no start immobilizer issue (1 Viewer)

[Elijah]

Did a quick overnighter to Moab, left Friday morning and got back to SLC area Saturday evening. Took my cousin who was anxious for his first taste of Moab and offroading. In Arches National Park we had a no start issue after coming back from a vista. After multiple turns of the key it did finally fire up. I didn't notice then if there were any immobilizer issues going on. The starter would sit and turn the engine very strongly and never actually fire up though. Did the rest of stops in Arches without turning off the LC for fear of a no start issue again. Got to the Archway hotel, or something like that, and turned off engine and went and checked in. Came back to Cruiser to move it by the closest entrance door to our room and it wouldn't start again. So we left the Cruiser up front carried our backpacks to the room and I started to search IH8MUD. Came across an excellent "no start" thread and it seemed to have the same issues described that I was experiencing. While key is inserted in ignition the flashing red vehicle with the key in it continues to flash and it should stop flashing, if the key is recognized by the immobilizer system. So there were a few suggestions in that thread. One said that replacing the EFI fuse fixed it. So I pulled the fuse and inspected it as best as I could in the dark, wiped the blades with my shirt and it looked fine, so I put it back and still had the flashing immobilizer light and still no start. I whacked the EFI relay a few times and still the flashing light and no start. I was getting ready to go after the ignition cylinder when I thought maybe I'll just swap that fuse out even though it looked fine. Sure enough, swapping that fuse out for a new one fixed the issue, immobilizer light stopped flashing with key in ignition and engine fired up right away. Why it did, who the hell knows. Makes no sense to me. I'm sure glad that was all it needed though. I had a rough set of wrenches and ratchet/sockets and that was it. Here are couple pics from Chicken Corners, I know, I know... Oh yeah, newer to me 1998 LC with rear locker and no rear A/C and ~230k miles.

 

[96crooser]

I"m bumping this tread because I just experienced the exact same scenario as Elijah. The only thing I can figure out about why this happens is the EFI fuse must gradually degrade over time which causes the failure to be sporadic at first leading too permanent even though the fuse looks ok. Has Anyone else experienced this or have any impute.

 

[Ermagerd]

Or it blew and just wasn't visible. Have either of you checked the resistance of the old fuse?
Another thing I have seen is a fuse blow, but the element was still making slight contact. That was once in 15 years on a maxi fuse- it shouldn't be a regular occurrence.

 

[yeti in ga]

I had an issue with the fuse box itself on the bottom, or something like that. only time so far I have had to tow my truck.

 

[96crooser]

thanks for the response. the issue has returned two days latter this time replacing the fuse doesn't fix the problem. I will be checking the connections too the fuse box.

 

[Ermagerd]

Are there any immobilizer codes?

 

[96crooser]

no codes, I'm going to try and replace EFI fuse with a jumper as others have and had success

 

[Ermagerd]

The fuse didn't work, so the smart money is on a jumper not solving it either.

 

[Ermagerd]

After reading the other thread about fuse panel issues, it makes a little more sense how some people's jumpers are working. Male spade connectors are larger than the fuse spades. That may be making up for a bad contact condition when the fuse is in place. On a different note, my guess is the problem also worsens when the engine is at operating temp. Heat increases resistance.

 

[96crooser]

Thanks for your input, well when I got home from work I installed a jumper I made from solid copper wire. It has worked perfectly so far. Further more my problem has only happened on cool mornings after sitting all night.

 

[Ermagerd]

Further more my problem has only happened on cool mornings after sitting all night.

That's interesting.

 

[96crooser]

That's interesting.

Yes it is, I chalk it up to a major design flaw that should be recalled

 

[Jimthom]

I have also been following these two threads and some earlier ones as well.
To summarize, and simplify, the problem seems to be a bad connection to the spade fuse. This is why a larger spade jumper or a wire makes better contact and fixes the problem. The prongs in the socket must become spread further apart and not make a good enough connection to carry the current. Can the prongs in this socket be fixed short of replacing the entire fuse box?

 

[96crooser]

Good question, I was also thinking on similar lines. How come there isn't problems with other spade fuse connectors. It seems to me the fuse connector is the week link in a circuit that is inherently insufficient to Carrie the required amps too close the circuit. I"m considering immobilizing the immobilizer.

