Wont run smoothly

[Grover-98]

I have a 89 Sierra with the 1.3L carby. Yesterday whilst driving it started to surge and now will not idle and does not hold a constant rpm rather it surges and splutters. I Just drained the Carby thinking there may have been crap in the carby and adjusted the idle but the problem continues. It will also not start with out the throttle being applied.

Any ideas what i should be checking?

Cheers!

[FC3892]

ide say u have some crap in the fuel bowl

[Grover-98]

How do i fix or check this?

[Toyfj45]

I had a similar problem, and after changing fuel filter,cleaning carbie, checking and replacing dissy cap, rotor button, and leads turned out to be a vaccum leak at the intake manifold. One of the bolts had got loose.

[Grover-98]

Cheers guys, but how do i check these things its a bush basher so i dont have a manual.

[lay80n]

Manifold bolts are easy, just check that they are tight. The carby can be checked by removing one of the jet access bolts at the bottom the float bowl and pumping a small amount of compressed air in there to blow them out. Then remove the idle solenoid and do the same. See how you go from there. It sounds for all the world like a blocked carby. Also check that your fuel in the tank is good.

If you get stuck im local, i could take a quick look for you at some stage.

Layto....

[Grover-98]

Its all new fuel so it shouldn't be that i drained the carby by removeing the bolts at the front and removed the main plug then cranked it over for a little while will that clear it enough?

It still seems to have the same problem.

[lay80n]

Its all new fuel so it shouldn't be that i drained the carby by removeing the bolts at the front and removed the main plug then cranked it over for a little while will that clear it enough?

It still seems to have the same problem.

You need to physically clean out the carby jets.

Layto....

[Grover-98]

The latest news on the zook is as follows.

It will now start with no throttle and idle but is rough and will rev without cutting out. I have heard of a thing called "turbulence" which is caused by holes in exhausts and mine does have one which happened yesterday at about the same time it started this new drama.

Do any of you guys know of this being a problem and if so being a bush basher i was thinking i would just cut the exhaust before the hole!?

Cheers!

[FC3892]

ide, rip the top off the carb, easy to do. just dotn lose the lil clips!!! u will know where i mean.... mine picked up some crap once an slowly did the same thing..... i found turning the car off while driving still in gear was sometimes enough to suck the dirt out.... dont take much to stuff them up... sounds like it's in your main jet, if it will idle fine! will it go with your foot right down?

Adam

[Toyfj45]

A quick way to check if it is the carb is to swap the #1 lead on the dissy with the #4 lead. Start it up and let it back fire for a minute. Shut if off and put the leads back the right way. When you fire it up after that and it runs smoothly then its to do with the carb. Make sure you keep the air cleaner on when doing it though, dont want to be leaning over the carbie when you do this.

[Grover-98]

Ok so i will check the carby this way, is the 1# lead the one cloesest to the firewall?

And what else should i be doing if anything. Should i rev it whilst doing this?

[Toyfj45]

Ok so i will check the carby this way, is the 1# lead the one cloesest to the firewall?

And what else should i be doing if anything. Should i rev it whilst doing this?

The dissy cap should have a number next to each lead, looking from the drivers side #1 should be top right, and #4 should be bottom left. Yeah give it short stabs on the throtle, each time you take your foot off should go BANG!!

[Grover-98]

Ok so i will check the carby this way, is the 1# lead the one cloesest to the firewall?

And what else should i be doing if anything. Should i rev it whilst doing this?

The dissy cap should have a number next to each lead, looking from the drivers side #1 should be top right, and #4 should be bottom left. Yeah give it short stabs on the throttle, each time you take your foot off should go BANG!!

I just went out and swapped the plugs and started her up. It idled very roughly which i expected and after giving it short punches there was no really loud back fire like i was expecting i then plugged the leads back the correct way and it was the same as always idle a little rough die after a big rev unless eased back down and then after a while of idle it would die.

Someone had mentioned the crack in the exhaust could be causing "turbulence" could this be the reason?

[FC3892]

dont think it really could do that much with just a crack.... it's easy to get the jets out.... top of carb.. bowl drain bolt out.. unsrew them, clean or get angry if there fine.... if u do open it up, make sure u have a look to see if the bowl is clean also....