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Otten33

Cadillac Deville crank but no start

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That is exactly where I want wanted you to get the fuel from, the fuel rail, through the fuel pressure gage!   You can't do that?   That does not sound right, but you get 38 PSI at the fuel rail schrader valve?

What is the fuel pressure when you crank?

When you pull the intake check for cracks, check the valve in the intake behind the power steering pump.  That is a valve that opens in the event of a backfire in the intake to prevent the intake from blowing up and hurting shrapnel.  If that valve is stuck open you won't draw air/fuel mix

 


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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Ok I pulled plenum off and sure enough there was a 5 inch tear.  I will order a new one.  Don't see how it could cause a no start situation but at least it will be fixed.  I pulled gas from fuel rail but barely any even though I show 38 PSI.  I have pressure just not volume.  Only can draw like an ounce through the bleeder hose.  Not sure why it doesn't drain like you guys think it should.  I did happen to brake or it was already broke a sensor on top of throttle plate.  Not sure what it is.  It is 38 PSI when cranking also.  Did notice a few fuel injectors were fouled even though I had cleaned them before installing last time.  I sprayed them with brake clean and oiled the o-rings last time.  Do you think the fuel injectors are not spraying gas into intake?  I will go out and check for valve in the intake manifold later tonight.

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Would gas from fuel rail lite up right away if there were water in the gas?  Because I lite it on fire and it went right up like normal gas does.

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A torn plenum boot will cause the air to be pulled from there rather than the TB.

Causes multiple issues. Lean conditions, misses, bucking, and possibly no start


GM FAN FOREVER

Nice, clean, luxury= fine automobile

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A 5 inch crack is easily enough to cause a no start.  Good find.  

Fix the sensor you broke.

Lets see what happens after you replace the plenum.

For future reference don't mess with the injector tips.


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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Hopefully that's my issue then.  I won't get part till end of the week.  So you don't think I should try and clean fuel injectors while I have them out?  Plenty of YouTube videos showing how to do it.  Any ideas as to the volume of gas I'm not getting?  Way to measure it?

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23 hours ago, Otten33 said:

Hopefully that's my issue then.  I won't get part till end of the week.  So you don't think I should try and clean fuel injectors while I have them out?  Plenty of YouTube videos showing how to do it.  Any ideas as to the volume of gas I'm not getting?  Way to measure it?

Personally I never try to clean injector tips. The best thing you can do is to leave them alone and use Techron fuel system cleaner that's the only cleaner I would use. The injectors are not causing you're no start condition. It very well could be that the low flow that you're experiencing is related to your gauge. You do have 38 PSI. Logan is of the opinion if 38 PSI is low and that may be a problem. But let's wait to see what happens after you replace the plenum that is the number one problem right now.


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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Ok so I'll leave fuel injectors alone.  I do have 38 PSI but very little volume when I use the button on fuel pressure gage.  Very little fuel drains out the bleeder hose.  I read that modern cars rely on both pressure and volume to start.  What do you guys think?  Also I haven't checked spark on back coils because I'm not sure how to take cover off.  Do I need to remove air pump thing that sits on top?  I would think so.

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4 hours ago, Otten33 said:

Ok so I'll leave fuel injectors alone.  I do have 38 PSI but very little volume when I use the button on fuel pressure gage.  Very little fuel drains out the bleeder hose.  I read that modern cars rely on both pressure and volume to start.  What do you guys think?  Also I haven't checked spark on back coils because I'm not sure how to take cover off.  Do I need to remove air pump thing that sits on top?  I would think so.

When you push the button on the gage is the key on?


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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Also spark seemed weak in the front but maybe I'm am expecting too much.  I can't remember but I would say no.  Try it with key on?

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Of course, once the key is off those 38 psi just equalize and poof, that is it....

With the key on, the pump will push fuel and you will easily fill a jar quickly.  


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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Makes sense.  I'll try it once i get the plenum installed and everything back together.  Any idea what sensor sits on top of the throttle plate?

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31 minutes ago, Otten33 said:

Makes sense.  I'll try it once i get the plenum installed and everything back together.  Any idea what sensor sits on top of the throttle plate?

Post a photo of it


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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On 4/9/2018 at 6:24 PM, BodybyFisher said:

That is exactly where I want wanted you to get the fuel from, the fuel rail, through the fuel pressure gage!   You can't do that?   That does not sound right, but you get 38 PSI at the fuel rail schrader valve?

What is the fuel pressure when you crank?

When you pull the intake check for cracks, check the valve in the intake behind the power steering pump.  That is a valve that opens in the event of a backfire in the intake to prevent the intake from blowing up and hurting shrapnel.  If that valve is stuck open you won't draw air/fuel mix

 

I didn't see a valve.  Saw a hole.  You were talking about the side the hose comes out of right.  The left side of the intake when looking at it.

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Glad to hear it!


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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Ok installed MAP sensor and started the car.  She started!  Lol for about 3 seconds then died.  It would not start after that. I primed fuel system before attempting any starting.  Checked fuel pressure at it was about 37 PSI.  Tried to bleed gas and nothing came out.  This time I made sure the car was one.  Tried fuel pressure test a couple more times and fuel pressure fell to 30 PSI and stayed.   Seems to me like the car is not getting enough gas.  Fuel filter is new.  Should I be looking into the pump?

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YES, but I would check power at the pump, we will need to get you a diagnostic.

 @Logan  Is there a test or load test that can be done at the pump to confirm that adequate power is being delivered to it?  The pump is fed through a relay, correct?

If I recall, earlier in this thread Logan mentioned that the connector at the fuel pump can melt from overheating and oxidize/corrode.  I have seen this in an 02 Chevy pump.  @Otten33 without having to go back in this thread, I think you checked the connector for condition, overheating and corrosion, correct?

If the relay contacts are burned, you will get intermittent power/current at the pump.

I don't want you to buy a new pump only to find out that you have compromised current supply.  

You are getting close!  Good persistence 

 


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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 checked connectors.  They looked fine but I did notice they were dusty and didn't necessarily look new considering a new pump was put in only 2 months before and the guy lived in the city.  Who knows if guys mechanic actually put in new pump or not or reused connectors.  Is there a way to check with multimeter?  Am I checking harness on pump and fuel relay?

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That is very interesting

If in fact the pump was replaced, then we need to check power.

Ill check my manual for a diagnostic but my manual is a 96.  

@Logan will see this in the morning and may have an idea.  I get a feeling you may have a power issue, assuming the pump was changed.  That the pressure dropped so low tells me you found the problem.

Hang in there.


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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 was thinking based on what you said about the pump and connectors being dusty that he replaced the pump, it made no difference and the old one was put back in.   What do you think?

It is possible that because the connectors looked good, that he didn't replace them?


Pre-1995 - DTC codes OBD1  >> http://z-cut.de/US/dtcobd1.html

1996 and newer - DTC codes OBD2 >> http://carprogrammer.com/Z28/PCM/OBD2/On-BoardDiagnosticTroubleCodes(OBD-II).mht

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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