Truck cranks but won’t start then starts right up an hour or so later

[leftylou]

My truck has been starting right up for since I got it running but recently things have changed. When I initially try it cranks but will not start after 5 or so tries letting it crank for a few seconds each time. If I come back an hour or so later it starts right up. What would you check first?
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[Steeveedee]

If you have points ignition make sure that the yellow wire from the "R" terminal on the starter to the coil has good connections.

[HO455]

Check for 12 volts at the plus terminal on the coil. Both before cranking and during cranking.
If you have 12 volts then check for spark at 2 spark plugs.

[guyryan100]

I was thinking fuel filter. You either don't have a spark or don't have gas, right?

[leftylou]

Originally Posted by HO455

Check for 12 volts at the plus terminal on the coil. Both before cranking and during cranking.
If you have 12 volts then check for spark at 2 spark plugs.

I’ll check that tomorrow. Thanks.
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[leftylou]

Originally Posted by guyryan100

I was thinking fuel filter. You either don't have a spark or don't have gas, right?

That was my thought too but I have a fuel pressure gauge and I am seeing 6 pounds of pressure after the filter. It seems like this would rule out a clogged filter. Do you agree with that?
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[Sheepdip]

Originally Posted by leftylou

That was my thought too but I have a fuel pressure gauge and I am seeing 6 pounds of pressure after the filter. It seems like this would rule out a clogged filter. Do you agree with that?
Posted via Mobile Device

6 PSI is too much you should be 3-4 PSI. That could possibly be the culprit.

[franken]

The OP probably needs to think and possibly search the internet about what's needed to make an engine run.
Then they need to think about how to test and troubleshoot those things.
Then do the tests.

Asking people to give WAGs about what the issue is, generally winds up with the OP replacing random parts and wasting time, money and resulting in frustration.

Also, posting almost no info about the situation doesn't help.
If someone wants to deal with an old vehicle, they need to learn about how they work, get some tools, and think, as well as research. After 30 years, pretty much any question that can be asked, will be answered in a second by an internet search. Many answers will be incorrect, just as the responses here are.

[Sheepdip]

Originally Posted by franken

The OP probably needs to think and possibly search the internet about what's needed to make an engine run.
Then they need to think about how to test and troubleshoot those things.
Then do the tests.

Asking people to give WAGs about what the issue is, generally winds up with the OP replacing random parts and wasting time, money and resulting in frustration.

Also, posting almost no info about the situation doesn't help.
If someone wants to deal with an old vehicle, they need to learn about how they work, get some tools, and think, as well as research. After 30 years, pretty much any question that can be asked, will be answered in a second by an internet search. Many answers will be incorrect, just as the responses here are.

FYI,,,I only give.. SWAGS.. Scientific Wild A** Guess's

[leftylou]

Originally Posted by Sheepdip

6 PSI is too much you should be 3-4 PSI. That could possibly be the culprit.

I have an edelbrock carburetor. This is edelbrocks recomended psi. Maybe I should have added that detail to the post.
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[leftylou]

Originally Posted by franken

The OP probably needs to think and possibly search the internet about what's needed to make an engine run.
Then they need to think about how to test and troubleshoot those things.
Then do the tests.

Asking people to give WAGs about what the issue is, generally winds up with the OP replacing random parts and wasting time, money and resulting in frustration.

Also, posting almost no info about the situation doesn't help.
If someone wants to deal with an old vehicle, they need to learn about how they work, get some tools, and think, as well as research. After 30 years, pretty much any question that can be asked, will be answered in a second by an internet search. Many answers will be incorrect, just as the responses here are.

I have a general understanding of how an engine works. I have also done some searching to try to find my problem but have not been successful. For example I considered a clogged filter but I am getting good fuel pressure so that seemed to eliminate that. I also checked my alternator and battery which test good. I thought that the fact that it will crank but not start only to start right up an hour later was enough info to start with. I thought the whole point of a forum like this was to ask questions when you were unable to find the answer yourself. If any question can be answered by an internet search why does this forum exist?
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[MARKDTN]

So to run an engine needs fuel and spark. When the problem occurs do you have spark? If you have an HEI it could be the module for example. Could be fuel pressure as discussed. Could be the starter is too slow when it's hot. Could be a lot of things. You can fire the parts cannon at it and probably eventually fix it, or you can be systematic and figure out why it's doing what it's doing. My .02

First thing I would want to know is if it has spark when it won't start. Then you can focus on the fuel or spark side with further diagnostics.

