starter turns but intermittant start (fire)

[Eric_FJ40]

Well, maybe if I hadn't decided to upgrade my battery cables with some that I made with welding cable this would not be happening...

After replacing cables and messing around some with the fusible links to reconnect them, I found that the truck would not fire even though the starter was cranking just fine. This was yesterday.

This morning, it started right away and upon turning the truck off it even started a second time. Third try no-go.

I searched and found a thread where jonheld supplied a link to his site with some very good 3FE diagnostic info - by the way, we're talking about a 1991 FJ80 with a 3FE here.

With the key in the 'on' position I do have a CEL at the dash. I also have 12V at the screw in the engine bay fusebox.

I have replaced all three fusible links at the battery with the appropriate sizes (near as I can get from Pep Boys).

I went on to check the coil and found that the primary coil resistance was out - fluctuating between .4 and .8 - sometimes .9 Ohms. The secondary coil resistance did check good at about 12.9 kOhms.

So, I think the coil needs replacement. After that, I checked the connections of all the plug wires and went to see if it would start.

Now, the symptoms seem to be all over the place here, so I need some suggestions.

Sometimes the starter will turn strongly but no fire.

Sometimes the starter will turn and the truck seems to try to fire, but doesn't.

Sometimes the truck starts on the very first revolution of the starter.

Sometimes the truck starts after a couple turns of the starter.

Sometimes I get just a click - like the starter is bad.

I am fairly comfortable with it at the moment that I am going to see if I can go run some errands. It seems to start at least half of the time if I keep trying.

My new battery cables are #1 welding cable with crimped and soldered lugs. All connections seem to be good and clean.

Help!

 

[jonheld]

Sounds like you have more than one issue here.

Brief history needed. Was everything fine before you changed cables? Never a "no fire"? Always a good crank?

How old is the battery?
Is the starter original?
Starter contacts ever replaced?

Good battery negitive connection to engine block just as important as +12.

Next "crank fine but no fire" check for spark at one of the plugs.

 

[Eric_FJ40]

Thanks for the reply Jon - you've got some good info up on your site.

Recent history (this past week) includes an episode of "my brake lights, dash lights , marker lights don't work and my shift lock has to be pressed to get into gear.

Replaced main fusible link and about six inches of the pair of wires coming off the alternator. Thread here:

https://forum.ih8mud.com/80-series-...e-circuits-out-tranny-shift-lock-engaged.html

Never had a problem with this truck before - always a good starter.

Battery is probably about two years old.

Not sure if starter is original, but I have not replaced it or the contacts since I've owned it ~ 4 years.

I need to go back out and shoot the new cables for resistance and check the connections again. I know a bad ground can cause all kinds of weird things.

I'm going to order a coil since it didn't pass the resistance checks, but I'm not sure of that will do it or not.

Part of this almost seems like a timing issue - but what could I possibly have done to mess that up?

I'll check for spark tomorrow. I'm sure I'll have the chance.

Just out a while ago: took 3 starts to leave apartment, 3 starts to leave laundromat and 4 starts to leave Wal Mart. Strong cranking in all cases.

A question for you on the side:

How difficult was it for you when you replaced the cable between the alternator and the battery? I noticed that there are two cables spliced at the ring terminal at the alternator. I'm pretty sure that only one goes to the battery and the other goes elsewhere. Now that I've made that repair, I want to replace the whole run soon.

thanks for looking in...

 

[Eric_FJ40]

strange behavior elaborated...

Today at lunch (with sound effects):

*crankcrankcrankcrankcrankcrankcrank*

*crankcrankcrankcrank K N O C K K N O C K K N O C K cra..*

(what the?)

*crankcrankcrankKNO-VROOM...*

Seems to be a knocking some of the time while crank over the engine. Is this timing? Pre-ignition?

When it did start, it was right as it seemed to be knocking again, but the motor fired up.

Once started, the truck idles fine and runs as well as it ever did. There are no symptoms or ill-effects when running.

