Truck turns over slowly and won't start. Stumped!

[Mfosmo]

So my truck isn't wanting to start. It started acting weird when it started getting cold outside. Last winter it had zero problems with the cold weather. it would struggle to turn over and fire up, almost acting like it was flooded. But not all the time! Only sometimes after sitting overnight. Sometimes it started right up. And it always runs perfect once it starts. And once it's warmed up it started fine for the rest of the day. I started replacing parts. Each time I thought it fixed it until the next day I would try to start it and it would still  just turn over but won't fire up. It progressively began to turn over slower than usual over the course of about a month of me trying to figure this out. I replaced the spark plugs, plug wires, distributor cap and rotor, starter, battery, cleaned dirty wire connections, and cleaned the carb (weber 38/38). I know im getting fuel. I know the battery is holding a charge. And I know I have spark to all the plugs. I have usually been able to get it to start eventually on most days but this last week I haven't had any luck at all and I am completely stumped on what it could be at this point.

[datzenmike]

6 hours ago, Mfosmo said:

 I replaced the spark plugs, plug wires, distributor cap and rotor, starter, battery, cleaned dirty wire connections, and cleaned the carb (weber 38/38). I know im getting fuel. I know the battery is holding a charge. And I know I have spark to all the plugs. I have usually been able to get it to start eventually on most days but this last week I haven't had any luck at all and I am completely stumped on what it could be at this point.

 

 

Wow that must have been expensive throwing parts at it.

 

That said, I would clean the battery cable ends and the battery posts to assure good electrical connection. New battery or just another battery? Have it load tested it may be faulty even if new.

 

Is it possible that there is a parasitic drain on the battery? like the brake lights on all the time or the interior light left on?

 

Do your horns work???

 

 

[datzenmike]

Damn I posted this 4 hours ago forgot to approve it.

[bottomwatcher]

Got a pair of jumper cables? Try attaching the cable from the negative post to the block and see if there is an improvement. If not leave that in place and attach the positive cable to the positive post at the starter then touch the other end to the positive post of the battery. This will check for high resistance somewhere in the start circuit. Cables do go bad and most of the time it is the ground wire.

[datzenmike]

You could also try jumping from a known good battery. If an improvement maybe your battery is at fault. A new battery is no guarantee that it's good.

[Crashtd420]

The one thing I noticed was your using a 38/38 carburetor..... 

You could be running really rich and fouling out the plugs..

 

You said you replaced the plugs, what did they look like when you did?

How do the new ones look?

 

I had this same issue with my 521, I had too much fuel pressure causing an over rich condition... it was tough to start at times and then at some point I couldnt fire the truck up because the plugs were getting to fouled..... once it got colder out it was even harder to start.....

 

 

Edited November 16, 2020 by Crashtd420

[Mfosmo]

On 11/15/2020 at 8:15 AM, datzenmike said:

 

 

Wow that must have been expensive throwing parts at it.

 

That said, I would clean the battery cable ends and the battery posts to assure good electrical connection. New battery or just another battery? Have it load tested it may be faulty even if new.

 

Is it possible that there is a parasitic drain on the battery? like the brake lights on all the time or the interior light left on?

 

Do your horns work???

 

 

Battery cables are clean. I also cleaned the starter connections and grounds. My battery holds a charge. There's no drain. I put my giant battery from my benz in the truck and it was doing the same thing also tried jumping the truck off the a running vehicle and it made zero difference. The horn works.  

[Mfosmo]

So a small update. I've gotten the truck to start a few times since I originally posted. But my problems have not gotten any better. 

I readjusted my choke and re cleaned my wire connections.

For the last week the truck has barely been turning over and it started 4 out of 9 separate times I tried.  On the times it did start i was not expecting it to because of how slowly the truck is turning over. Once it started It runs great. I'm able to drive it around no problem. I can shut it off and go into stores and when I come out it starts up perfect. There was only one occasion this week I tried to start the truck about ten minutes after shutting it off, so it was still warm. and it acted like it was flooded. I waited 15 mins and it started like normal. 

On the times it didn't start i would hold the key in the start position and it would crank very slowly, it would turn over maybe 5 or six times then stop. If I tried again it would only be once or twice.

I'm gonna try connecting cables to the block in the morning and I'll also check condition of my new plugs.

[datzenmike]

4 minutes ago, Mfosmo said:

 

I'm gonna try connecting cables to the block in the morning and I'll also check condition of my new plugs.

 

What?

 

The negative cable should be bolted to the intake near the thermostat housing.

[Mfosmo]

38 minutes ago, datzenmike said:

 

What?

 

The negative cable should be bolted to the intake near the thermostat housing.

I'm gonna try connecting jumper cables to the block like bottomwatcher mentioned

[datzenmike]

Well the negative one to the block the positive one to the starter lug.

 

If it spins faster one of those cables is bad.

If no change then the starter is bad.

 

 

[Mfosmo]

Well connecting jumper cables from the negative to the block did not help at all. I left that and connected the positive battery post to the positive connection on the starter. This also did not help. I checked my plugs and they look normal. Definitely not fouled. And I don't think I'm getting to much fuel. My younger brother who is much better with working on cars then me told me it could be my new starter so I'm gonna bring it back into oriellys so they can test it for me.

[Mfosmo]

Oriellys says the starter is good. I'm stuck on what to do at this point. I might just take it to a shop as a Xmas present to myself

[datzenmike]

How slow is slow to you?

 

Have you checked the timing??? If too advanced it will fight the starter. Z24 should be 5⁰

[Mfosmo]

3 hours ago, datzenmike said:

How slow is slow to you?

 

Have you checked the timing??? If too advanced it will fight the starter. Z24 should be 5⁰

Its like I'm trying to start the truck with an almost dead battery. As I said it barely turns over. I can hear it turn over only a few times and it will just stop. 

The timing is the next thing I will check. 

[Buckner99]

On 11/22/2020 at 6:23 PM, datzenmike said:

How slow is slow to you?

 

Have you checked the timing??? If too advanced it will fight the starter. Z24 should be 5⁰

Hi datzenmike, following your timing comment id like to know some information about the distributor position. I am sticking a timing light on it tomorrow and I would like to know what degrees to set the timing light too. I read somewhere else that it was 15 degrees. I know that you have to disable the vac advance from the distributor before doing anything with the timing light. thank you for any information. much appreciated. by the way, its on a 1984 Nissan 720 z24 2.4 liter.. 

[datzenmike]

Z24.... 5⁰ BTDC

 

All carburetors since the late 60s uses ported vacuum advance. The port is above the throttle plate when idling so there is no vacuum only atmospheric. Above idle the throttle plate moves to and above the port exposing it to intake vacuum. You do not need to pull the hose off to set the timing. You can if you want.

[Lockleaf]

There is another thing you could check though i consider it low on the list of possibilities.

 

Pull the starter and inspect its face where it touches engine/transmission and also that same face where the stater connects to the drivetrain.

 

My buddy had a Z with starting issues.  Turned out there was enough corrosion between starter body and drivetrain that it couldn't get good enough ground.  Wire brushed those faces and it worked fine after that.