[Grumpy old man]

The forum exists to share information on our Chevy/GMC trucks , There are lots of guys in here that actually want to help out and will given all the information based on your questions , I had to go thru your past posts just to find out what you have and what you've done to it lately that may have caused this issue your now having . Not posting what engine/ trans even what year your truck is leaves people guessing what may be the problem , So in other words you'll get responses that may not have anything to do specifically with your truck . You just replaced the carb does it have a manual or automatic Choke , Are you just jumping in and turning the key, for how long ? or do you depress the gas pedal a couple times before you turn the key ? ( old school ) to allow the auto choke to set ? Posting a picture of the engine can answer a LOT of questions related to your problem ,Even better would be a short video of what the truck sounds like and allows the guys to get a better view of whats really going on . If it starts fine an hour after trying the first start , I think your problem is your starting procedure and not the truck it's self . Don't get frustrated just post as much information about your problem when you post your questions , A picture posted with your qestion always helps you get good advice .

[leftylou]

Originally Posted by Grumpy old man

The forum exists to share information on our Chevy/GMC trucks , There are lots of guys in here that actually want to help out and will given all the information based on your questions , I had to go thru your past posts just to find out what you have and what you've done to it lately that may have caused this issue your now having . Not posting what engine/ trans even what year your truck is leaves people guessing what may be the problem , So in other words you'll get responses that may not have anything to do specifically with your truck . You just replaced the carb does it have a manual or automatic Choke , Are you just jumping in and turning the key, for how long ? or do you depress the gas pedal a couple times before you turn the key ? ( old school ) to allow the auto choke to set ? Posting a picture of the engine can answer a LOT of questions related to your problem ,Even better would be a short video of what the truck sounds like and allows the guys to get a better view of whats really going on . If it starts fine an hour after trying the first start , I think your problem is your starting procedure and not the truck it's self . Don't get frustrated just post as much information about your problem when you post your questions , A picture posted with your qestion always helps you get good advice .

Thanks Grumpy I appreciate the constructive criticism of my original post. Here is all theninfo I have along with a couple of pictures of the motor. I have a 1970 c10 that I bought about 8 months ago. It has a small block 400 with a th350 transmission, as far as I can tell the engine is stock. It has the original heads and intake anyway. It has a points distributor and a carter afb carburetor with a manual choke, I know I said edelbrock but as far as I know the afb is the same as the Edelbrock performer. It’s not a new carburetor, it was on the truck when I bought it. When I bought the truck the fuel tank was in the bed. I installed the tank, fuel lines and new fuel filter and got it started pretty quickly. Since then the starter and alternator have been changed. I also replaced the coil since the old one tested out of spec and added a pressure regulator and gauge. The truck doesn’t get driven yet but I try to start it a couple of times a week. Until recently iI would have to crank it a bit, I assume because the fuel had evaporated from the carburetor but after about 2 cranks it would start right up. One day I tried to start it and it wouldn’t start I cranked it 6 or 7 times but it just wouldn’t start. A couple of hours later I got my son to come turn it over so I could see what was happening fuel pressure wise then I was going to check my spark. He turned the key and it started right up. Since then that has been the pattern. I thought maybe a clogged fuel filter but I am getting good pressure so that seems to indicate something else, maybe I’m wrong.
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[Getter-Done]

Flip for ya

[Grumpy old man]

The first thing I would do is get rid of that small air cleaner it's not doing you any favors other than possibly making the truck run rich . second thing is the next time you go to start it ,BEFORE you turn the key or step on the gas pedal remove the aircleaner and check the position of the choke plate , it should be open , then step on the gas pedal and check it again . I don't see a manual choke cable ? Your poblem isn't electrical if it starts after sitting for an hour , I think your flooding it , Mis adjusted choke , too small of an air cleaner , too much fuel pressure , it's a fuel issue . post a picture of both sides of the carb .

