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1996 Eldorado ETC
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33 Posts
Discussion Starter #1 (Edited)
96 Eldo ETC, 126,000 miles

EDIT: See Updated Post 5/5/15 for 'current'.

Issue:
-Just started happening within last week
-When sits overnight, the 'first start' is not starting on first effort (See edit:below. it just repeated with less than 12 hour sit time)
-Crank for a 'normal period + several more revolutions', nothing
-2nd time i turn it over, it normally fires and runs fine (sometimes has to go to third start, but typically 2nd effort starts it)
-Cranks fine from that point on, as well as throughout day, so long as i'm starting it such as drive to work, crank at lunch, crank to go home type timing.
-ONLY seems to be doing it when it is sitting 'overnight' (is inside, so no extreme temp issues)
-EDIT: It did it again after about a 2 hour 'sit', so I can no longer say it is only doing it over night.
-It is smooth at idle, be it cold or hot. it pulls strong with no misses or skips.
-Plugs and wires are probably 2000 miles old.
-Only code it has kicked was the 1350/1375 when I sat on the starter for an extended time. I cleared those and they haven't come back, when I just do the routine stated above.


first guess was 'leakdown' of fuel system

-48+/- psi on fuel pressure when Key on, Engine Off, so the fuel pump is charging (EDIT: It does 'drop off some' on fuel pressure gauge, but i don't know what is 'normal' and what is problematic.
-Have checked plugs on ICM
-Have check wiring (albeit, I'm not sure how this can be electrical, but it very well could be anything I suppose?)
-No sign of fuel at Fuel Pressure Regulator (and it was replaced about 2 years ago)

-I pulled injector rail and pressurized. no 'visible' sign of leaking injectors, but this would have to be a VERY small leak. Should I try to figure out how to pull and let it sit for a full overnight cycle somehow?

-I've done best i can to inspect fuel line fittings underhood and fuel filter and see no sign of any fuel or 'condensation'

I only get 'one shot' a day on my 'intial test', and I haven't tried the 'key on, engergize, key off, wait, key on energize, key off, key on, start, when overnight wait.

I'm considering getting a salvage ICM/coil pack and swapping, just to eliminate that as possible cause, but I don't want to just start throwing away money.

EDIT: I just swapped in a salvage fuel rail, FRP and all the injectors, just to eliminate THAT as possible cause. Will be a few hours before i can tell if it made any difference.

This was my late dad's car, in generally good condition so I was trying to keep it going for a while longer. Not at a throw away state by any means, just would like for it to start the way it is capable.

ANY OTHER IDEAS THAT I'M OBVIOUSLY OVERLOOKING?

Thanks, any other ideas?
 

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White Diamond '03 DHS (with DTS floor shift)
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My guess is that the fuel pump check valve is leaking down. I'd leave the fuel pressure gauge on it overnight and see where your pressure is in the morning and then see how long it takes to pressurize while cranking.

One thing you might also try to (most likely) confirm the check valve is to go key on (do not crank) for 3 seconds to energize the fuel pump and pre-pressurize the fuel system. Try that 2 or 3 times (remember, the pump only runs for 3 seconds without a crank signal being detected). If it starts on the first try after that, you can be pretty sure it is the check valve.
 

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1996 Eldorado ETC
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33 Posts
Discussion Starter #3
Quick and/or Stupid Question... I'm assuming the check valve is IN the fuel pump assembly and not a separately serviceable item? i.e. I need to drop tank and swap in a new fuel pump? Thanks,
 

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2002.5 F55 CORSA STS, 2014 Explorer XLT FWD
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Unfortunately, the inlet check valve is in the pump assembly.

If you hook up the test set, turn the key ON, pressure should jump to ~40 psi and stay near there for quite a while.

A leakdown overnight would not necessarily cause long cranks/hard starts: The system does a prime at key ON, the pump runs constantly during start, then latches ON after engine idle comes up to speed.
 

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If your check valve is at fault, it will take long to start if you straight out turn the key to START without waiting at the ON position, but if you follow Ranger's suggestion and pressurize the system (multiple times) before START, it will start like nothing is wrong.
 

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1996 Eldorado ETC
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33 Posts
Discussion Starter #6
I'm ORIGINAL POSTER:

Swapped Fuel Rail, FPR and ALL injectors from a running engine. At first thought it was 'fixed', but that didn't last long and didn't expect it to once I found out the fuel pump has a check valve. Swapped out fuel pump with AC Delco replacement part. Unfortunately NO change and REALLY thought that was going to be the deal. (I also swapped fuel filter while I was under there, again using AC Delco part)

If it isn't in the fuel rail/injectors, and it isn't the fuel pump, does it not have to have a pressure leak somewhere between? Could a quick disconnect be 'loose' after these years?

My 'problem' now and maybe you can help is how to isolate where the leak might be. I'm assuming I need to put the guage on end of each fitting, starting under the hood and working backwards.

It appears the fittings are:

-Fuel pump to pressure line out
-Pressure Line out to fuel filter IN
-Fuel Filter OUT to Pressure Line
-Pressure Line OUT to Fuel Rail IN

I'm assuming a one piece line from fuel filter to underhood, but no real idea.

Seems to me I need something that has a quick disconnect (male for under the hood connection to mimic the fuel rail male and female for the other connections?) on one end to put to the various fuel line ends and a schrader valve on the other end so I can hook my gauge to it. I've yet to find an adapter set up that way. I could cut an old fuel rail apart and try a piece of rubber hose between or go totally crazy and have the line in end and the schrader valve welded together (by someone else), but I can't believe you can't buy the equivalent.

I'm assuming I'm overthinking it, but I assume I have to be getting closer?

Any thoughts?
 

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White Diamond '03 DHS (with DTS floor shift)
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:hmm: I think you have replaced every component in the fuel system. :noidea:
If it where leaking externally you should smell fuel.
 

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1996 Eldorado ETC
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33 Posts
Discussion Starter #8
I agree with your analysis. 'losing pressure' on a fitting? I would think that if it was losing 'pressure' when there was fuel, I'd see or smell some sign of gas. I don't see how it could be leaking 'air only' if it is in a pressurized line. after sitting, key on, key off, key on, key off, key on, start, cranks/runs fine. (and some times can just leave off one of the cycles). it is still going down to anywhere from 0-5lbs overnight. and all the way to 0 if I wait long enough.....

And I appreciate your responses. Even if I'm still stumped, at least it helps to have some input on my 'process'.

Thanks,
 

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White Diamond '03 DHS (with DTS floor shift)
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Well, it is obvious that you have a leak. Since you do not smell fuel, it has to be leaking into the tank or the intake.
Try letting it bleed down, but before you crank it, remove the air filter (or already have it removed). Hold the throttle plate wide open and get you nose in there. If you smell gas, chances are it either the FPR or an injector leaking. If not, then I'd suspect the fuel pump check valve.
 

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1996 Eldorado ETC
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Discussion Starter #10
With the help and guidance of Ranger, I somewhat went 'full circle' back to the first things I checked. I checked the FPR (Again, after no signs of leaking the first time). Indeed, this time, on idle, hose off, it was spitting an ever so slight amount of fuel. I had already gotten a new ac-delco FPR anyway, so I installed. After 2 "12 hour" waits and now one "25 hour wait", it has started fine each time. I never consider anything 'fixed' unless I come back two weeks later and the problem hasn't 'reappeared', but at least it is again starting as it should. And for the 'tracking', this was the 2nd FPR as it was the one on the used injector rail that I swapped in. Current Fix: Replaced Fuel Pressure Regulator

THANKS!
 
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