Long Crank - Where to Begin

[banderso]

I'm having issues with long cranks and could use a little help diagnosing. The video below is from my start this morning. The truck had been sitting for almost 48 hours and outside temperature was 39f. This afternoon, after sitting for 8 hours, the truck started almost instantly at 64f ambient. The issue isn't noticeably worse when the truck has been sitting for a week or more. The issue seems to correlate more closely with temperature. From what I've read, long cranks are usually due to air intrusion, or slow cranking.

https://youtu.be/fW_lGGH8rIY

On the air intrusion side, I've read 'starts then stalls' is a typical symptom. I've never seen that or had any roughness after starting. I don't see any smoke while cranking, but I do see a big cloud when the truck starts - the longer the crank, the bigger the cloud. Not sure if that's significant.

To me, it seems like it's cranking too slow. The tach looks like no more than 200 rpm and the sound isn't too confidence inspiring. The batteries are 1000+ cca new last January. The cables look good visually, but I haven't put an ohm meter on them and I'm not sure what an acceptable reading would be. Starter has an unknown history.

Glow plugs are new Beru parts last January when I got the truck.

I'm tempted to throw a new starter on this thing.

Any input would be appreciated.

 

[Kizer]

I'd bet on slow cranking RPM. Check: batteries, battery cables, starter solenoid and starter.

 

[banderso]

That was a fast response. Thanks. What's the deal with the starter solenoid? Is it in the passenger fender? They can go bad without failing completely?

Sorry for the sideways video.

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[Kizer]

You're welcome sir. On the fender, yes. As for how it fails, my experience has been "clicking" upon failure...I'd check current on each side anyway, before I started throwing parts at it.

 

[Matt_INW]

It sounds a little slow... Was my starter when mine started cranking slow. A week or two was just a little slow, then it got slower each day till it barely turned over. Was 2-4 weeks from start of symptoms to nearly not starting for me.

 

[Greg5OH]

really? that sounded pretty good to me IMO...(the cranking speed)

 

[sjwelds]

Just went through this on mine. Found out it was the main power wires feeding the glow plug relay. It would crank and crank and finally start, and then ran perfectly (no dying, like air intrusion would have caused). It did smoke a fair amount too. I just bypassed the two yellow wires feeding the GPR and ran my own heavy battery cable directly to the relay. Starts even quicker now than it did before having problems.

Edit: on mine I found out the hard way that you do have to leave the yellow wires connected at the starter relay, as they supply power to the fuse box. Mine's a '92. FWIW.

 

[IDIoit]

speed sounds good to me.
with the way it coughed but wouldn't fire, I would suspect air in the filter head.
next time you cold start it, crank it for a second, and see if there is air coming out of the Schrader valve

 

[Greg5OH]

BTW once it does fire, sounds reaaall nice.
Definitely post back what you find out.

 

[banderso]

Thanks to everyone that's taken the time to watch the video and comment so far.

I've checked all the cables with a multi meter, and none show more than a couple tenths of an ohm.

I'm not getting anything out of the Schrader valve, but after a couple seconds of cranking or after a short drive. I assume I should get fuel out of here. What's that tell me?

I'm still trying to find the right yellow wires for the glow plug relay.

I should add that the truck is a '93 with a non original motor (possibly an '88).

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[banderso]

BTW once it does fire, sounds reaaall nice.

Thank you. The previous owner straight piped it. I'm undecided on adding a muffler in the future.

 

[IDIoit]

if you don't immediately get fuel from the Schrader valve, you have a hiccup in the line, or the return caps.
I always preach fuel system maintenance from the pick ups to the injectors, and back.
these engines can be a pita when air is introduced.
the leak could be anywhere.
new shower heads, replacing all rubber lines, and all of the return system should be done to prevent future issues.

 

[banderso]

The only time I get fuel from the Schrader valve is when the engine is running. So it seems like IDIoit nailed it.

I'll order a return line kit from Conestoga. But what are the shower heads? And just replace every rubber line I can find? Sorry, but I haven't seen an 'air intrusion 101' and I'm still pretty unfamiliar with this engine.

Assuming I don't see fuel leaking or wetness anywhere, there's no way to narrow down the source I assume?

Thanks for all the info so far.

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[IDIoit]

shower heads reside on the fuel sending units in the tank.
its a crappy place to start, yet it wont cause air intrusion, but it will ensure screened fuel from the pick up.

inspect all nylon lines for holes, cuts, anywhere its leaking.
they are usually pretty good.
unless its obviously wet.

then you have the fuel switch valve.
this piece of nifty equipment sucks, I mean directs fuel to the desired tank,
located on the drivers side frame rail behind the "front" saddle tank.
have fun getting to it
these are prone to getting *****'d
expensive to replace.
there are other options, but no direct replacement besides purchasing the correct part.
if you have issues with your fuel gauges, this is a primary concern.

all rubber line (not nylon)must be replaced in my opinion.
they dry rot and can let air in. cheap insurance.
if you decide to rip it all apart, blowing air through the lines is a good idea, but don't blow mass quantity's of PSI into unknown showerheads.

from there you have a mechanical fuel pump. I delete it and run electrical, everyone has their own opinion on which one to run, figure yours out.
if not electrical, replace it.
then you have a number of steel/brass stuff that don't usually leak, but they can.
they have little rubber tubes for gaskets called "olives" these crack and suck in air.

the fuel filter head, has a heater, if its wet, you need to either replace or modify it.

more steel lines, olives, and then you have the return line. this goes around all injectors and to the IP, all plastic rubber parts should be replaced.
and then run it back to the tank!

this is just a brief summary. I could have missed a few things, im a deplorable pothead.