engine is hesitating

[coolioni]

Recently I have done the following to get my engine working right.

New timing kit ( chains, sprokets, guides, tensioner , the whole thing) , new weber carb, new plugs, new wires, clutch master cylinder, new radiator, and new water pump.

Even after warming the truck up, it tends to start getting real choppey(hesitating) when trying to accelerate. Sometimes I will take the truck out of gear and give it a few revs, and sometimes it goesw away, and sometimes it does not.

I have brought it to my mechanic several times, and he cant seem to figure out what is causing this.

Any ideas where I can tell him to look ?

Thanks!

[Mandingo]

did you check fuel pump, filter?

[banzai510(hainz)]

Is it eleltrically timed? correctly.

I assume the cam timming is OK since you installed the chain. as you say its OK then not OK.

 

Make sure the distributor is locked down OK.

 

Is this points or Electric Ignition?

 

valve lash adjusted???? I dont think this is it.

 

Is this a electric Choke? is the plate open when warmed up? I have seen if not adjusted correctly during the inbetween the cold(closed) and warm(open) there can be a stumble. If plate is fully open when warn and still does it then its the a NOT choke proplem.

Edited January 16, 2009 by banzai510(hainz)

[coolioni]

did you check fuel pump, filter?

 

yes i just put a new filter.

But I have not had the pump checked.

[coolioni]

Is it eleltrically timed? correctly.

I assume the cam timming is OK since you installed the chain. as you say its OK then not OK.

 

Make sure the distributor is locked down OK.

 

Is this points or Electric Ignition?

 

valve lash adjusted???? I dont think this is it.

 

Is this a electric Choke? is the plate open when warmed up? I have seen if not adjusted correctly during the inbetween the cold(closed) and warm(open) there can be a stumble. If plate is fully open when warn and still does it then its the a choke proplem.

 

I am going to have my mechanic check all of this stuff and let you guys know.

Thanks for the suggestions.

[banzai510(hainz)]

this is stuff you can ck yourself and not cost you.

[datzenmike]

Assume it's an '83 720.

 

Weber carbs tend to like fuel pressure below 3 psi. The 720 electric fuel pump produces a pressure of 2.7-3.4psi. and can over power the Weber float and needle valve and cause it to flood. Not saying you should run out and get a fuel pressure regulator, but check into this.

[Jason]

Another thing it could be is the ignition wires. I had a misfire and hesitation on acceleration and pulled my hair out until I took a multimeter to the ignition wires. Turned out that 2 and 4 had super high resistance compared to 1 and 3, 1 year old set of AC Delco wires too ....

[coolioni]

i have wires that are about 4 months old on it.

I bet they are fine.

I have a funny feeling it may have something to do with the clutch.

It is getting harder and harder to get it going into first gear without giving it alot of gas to keep it from stalling out.

Something is definatly wrong, but my guy just cant figure it out.

I am getting sick of fixing things and still having this hesitation problem.

I thought it would go away when I redid the whole timing system, but it is still there.

Now it is just nice and quiet and can easily do 85 on the highway.

I have not pushed it faster, but there is definatly some pedal left to get it going faster.

What is the normal top speed on this truck ????

[datzenmike]

New Weber carb? Like new out of the box. For what motor?

[coolioni]

yes brand new weber out of the box. I have a 2.4 liter Z-24 engine.

The truck is a king cab 4x4.

[banzai510(hainz)]

Z24 that is a 8 plug head.?????

I assume the wires are on there correct as there is a before and after firinging sincd it usinf 2 wires per cyl??

 

Im only guessing here on the if it does 85mph I think ithe motor would be OK.

I cam only wish to drive my Datsun 521 85mph

[a.d._510_n_ok]

Is this a electric Choke? is the plate open when warmed up? I have seen if not adjusted correctly during the inbetween the cold(closed) and warm(open) there can be a stumble. If plate is fully open when warn and still does it then its the a NOT choke proplem.

 

hmmmmm, mine never stumbles when cold but will when warm........?

[coolioni]

Z24 that is a 8 plug head.?????

I assume the wires are on there correct as there is a before and after firinging sincd it usinf 2 wires per cyl??

 

Im only guessing here on the if it does 85mph I think ithe motor would be OK.

I cam only wish to drive my Datsun 521 85mph

 

How fast does a 521 go up to ?

One of these days I will see how fast I can get mine going.

I just want to make sure everything is running perfectly beforeI really push the engine.

 

Yes there are 8 plugs on this engine.

Kind of neat for a 4 cylinder engine.

This herky jerky stumbling thing is driving me mad!

I am getting sick of bringing it up to the shop.

Just last week I was driving down the expresway and some road debrie from construction got into my engine. It put a hole in my new radiator and caused the water pump to break!

There went another $460 !

It is a shame I love this truck, becuase lately I have been spending so much money restoring it, I could be driving a brand new truck. Probally for even less money. But this truck is one of the best looking trucks from back in the 80's along with the Landcruisers. But they are in a totally different class.

One is a pickup and one is a SUV.

[what]

wow man. hell of a thing.