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93 Deville Stalling


beefy

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Ok now that the car is running I have another problem. When I let the engine sit to idle the rpms drop gradually to where its about to stall, at which point the isc will kick out to keep it going. After a second the rpms start to drop again, and the isc will kick again. This will happen 5-10 times, each time the rpms dropping lower and lower until finally the car dies. I dont have any codes at the moment but I had the battery disconnected all day. Any thoughts?

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Icons on the climate control? you mean in diagnose mode? I would love to know what to look for. I replaced the isc about 2 years ago because it was surging(not stalling) THe problem got better with this isc before it began to stall. I also replaced the pickup in the distributor because the engine would stall every time i hit the gas... it would also stall if I let it idle like it is doing now. Now I can rev fins but it wont idle.

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Icons on the climate control? you mean in diagnose mode? I would love to know what to look for. I replaced the isc about 2 years ago because it was surging(not stalling) THe problem got better with this isc before it began to stall. I also replaced the pickup in the distributor because the engine would stall every time i hit the gas... it would also stall if I let it idle like it is doing now. Now I can rev fins but it wont idle.

Clean your mass air sensor with some Mass Air Cleaner and see if that helps.. Also check for vacuum leaks as well. Also a bad FPR would do this at idle, if too high it will flood the engine till it dies.

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Icons on the climate control? you mean in diagnose mode? I would love to know what to look for. I replaced the isc about 2 years ago because it was surging(not stalling) THe problem got better with this isc before it began to stall. I also replaced the pickup in the distributor because the engine would stall every time i hit the gas... it would also stall if I let it idle like it is doing now. Now I can rev fins but it wont idle.

Clean your mass air sensor with some Mass Air Cleaner and see if that helps.. Also check for vacuum leaks as well. Also a bad FPR would do this at idle, if too high it will flood the engine till it dies.

WIll clean the maf sensor tomorrow and Ill check the fpr... pull the vacuum hose and look for dripping gas right?

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Icons on the climate control? you mean in diagnose mode? I would love to know what to look for. I replaced the isc about 2 years ago because it was surging(not stalling) THe problem got better with this isc before it began to stall. I also replaced the pickup in the distributor because the engine would stall every time i hit the gas... it would also stall if I let it idle like it is doing now. Now I can rev fins but it wont idle.

Clean your mass air sensor with some Mass Air Cleaner and see if that helps.. Also check for vacuum leaks as well. Also a bad FPR would do this at idle, if too high it will flood the engine till it dies.

WIll clean the maf sensor tomorrow and Ill check the fpr... pull the vacuum hose and look for dripping gas right?

yes... Check for dripping gas or oders.. it should hold vacuum.

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yes... Check for dripping gas or oders.. it should hold vacuum.

Odors? Because when I checked mine I could smell a fuel smell from it. No dripping fuel tho, and I put vacuum pressure on it (sucked on the hose) and no fuel came out.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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this is a 4.9, hmmm

Have you changed the fuel filter?

If you have not done so, start the car while the vacuum hose is off the FPR and look closely for fuel put a piece of paper in front of it and look for spitting fuel.

When it stalls, is the exhaust black? or normal

Is the EGR valve stuck open, do you have any EGR codes? GENTLY push up on the EGR valve diaphram and see if it appears to open and close. Next time the engine is cycling like that, gently push up on the EGR diaphram and see if you sense a change in the engine when you do, doing that SHOULD make it run worse/stall it, if not, your EGR might be stuck open or cracked open

Put a fuel pressure gage on your fuel rail and check the fuel pressure

Check all vacuum hoses for leaks and cracks, especially the big lines like the one to the brake booster, check for a crack in the plastic fitting at the booster

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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Wait, isn't the FPR on this can in the intake plenum?,

If I am not mistaken the 93 and 94's FPR is inside the intake under a cover and it draws its vacuum directly from the intake, there is no vacuum hose on it.

Someone clarify this for me, Thanks

From what I've read on here, you're right. I have a 95 with a vacuum hose, and a fuel odor from the hose. No dripping fuel though.

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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Wait, isn't the FPR on this can in the intake plenum?,

If I am not mistaken the 93 and 94's FPR is inside the intake under a cover and it draws its vacuum directly from the intake, there is no vacuum hose on it.

