Shut off while going over 30..

So, I was driving around 30-35mph when the engine just stopped…
I was taking a turn, thankfully- no accidents happened…
The car had been having issues accelerating, so I changed the fuel pump,
Maf, o2, fuel filter and bunch of other stuff…

It also started shutting off after starting… so I thought it was Idle valve control, so I ordered it,
I also got a Throttle position sensor and am gonna replace them soon…

However, I am not 100% it will fix the issue…

I also have a bad supercharger coupler that needs to be replaced… I don’t drive it a lot, so I was thinking of changing it in the summer. Could that be causing the engine to die like that?

Please let me know what you think it could be
And also how to start diagnosing to find what it is…

I know it could be a lot of things, possibly, but I really need to fix it!
I love my Rivie, won’t let her go

If it shuts off very suddenly, as opposed to slowly shutting off, that points to ignition. Does it restart immediately? The most likely cause is the crank sensor.

It could also be the ignition switch. With the engine running, move the switch around. If you can re create the shut off, replace the switch.

My car did the same thing going up a hill it would shut off changed the CS never did it again

Thanks for the replies!
I changed the crank sensor like 10kmiles and 2 years ago…
I just ordered another one, let’s see if it fixes it…

try and get a delco part or OEM like quality all these off brand parts are junk

My Riviera was doing the same thing - cutting off and cranks wont start - both cam and crank sensors went bad - one right after the other...both times the service engine trouble codes for cam circuit then crank circuit were generated and both times the Trac off light, but other times no trouble codes so was intermittent at time and maybe good to know did your PCM generate a trouble code?

VaRiviera wrote:

My Riviera was doing the same thing - cutting off and cranks wont start - both cam and crank sensors went bad - one right after the other...both times the service engine trouble codes for cam circuit then crank circuit were generated and both times the Trac off light, but other times no trouble codes so was intermittent at time and maybe good to know did your PCM generate a trouble code?

That’s the thing… I got no codes

BuickRivieraGeorgia wrote:

VaRiviera wrote:

My Riviera was doing the same thing - cutting off and cranks wont start - both cam and crank sensors went bad - one right after the other...both times the service engine trouble codes for cam circuit then crank circuit were generated and both times the Trac off light, but other times no trouble codes so was intermittent at time and maybe good to know did your PCM generate a trouble code?

That’s the thing… I got no codes

Temporary failure of the crank sensor will not set a code. It will just randomly stall the engine when hot.

Quote :

Temporary failure of the crank sensor will not set a code.  It will just randomly stall the engine when hot.

It stalls right after starting more often than when it’s hot…
I hope it’s the TPS…

BuickRivieraGeorgia wrote:

Quote :

Temporary failure of the crank sensor will not set a code.  It will just randomly stall the engine when hot.

It stalls right after starting more often than when it’s hot…
I hope it’s the TPS…

You are losing spark when it stalls suddenly. You can guess and change parts if you want. That will be frustrating and expensive.

The TPS can easily be checked with a multi meter. It has 3 wires. One is 5 volt, one is the signal wire back to the PCM, and 3rd is ground. Closed throttle, the signal wire should read about .40 volts. Wide open throttle, about 4.5 volts. The voltage should increase uniformly as you open the throttle.

Can you make the engine stall if you push and pull on the ignition lock cylinder? Might be that.

LARRY70GS wrote:

BuickRivieraGeorgia wrote:

Quote :

Temporary failure of the crank sensor will not set a code.  It will just randomly stall the engine when hot.

It stalls right after starting more often than when it’s hot…
I hope it’s the TPS…

You are losing spark when it stalls suddenly.  You can guess and change parts if you want.  That will be frustrating and expensive.

The TPS can easily be checked with a multi meter.  It has 3 wires.  One is 5 volt, one is the signal wire back to the PCM, and 3rd is ground.  Closed throttle, the signal wire should read about .40 volts.  Wide open throttle, about 4.5 volts.  The voltage should increase uniformly as you open the throttle.

Can you make the engine stall if you push and pull on the ignition lock cylinder?  Might be that.

I doubt it’s the ignition lock…
It starts right up after stalling…
I will try to wiggle the key when running, I suppose…

Also, where exactly is the TPS on the 95?
I can see the Maf and right under it the the Map sensor,
But couldn’t find the TPS…

You doubt it's the ignition switch. Famous last words It takes 10 seconds to check and it's free.

The TPS is very near the throttle shaft. It looks like this,

https://www.rockauto.com/en/moreinfo.php?pk=87482&cc=1022016&pt=5136&jsn=493&_nck=ZExt1ysfqhqWnq%2BEvUNdS3Txyey60IDtnjPWF5UU9J0BWQv7pvqZbkEUk86%2BAYIhylPKrF7bIqEdzCrwNv0t5YtVtHpkast1%2FcAiIo3jWKeYdxE5VWqIf3Ho3Ydappi6IwZ5FsNuYPewHVgyJAKygNUstSFxjqblaHuMtkUEujRbSfz85qXX8OPHsB2PIQvHyFMWj8bNzeUTPDtWUScNXBcdG2RZw9xBCmBtVE3%2BMRdOE1rvmWZ0XzN72Cz5s7XkOdrcT4q51obsIX%2BYaw17izCEHjKZ%2Fq4r4QbkmHikPi0gCqCNbnF3K3wSwiYeTkr%2F6WWQkMqJ5ANuOHAeRGX8H7e7sPq%2BaYtv

Shouldn't be too hard to spot.

