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What's wrong with my car? 97 STS - Something with the fuel system?


mistermau

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Hi Folkz.

I've got a 97 STS, with the replacement fuel rail.

The issue is...I got the fuel rail replaced around the same time I hit a possum. (darn possum)

As far as I can figure, right about that time, the car starting very roughly. It's just gotten worse since then, and this was maybe a year ago!

The engine cranks and cranks before it finally starts. This happens both when the car is cold, and when it's warm. If the car has been sitting for more than 10 minutes or so, then I get the problem. It can crank for 20 seconds easily.

When it finally starts, I usually get a big plume of "gassy" smoke.

Letting the car sit with the switch on for a while before I actually try to start it doesn't work, either. I've let it sit this way for a minute or more.

I feel like I'm rambling here.

Any ideas? I can't really afford to give a shop or the dealer a "free pass" to go replacing stuff willy nilly.

-Mau

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Hi Folkz.

I've got a 97 STS, with the replacement fuel rail.

The issue is...I got the fuel rail replaced around the same time I hit a possum. (darn possum)

As far as I can figure, right about that time, the car starting very roughly. It's just gotten worse since then, and this was maybe a year ago!

The engine cranks and cranks before it finally starts. This happens both when the car is cold, and when it's warm. If the car has been sitting for more than 10 minutes or so, then I get the problem. It can crank for 20 seconds easily.

When it finally starts, I usually get a big plume of "gassy" smoke.

Letting the car sit with the switch on for a while before I actually try to start it doesn't work, either. I've let it sit this way for a minute or more.

I feel like I'm rambling here.

Any ideas? I can't really afford to give a shop or the dealer a "free pass" to go replacing stuff willy nilly.

-Mau

Sounds pretty much like a bad FPR - Fuel Pressure Regulator. Make a search you'll find a lot of info on that. Besides, there were several posts concerning failing spark plug wires right after fuel rail replacement has been performed. You may have one or both of mentioned problems. Start with the FPR.

The saddest thing in life is wasted talent

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HHmmmmmm...I suppose it could be either of those things.

I've been admittedly negligent with the regular services. (none of them have been done in the last 90K or so miles).

I'll see how much the shop will charge to change out the FPR, and the plugs and wires for me.

Or is this something I can manage myself? I'm not the MOST mechanically inclined guy, but I'm no "Ken Doll" either.

I'd say a solid 5 on a scale of 1-10?

-Mau

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The clue is a bunch of gassy smoke. That smacks of leaking injectors.

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Okay, it's from left field, but here I go . . . . .

While I'd be inclined to pay closer attention to the above remedies, you might want to consider the fuel pump relay.

In the event the fuel pump relay fails to energize the fuel pump, a secondary path exists to "ignite" the fuel pump. After the oil pressure reaches a certain point (during cranking), a contact closure on the oil pressure switch will provide voltage to the fuel pump to get you going.

The result? You crank its brains out and then it finally starts. Just a thought.

Unplug and then reseat the fuel pump relay in the engine compartment just to clean its contacts. Yeah, I know, . . . . . a long shot.

Regards,

Warren

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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VERY thought-provoking, Warren. Indeed.

Can anyone tell me where the fuel pump relay resides? Is it possible that rather than needing the contacts cleaned, the relay itself is bad?

What could cause a bad relay? What could dirty the relay contacts this much? Would this relay problem account for it starting immediately within 10 minutes or so?

Very interesting. I suppose I can do this when I change out the FPR?

-Kamau

Okay, it's from left field, but here I go . . . . .

While I'd be inclined to pay closer attention to the above remedies, you might want to consider the fuel pump relay.

In the event the fuel pump relay fails to energize the fuel pump, a secondary path exists to "ignite" the fuel pump. After the oil pressure reaches a certain point (during cranking), a contact closure on the oil pressure switch will provide voltage to the fuel pump to get you going.

The result? You crank its brains out and then it finally starts. Just a thought.

Unplug and then reseat the fuel pump relay in the engine compartment just to clean its contacts. Yeah, I know, . . . . . a long shot.

