damo

 

 

check for vac leaks! check all the manifold/carby bolts for tightness.

 

 

:no2:

 

I checked majority of the vaccuum lines that were easy to get to. Is there any that I should look at in particular?

[altezzaclub]

Take the top off the carby & take the float needle out. Give it a quick crank over to wash petrol through & clean out any rubbish that could hold the needle open and flood the carb. If there is dirt in the bottom of the bowl clean it out and if you're keen strip the carb and blow out the drillings and the jets.

 

..and swing a spanner on the manifold nuts/bolts as Evan suggested, just in case one worked loose.

 

When it runs badly, how does pulling out the choke change it??

 

An intermittent problem like this is the hardest to solve. Dad had a leaf in the fuel tank that occasionally got sucked over the outlet and the car would die. The moment the motor stopped it floated away and the motor would restart and run fine... Took ages to solve!

 

 

 

 

 

[B.L.Z.BUB]

Perhaps one of the items you replaced is poked. Swap them out one by one with the old stuff and eliminate faults in them.

[WA_TRD_83]

Take the top off the carby & take the float needle out. Give it a quick crank over to wash petrol through & clean out any rubbish that could hold the needle open and flood the carb. If there is dirt in the bottom of the bowl clean it out and if you're keen strip the carb and blow out the drillings and the jets.

 

..and swing a spanner on the manifold nuts/bolts as Evan suggested, just in case one worked loose.

 

When it runs badly, how does pulling out the choke change it??

 

An intermittent problem like this is the hardest to solve. Dad had a leaf in the fuel tank that occasionally got sucked over the outlet and the car would die. The moment the motor stopped it floated away and the motor would restart and run fine... Took ages to solve!

 

cool thanks mate. really hope its not something in the fuel tank - that would be a bastard!

 

pulling out the choke is the only real way to try and keep the motor running. it brings the revvs up just enough to keep it running for a while. but its still coughing and struggling with the same symptoms

[towe001]

My thoughts is that its not spark related

- new mechanical fuel pump

 

last weekend

I replaced fuel filter, distributor condensor, and sprayed a hell of a lot of carbie cleaner in.

Still seems to be getting fuel in the carby, so seems to be more an ignition/spark issue.

Did you pullthe fuel line off the carby, something a 17mm spanner, with a container under the fuel line, pull the lead off the coil and give the motor a kick in the guts ? Just to make sure the "new" fuel pump was pushing clean fuel through ?

Are all four nuts holding the carby onto the manifold tight ?

If you take the air cleaner off and have a look down the carby, you should be able to see a shot of fuel get squirted when you give the throttle a twist. And not while the motor is running, i've seen that happen and it was piss funny when the guy burnt his eye brows off.....

 

All vaccuum lines appear to be connected and in good condition, nothing dried out or cracked that I could see.

Never assume cause it can make an ass of you.

Have a good look at them all and give each one a pull as you look at them.

Something like a 14mm socket on the manifold and a 12mm spanner on the carby base.

And a phillips screwdriver on the top of the carby.

 

If none of that works then it might be a case of a compression test.

Might even be a good idea on getting a vacuum gauge and learning how it works.

 

The other option that might have to be done is pull the carby off, strip it down, soak it overnight in carby cleaner and put a new carby kit through it.

 

An intermittent problem like this is the hardest to solve. Dad had a leaf in the fuel tank that occasionally got sucked over the outlet and the car would die. The moment the motor stopped it floated away and the motor would restart and run fine... Took ages to solve!

A mate of mine had that happen to his hi-lux. It'd be all fine and dandy for a few kays and then it'd sputter and die, let it sit for a while and then drive off for a few kays and then it'd sputter and die again....

[Token]

Check the timing.

[altezzaclub]

pulling out the choke is the only real way to try and keep the motor running.

 

OK, its often really hard to tell the difference between too much fuel and too little. So a bit of shit comes along the fuel line and sits in the tiny gap between the needle & the seat, stopping the fuel from being shut off and over-filling the bowl. It runs really rich, coughs & splutters and only goes when the revs get up.

 

Then maybe it gets past the needle and into the bowl, and gets sucked into a jet, say the idle jet, seeing its the smallest, and it half-blocks that. Then the car is too lean, and coughs & splutters and hates to go. Same effect as an air leak through a loose bolt.

 

If the choke improves it by making it richer, then its too lean. So it would have that effect cruising along at 50 or 60kph. If the choke improves it by raising the idle speed, on half-choke, it could be rich or lean, but pulling the choke out that little bit more to close the flap over and it will die if its already too rich.

 

Not much help, but this problem is one where you need to be there, not on the net...

 

 

[WA_TRD_83]

ok... who had money on distributor points ?

one of the simplest little things that seem to be overlooked.

had a couple of mates mention points gap, but without a feeler gauge handy I had no way to check.

 

picked up my new ignition points on Tuesday that I had to order in from the parts store.

went to fit them in the dizzy last night and just for interest sake, thought I would see what the gap was like on the current points. borrowed feeler gauge from my brother.

turned motor to TDC - no gap

backed it off a little to high point in dizzy shaft - hardly any gap ... couldnt even fit a 0.2mm in there

WTF... ?!

 

So just to confirm this as the problem, I loosen the adjustment screw, which was tight as by the way - and regapped the points to about 0.457mm (which is the gap spec I noticed mentioned on another thread)

 

replace rotor and dizzy cap, start up 4K motor

REVVVVVV... singing along beautifully :laff: Happy Days!

even took it for a test lap around the block and gave it some stick - ran fine

 

in summary, have no idea how or when the points got so far out of wack, esp with the adjustment screw tight.

and EPIC FACEPALM for me not checking the gap sooner before starting a new thread in the tech section and causing concern. :bash:

 

I guess thats what you get for a n00b backyard mechanic working on his first car that has ever had dizzy points to be replaced :blush:

 

I will fit my actual new set of points on the weekend and gap them properly and hopefully that will be the end of my ignition problems for a while *fingers crossed*

 

now I can go back to modifying!! :cool:

 

Damo

[towe001]

Cool.

Its always the simple things.

But i thought the points gap was around 0.8mm or the thickness of a hacksaw blade.

Anywho, when i had my old '30 about the first thing i did was convert it to electronic and pissed the points crap off.

[B.L.Z.BUB]

The plug gap is 0.8, the points around 0.45.

[altezzaclub]

lol !! :laff:

 

 

 

 

Education continues!

 

 

[WA_TRD_83]

The plug gap is 0.8, the points around 0.45.

 

yeah - what he said :happy:

[towe001]

Bha, i always set it for 52deg