LARRY70GS wrote:

You doubt it's the ignition switch.  Famous last words   It takes 10 seconds to check and it's free.

The TPS is very near the throttle shaft.  It looks like this,

https://www.rockauto.com/en/moreinfo.php?pk=87482&cc=1022016&pt=5136&jsn=493&_nck=ZExt1ysfqhqWnq%2BEvUNdS3Txyey60IDtnjPWF5UU9J0BWQv7pvqZbkEUk86%2BAYIhylPKrF7bIqEdzCrwNv0t5YtVtHpkast1%2FcAiIo3jWKeYdxE5VWqIf3Ho3Ydappi6IwZ5FsNuYPewHVgyJAKygNUstSFxjqblaHuMtkUEujRbSfz85qXX8OPHsB2PIQvHyFMWj8bNzeUTPDtWUScNXBcdG2RZw9xBCmBtVE3%2BMRdOE1rvmWZ0XzN72Cz5s7XkOdrcT4q51obsIX%2BYaw17izCEHjKZ%2Fq4r4QbkmHikPi0gCqCNbnF3K3wSwiYeTkr%2F6WWQkMqJ5ANuOHAeRGX8H7e7sPq%2BaYtv

Shouldn't be too hard to spot.

I see… then the TPS I got from Rockauto is the wrong one…

I’ll check the ignition switch first thing tomorrow

Thanks a lot for your help

BuickRivieraGeorgia wrote:

LARRY70GS wrote:

You doubt it's the ignition switch.  Famous last words   It takes 10 seconds to check and it's free.

The TPS is very near the throttle shaft.  It looks like this,

https://www.rockauto.com/en/moreinfo.php?pk=87482&cc=1022016&pt=5136&jsn=493&_nck=ZExt1ysfqhqWnq%2BEvUNdS3Txyey60IDtnjPWF5UU9J0BWQv7pvqZbkEUk86%2BAYIhylPKrF7bIqEdzCrwNv0t5YtVtHpkast1%2FcAiIo3jWKeYdxE5VWqIf3Ho3Ydappi6IwZ5FsNuYPewHVgyJAKygNUstSFxjqblaHuMtkUEujRbSfz85qXX8OPHsB2PIQvHyFMWj8bNzeUTPDtWUScNXBcdG2RZw9xBCmBtVE3%2BMRdOE1rvmWZ0XzN72Cz5s7XkOdrcT4q51obsIX%2BYaw17izCEHjKZ%2Fq4r4QbkmHikPi0gCqCNbnF3K3wSwiYeTkr%2F6WWQkMqJ5ANuOHAeRGX8H7e7sPq%2BaYtv

Shouldn't be too hard to spot.

I see… then the TPS I got from Rockauto is the wrong one…

I’ll check the ignition switch first thing tomorrow

Thanks a lot for your help

Which one did they send you?

https://www.rockauto.com/en/catalog/buick,1995,riviera,3.8l+v6+supercharged,1022016,fuel+&+air,throttle+position+sensor+(tps),5136

They sent this one:
https://images.app.goo.gl/Kw1yFo5oDrwcQiXM6

That looks like an Ebay link, 1999-2005 Lesabre

https://www.rockauto.com/en/catalog/buick,1999,lesabre,3.8l+v6,1352797,fuel+&+air,throttle+position+sensor+(tps),5136

@BuickRivieraGeorgia: your failure after replacing the crank sensor 2 Y ago is *exactly* what happened to me. The local GM dealer had installed a 'Standard' brand CPS b/c it would have taken them a couple three days to get a Delphi at the time. When the failure repeated I took the car back to them (they have a tech who's good at getting the harmonic balancer off/on without effing it up). This time, they waited for the Delphi.

I chatted with the service manager about the situation. What I learned (1) when I rolled in with the problem it was the first CPS failure they'd seen. They tried a couple things that didn't work, and could not find the problem. I had them replace the CPS "customer request" based on what I'd learned off a Saturn forum, because they could not find "the problem". (2) The service manager and one of the techs came up with a way to wire up some LED Noid lights as pilot lights to tell when the CPS was failing intermittently - basically it leaves the ignition on but other things in an off state, and you can tell immediately by the pattern of off-on NOIDs that the CPS had fainted (versus ignition switch failure or a fault in the PCM). That was so they could comply with the GM rule that a problem be diagnosed before repair attempts and as well reduce the number of diagnosis events required before figuring out the problem was indeed the CPS. They had me test the protocol when I came back after 2 years and told them to replace the crank sensor. They said, 'not so fast, we think we can tell if yoru CPS is dying" and it worked. I have no idea if their technique has been shared. Even among the local community of independent mechanics, the local GM dealer's service ops have a good reputation (One indie says, "they are expensive but those guys know what they are doing and they are good").