 

[Ermagerd]

I have also been following these two threads and some earlier ones as well.
To summarize, and simplify, the problem seems to be a bad connection to the spade fuse. This is why a larger spade jumper or a wire makes better contact and fixes the problem. The prongs in the socket must become spread further apart and not make a good enough connection to carry the current. Can the prongs in this socket be fixed short of replacing the entire fuse box?

You could just squeeze the terminals tighter. On different vehicles, I've just used a pick and pushed on the open female spade ends to close them a little. Various companies do make female spades that will clip into the plastic in the fuse panel. Wurth is the first company that comes to mind.

 

[timmbuck2]

Hey all, I just made maybe an important discovery regarding this issue!!

I have had this happen to me 3 times...

Last winter I went to my truck at lunch (2000 LC) and had the crank but no start issue. Did not think to look at the security light, just assumed I had a clogged fuel filter or something. Went back to the office for a few hours, then went out to the truck and tried again and still no start. So I sat in it listening to the radio and called AAA to tow it home. While I was sitting on hold, I tried it one more time, and it started! Went home to research on MUD and then forgot about it.

A few months later, it happened again at the grocery store. Since the last time it seemed to start again fine after a few hours, I walked home, then went back a few hours later. Again did not think to look at the security light. Again no start, so I sat listening to the radio again and called AAA. About 30 minutes later the tow truck driver called to say he was 5 minutes away. I decided to try one more time for fun, and it started!! Again did more research on MUD but did not see a silver bullet solution. Just hoped it did not happen again while camping deep in the Colorado wilderness.

Now yesterday I get in the truck to go pick up my son and again no start. This time I did look, and the security light was blinking no matter what I did. So used the Lexus to go get him and then did more research. I changed the fuse, no change. (although the light did go out for a minute...) I unhooked the battery for a few hours, no change. Then left it overnight, which seemed to help the other times, but did not start this morning. Then I had an ah-ha moment. What was common about the first 2 times it happened, and started again? I was thinking the 3-4 hour wait, which did not work this time.....but the previous 2 times I had the key in the on position while I listened to the radio! So I went out and put the key in the on position, then 20 minutes later I went out and IT STARTED! So for some reason it is taking it's own sweet time to realize the key is there. I have no theories on how or why, but it worked! Just went out again and it started right up. This won't help if it happens when you are running late, but if stuck in the mountains, is a good thing to know.

So, any ideas???

Hope this helps someone

Tim

 

[96crooser]

Hey all, I just made maybe an important discovery regarding this issue!!

I have had this happen to me 3 times...

Last winter I went to my truck at lunch (2000 LC) and had the crank but no start issue. Did not think to look at the security light, just assumed I had a clogged fuel filter or something. Went back to the office for a few hours, then went out to the truck and tried again and still no start. So I sat in it listening to the radio and called AAA to tow it home. While I was sitting on hold, I tried it one more time, and it started! Went home to research on MUD and then forgot about it.

A few months later, it happened again at the grocery store. Since the last time it seemed to start again fine after a few hours, I walked home, then went back a few hours later. Again did not think to look at the security light. Again no start, so I sat listening to the radio again and called AAA. About 30 minutes later the tow truck driver called to say he was 5 minutes away. I decided to try one more time for fun, and it started!! Again did more research on MUD but did not see a silver bullet solution. Just hoped it did not happen again while camping deep in the Colorado wilderness.

Now yesterday I get in the truck to go pick up my son and again no start. This time I did look, and the security light was blinking no matter what I did. So used the Lexus to go get him and then did more research. I changed the fuse, no change. (although the light did go out for a minute...) I unhooked the battery for a few hours, no change. Then left it overnight, which seemed to help the other times, but did not start this morning. Then I had an ah-ha moment. What was common about the first 2 times it happened, and started again? I was thinking the 3-4 hour wait, which did not work this time.....but the previous 2 times I had the key in the on position while I listened to the radio! So I went out and put the key in the on position, then 20 minutes later I went out and IT STARTED! So for some reason it is taking it's own sweet time to realize the key is there. I have no theories on how or why, but it worked! Just went out again and it started right up. This won't help if it happens when you are running late, but if stuck in the mountains, is a good thing to know.

So, any ideas???

Hope this helps someone

Tim

That is a interesting point. That confirms to me that it is caused by a week spot in the circuit as I thought. At the EFI fuse . I think having the key in the ignition for a period of time alows time for the circuit to close. A jumper in place of that fuse so far has been the only sure fix for the problem so far for me.