Someone clarify this for me, Thanks

From what I've read on here, you're right. I have a 95 with a vacuum hose, and a fuel odor from the hose. No dripping fuel though.

I am sorry lothos, I initially posted the post that you responded to, thinking it was a Northstar, but it was a 4.9, and I edited my post, but NOT quick enough to stop you! :lol:

Yes, on the 93/94 NS, the FPR is in the intake, on the 4.9, its on the fuel rail, like the later Northstars.

By the way, you can check the FPR regulator two way, with the engine OFF and with it ON, look for spitting while the engine is running..

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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I am sorry lothos, I initially posted the post that you responded to, thinking it was a Northstar, but it was a 4.9, and I edited my post, but NOT quick enough to stop you! :lol:

Yes, on the 93/94 NS, the FPR is in the intake, on the 4.9, its on the fuel rail, like the later Northstars.

By the way, you can check the FPR regulator two way, with the engine OFF and with it ON, look for spitting while the engine is running..

I actually ran out and checked, no dripping fuel with the car running either. Still smells like fuel though, but I was told it should be good.

Also I read on here that you should not turn on the car on a 93/94 N* with the top cover off, in case someone was thinking of trying it :D

WARNING: I'm a total car newbie, don't be surprised if I ask a stupid question! Just trying to learn.

Cheers!

5% discount code at RockAuto.com - click here for your discount!

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I am sorry lothos, I initially posted the post that you responded to, thinking it was a Northstar, but it was a 4.9, and I edited my post, but NOT quick enough to stop you! :lol:

Yes, on the 93/94 NS, the FPR is in the intake, on the 4.9, its on the fuel rail, like the later Northstars.

By the way, you can check the FPR regulator two way, with the engine OFF and with it ON, look for spitting while the engine is running..

I actually ran out and checked, no dripping fuel with the car running either. Still smells like fuel though, but I was told it should be good.

Also I read on here that you should not turn on the car on a 93/94 N* with the top cover off, in case someone was thinking of trying it :D

Having the top cover off or not makes no difference... It's a beauty cover hold no function what so ever..

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Icons on the climate control? you mean in diagnose mode? I would love to know what to look for. I replaced the isc about 2 years ago because it was surging(not stalling) THe problem got better with this isc before it began to stall. I also replaced the pickup in the distributor because the engine would stall every time i hit the gas... it would also stall if I let it idle like it is doing now. Now I can rev fins but it wont idle.

Yes - you must be in diagnostic mode. Do a search in the archives - I think it is the OFF icon but I am not positive.

I am sorry lothos, I initially posted the post that you responded to, thinking it was a Northstar, but it was a 4.9, and I edited my post, but NOT quick enough to stop you! :lol:

Yes, on the 93/94 NS, the FPR is in the intake, on the 4.9, its on the fuel rail, like the later Northstars.

By the way, you can check the FPR regulator two way, with the engine OFF and with it ON, look for spitting while the engine is running..

I actually ran out and checked, no dripping fuel with the car running either. Still smells like fuel though, but I was told it should be good.

Also I read on here that you should not turn on the car on a 93/94 N* with the top cover off, in case someone was thinking of trying it :D

Having the top cover off or not makes no difference... It's a beauty cover hold no function what so ever..

If you start the engine on a '93/'94 Northstar without the top cover, there is no throttle control and the engine will run wide open... the top cover and intake are an assembly. The '95 and later Northstars have the "beauty cover".

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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It may be a bad closed throttle switch that is integral to the idle speed controller. There is a ton of information in the archives - one of the icons on the climate control panel indicates the state of the closed throttle switch. I can't remember which icon but it will change state when the accelerator is pressed down and when it is released.

Icons on the climate control? you mean in diagnose mode? I would love to know what to look for. I replaced the isc about 2 years ago because it was surging(not stalling) THe problem got better with this isc before it began to stall. I also replaced the pickup in the distributor because the engine would stall every time i hit the gas... it would also stall if I let it idle like it is doing now. Now I can rev fins but it wont idle.

Yes - you must be in diagnostic mode. Do a search in the archives - I think it is the OFF icon but I am not positive.