Regards,

Warren

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The reason I suggested it was from "left field," was simply because the relay fails so infrequently. Nevertheless, it's something to look into. :D

Regards,

Warren

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There is no means of avoiding the final collapse of a boom brought about by credit expansion. The alternative is only whether the crisis should come sooner as the result of a voluntary abandonment of further credit expansion, or later as a final and total catastrophe of the currency system involved. - Ludwig von Mises

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The clue is a bunch of gassy smoke. That smacks of leaking injectors.

I was going to let this go. But if someone else reads it, they might think that using STP gas treatment is sanctioned by this board. It is NOT. Especially STP gas treatment. We do not believe in injector cleaner and believe that it can damage the windings on the fuel pump and the injectors. This came directly from the guru.

You often quote from the FSM. If you read the FSM you will see that there is an injection cleaning procedure, disabling the fuel pump, using a pressure attachment to the fuel rail using GM upper engine cleaner while running the engine till it stalls, then letting it sit.

Pre-1995 - DTC codes OBD1  >>

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

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VERY thought-provoking, Warren. Indeed.

Can anyone tell me where the fuel pump relay resides? Is it possible that rather than needing the contacts cleaned, the relay itself is bad?

What could cause a bad relay? What could dirty the relay contacts this much? Would this relay problem account for it starting immediately within 10 minutes or so?

Very interesting. I suppose I can do this when I change out the FPR?

-Kamau

Okay, it's from left field, but here I go . . . . .

While I'd be inclined to pay closer attention to the above remedies, you might want to consider the fuel pump relay.

In the event the fuel pump relay fails to energize the fuel pump, a secondary path exists to "ignite" the fuel pump. After the oil pressure reaches a certain point (during cranking), a contact closure on the oil pressure switch will provide voltage to the fuel pump to get you going.

The result? You crank its brains out and then it finally starts. Just a thought.

Unplug and then reseat the fuel pump relay in the engine compartment just to clean its contacts. Yeah, I know, . . . . . a long shot.

Regards,

Warren

Warren brings up a very good point. The "starting immediately within 10 minutes or so" could be an intermittent bad relay (if that is possible). Relay is located in the fuse block under the hood (drivers side wheel house I believe).

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Hi Folkz.

I've got a 97 STS, with the replacement fuel rail.

The issue is...I got the fuel rail replaced around the same time I hit a possum. (darn possum)

As far as I can figure, right about that time, the car starting very roughly. It's just gotten worse since then, and this was maybe a year ago!

The engine cranks and cranks before it finally starts. This happens both when the car is cold, and when it's warm. If the car has been sitting for more than 10 minutes or so, then I get the problem. It can crank for 20 seconds easily.

When it finally starts, I usually get a big plume of "gassy" smoke.

Letting the car sit with the switch on for a while before I actually try to start it doesn't work, either. I've let it sit this way for a minute or more.

I feel like I'm rambling here.

Any ideas? I can't really afford to give a shop or the dealer a "free pass" to go replacing stuff willy nilly.

-Mau

Pull the vacuum hose off of the Fuel Pressure Regulator and see if you have fuel present.

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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VERY thought-provoking, Warren. Indeed.

Can anyone tell me where the fuel pump relay resides? Is it possible that rather than needing the contacts cleaned, the relay itself is bad?

What could cause a bad relay? What could dirty the relay contacts this much? Would this relay problem account for it starting immediately within 10 minutes or so?

Very interesting. I suppose I can do this when I change out the FPR?

-Kamau

Okay, it's from left field, but here I go . . . . .

While I'd be inclined to pay closer attention to the above remedies, you might want to consider the fuel pump relay.

In the event the fuel pump relay fails to energize the fuel pump, a secondary path exists to "ignite" the fuel pump. After the oil pressure reaches a certain point (during cranking), a contact closure on the oil pressure switch will provide voltage to the fuel pump to get you going.

The result? You crank its brains out and then it finally starts. Just a thought.

Unplug and then reseat the fuel pump relay in the engine compartment just to clean its contacts. Yeah, I know, . . . . . a long shot.

Regards,

Warren

Warren brings up a very good point. The "starting immediately within 10 minutes or so" could be an intermittent bad relay (if that is possible). Relay is located in the fuse block under the hood (drivers side wheel house I believe).

Likely the system is still under pressure in 10 minutes. It may be just enough to start the engine with the fuel pump relay out of loop.

The saddest thing in life is wasted talent

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Well, THAT was easy.

