Chasing endless hard start cold problems

4699 Views 20 Replies 9 Participants Last post by Xyz-xyz, 27 d ago

Xyz-xyz

Discussion Starter · 6 mo ago

Hey everyone. Ever since I got my 2000 7.3 a couple years ago I’ve been chasing winter starting problems. I live in a cold climate where it gets -40 some days.

In February I gave up figuring it out myself because I didn’t have a heated shop to work in so I brought it to a local diesel shop. They replaced the glow plugs, air intake heater, and both of those relays which were apparently all bad. They told me the batteries and alternator were weak. I replaced the batteries with two Costco units. The truck started fine for the rest of the winter, with me plugging in below about 5F.

Now the cold weather is back and I’m having problems again. I let the glow plugs go for about 15 seconds past the WTS light and the cranking makes a slow chugga-chugga-chugga sound and I hear relays clicking. I replaced the alternator and batteries, and it cranked fast and started right up, but only that one time. Every subsequent cold start has been a slow chugga-chugga crank with clicking relays, unless I boost it off my car, in which case it still cranks kinda slow but will start. I measured 12.6volts at each battery.

Today was a warm day at about 28F after sitting for a few days at 0F. I measured 12.0 volts on one battery and 12.4 on the other. I tried to start it, slow chugga-chugga crank with clicking relays.

I have a heated shop to work in now so I can hopefully figure this out with your help. What’s going on here and what should I check next?

1 - 20 of 21 Posts

NoRalPh

· #2 · 6 mo ago

First, wait a Full Minute After the WTS goes off in the really cold (maybe even 1-1/2)

Next, forget the battery voltage Before you crank, what's important is While you're Cranking (the in-cab "Outlet" is a good place to monitor). "Clicking Relays" is a sign of low voltage. Did you replace your batteries with High Capacity Batteries (at Least 800CCA?)

Xyz-xyz

Discussion Starter · #3 · 6 mo ago

These batteries are group 65, the sticker says 1000CCA at 0C and 850CCA at -17C. I got them at a Costco in Canada so that is 850CCA at about 0F. These are also the same batteries I used in February when I had no trouble at all getting the truck started.

I will check out the voltage like you mentioned as soon as I can. What should I expect, and what if it’s lower?

Jimmy's Pilot Service

· #4 · 6 mo ago

I will throw in here as well.

Batteries are extremely important when it comes to a good start. Resting voltage needs to be 12.6 volts or greater when resting for a couple of hours to be properly charged. Keep in mind voltage is only part of the story but most of us do not have a proper high capacity restive battery tester on hand. As you noted you have almost dead batteries with the voltage you noted. If you keep them in this state you will be replacing them again.

A note on the AIH.... It is for running smoke prevention not starting. Any mechanic that says this is a problem for starting does not know what they are doing or talking about. Find another mechanic or learn how to fix your truck yourself.

Are you making short drives in your truck? A cold start could take at least an hour of driving to charge the batteries up if every thing is correct. If your drives must be short you need to invest in a quality minimum 10 amp or so charger, maintainer, de-sulfating unit (NOCO makes a good one). When I so short runs during the day, especially in the colder months, my batteries get plugged in when I am done.

Invest in a USB cigar unit with a built in volt meter, it is worth way more than you paid for it. You should monitor voltage anyway in the truck and this is the easiest way to do so.

When you get into the truck in the morning you should see at least 12.6 volts (not on the charge overnight) if not fix the issue.

You should have a voltage drop to about 11.5 volts when you key on for the heat cycle for at least a minute in those temps.

After start and idle for about another minute or so you should see at least 14.0 volts to 14.3 at idle once the glow plugs cycle off. If you are not at this voltage you have a charging issue..

Things you need to check, physically and visually:
All connections, especially at the batteries. Tight, clean, not burnt, no corrosion or history of such. If any history of corrosion you need to seriously consider replacing the entire cable as the corrosion is not just visible it goes inside the cable and that is a serious resistance issue. Do not purchase cables from the corner story, the do not have what you need, they are cheep and undersized. Also screw compressor type fittings for the cables are not going to work.

Check every power connection at the battery including the crossover, positives and grounds. Check the starter connection. Check the grounds going to the fenders, block (one for each battery) behind and under the balance, and the grounds from block to frame.

With the voltages you indicated you have issues somewhere in the system if you are indeed driving the truck at least an hour for each start.

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Reactions: 3

SuperCrutyPS

· #5 · 6 mo ago

Do you have the capability of plugging in the block heater to if starting improves?
How old is your starter? Could it be drawing a lot of juice?

Reactions: 1

Xyz-xyz

Discussion Starter · #6 · 6 mo ago

Jimmy's Pilot Service said:
I will throw in here as well.

I appreciate all the advice. I will check out those things and report back.

There is a variety of driving, but most common is my work commute of about 40 minutes each way all highway. Sometimes there’s many short trips in a day but only the first start is cold, sometimes I make a 2+ hour drive in one go. Sometimes I don’t drive it at all for a few days, but I’ve never had a low battery in the summer.

Xyz-xyz

Discussion Starter · #7 · 6 mo ago

SuperCrutyPS said:
Do you have the capability of plugging in the block heater to if starting improves?
How old is your starter? Could it be drawing a lot of juice?