 

[jonheld]

Once started, the truck idles fine and runs as well as it ever did. There are no symptoms or ill-effects when running.

If it's running well then it really can't be the igniter or coil.

When was the last time you changed the dissy cap/rotor. A bad center connector on the cap will cause hard/intermittant starts but once running will be fine.

In fact, when was the last full tune up?

 

[Eric_FJ40]

If it's running well then it really can't be the igniter or coil.

When was the last time you changed the dissy cap/rotor. A bad center connector on the cap will cause hard/intermittant starts but once running will be fine.

In fact, when was the last full tune up?

Well, I haven't touched the cap, rotor, plugs or wires since I got it, so about 4 years.

I just happen to have a new cap and rotor on hand. I'll go ahead and swap them out. Need to go get plugs and wires though.

Watch this all turn out to be just a plain lack of regular preventative maintenance. I should be exiled!

 

[Eric_FJ40]

This evening I changed the plugs, wires, cap and rotor. Inspected all the wiring and plumbing in the area.

Still have the hard/no start condition.

It wasn't until I was all cleaned up and back inside that I remembered that I didn't pull a cable and visually check the spark.

What I did do, however, is use this little tool I picked up the other day. It's for checking the spark - clamps to ground and then you put the probe over the plug wire and it flashes - sort of like a timing light.

What I did notice from that is that the signal seemed very weak. Does an inductive pickup like that represent the strength of the signal? If so, I'm looking at a weak spark I can tell. I did see some variance in the strength of the light as it pulsed too.

Does this confirm my tests on the coil - that it is bad? I ordered one yesterday just based on the resistance measurements (bad) and it will be here Thursday.

I hope that's what it is...

 

[Eric_FJ40]

Well, new coil didn't fix it.

Stay tuned and I'll keep messing with it...

 

[jonheld]

Just to confirm...in a no start situation, you have a CE light correct?

 

[Eric_FJ40]

Just to confirm...in a no start situation, you have a CE light correct?

Affirmative.

 

[jonheld]

OK. Then we really need to see if you're getting spark in a "no-start". I know you have a fancy lamp, but unless you hook it up to a well running 3FE as a reference, then I have no idea what you're looking at.

I mean this is a pretty straightforward motor. If spark and no start, then no fuel.

Hey, when was the last time the inline fuel filter (right side frame rail under the oil filter) was changed. For that matter, when was the last time the pre-filter on the fuel pump was changed?

Assuming this truck runs well...

IF spark AND no start THEN no fuel.
IF fuel AND no start THEN no spark.
IF fuel AND spark THEN start.

 

[Eric_FJ40]

Changed inline fuel filter 4 years ago when I bought the truck.

I have no idea about the prefiliter - I assume it is original.

I am going to go back to my battery cables and measure the resistance. Could a bad ground do this?

 

[Eric_FJ40]

F I X E D ! ! !

Seems like when it rains it pours...

Fortunately I have had a friends truck to drive this week while my Cruiser has been down.

Last Saturday the truck started running very poorly and not idling well at all. Quick visual inspection in the field did not show anything (looked over the intake hoses).

During the week I dropped by and looked again and found that the intake hose at the throttle body was split at least halfway around in one of the pleats. In a way, I felt better because I knew that was the reason the truck was not running well.

I ordered parts from CDan's crew and waited until this weekend.

Today I installed the new hoses and (despite the aforementioned hard starting) the Cruiser fired up and ran just fine.

Now to take a look at the starter. I grabbed the positive cable at the starter and tugged a little and it moved...

Seems that the stud was loose - this stud also secures the contacts as well.

So I disconnected the ground and took the starter cable off and sure enough - I got about another 1/8th of a turn on the nut securing the stud there. Connected everything back up and it's back to normal.

So I'll be contacting Dan again in the near future to order some starter contacts and a plunger just to make sure things are good down there.

Thanks to everyone that chimed in. Sometimes it's the simplest of things, but you just have to make time to look into it.