Although the harmonic balancer pull is a pain, the diagnosis of this problem being your CPS is probably spot on.

What happens is when your car is cold, it behaves normally but when it warms up it quits. What's happening is the electrical connections in the CPS have been compromised by thermal cycling and after a while they start to let go when warm. Delphi has engineered a better connection and encapsulation.

I'd get a WVE, Delphi or GM original eq (NOT a Delco Gold Professional) CPS and be done with it.

albertj wrote:

@BuickRivieraGeorgia:  your failure after replacing the crank sensor 2 Y ago is *exactly* what happened to me.  The local GM dealer had installed a 'Standard' brand  CPS b/c it would have taken them a couple three days to get a Delphi at the time.  When the failure repeated I took the car back to them (they have a tech who's good at getting the harmonic balancer off/on without effing it up).  This time, they waited for the Delphi.  

I chatted with the service manager about the situation.  What I learned (1) when I rolled in with the problem it was the first CPS failure they'd seen.  They tried a couple things that didn't work, and could not find the problem.  I had them replace the CPS "customer request" based on what I'd learned off a Saturn forum, because they could not find "the problem".  (2) The service manager and one of the techs came up with a way to wire up some LED Noid lights as pilot lights to tell when the CPS was failing intermittently - basically it leaves the ignition on but other things in an off state, and you can tell immediately by the pattern of off-on NOIDs that the CPS had fainted (versus ignition switch failure or a fault in the PCM). That was so they could comply with the GM rule that a problem be diagnosed before repair attempts and as well reduce the number of diagnosis events required before figuring out the problem was indeed the CPS. They had me test the protocol when I came back after 2 years and told them to replace the crank sensor.  They said, 'not so fast, we think we can tell if yoru CPS is dying" and it worked.   I have no idea if their technique has been shared. Even among the local community of independent mechanics, the local GM dealer's service ops have a good reputation (One indie says, "they are expensive but those guys know what they are doing and they are good").  

Although the harmonic balancer pull is a pain, the diagnosis of this problem being your CPS is probably spot on.  

What happens is when your car is cold, it behaves normally but when it warms up it quits.  What's happening is the electrical connections in the CPS have been compromised by thermal cycling and after a while they start to let go when warm. Delphi has engineered a better connection and encapsulation.  

I'd get a WVE, Delphi or GM original eq (NOT a Delco Gold Professional) CPS  and be done with it.

I see…
I would agree with all of it, however it stalls the often more when it’s cold…
I remember how it acted when it was the Crank/cam sensor…
This time it feels different…
Obviously, I cannot be sure of any of it, but it’s just a hunch…
I will post the updates once I get to fixing!

Thanks for the replies

Stalling more when cold?

Actually, thinking about it and given your year, it could be the wiring harness at the firewall or PCM (coils) connector - you have to check for a wire broken inside the insulation.  This is a difficult one -- using needlenose pliers or some such wiggle the wires at the connector one by each to check if they are broken.  If you do it while car is running - be sure to watch out for the moving parts.

Context: some of the wire GM used at that time wasn't such a great alloy and tended to work harden in areas that it flexed a lot.  The wire would fracture.  The break being inside the insulation the fracture might or might not separate and would make-and-break.  I suspect a number of people junked their cars over that wiring issue.  

There was a real nice writeup about this broken-wire problem on this site but I can not find the link to it.  Maybe the original author or one of the admins can help locate it.

The hint for me is "shutoff while going over 30" - you'd have the engine rocking a bit as the transmission goes thru the gears. The wiggles would be enough to mess with any broken wire especially on the ignition module. "going over 30" sounds like your car finds the jostling at the 2-3 gear upshift to be, well, triggering... Maybe.

Albert, are you talking about the thread about the Cam Sensor code?  P0341?  I had that problem but it never caused a stall, just a CEL.  Had a friend hook up a Tech 2 to monitor the Cam Sensor Signal.  I could watch the signal go in and out as I wiggled the wire from the harness connector.

https://rivperformance.editboard.com/t4703p180-faq-p0341-camshaft-position-sensor-cam-sensor-timing-chain?highlight=camshaft+position+sensor

LARRY70GS wrote:

Albert, are you talking about the thread about the Cam Sensor code?  P0341?  I had that problem but it never caused a stall, just a CEL.  Had a friend hook up a Tech 2 to monitor the Cam Sensor Signal.  I could watch the signal go in and out as I wiggled the wire from the harness connector.

https://rivperformance.editboard.com/t4703p180-faq-p0341-camshaft-position-sensor-cam-sensor-timing-chain?highlight=camshaft+position+sensor

Yes.

I remember insisting that you check that blasted connector - you finally did - and then you wrote a stellar description of finding and fixing the problem. I am still impressed!

Different wire broken = different behavior from the car. So yeah it might be nothing but check the wiring at that connector.