Hard to start after driving

[Lee R]

*edit - sorry...should have put in the engine section*

 

Just recently after driving and engine is full warmed up, I would stop somewhere to run some errands and when I come back to start it back up...it takes a little while to turn over. Maybe 3-4 times to turn over. It only does this when the engine is fully warm and I have been out driving around. When it does finally start up, it runs horrible for a few seconds like the timing is off.....I gas it a little and it smooths out and runs fine.

 

Checked the timing and it is set to 12 degrees (74 620 L18 specs) and also checked the neg ground on the battery which is secured. When the engine is cold, it starts right up.

 

Could the starter be having problems due to heat? Alternator?

[metalmonkey47]

What kind of battery are you using?

[Lee R]

What kind of battery are you using?

 

Super Start 480 from Oreillys.

[metalmonkey47]

Super Start 480 from Oreillys.

 

Have it load tested when warm.

 

Also, at the same time have the starter current tested. I have seen the fail a few times when warm, but absolutly fine when cold.

 

 

 

 

Lastly, check the condition of battery cables and replace if necessary.

[Lee R]

Have it load tested when warm.

 

Also, at the same time have the starter current tested. I have seen the fail a few times when warm, but absolutly fine when cold.

 

 

 

 

Lastly, check the condition of battery cables and replace if necessary.

 

Appreciate your responses....the starter is pretty old however I have never had a problem with it. Will get to testing soon.

[metalmonkey47]

Appreciate your responses....the starter is pretty old however I have never had a problem with it. Will get to testing soon.

 

Is it a reman unit? Any kind of tags on it indicating aftermarket status? Just curious... if so I'd suspect it.

 

 

 

Could be a load of other parts, but with my experience with these kinds of problems, I always like to look into the simplest parts..

[banzai510(hainz)]

need tro be more clear hard to start???????

like the starter is clicking or the starter motor is still turining over but the motor is not starting.

If starter motor is still turing the motor over while kkey is in start it cant be the starter.

Or does it turn motor over then stops and starts clicking. If so its a weak connection at the starter or the selinoid is weak or voltage loss at the key switch.

[Lee R]

need tro be more clear hard to start???????

like the starter is clicking or the starter motor is still turining over but the motor is not starting.

If starter motor is still turing the motor over while kkey is in start it cant be the starter.

Or does it turn motor over then stops and starts clicking. If so its a weak connection at the starter or the selinoid is weak or voltage loss at the key switch.

 

Well the starter isn't clicking or anything. I don't want to sound childish but it is basically the "errrrrrr...errrrrrrrr.....errrrrrr" sound of an engine turning over until it starts up usually after 3-4 turns of the key. I was thinking it was carb/fuel related but it only happens after the engine has been warm and driving. All other time, it starts up with no problems.

[Lee R]

Is it a reman unit? Any kind of tags on it indicating aftermarket status?

 

Original but rebuilt possibly 2 times. i'll check it out for any numbers.

[banzai510(hainz)]

I wouold a basic ck of the valve lash and ck the intake bolts and carb bolts to make sure they are tight.

 

every L motor guy should have spare L series starters anyways to try out.

 

tighten clean battery terminals and maybe time for a new shorter batt cabe with the nice molded ends.

 

 

alternator? get a plug in cig light volt meter from Equus

http://www.equus.com/Product/3721/Battery-Monitor

[Lonestar]

I wouold a basic ck of the valve lash and ck the intake bolts and carb bolts to make sure they are tight.

 

every L motor guy should have spare L series starters anyways to try out.

 

tighten clean battery terminals and maybe time for a new shorter batt cabe with the nice molded ends.

 

 

alternator? get a plug in cig light volt meter from Equus

http://www.equus.com...Battery-Monitor

 

 

Agree, it sounds more like a current problem to me anyways, check your batt cables really good. Take them off and flex them back and forth. Sounds like there may be a break inside the cable you can't see and spread apart when it gets hot, leaving a gap for the current to jump across and making it harder to start. If you don't feel anything or hear anything that sounds like crackling, check the ends over really good for corrsion. Sometime the corrsion will pass the treminal and speard under the plastic covered wire and you'll never know because it will never show. Just my 2 cents. Goodluck!

[Lee R]

Yeah....I'm going to check everything out in the next day or so. Thanks all for the help!

 

The only thing that REALLY puzzles me is when it does turn over, it stutters and shakes until I give it some gas. Then it smooths out.

[datsunaholic]

I'm going to ask what might sound like a really dumb series of questions, but when you say "turn over" do you mean "run"?

 

"Turn over" is when it goes "rrrr-rrr-rrr'. Same thing as cranking. It can turn over, but still not start.

 

If it's not turning over, it of course can't start. Not turning over is "turn key, nothing happens" or, "turn key, hear click", or "turn key, it sounds like it just can't make the engine move".

 

"Run" is when it goes "vroom".

 

So, when you say it takes 3-4 turns with the key, do you mean you have to turn the key 3-4 separate times to make it CRANK, or it takes 3-4 tries (but it always cranks) to make it START, or it takes 3-4 revolutions of the engine to make it start?