These old engines don't like to be started and ran for just a few minutes , you'll end up fouling plugs always allow them to reach operating temps will save you issues down the road .

you need 3 things for ignition
Fuel - ? too much or too little ?
spark - it starts after 1 hour
compression - it's turning over

https://www.summitracing.com/parts/s...waAvIuEALw_wcB

[Grumpy old man]

One of the best "low buck" upgrades you can do for your truck will be to switch over to an HEI distributor and wires , Easier starting , better running overall a good idea . I ran points ignition for many many years , unless it's a factory stock truck build I'd toss them .

[LNP]

Originally Posted by leftylou

I have an edelbrock carburetor. This is edelbrocks recomended psi. Maybe I should have added that detail to the post.
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Heres a link to a fuel pressure chart in accordance to carb manufacturer. I always run 6psi to my carbs and never have a issue. I do run Holleys though and the manufacturer spec for them is 5.5-7.5 Your Edelbock has a max pressure of 6.5. I would turn it down to 5-5.5 myself.

I didnt see a electric choke so it should be manual then. But then I didnt see a choke cable either. How are you working the choke?

[CC69Rat]

Turn your FPR to 4 PSI and try it.

Is it leaking gas out of any of the linkage ports, or anywhere it shouldn't be?

['68OrangeSunshine]

You have a Carter AFB with a manual choke. If it's the 600 CFM unit, it could be a 9635S.
That's what I have on a 350 in a '71 Jimmy. Great carb.
For tuning purposes, I consider it an ''Edelbrock Performer 1405.'' You can call Edelbrock's 800 # Tech Line, and talk with an adviser. [Just don't tell him it's a Carter -- he'll clam up.]
The carb numbers are stamped into the 'foot' of one of the carb corners.
Obtain the Edelbrock Performer Carburetor Owners Manual. [Free] The book has charts and graphs and tables that list what parts -- i.e. Jets and Metering Rods, that can be obtained to put your carb in the right ballpark.
AFB means Aluminum Four Barrel. The Series is 9600. -35 = Chevy applications. You will have to research what Carter model numbers correspond to Edelbrock numbers. Usually it's done by CFM comparison.

EDIT. I just found out 9 = 9000 Series performance carbs, and 635 = the CFM. S = assembled unit.

[LNP]

Just realized I didnt post the link I mentioned.

https://help.summitracing.com/app/an...my-new-carb%3F

[schovil69]

Hey Leftylou,

What you're going through with your pickup sounds quite familiar to me. Pickup was hard to start and a complete crap shoot when warm. First stop was a new carb which appeared to have the desired result. Interesting how the wrong solution works for a short period of time. Then one day there was no getting it started. Replaced the starter switch and fuel pump to no avail. The culprit turned out to be a wire that was broken in half but the two halves were not separated enough to cause issue. Then one day I guess they work apart enough for the pickup to never start.

It was the wire going to the coil for a points distributor and the break was located right in the middle of that wire loom going across the top of the firewall.

[Rich72C10]

Hey leftylou - seems we are neighbors!

Great suggestions from the guys, I'd say Grumpy's suggestion on points is spot on and then schovil69 post is a very good one too (gremlins in wiring is a bit*ch to even realize). Between old points setup and possible dodgy wire(s) you could be falling into a random electrical (spark) problem.

I have a "spare" full-on Pertronix Distributor and I think coil (I think I kept it). I am happy to loan this setup to you (though you'd need new wires and deal with the resistor wire). I keep it on the shelf if my fancy Progression Ignition dies on me.

Edit: I forgot I have this extra air cleaner setup - I changed it out with a better one (you clean/oil it). You can have it, assuming it fits (I have a Quadrajet). I also see I put a coil in with the box of the distributor. You can just PM me if you wanted to follow up. Though the distributor would be just "on loan".