There are plug-ins at my home and work, which are the only places I expect to regularly have a cold start, although the cord seems to have gone bad so I have to go pick up a new one. I usually plug in when it gets below 15F, but I shouldn’t have to. If I’m out hunting in the bush or whatever it should be able to start unplugged at 0F like any modern vehicle, and I want to get to the bottom of why it won’t.

The starter looks pretty old, could be the original one from 1999. Although I get a strong crank when the engine is hot.

Reactions: 1

7.3_TurboDiesel

· #8 · 6 mo ago

I’d vote for replacing the starter with a gear reduction unit, even if this isn’t the root of your problem it will help tremendously at those temps

Also I would switch to 0w-40 synthetic if you haven’t already

Sent from my iPhone using Tapatalk

Hydro

· #9 · 6 mo ago

All of these starters are the gear reduction type -- factory was planetary
but def the newer design has more cranking power

Battery voltage while cranking is the only important value for starting -- need to see 10 volts plus

Worn injectors will cause hard starting -- the control valve will not open well with cold oil -- sometimes plugging in the block heater will help this
if the injectors have over 200 k miles on them, then they are suspect for wear

Jimmy's Pilot Service

· #10 · 6 mo ago

Been flying and this it the first chance to get back with you on the issue.

Hydro got what I forgot to mention last night.

Again going to stress the batteries. You must maintain at least 10 volts while cranking or the PCM will go off line and you again will have a fail to start. Very good reason for the (EDIT...Cigar port) USB volt meter.

The block heater and oil are going to help, however again, get the batteries sorted out. Saying it is a 12 volt system is misleading. See the chart attached for reference.

Rectangle Font Parallel Symmetry Number

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Reactions: 1

PSexcursion7.3

· #11 · 6 mo ago

Sorry I haven’t read through the posts. I hack sawed the original battery connectors from cables ends and crimped new eyes with new post connectors. This solved my slow crank and premature dead battery problem.

PSexcursion7.3

· #12 · 6 mo ago

PSexcursion7.3 said:
Sorry I haven’t read through the posts. I hack sawed the original battery connectors from cables ends and crimped new eyes with new post connectors. This solved my slow crank and premature dead battery problem.

Battery to starter is 3.00 and other three are 2.00

Hydro

· #13 · 6 mo ago

Don't overlook the grounds -- they are just as important as the hot cables

Reactions: 1

greenskeeper

· #14 · 6 mo ago

If you are handy, wire a switch to the cab with an LED light that splits the grounding wire from the PCM to the GPR. That way you can see when the GPs are actively glowing and also have the ability to cut power when cranking or they simply aren't needed.

Anything below zero F I would be glowing for long past the "WTS" light illuminates, which is exactly what the PCM probably is doing.

Personally with my trucks, that have the LED switch combo, anything above 40F I do not power the glow plugs. Anything below 40F I will progressively leave the glow plugs energized. However, when I decide it's time to crank, I cut the power to the glow plugs at the same time I hit the key to start.... you'd be amazed at how much more cranking amps are available to the starter without the glow plugs energized at cold temps.

Fair warning... without the glow plugs energized after the engine starts your exhaust WILL be smokey. But the benefit is less wear and tear on the GPs, GPR, batteries, etc.

Reactions: 1

slowpokedodge

· #15 · 6 mo ago

That is a great idea, I am going to do that!

Xyz-xyz

Discussion Starter · #16 · 2 mo ago

Okay I got it all done. I replaced the starter with a 6.7 starter, replaced the batteries again, and replaced all the cables that you folks mentioned. Also wired a glow plug indicator to see when the relay goes on/off. Now my 7.3 cranks really fast even when cold.

However that still doesn’t seem to help the cold starts. It sounds like it’s not even trying to fire the injectors, even when it’s as warm as +15F outside. If you’ve ever had your CPS go bad you’ll know what I mean, you can keep cranking but it never catches, it sounds like that.
If I plug in the block heater then it starts fine so it’s still something to do with the cold weather.

Hydro

· #17 · 2 mo ago

What weight oil you run ?
How many miles on the injectors ?
When it is cold and not starting, do you get smoke out the exhaust ?

Xyz-xyz

Discussion Starter · #18 · 2 mo ago

Hydro said:
What weight oil you run ?
How many miles on the injectors ?
When it is cold and not starting, do you get smoke out the exhaust ?

I generally run 5-40 in the winter, 15-40 in the summer.

I bought this truck 4 years ago at auction and I know nothing about how the previous owner maintained it. For all I know the injectors might be factory, 23 years old and 350,000 miles.

I haven’t thought to look at the exhaust. It’s warm here right now, but when it goes back to 10F on Monday I’ll crank it and let you know.

Hydro

· #19 · 2 mo ago

High mileage injectors will have problems when cold, opening the injector oil control valve
some have shimmed the valves to get a little more life
but with that many miles, ...the injector spray pattern has degraded
you will get better starting and fuel mileage by getting new injectors

Xyz-xyz

Discussion Starter · #20 · 2 mo ago

Hydro said:
High mileage injectors will have problems when cold, opening the injector oil control valve
some have shimmed the valves to get a little more life
but with that many miles, ...the injector spray pattern has degraded
you will get better starting and fuel mileage by getting new injectors

I will look at replacing injectors. But that’s awfully expensive, anything else to rule out first?

If it comes to injectors, what’s recommended? It seems like nobody sells new Motorcraft injectors, only remans

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