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The fuel pump went out and I had it replaced along with the screen and fuel filter.  Then when the car got warm it spits,  sputters, hesitates and sometimes dies.  If it dies it does start again right away, sometimes it's a hard start.   If the windows are up i smelled fuel when this happens. I replaced the injectors  2 days ago and thought i had the problem licked but it started the same thing again today. I did not have this issue before replacing the pump. I did not have the windows up today (gorgeous day in So Cal) so I don't know if there was a gas smell like last time. 

The mechanic working on the car is stumped.  Any idea what to do next? 

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Have you checked the fuel pressure regulator?  I don't know this engine, what is this a 4.5L?

Locate the fuel pressure regulator, with the engine idling/running, pull the vacuum hose off the regulator, if it spits fuel, its diaphragm is damaged, replace 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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It is the 4.5. The pressure regulator was checked and I was told it's working fine. The only problem there is that when it idles it idles fine.  When I step on the throttle it will act up.  I'll have to see if it will miss when im in park and rev it. 

Thanks for the reply! 

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What is the fuel pressure at idle and at 2,000 rpm?  This is important.  Keep in mind that just because the pump is new that there is a possibility that it is defective.  What make of pump did they install do you know?

A fuel smell is usually an indication that the regulator is bad, but you did say that this happened after the fuel pump went in correct? 

Check the fuel filter to make sure they snapped the quick disconnects solidly.  No leaks around the fuel filter?  Get under the car and inspect for leaks in front of the fuel tank in the center (left to right center). 

Can you check for diagnostic codes? Are there any check engine messages?


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 bought an Autobest pump from Rockauto.com.  Will it make a difference if it's not under load at the 2k rpm? The guy who installed pulled the tank a second time to make sure al the connections were good. He's going to get a fuel pressure gauge with a long hose so he can check it while I'm driving. It wouldn't surprise me if the pump was bad. The strangest thing happen to my vehichles. As for codes it's not throwing any..

But it gets me to and from work with a minimum of fuss until I can get this figured out.

Thanks for the help.

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It won't make a difference if its under load.  You need the fuel pressure at those two points.  

Based on this it looks like you bought an economy pump.  Given that they are discussing the pump diameter, strainers, flanges and that the tank has to be dropped to replace it, I would have gone with an OEM AC DELCO or Delphi unit and not risked quality or fit issues.

Screenshot_20200727-051057_Samsung Internet.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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2 hours ago, herownbagger said:

Unfortunately with the covid thing I'm tight on money.  If I have to replace it I will do that.

I hear you, but there are places to skimp and places not to skimp, dropping the tank is a pain a job you don't want to do twice.  Please let us know what the pressures are, look over the regulator again also.

This is your regulator, start engine, pull vacuum hose off, hold piece of brown paper bag in front of nipple, rev engine, if it spits any fuel, its bad.

Also, check to see if you have a fuel pump relay, I am pretty sure you have one, if it has burned contacts or is corroded you can get pump motor intermittents, high resistance, etc.  It might have been the problem from the beginning.  

Screenshot_20200727-140047_Samsung Internet.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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So he doesn't have a fuel pressure gage but he is going to get one. 

But he checked the fuses and the relay and it's looks good.  He pulled the vacuum line off the regulator and did the paper bag thing and no fuel spitting .

He looked the  pumps over before he put the new one in and they were the same fittings. 

Anything else you can think of?

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Report back your fuel pressure

Tell me your history, why did you replace your fuel pump?, you said it died?, explain.  

If you have no fuel pressure gauge how did you know it died?

Fill us in on the history.  You might be experiencing the same problem you experienced before the pump was changed.

How did he test the relay?, did he test it with a load 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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So I've only had this car since Feb. A friend gave it to me after my old car gave up the ghost.  It only had 56000 miles on it and it's in almost perfect condition. So with that amount of miles it hasn't been driven much and now that it's my daily driver it's not liking this :)

the guy working on it is a mechanic at Honda but he's a younger kid, in his 30s so he's not too up on the older stuff. I have talked to my 2 brothers, my old mechanic from Las Vegas and the guy I got the car from. They didn't have any ideas. They're all older guys.

We did replace the fuel pump. It died on the way home. He made sure it was the pump by spraying starter fluid in it and it started. So I also replaced the strainer and the filter. After replacing it it started this spitting and sputtering and Jonah wasnt sure what it was. He dropped the tank again to check the connections and all was good. Still did it. So i took it to a shop. They said it was an injector stuck open. They said the fuel pressure was fine. Well, at $1500 to fix i brought it home,, ordered the injectors and Jonah put those in. It was just injectors, no connectors.It ran fine for about 25 miles then it started again.

He just looked at the relay. It was a bit dusty so he cleaned it off. He didn't take a meter to it

I want to mention again that I smell gas when it does start spitting and sputtering. I live in San Diego so half the time I have the windows down. I don't smell the gas when they are down. I don't know if this helps at all.

One thing i should tell you is that i have the weirdest things happen to my vehicles. So if you have something out of left field let me hear it. FYI I had a pick up that when the fuel pump p went out in it it would idle but do this spit and sputter under load and on my motorcycle when the rear brake light switch failed it failed in the closed position even tho they usually fail open.

In researching this issue i did see where the fuel lines were a recall and they were replaced with metal ones.

Again thanks for all the help.

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I am very busy and will read the above and reply in detail.

But, looking at a relay means very little.  The fuel pump constantly draws power, it clicks on every time the key is turned on. A defective pump can draw excessive current damaging a relay.   There are contacts in there that can pit and burn over time from increased resistance.   Replace it with a known good relay.  Even swap in the same relay from a non critical system as a test.  BE SURE TO WATCH THE RELAY'S ORIENTATION, ONE SIDE IS POWER, THE OTHER LOAD.  Watch for corrosion on contacts and sockets in a car that old.  

We need fuel pressures to move forward.


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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@herownbagger

What is the status, did you hook up a fuel pressure guage and check the relay?

One other thing comes to mind, consider that the exhaust is restricted, the CAT can self destruct and clog the outlet.  Do you hear any rattling when the engine idles?

I had a clogged CAT on a 91


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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