Slow crank/no start condition

[BigCore1990]

2001 Ford Explorer 4.0 SOHC Automatic 4WD 210,000 Miles

Last Wednesday I got up, it started right up as always, drove to work. I went out to start the truck to go grab lunch about 6 hours later, and it cranked very slowly, and eventually no crank at all. Tried to jump it and still the same.

Figured the starter was on it's way out, since it's never been replaced. Pulled the starter, noticed b+ terminal was in rough shape. Replaced the starter with a new unit and ran a new power cable (2awg) from the battery so the solenoid. Still the same condition.

I ran some electrical tests and found the following:

b+ battery post to b+ terminal on the starter
~1.5V drop; 0.23ohms resistance

- battery post to case of the starter
~1.5V drop; 0.15ohms resistance

I'm thinking with the mileage that there may be some corrosion or wear on the battery cables, but im not sure (haven't split the harness yet.)

Anyone have similar experience, or any suggestions?

 

[C420sailor]

Could be…but it’s odd for it to go from cranking fine cold to no crank from harness corrosion. That’s normally a slow process.

There’s a saying in motorcycle maintenance. IATB. It’s always the battery…until it’s not.

How old is the batt? Voltage? Did you try charging it or a jump start? Electrolyte level good? Posts clean and connections tight?

Rapid clicking while trying to crank? Does the solenoid click at all when the key is turned? Do the lights/power to the truck go out when attempting to start?

voltage after a successful jump?

Need more details

 

[Josh P]

Possible ground issue. I've had my van start fine one time and nothing the next. Replaced battery cables ,then worked fine again.

 

[BigCore1990]

Could be…but it’s odd for it to go from cranking fine cold to no crank from harness corrosion. That’s normally a slow process.

There’s a saying in motorcycle maintenance. IATB. It’s always the battery…until it’s not.

How old is the batt? Voltage? Did you try charging it or a jump start? Electrolyte level good? Posts clean and connections tight?

Bought the battery in October/November time frame of 2022, so fairly new. Same condition whether it's jumped or charged. Have not checked electrolyte level, but all signs point to the battery being okay. Tried to start with two other batteries as well.

Rapid clicking while trying to crank? Does the solenoid click at all when the key is turned? Do the lights/power to the truck go out when attempting to start?

No click, just a very slow crank then nothing. Try to start again, same deal, slow crank, then nothing. If the voltage drop is correct, there's only ~9.5 to 10 volts going into the starter, which isn't enough to turn over a motor.

voltage after a successful jump?

Need more details

 

[C420sailor]

You can try jumping what you suspect is the corroded cable with jumper cables, see if it improves.

If it does, that narrows it way down

I’d start by using the cables to confirm a good ground to the negative. Jumping the positive is more…adventurous

 

[BigCore1990]

Replaced both positive and negative battery cables. No luck.

I still have voltage drop at the B and M terminals, and at the case, however, when I run a voltage drop from the battery to the negative post, its good at about 0.2~0.3. I somewhat expecting I got a bad new starter.

I'm pretty lost...checked all my chassis grounds that I could find.

Next step is load testing the battery. On attempting to start, it drops to around 8~9 volts.

 

[C420sailor]

8-9 is absolutely too low. In many vehicles, the FI system will drop out when voltage gets that low. I don’t even think that’s enough to hold the start solenoid closed. What’s the No-load voltage on it? Should be 12.4-12.8ish.

 

[BigCore1990]

8-9 is absolutely too low. In many vehicles, the FI system will drop out when voltage gets that low. I don’t even think that’s enough to hold the start solenoid closed. What’s the No-load voltage on it? Should be 12.4-12.8ish.

Correct, right in that 12.5-12.7 range.

 

[C420sailor]

So…new cables, new starter. Battery has good charge and is only 3 years old. I’d still take it to get load tested bc this doesn’t make sense.

Any chance the cylinders are flooded? Check your oil and coolant levels?

 

[BigCore1990]

So…new cables, new starter. Battery has good charge and is only 3 years old. I’d still take it to get load tested bc this doesn’t make sense.

Any chance the cylinders are flooded? Check your oil and coolant levels?

Oil and coolant are as good as it can be (pretty sure my valve seals are leaking, and I have a coolant leak somewhere) but I put in fresh oil after I dropped my pan.

Possible cylinders are flooded but I pull three spark plugs to easy compression just to see. Still no crank.

Unfortunately I found that I can only get the motor to rotate counter-clockwise by hand, it seems to be locked when trying to rotate clockwise (which I believe is standard engine rotation direction). All signs are pointing to either a bad (new) starter or the motor locked up on me.

 

[donalds]

If you can only rotate the engine backwards then it's not seized
I wouldn't rotate it backwards
sounds like when you try and rotate forward a Broken timing cassette is getting stuck in between the chain and head Due to it being broke
Just my thoughts

 

[Fix4Dirt]

If you can only rotate the engine backwards then it's not seized
I wouldn't rotate it backwards
sounds like when you try and rotate forward a Broken timing cassette is getting stuck in between the chain and head Due to it being broke
Just my thoughts

aint ya not supposed to rotate it backwards isnt that how it gets out of time on a sohc? or is that not true? i had thought so but you are the sohc expert

 

[donalds]

A very slim chance that it would take it out of time however a very good chance of breaking timing guide cassettes
Pretty sure the oil pump drive shaft and pump don't like spinning backwards

 

[Fix4Dirt]

A very slim chance that it would take it out of time however a very good chance of breaking timing guide cassettes
Pretty sure the oil pump drive shaft and pump don't like spinning backwards

i see good to know thanks man!

 

[C420sailor]

what about the accessories? You may have a seized bearing or something causing it to not want to rotate.

I’d pull the starter and the belt and try turning it by hand. If it still won’t go, you have a problem.

 

[Josh P]

There is a slim chance it's a transmission issue. I bought a transmission off Craigslist from someone parting out an explorer. Motor was locked up so he gave it to me since it was no good. I separated the transmission from the engine. Motor then turned over fine, even dropped the oil pan to confirm. Threw the transmission out and kept the motor. Never did open the trans to figure out how it kept the engine from spinning.

 

[Mbrooks420]

Yeah, you definitely don’t want to spin a SOHC backwards.

 

[C420sailor]

Yeah, you definitely don’t want to spin a SOHC backwards.

Drive becomes reverse and reverse becomes drive

 

[Mbrooks420]

5 reverse speeds though….

 

[Fix4Dirt]

5 reverse speeds though….

time to do some backwards driving