crankshaft position sensor, slow crank?

[willholl79]

Will an unplugged or bad crankshaft position sensor cause a slow crank?

I put my truck back together after studs, injectors, etc and it cranks VERY slow. The batts are good, the starter is 1 month old.

The only thing I know that's not right is the clip is broken on the crankshaft sensor and the plug will not stay on. I am wondering if this is causing a slow crank.

 

[DEEZUZ]

No.

 

[willholl79]

Hmm, guess I'll pull the starter and have it tested. It's a cheap reman, but only a month old.

 

[willholl79]

When I finished putting it back together and went to fire it up, the first time i bumped it for only a second or two and the motor turned over like normal no unusual noises.. I started it again and from then on it turns over SLOW, maybe 100 rpm.

I've checked AC compressor, its free.
The plug for crankshaft sensor came off when i checked it this am before work. I was hoping maybe it was on for the initial start then vibrated off, causing a slow crank.

 

[Lassie]

Have you checked your fluids since this started? It's not hydrolocking is it?

 

[willholl79]

Have you checked your fluids since this started? It's not hydrolocking is it?

Coolant is normal, haven't pulled oil dipstick.

 

[Lassie]

Check oil for fuel

 

[willholl79]

The injectors are fresh rebuilds.

I'll check the oil when i get home.

 

[willholl79]

Check oil for fuel

What would be a likely cause? Injector stuck open?

FWIW there's no smoke coming from exhaust while cranking.

 

[Lassie]

It's most likely going to be batteries if the truck was down for a while..don't get too worried yet. Just check the water and oil for peace of mind. Have you charged your batteries or are you using a jump box or something to help them?

 

[pyrotec220]

just had same issue. slow cranking, hot or cold. charged batteries still didnt help. took to nappa since they were only 20 months old and one tested 730cca and the other 300cca. both were rated at 1040cca. Had the 300 replaced under warrenty and the other 2a trickle charge overnight and it was up to 100% . Fired right up! anyway, Id start with batts as lassie stated

 

[pyrotec220]

oh and i picked up a new iternational cps same time as the batteries as i was getting an intermittant tc for it. since batteries replaced, no code. so i just keep in the glove box for a spare

 

[willholl79]

It's most likely going to be batteries if the truck was down for a while..don't get too worried yet. Just check the water and oil for peace of mind. Have you charged your batteries or are you using a jump box or something to help them?

Batts are 100%. Charged them up before putting them back in the truck.

 

[willholl79]

Like I said earlier, the first crank was normal. The second was slow. Nothing gradual about it, night and day difference.

 

[willholl79]

Update: I got home today and took starter off and had it load tested, it's good. I fixed the crankshaft sensor plug, and removed all glow plugs, still turns over slow. Not hydrolocked. I turned the motor over by hand, its fairly easy to turn.

Ground issues? Wiring harness?

 

[Snoop]

Get your batts load tested for sure. I'd double check that you have your grounds hooked up tight. If I remember, there's a big ground near the a/c compressor. Also double check to make sure all of your electrical connections are tight involving the starter. A loose connection will allow the correct voltage to activate things but will not allow enough current to flow.

 

[willholl79]

Update: Had batteries tested. One was bad, replaced it. Still cranks slow.
Removed all grounds, cleaned, re-connected. Still cranks slow.

Gonna check voltage at starter, and check wires for damage.

Any other ideas? I really need to get this truck back on the road.

 

[Spindrift]

Harness ground on the back side corner of the FICM connected?

 

[willholl79]

Harness ground on the back side corner of the FICM connected?

Yes. I actually had to splice a connector to it when I reinstalled it, broke when i took it off. I wonder if its a bad connection? I'll check it this evening.

 

[Snoop]

Check wires. How old is your starter? I had replaced my starter and then 6 months later the solenoid started to crap out because of corrosion. Had to clean the wire connections and new starter again.