[jdcaudle]

Hi all.

I've got a non-starting 2016 Ford Transit 350 (3.5L ecoboost engine). I'm *hoping* the problem can be solved with some electrical troubleshooting and not a tow to the dealership followed by a huge bill.

What happened:
It was very cold here for about a week (persistent -35 to -40 C air temp) and the van would only start with a jump. Engine block heater, oil pan heater, battery heater all installed and assumed to be working - I felt the first two for heat but not the battery heater because it's hard to get at (below driver's seat). Even with a jump it struggled, with a few false starts (engine started but died after a few seconds). Finally, when jumping it one morning, after about 3 tries, the starter stopped engaging - even when jumped to another vehicle's battery.

What I tried:
I put my finger on the relay and felt/heard nothing when attempting to start (turning the key). Pulled the starter relay and tested it - it works fine when tested with another battery (both an audible click and continuity as measured with multimeter). I tested the relay socket in the fuse box while turning the key. Testing with positive probe on the socket for relay terminal 1 (and negative on terminal 2) I get a steady standing (not starting) reading of +2V. When trying to start the reading goes to -11V for about a second and then drops back to 2V.

I don't think this is a battery problem because the problem is identical with a boost - please correct me if that's a bad assumption.

Questions:
1) Doesn't polarity matter for relays? The electromagnetic field that pulls the switch closed would be reversed if + and - were switched, right? If so, is the negative voltage I'm getting the reason for non-start?

2) If the reversed voltage is the problem, what would cause this?

3) If the reversed voltage is normal, what should I test next?

 

[Oso954]

Try taking a voltage reading of the battery (terminal to terminal) and post it.

 

[raylo32]

Really sounds like a battery. If your battery has a shorted cell it can hinder jump starting. Before you potentially waste time troubleshooting the circuit I'd test the unloaded voltage as Oso recommended or take it to auto parts for a load test. Or just try another battery.

 

[jdcaudle]

I tested the voltage in the AM, after playing with the relay: 12.09 V
I tested it at noon after removing the battery: 12.16 V

It's currently on a trickle charger in a warm room. I'm out for the afternoon and will see what it's at later.

Thanks.

 

[Oso954]

I don’t think a trickle charge is going to do much good. It needs full power charging.

When you drop a lead acid battery below 12.4 volts sulfation begins. A hot charge will stop the process, even reverse it slightly.

However, if it’s been discharging below 12.4 repeatedly, sulfation is likely to be bad and your battery is probably ruined.

Getting the battery fully charged and load testing it is your best bet.

 

[raylo32]

Or just buy a new battery and mark this thread "solved".

I don’t think a trickle charge is going to do much good. It needs full power charging.

When you drop a lead acid battery below 12.4 volts sulfation begins. A hot charge will stop the process, even reverse it slightly.

However, if it’s been discharging below 12.4 repeatedly, sulfation is likely to be bad and your battery is probably ruined.

Getting the battery fully charged and load testing it is your best bet.

 

[ServiceCall]

I have a transit and the battery’s suck

 

[huesmann]

When you say the starter stopped engaging—does that mean it spun, but the solenoid failed to engage the starter pinion with the ring gear on the engine? Or the starter did nothing at all?

 

[Brainbucket]

A fully charged battery is around 12.75 volts. Measure battery voltage when starting vehicle. If it hits 9 volts area, bad battery or not fully charged.:vs_cool:

 

[jdcaudle]

When you say the starter stopped engaging—does that mean it spun, but the solenoid failed to engage the starter pinion with the ring gear on the engine? Or the starter did nothing at all?

The starter did nothing at all.

 

[jdcaudle]

I don’t think a trickle charge is going to do much good. It needs full power charging.

When you drop a lead acid battery below 12.4 volts sulfation begins. A hot charge will stop the process, even reverse it slightly.

However, if it’s been discharging below 12.4 repeatedly, sulfation is likely to be bad and your battery is probably ruined.

Getting the battery fully charged and load testing it is your best bet.

The trickle charge brought the voltage up to 12.6 after a few hours yesterday. I then took the battery in to the dealership for load testing. The battery is fine.

I got an answer about relay polarity: it doesn't matter. I was told this and also tested for myself - continuity was established whether I put positive on terminal 1 and negative on 2, or vice versa.

So, where I'm at now:

• battery is fine
• relay works fine
• had a standing 2V voltage drop across the relay activation terminals (with relay removed)
• got a momentary -11V voltage across the relay activation terminals in the fuse box when trying to start the van.

Any suggestions what to check next? I know it could be a failed starter, but I'd like to be sure everything up to that point is working fine before pursuing. I doubt I can change a starter myself - but I do have some electrical skills.

 

[jdcaudle]

Well, after putting the topped-up battery back in, and warmer weather (-14C) the van started after a few tries. There is still a problem, I think, if it is having so much difficulty starting even with the engine block heater, oil pan heater, and battery warmer all in use. The good news is that the problem *might* be powertrain related and thus still on warranty

Thanks everyone for the help. As the specific questions in this thread are either answered or irrelevant, I'll call it done for now.