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If timing chain breaks, would it.....

9K views 32 replies 7 participants last post by  truckinman 
#1 ·
.....kill the engine instantly at 70 mph, or would it kick off the cruise, start rapidly down shifting to slow the car down without using brakes, then once at a safe enough speed to do so, shut the car off? Also I've never heard any rattling from the engine. I never let oil get low.
 
#3 ·
It's at a shop now but no one to look at it until later today. To me it seemed exactly what happens when on star shuts down a stolen vehicle. I'm just hoping for the best but preparing for the worst so I'm just trying to get your input. I'd think if it broke at 70, and junked the engine, the engine woulda been been shut off immediately instead of actually continuing to run smooth other than me dimly not having control of the car. It just felt like someone remotely took charge of it. Weirdest damn thing. It cranked just fine too once stopped. Just wouldn't start.

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ddalder said:
I can't see any possible scenario that if a timing chain did break while running that the engine would be salvageable. What you're describing would basically require and act of God.
That's what I'm saying. I don't know if it was the chain or something electrical.
 
#4 ·
There's something else at work here for sure. I really can't see the timing chain breaking being the cause. If it cranked well afterwards and nothing sounded out of the ordinary, it's not a broken chain. I'll be interested in hearing what this turns out to be. I can see the correlation you're making with the OnStar gradual vehicle slow-down, but it wasn't available for a few years after yours was made so that won't be it either.
 
#5 ·
ddalder said:
There's something else at work here for sure. I really can't see the timing chain breaking being the cause. If it cranked well afterwards and nothing sounded out of the ordinary, it's not a broken chain. I'll be interested in hearing what this turns out to be. I can see the correlation you're making with the OnStar gradual vehicle slow-down, but it wasn't available for a few years after yours was made so that won't be it either.
Hm. Ok. Well your giving me hope that my suspicion about it not being the chain could be confirmed. Lol. But is there a sensor or something that could go out causing it to do ANYTHING like that? I mean when the cruise stopped, I hit the gas an nothing. No revving like the tranny was slipping or anything. It was JUST like someone hit a button that disconnected me from having any control at all. Kinda freaky in a way.

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I've searched high n low on here and google but can't find anything remotely like this.

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I know a fair share about working on cars but this really leaves me dumbfounded.
 
#7 ·
Yea fuel related is only thing I can think of too. Only issue I've had with this car in the 14 months I've had it was a simple ignition coil that I replaced. Other than that its run like a dream. I've put nearly 20k miles on it. The CEL did come on AFTER it died. Lol. Well once I tried restarting it, the light came on solid.

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All I can say is, it's been a good 7 years since I've had to rely on a mechanic. Me and or my friends can always figure out the issue. But I could only do so much on the side of the road with my portable craftsman tool set lol. I was 60 miles from home, and after the second sheriff stopped, he made me get a wrecker lol. So I just had it towed straight to my wife's families garage. They seem to do a good job on their cars.
 
#8 ·
Definitely let us know what it ends up being. I'm guessing something simple like your fuel pump went out or a sensor or a theft deterrent relay activated for some reason.

The down shifting was probably just the fact that the car was slowing down. If the timing chain broke at that speed it would probably bend the hell out of the valves and should not have sounded very good.
 
#9 ·
carter's_sts said:
Definitely let us know what it ends up being. I'm guessing something simple like your fuel pump went out or a sensor or a theft deterrent relay activated for some reason.

The down shifting was probably just the fact that the car was slowing down. If the timing chain broke at that speed it would probably bend the hell out of the valves and should not have sounded very good.
That's what I'd think too. And it wasn't downshifting like it does when you coast to a stop. It was violently down shifting like it was programed to do that to bring it to a safe speed to shut off by just using the compression of the engine. I know I'm very anxious to figure out the mystery.

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Hmm. Just thought of something. A couple weeks ago I was having an issue with my hood latch theft deterrent. The alarm kept going off one night and it kept saying on the information display that a theft was attempted thru my hood and to service the theft system. It never acted up again so I never replaced the latch. Could there POSSIBLY be some sort of affiliation between the two?? Merely a thought as of right now...
 