Pulled off the vaccum line, turned the key to ON, and by the time I got back out of the car, and around to the front of the car, there were definitely drops of fuel to be seen.

Where is the cheapest place to fine one of these. In the Atlanta, area?

How much will I overspend if I just go to the dealership?

It feels great to be solving this after so long! I'll still look into changing the plugs and wires, though.

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Easy to do, just a clip holds it, you can try the dealer (more $$) or send www.gmotors.com a quote request, I think mine was $42.

Pay attention to the o-rings, use white lithium grease and make sure they are seated properly, there are two. Make sure you get the old o-rings out

Here is a photo of mine, for a 96, Mike

post-2998-1153348834.jpg

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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No, if you have a fuel pressure gage, they have a pressure release button that will allow you to release the 'system' pressure. without that, you will need to slowly release pressure into a can of some sort, if you can do so. I do believe that its the same fitting as the old R12 AC charge tap you could use one of those placed in a can. Sears sells reasonably priced fuel pressure gages. Mike

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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One more question...

I did try to release the pressure in the rail before I started, but there was no pressure in the line after the car sat all night and all day.

Does this further support the "bad FPR" conclusion?

Possibly. Could also be a bad check valve in the pump allowing fuel to bleed back into the tank overnight. Not a big deal as long as you have enough running pressure.

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One more question...

I did try to release the pressure in the rail before I started, but there was no pressure in the line after the car sat all night and all day.

Does this further support the "bad FPR" conclusion?

Wow I just read Rangers reply to this, I totally misread your post, you said there was NO pressure, in the line, I read that there WAS pressure in the line after sitting, sorry.....

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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Just FYI. The GM service manuals indicate that the fuel system should hold pressure overnight etc.

Yeah right...I dont think I have ever seen a GM system hold fuel pressure for more then 30 minutes max. Just FYI.

As for FPR's. I remember one GM Quad 4 we worked on. Total FPR failure. This baby had like it's own 30 psi direct fuel line into the intake. Very interesting red hot exhaust system.

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  • 3 weeks later...

Hi Folkz.

I've got a 97 STS, with the replacement fuel rail.

The issue is...I got the fuel rail replaced around the same time I hit a possum. (darn possum)

As far as I can figure, right about that time, the car starting very roughly. It's just gotten worse since then, and this was maybe a year ago!

The engine cranks and cranks before it finally starts. This happens both when the car is cold, and when it's warm. If the car has been sitting for more than 10 minutes or so, then I get the problem. It can crank for 20 seconds easily.

When it finally starts, I usually get a big plume of "gassy" smoke.

Letting the car sit with the switch on for a while before I actually try to start it doesn't work, either. I've let it sit this way for a minute or more.

I feel like I'm rambling here.

Any ideas? I can't really afford to give a shop or the dealer a "free pass" to go replacing stuff willy nilly.

-Mau

I had the problem and the nice guy at the dealership told me to change the fuel pressure regulator. You can find it by following the fuel line (rail). mine was on the left side,,, start at the master cylinder and look towards the center of the engine,,, find the fuel rail and you should see the regulator. Hope that works.

Bernie

Hi Folkz.

I've got a 97 STS, with the replacement fuel rail.

The issue is...I got the fuel rail replaced around the same time I hit a possum. (darn possum)

As far as I can figure, right about that time, the car starting very roughly. It's just gotten worse since then, and this was maybe a year ago!

The engine cranks and cranks before it finally starts. This happens both when the car is cold, and when it's warm. If the car has been sitting for more than 10 minutes or so, then I get the problem. It can crank for 20 seconds easily.

When it finally starts, I usually get a big plume of "gassy" smoke.

Letting the car sit with the switch on for a while before I actually try to start it doesn't work, either. I've let it sit this way for a minute or more.

I feel like I'm rambling here.

Any ideas? I can't really afford to give a shop or the dealer a "free pass" to go replacing stuff willy nilly.

-Mau

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If you change your FPR make sure you get an OEM FPR. I tried to get one from NAPA for my 94 Concours and it just would not fit. Then I bought one from Advance and it lasted 1 year then spewed gas like a whale. Finally I put my old one back in and it is still working after 3 years. Go to the dealership and just ask if they can do better on the price. Mention that you could get it online cheaper and they might match it. I usually get all my parts from my local dealership at a discounted rate just because I ask.

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