Random hard miss, then cut off while driving, then no start, then no crank...Help Please (1 Viewer)

[Cornhusker]

I've searched and searched and searched, but can't find a definitive answer on here as I can only find answers to bits and pieces, mainly the no crank leading to the starter.

The vehicle in question is a 2006 LX470 - Extremely well maintained with 258k miles

This past week I started having what seemed like a random hard miss while driving. I thought it may have been bad fuel, as there was no pattern and there was no check engine light. It would happen and then keep running fine.

The other night I was driving and the symptom happened again, then a short while later it cut out while driving and I was able to put it into neutral and start it up again and had to repeat this twice to get to a safe place to stop, when it died and I rolled into place.

Once parked, I tried to start it, but it would not crank at all. I left for a couple hours and came back and was able to get a crank, but no start and it did this a few times while the ignition continued to tried to start it while cranking (IE the starter grind from already working). It again died and did the no crank no start.

I had it towed to the house where it still does the no crank, no start. All power accessories work as should. I have two 100 series, so tried the EFI relay from the other and still nothing. I also checked every fuse and none are blown. I have not tried the fuel pump relay, but that shouldn't cause a no crank. My security light does not continue blinking after the key is inserted, so do not believe it to be the immobilizer. I also tried the batter out of my other 100 and it didn't make a difference, as well as I even tried jumping off the other 100.

I also noticed that I do not have the Check Engine Light on when the key is moved to the start position and when I hooked up my OBD2 Tester today, it is not communicating, thus leaving me unable to pull any codes.

If it was just a no crank no start or crank no start, it would be narrowed down to the starter or fuel pump. Due to the combination of the random miss, vehicle dying, no start and then the no crank, I am at a loss. Any input or suggestions on this would be greatly appreciated.

 

[G-Cat]

Broken spark plug? I had similar symptoms and one of my plugs was in 2 pieces. (Random miss, shutdown) I don’t remember it not restarting, though.

 

[UltraFJ40]

Maybe give this a read: My immobilizer fix

I was thinking coil pack but that wouldn't cause your issue and would throw a code. I know that personally (x 2).

 

[Eicca]

Does the vehicle have tap start, I.e. you don’t have to hold the key to the “start” position to crank it, you can just click it once to “start” and it’ll crank itself.

 

[Ayune]

I also noticed that I do not have the Check Engine Light on when the key is moved to the start position and when I hooked up my OBD2 Tester today, it is not communicating, thus leaving me unable to pull any codes.

This part is the most telling, it means the Engine Control Module is offline. Ain't nothing gonna happen without that working. The 20A EFI fuse is what supplies power to the ECM. The fuse may be good but the wiring below it may be bad. Search this forum for "EFI fuse" to start you down the right track.

Once you get the ECM working you can pull codes if they're there. Or maybe a fuse/wiring issue is the only issue.

 

[Cornhusker]

Does the vehicle have tap start, I.e. you don’t have to hold the key to the “start” position to crank it, you can just click it once to “start” and it’ll crank itself.

I believe it does.

 

[Cornhusker]

This part is the most telling, it means the Engine Control Module is offline. Ain't nothing gonna happen without that working. The 20A EFI fuse is what supplies power to the ECM. The fuse may be good but the wiring below it may be bad. Search this forum for "EFI fuse" to start you down the right track.

Once you get the ECM working you can pull codes if they're there. Or maybe a fuse/wiring issue is the only issue.

I’ve been searching that quite a bit. Most of what I find is for earlier 100 series though.

 

[abuck99]

TechStream would help you observe and test function of each ECM/ECU. If you dont have it- maybe someone local to you does.

 

[Eicca]

I believe it does.

Ok, that means there’s a computer between the ignition and the starter. That, plus the fact that OBD isn’t working, suggests a fuse or bad connection/ground.

In the older vehicles where the ignition is more or less directly connected to the starter solenoid, it’s very rare that a no-crank happens without a serious power loss to the rest of the vehicle.

 

[Eicca]

Also, have you tried jump starting it?

The easiest and least expensive solution is always worth a shot, especially on these super computerized cars. You never know what a glitch in the charging system will do to them.

 

[ColoradoBoy]

This sounds like the issue I had with my 91- was poor connections at the EFI relay under the hood. Rig would cut out randomly as it hit bumps in the road an catch itself back on again, intermittantly the CEL would not come on when trying to start. Pop the hood, wiggle the relay, and then the CEL would come on and start. Verified wires and connections, found a loose connector at the EFI relay. Problem solved.
Hope you find it. Check out Jonheld's postings about the EFI system- he is a GOD when it comes to this.
Good luck!

 

[birch hill]

My 05 f150 just did the exact same thing. It ended up being a bad relay. If this relay did not close it did not trigger both the starter relay and ecm relay. I also could not pull codes.

 

[Cornhusker]

Thank you everyone. I have messed with that EFI relay a lot to try and trouble shoot it. I am going to take apart the main fuse box and check the connections underneath. I will also be checking the Fuel Pump relay that is right next to the Main EFI relay.

 

[Cornhusker]

An update on this. I haven't had time to mess with it due to a move, trying to sell a house and getting ready to retire. I went and rechecked everything that I hadn't, have already checked, and haven't replaced fuse or relay wise. I check the Cam Sensor wiring again and noticed that it was sitting on the belt and had rubbed through. I moved it and went and checked the dash and boom! CEL and all the lights were working again. It's always something so simple that you can miss.

 

[ColoradoBoy]

Glad you found the issue. Cheers!