I am sorry lothos, I initially posted the post that you responded to, thinking it was a Northstar, but it was a 4.9, and I edited my post, but NOT quick enough to stop you! :lol:

Yes, on the 93/94 NS, the FPR is in the intake, on the 4.9, its on the fuel rail, like the later Northstars.

By the way, you can check the FPR regulator two way, with the engine OFF and with it ON, look for spitting while the engine is running..

I actually ran out and checked, no dripping fuel with the car running either. Still smells like fuel though, but I was told it should be good.

Also I read on here that you should not turn on the car on a 93/94 N* with the top cover off, in case someone was thinking of trying it :D

Having the top cover off or not makes no difference... It's a beauty cover hold no function what so ever..

If you start the engine on a '93/'94 Northstar without the top cover, there is no throttle control and the engine will run wide open... the top cover and intake are an assembly. The '95 and later Northstars have the "beauty cover".

I thought he meant the Beauty cover, not the entire top of the intake LOL...

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Clean your mass air sensor with some Mass Air Cleaner and see if that helps.

I don't think the 4.9 has a MAF sensor.

I was working late all week and didnt see the cadillac in the sun until today. I didnt see a MAF sensor... it has a map sensor I think, its like a seperate piece toward the firewall near the intake, looks like a small black rectangle on a bracket mounted about 4 inches above the intake manifold. It has a vacuum line running into it. The car actually runs perfectly when it was cold, the minute it got to operating temp it started doing its thing. I manually actuated the egr valve it almost died, Im assuming this means its ok. I pulled the vacuum line from the fpr and the engines revs shot up about 500rpm(vacuum leak) but this made it run better, it still sputtered alittle bit but it never tried to die. There was no fuel dripping from the nipple but I got a mild fuel odor from it. When I covered the vacuum line with my thumb the car died out completely and I got good suction, so its not clogged. However when I pulled the vac line to the egr there was no suction on it... I was thinking to look for the egr solenoid or whatever but it got too dark. I also noticed when I opened the throttle the isc plunger followed the piece where it contacts the throttle out about 1/2 an inch before it stopped, is that normal? Not sure where to go from here, the fpr had some rust forming on it, seems like its the original one at 130k.

Side note, the exhaust had started to fall apart so I had taken the muffler off after it broke, and I was hearing loud rattling sound from under the car (both before and after I removed the muffler). I think its the catalyst in the cat rattling around, when I had my head under the hood with the engine running I hear it mildly, it seemed to be coming from the bank of cylinders close to the firewall. Am I just hearing the sound from the exhaust manifold or do I have a more serious problem. Could a severely restricted cat be causing the stalling?

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Could a severely restricted cat be causing the stalling?

I think it can. I had a buddy with a Toyota that had a bucking and stalling problem and it turned out it was a plugged cat.

Jonah

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Clean your mass air sensor with some Mass Air Cleaner and see if that helps.

I don't think the 4.9 has a MAF sensor.

I was working late all week and didnt see the cadillac in the sun until today. I didnt see a MAF sensor... it has a map sensor I think, its like a seperate piece toward the firewall near the intake, looks like a small black rectangle on a bracket mounted about 4 inches above the intake manifold. It has a vacuum line running into it. The car actually runs perfectly when it was cold, the minute it got to operating temp it started doing its thing. I manually actuated the egr valve it almost died, Im assuming this means its ok. I pulled the vacuum line from the fpr and the engines revs shot up about 500rpm(vacuum leak) but this made it run better, it still sputtered alittle bit but it never tried to die. There was no fuel dripping from the nipple but I got a mild fuel odor from it. When I covered the vacuum line with my thumb the car died out completely and I got good suction, so its not clogged. However when I pulled the vac line to the egr there was no suction on it... I was thinking to look for the egr solenoid or whatever but it got too dark. I also noticed when I opened the throttle the isc plunger followed the piece where it contacts the throttle out about 1/2 an inch before it stopped, is that normal? Not sure where to go from here, the fpr had some rust forming on it, seems like its the original one at 130k.

Side note, the exhaust had started to fall apart so I had taken the muffler off after it broke, and I was hearing loud rattling sound from under the car (both before and after I removed the muffler). I think its the catalyst in the cat rattling around, when I had my head under the hood with the engine running I hear it mildly, it seemed to be coming from the bank of cylinders close to the firewall. Am I just hearing the sound from the exhaust manifold or do I have a more serious problem. Could a severely restricted cat be causing the stalling?