#10 ·
I don't think they would kill the engine if the hood latch switch was opening or closing. That would be too much of a safety issue. I think they just prevent starting.

I was just totally speculating about a theft deterrent thing. I know many cars will not let the fuel pump run if the alarm is activated. Not even sure if our cars do that. My thought was maybe a relay that does that got inadvertently activated/deactivated. There's probably a regular fuel pump relay also.

Let's hope for something simple that just seemed catastrophic.
 
#11 ·
carter's_sts said:
I don't think they would kill the engine if the hood latch switch was opening or closing. That would be too much of a safety issue. I think they just prevent starting.

I was just totally speculating about a theft deterrent thing. I know many cars will not let the fuel pump run if the alarm is activated. Not even sure if our cars do that. My thought was maybe a relay that does that got inadvertently activated/deactivated. There's probably a regular fuel pump relay also.

Let's hope for something simple that just seemed catastrophic.
Yep can't agree more. Will definitely keep y'all informed as I'm informed.
 
#14 ·
amunderdog said:
Hope they merge the threads
Or is this the sequel to original thread?
It's basically a sequel.

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carter's_sts said:
Also, you can pop the hood with the car idling and it doesn't shut off. So if it is related to the alarm, it must be something besides the latch.
Yea good point. I just wish I could figure this out on my own b4 the garage does. Lol. I hate that it's even at a garage. It means I failed as a "do it yourselfer". Lol.
 
#15 ·
Hopefully it isn't the chains..

But if the chains, or one snapped, I don't think it would stop the engine from turning. The force from the vehicle back through the trans would still rotate the engine, but with no valves opening and closing you would have no power. I had a motor cycle where the timing chain jumped a tooth. It basically died instantly, rammed several valves into the pistons and broke several tappets. The engine would crank freely though, just wouldn't fire. Amazingly enough no valves bent, it was a robust engine, and I was able to get it running again. I believe it was the way the valve train was designed. I'm not sure how the 3.6 is, if the cam lobes push directly on the valve or not. If my bike was designed where the cams pushed directly on the valves I'm guessing the outcome wouldn't have been so positive.
 
#19 ·
Figured it was something like that. I really couldn't see it being the hood switch. You can start and operate your car with the hood open. The hood switch is primarily to disable the remote start if the hood is open. This is a safety feature so someone can't accidentally remote start it while someone is working under the hood.
 
#20 ·
ddalder said:
Figured it was something like that. I really couldn't see it being the hood switch. You can start and operate your car with the hood open. The hood switch is primarily to disable the remote start if the hood is open. This is a safety feature so someone can't accidentally remote start it while someone is working under the hood.
Well does anyone know just how hard a fuel pump replacement is in one of these? He told me most of the cost was labor. I'm thinking I may tackle this job on my own. We've got 3 cars so if it takes a while so be it.
 
#22 ·
Parts Information OEM Part # Price
Fuel Pump 19151141 $374.11

Labor Information Skill Level Mfg. Warranty Standard
B 3.0 4.6
Does Not Include: Drain & Refill Fuel Tank.

Pump appears to be on the passenger side of the tank based on images from service manual.

If you were thinking of doing this on your own it looks like a special tool is needed:

Fuel Pump Lock Ring Tool AST tool# J 45722
Fuel pump lock ring tool that can be used on GM and Saab vehicles

Contact AST for pricing "Assenmacher Specialty Tools"
1 800 525 2943


But there is also this:
Primary Fuel Tank Module Replacement

Tools Required

J 45747 Fuel Tank Sender Wrench

Secondary Fuel Tank Module Replacement

Tools Required

J 45747 Fuel Tank Sender Wrench
 
#25 ·
ddalder said:
I can't imagine for a moment that I'd ever consider cutting new holes in my vehicle for something like this. Not to mention if the tank or line(s) were damaged while cutting the metal, it could lead to a catastrophic event. Some people should not be allowed to own or use tools.
No way in hell would I cut new holes. Lol. I dismissed that idea soon as I read it. When working around gas, the last thing I wanna do is create sparks

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I actually knew a guy who was doing this very job but on another type of car, as he was lowering the fuel tank, a spark was created and blew the garage up. Killing him instantly. So I don't take this stuff lightly
 
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