Hey all the 77 experts! R20 chinook wont crank after hot
 

So I have recently purchased a project . 1977 chinook camper 2wd . R20 engine. It was all original except for a new starter. The problem is after it's been running for awhile, it wont crank. Period. Lights come up on the dash ,but go dark when key is turned to start. Push it, and it'll pop instantly. Doesn't always happen, just in the worst times!
I'm fairly new to the whole mechanical world as well, which doesn't help when it comes to a problem like this.

Sounds electrical. Bad battery, bad ground somewhere, bad starter. You said the starter is new but that doesn't mean it isn't already failing. Just enough energy to turn on dash lights but not enough to spin the starter over. Or the starter brushes aren't always contacting.

thanks ! I'm going to start by cleaning/replace grounds. Is there a way to test the starter?

Really the only things you can do are try jumping the starter with a screwdriver. It will always spin if it's working. But it could also spin it if it's going bad.
On one of these occasions when it won't crank, you can climb under and give it some taps with a hammer. This can knock enough crud loose or move the brushes a little and then it might contact and work. It's an old shade tree mechanic fix for getting home when stranded but if this does work then your starter is definitely going bad.
Any Autozone or O'Reilly's will test your battery and alternator for you for free to make sure it's all charging properly and producing enough cranking amps.

You need to add a starter relay.
 

OP, you can try more things...
(1) Tighten ALL connections to the battery. Absolutely ALL between batt and statter.
(2) ADD battery negative to engine block ground (mid80s and later trucks have it)
(3) Have battery tested
(4) Last but not least, fix what Toyota did wrong at the factory, add a starter relay
Here it is explained.
https://www.yotatech.com/forums/f199...l#post52297396

The problem was not caused by the starter that's why after replacing the starter, the problem remained.
Your new starter is most likely good, and so was your old starter

Would be cool to see your Chinook. I used to own one.

Just so you sound like you know what you're talking about, it's a 20R. Says it right on the engine. Not sure why so many people reverse the order. :)

https://cimg5.ibsrv.net/gimg/www.yot...ac28246885.jpg
Here she is . 20R is correct ,I wasnt thinking clearly where composing the question. I think everyone got what I meant by it. I try better next time :help:

That Chinook is sweet! :wrench:

I have always wanted one.

I have always felt that the mid to late 1970s Chinooks were the perfect size camper. They were much more reasonable in size for the chassis and driveline than the large ones form the mid 1980s - early 1990s.

For the cranking issue, I would do what RAD4Runner suggested. Many people have fixed similar issues following RAD4Runner's post. If you need help navigating through it, I bet he will be willing to answer your questions. Just be aware that wire colors will probably be different as Toyota loved to change up wire colors all the time.

I am not sure if the Chinook wiring differs from factory Toyota wiring, as coach builders do alter stock systems to fit all of the camper add-ons. Just something else to be aware of.

:safari:

thank you for your advice! I will be sure to check all.

thank you ! I love the ole girl. Appreciate the advice.

Surprised it survived in Pennsylvania!

For whatever reason, R20 is a really common mistake.

Here's mine.


https://cimg2.ibsrv.net/gimg/www.yot...f1218b36d4.jpg

it spend most its life cali . Last 12 years in pa . The guy before me mostly lived in AZ
I'm excited to move into it in April and head west.
maybe we'll see each other someday ? Who knows
happy travels.

https://cimg6.ibsrv.net/gimg/www.yot...70568b78c8.jpg
Day one ,demo! Check out my instagram, @livingontheesch for my progress so far.

Could be! I sold mine to a guy in Idaho a few years ago and I moved into a camper trailer. I needed more space after spending most of a couple years in the Chinook.

If you haven't solved the problem, you might consider opening up the distributor and checking that. I was having an issue with mine and it would run, get hot and just die. It would crank, but not start and I wasn't getting a spark. Ended up needing to rebuild my distributor.

Distributor does not affect cranking..

Darn! You are right, I re-read the question and noticed it "won't crank", disregard what I said, ha.

yes,correct .it wont even try to crank . But its only occasionally . Usually after running for more than 45 mins.

LOL!
add starter relay and block ground and ul be good to go :)

My response was to him asking how to test the starter and had nothing to do with other things he needs to change under the hood.