Not having vacuum at the EGR valve is probably normal at idle - there should be a solenoid that regulates the flow of vacuum to the EGR.

Could a severely restricted cat be causing the stalling?

I think it can. I had a buddy with a Toyota that had a bucking and stalling problem and it turned out it was a plugged cat.

Toyotas break down??? Somebody should alert the news media! According to the media, they last forever - the owners never have to do anything except put gas in them. I heard the Toyota dealers don't even have a service department... :lol::lol::lol::lol::lol::lol:

Kevin
'93 Fleetwood Brougham
'05 Deville
'04 Deville
2013 Silverado Z71

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Toyotas break down??? Somebody should alert the news media! According to the media, they last forever - the owners never have to do anything except put gas in them. I heard the Toyota dealers don't even have a service department... :lol::lol::lol::lol::lol::lol:

LOL :lol:

Jonah

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Toyotas break down??? Somebody should alert the news media! According to the media, they last forever - the owners never have to do anything except put gas in them. I heard the Toyota dealers don't even have a service department... :lol::lol::lol::lol::lol::lol:

LOL :lol:

So, I guess, just pull the cat and see if it still sputters? And to get the egr solenoid to actuate I should pull the vacuum line to the egr and rev the engine? I should then feel vacuum apply?

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Toyotas break down??? Somebody should alert the news media! According to the media, they last forever - the owners never have to do anything except put gas in them. I heard the Toyota dealers don't even have a service department... :lol::lol::lol::lol::lol::lol:

LOL :lol:

So, I guess, just pull the cat and see if it still sputters? And to get the egr solenoid to actuate I should pull the vacuum line to the egr and rev the engine? I should then feel vacuum apply?

As KHE said the EGR is disabled at idle, so the EGR solenoid will not supply any vacuum to the EGR valve. But if you put it in D or R the EGR will be enabled and you will get vacuum from th ehose to the EGR valve. One person can hardly do this test though. :D

The test you have performed with your finger indicates that rather EGR passages are clean than the valve itself is good (it might be).

The saddest thing in life is wasted talent

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SO is the FPR bad or not? it smells like gas but isnt leaking any, I guess I need a vacuum pump top test the egr itself. THere was no black smoke from the tail pipe. I only get some oil smoke in the tail pipe, which developed after my brother drove it 500 miles with a spark knock.... it burns about 1qt every 3k miles, but thatas a different problem.

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SO is the FPR bad or not? it smells like gas but isnt leaking any, I guess I need a vacuum pump top test the egr itself. THere was no black smoke from the tail pipe. I only get some oil smoke in the tail pipe, which developed after my brother drove it 500 miles with a spark knock.... it burns about 1qt every 3k miles, but thatas a different problem.

A quart every 3000 miles is excellent, pay it no attention whatsoever. When you are using a quart every 1000 miles its time to panic. You are doing VERY good

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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SO is the FPR bad or not? it smells like gas but isnt leaking any, I guess I need a vacuum pump top test the egr itself. THere was no black smoke from the tail pipe. I only get some oil smoke in the tail pipe, which developed after my brother drove it 500 miles with a spark knock.... it burns about 1qt every 3k miles, but thatas a different problem.

A quart every 3000 miles is excellent, pay it no attention whatsoever. When you are using a quart every 1000 miles its time to panic. You are doing VERY good

Still got the knock though, but worrying about getting it to idle before getting it to drive:) Got a new cat comming any day now

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YOU have a 4.9, the 4.9 is KNOWN for a #1 main bearing knock, is that what you are getting? The #1 main bearing knock is just a annoying and NOT indicative of a serious problem. Do a search there is a LOT of info on it.

Pre-1995 - DTC codes OBD1  >>

1996 and newer - DTC codes OBD2 >> https://www.obd-codes.com/trouble_codes/gm/obd_codes.htm

How to check for codes Caddyinfo How To Technical Archive >> http://www.caddyinfo.com/wordpress/cadillac-how-to-faq/

Cadillac History & Specifications Year by Year  http://www.motorera.com/cadillac/index.htm

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