 

If it seems to be cranking just fine, but takes a while to START, plus it's really rough, but only when warm, I'd suspect you have a fuel boiling problem. This happens when folks remove the heat shield off the intake manifold (so the hot exhaust heat saturates the carb bowl and fuel lines), or when folks run a header, or when folks have removed the original steel fuel rail and replaced it with a couple feet of rubber hose. Later Datsuns (75+) had a return system that helped avoid that but a 74 and earlier didn't so they're more prone to it.

 

Having incorrect spark timing can cause the same issue, though. What was the saying? 95% of fuel problems are electrical?

 

Now, if it's having issues cranking (turning over slow or not at all) that's usually, but not always, a problem with the starting system. Too small of cables (using crap Autozone undersized cables), corroded connectors, bad starter, or the battery has gone flat.

[Lee R]

 

"Turn over" is when it goes "rrrr-rrr-rrr'. Same thing as cranking. It can turn over, but still not start.

 

3-4 tries (but it always cranks) to make it START

 

"Run" is when it goes "vroom".

 

 

^ these

 

 

I'll turn the key to start it and it will turn over...It takes 3-4 times of turning over meaning key goes to start and "rrrr....rrrr....rrrrr". I turn it off and try agaian. Same thing. Try again....same thing. Usually catches on the 3rd or 4th try and starts up...."vroom"...albeit running a little crappy until I gas it a little.

[Lonestar]

It may help those to help you if they were to know just which car you drive there Lee.

[Lee R]

It may help those to help you if they were to know just which car you drive there Lee.

 

 

My first post above......74 620 L18. I did not mention it is a Weber 32/36.:blush: :blush: :blush: :blush: Timing is at 12 degrees....would advancing it slightly do anything? The only thing I could think of is when I timed it a few weeks ago, it was advanced to maybe 16 degrees before i set it back to 12.

[banzai510(hainz)]

Im wingn this one but try regapn the points in case it changes the dwell,since you changed the timming abit.

[ggzilla]

"Turning over" means the starter is cranking the engine. Might be doing that perfectly well.

 

So is your engine having trouble "turning over", or does it crank fine but doesn't start right away? The latter is a carburetor heat problem.

[Lee R]

"Turning over" means the starter is cranking the engine. Might be doing that perfectly well.

 

So is your engine having trouble "turning over", or does it crank fine but doesn't start right away? The latter is a carburetor heat problem.

 

 

Yes. It cranks fine but doesn't start right away....only after fully warm and driving around do I have to keep on cranking until it starts. Last time it happened I drove maybe 2 miles. It sat in a parking lot for a little over an hour and it had a hard time starting. Cold starts are no problem.

 

Went over the carb and checked everything. No leaks, hoses are good, and everything is bolted down nice and tight. The battery wil be 4 years old come March. The cables do look a little tired so I will be replacing those as well.

[MikeRL411]

Vapor lock?

[ggzilla]

This is generally a fuel heat problem. Most commonly a vapor lock (fuel line heat soak), or carburetor percolation (carb heat soak). Maybe an internal leak.

 

 

Things to double-check:

 

* Fuel tank vent line is not blocked. See if you can blow air back through it (dont use high pressure air, use your mouth)

 

* Carb return line is not blocked

 

* Stock Carburetor heat shield is in place

 

* Stock intake-to-carb insulator is in place

 

* Heat riser valve is not stuck

 

* Choke is not sticking/should be partly open

 

* Air cleaner heat-tube valve is not stuck closed

 

* Tank vent control valve is working. Does the 1974 620 uses a charcoal canister like the 1975 cars, or a flow-guide valve like the older Datsuns?

[banzai510(hainz)]

choke still ON???????? or not adjusted

[ggzilla]

I was just thinking, wouldn't it be great if for every problem there was one and only one cause, a single part to replace that would fix it?

[Rays74]

*edit - sorry...should have put in the engine section*

 

Just recently after driving and engine is full warmed up, I would stop somewhere to run some errands and when I come back to start it back up...it takes a little while to turn over. Maybe 3-4 times to turn over. It only does this when the engine is fully warm and I have been out driving around. When it does finally start up, it runs horrible for a few seconds like the timing is off.....I gas it a little and it smooths out and runs fine.

 

Checked the timing and it is set to 12 degrees (74 620 L18 specs) and also checked the neg ground on the battery which is secured. When the engine is cold, it starts right up.

 

Could the starter be having problems due to heat? Alternator?

 

Sure sounds like it's loaded up, raw gas has dribbled into the manifold while sittin' waiting for you to return....is there black smoke puffin' out as the engine clears itself? I would check your float needle/seat and float height as well, take a look sometime directly after a drive when it's good and hot and see if you can see raw fuel dripping into the carb throat when the engine's off.

 

--Ray

[Lee R]

I was just thinking, wouldn't it be great if for every problem there was one and only one cause, a single part to replace that would fix it?

 

Tell me about it!!!

 

All fuel hoses are fine and not crudded up or blocked in any way.

 

Changed the fuel filter just in case.

 

Choke opens and closes with no sticky linkage.

 

Now....hehe....there never has been a heat shield under the carb and never had any problem with boiling in the past 6 months at least. I'm going to set the mixture and idle again to see if it makes a difference to anything and then re time it. Maybe a rebuild? Fun stuff. I think it is probably vapor lock but not sure why it would start all of a sudden.