06 intermittent no start

bens · Sep 18, 2019

This is my wife's cousin's truck, and I have not been able to personally look at it yet, but he has a mechanic who I have talked to and he seems like he knows what he's doing, and it is a problem I haven't heard before.

Hpo system is always perfect, ficm always syncs, has good supply and delivery voltage.

When the truck doesn't start, the injectors don't buzz when the key is turned. When they do, it fires everytime and runs great.

I had him double and triple check the plugs on the ficm and verify the wires are in good shape. He has also tried 2 other known good ficm's.

Any suggestions where to start, or look?

Thanks in advance!

Ben

6.0 Tech · Sep 18, 2019

Ficm relay?

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bens · Sep 19, 2019

It crossed my mind, but then I think the input voltage wouldn't be there if the relay is acting up.

BS Hauler · Sep 19, 2019

The relay might be letting just enough voltage thru for it to read but not enough to let the truck start.

bens · Sep 20, 2019

Got a relay on the way, simple and cheap enough to try!

bens · Sep 21, 2019

Relay didn't help the cause.

6.0 Tech · Sep 21, 2019

Your connectors dont have broken locking tabs on them, do they? Maybe theyre slightly falling out of the ficm. Try putting a piece of 5/8 heater hose under the connectors, then bolt the ficm down.

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Zeb · Sep 21, 2019

6.0 Tech said:
Your connectors dont have broken locking tabs on them, do they? Maybe theyre slightly falling out of the ficm. Try putting a piece of 5/8 heater hose under the connectors, then bolt the ficm down.

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Also, while you’re doing this, take the FICM off and carefully inspect the plugs with a good, bright light to make sure that none of the female side pins are pushed back.
I have seen them get pushed back before on trucks that have had the FICM off multiple times.

bens · Sep 22, 2019

I finally got to put my own eyes on the truck today, I wiggled the ficm plugs while the wife was cranking it, and it started to hit a few times. I'll bring it home tomorrow and pull the ficm and check the plugs out. Thanks so far for the ideas!

Ben

bens · Sep 23, 2019

Got the truck home today, pulled the ficm, all pins are straight. All sockets in the plugs are there. When I run a buzz test it sounds like only 2 injectors on the drivers side click.
Put it back together with a heater hose under the plugs, (they all clicked in good though.)

The guy that was working on it before supposedly tried a known good ficm, so I want to rule it out, only other possibility that comes to mind is 6 bad injectors, but seems odd because it supposedly runs great when it does. I am kind of at a loss other than to try a ficm, but unfortunately don't have any others to try.

Is it possible for the ficm to drop output to 6 injectors??

Thanks,
Ben

DEEZUZ · Sep 23, 2019

Nah, it would only drop a bank, not individuals. 1,4,6,7 or 2,3,5,8.

This being an international, you need to start at the batteries and check all the power feeds/fuses that are there. Unplug them at every connector from battery post to under chassis, to starter. They love to burn pins out and make ****ty connections.

Also the pins in the relay box themselves are known issues.

It's not uncommon to find wires cut out of the box and a relay hanging outside of the box for the ficm.

DEEZUZ · Sep 24, 2019

EDIT NEVERMIND. I read it as "06 international" LOL

bens · Sep 25, 2019

I decided to check the plugs at the injectors to see if they are being delivered power from the ficm, cylinders 1,3,5,7,8 are all getting power. 2,4,6 are not. I was having my wife cycle the key each time I moved to a different plug, since I was using the meter part of my scanner to do the testing. It is odd because when I plugged the drivers side bank back in they were no longer buzzing when i turn the ignition, but still had good power from the ficm.

I believe the buzzing at key on is to warm up the spool valves, so is it possible that by constantly going key on, they got warm and decided to stop buzzing by the time I got to test 2,4,6? And no longer buzzed when I plugged 1,3,5,7 back in?

Sorry for the long winded post, just trying to be as thorough as possible.

Thanks,

Ben

bismic · Sep 26, 2019

FYI (FICM information) to add on to CTCDeezul's post:

C1388B (X-2) Connector: Injector Control, Cyl. 2,3,5,8 (Middle plug)
C1388A (X-1) Connector: Injector Control, Cyl. 1,4,6,7 (end plug)

I believe that the spool valve actuating is temperature dependent (oil temp I believe).

Sounds like a harness issue to me. You need to test each wire IMO - preferably with a substantial electrical load.

bens · Sep 26, 2019

So tonight I retested everything, probing each injector plug for power and ground on each solenoid. 48v going to each solenoid.

This should mean the injectors should be clicking, only injector #8 clicks.

If I have every power at each injector, and they are not clicking, then bad injectors correct?

It just seems odd if they are all bad because he said the truck ran perfect just last week.

I am going to try to get a good injector from a friend tomorrow to plug into each plug just to absolutely verify that everything works.

Thanks,

Ben

bismic · Sep 27, 2019

So you thought 2,4, and 6 weren't getting power, but they are now?

So whose injectors are in the truck? Aftermarket? The only times I have seen most of the injectors bad at one time is with aftermarket injectors.

bens · Sep 27, 2019

They were not on wednesday night, but Thursday night they were. I thought maybe since I ran the key on and off so many times the buzz test at key on quit, not sure why there was no power wednesday and was on Thursday.

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Hartwig · Sep 28, 2019

if all is well on the electrical side, remove one of the defective injectors and check the spool valve. It must move easily without hooks (sorry don´t know the right word in english). I have done this here

https://www.youtube.com/watch?v=LrOIT1-EILI&t=13s

(this one is bad)

Greetings from Germany