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Car will only start with starting fluid on cold startup, runs fine, and starts fine when warm

My 2002 Oldsmobile Alero (3.4L V6) has developed this issue where it will only start with starting fluid when it is cold, but once it starts it runs normally, and it will start up just fine if it is still warm. It feels like it still has all of the power it had prior to this issue, and it handled my 20 mile drive to work just fine. There are no new engine codes or anything like that.

I do live in Iowa, so when I say cold start, we’re talking single digits to low teens.

If I crank it without starting fluid in when it’s cold, it sounds like a normal crank, but the engine doesn’t feel like it’s getting close to turning over. As soon as I use the starting fluid, it’ll chug for a second and then fire up.

How long do you crank it? Just a couple of times and then you go to the starting fluid?

Maybe the fuel pump is weak and it needs a shot of starter fluid to build up enough voltage to start the car. I’d start there. Test that with a fuel pressure gauge. Turn the key to run, but not crank and see if the pump builds the correct pressure. It should already have pressure when you hook the gauge up, if it doesn’t, the pump or an injector is leaking. Crank it and see what happens to the pressure, if it drops, the pump’s probably bad. If you shoot in a bit of starter fluid the the pump pressure builds to the correct or low end of the spec, it may be a bad regulator or bad pump.

If pressure is OK, I’d start with a bad air intake temp sensor, or bad coolant temp sensor. If the coolant temp gauge is not reading correctly, I’d go straight there.

Give that a try and post back.

The next time you go to start the engine cold, turn the ignition switch to the run position so the dash lights come on for two seconds, and then turn the ignition switch off.

Repeat this a half dozen times and then try starting the engine.

If the engine starts right up, it points to a problem with the anti drain-back valve on the fuel pump assembly.



@Mustangman I gave it a good long while the first time I tried it, and it didn’t sound like it was even starting to catch. I am waiting for the car to cool down right now to test the pressure when it is cold. When it’s warm, it jumps right up to spec and it doesn’t seem to decrease with time.

@Tester I tried this when I first had this problem, because I was stranded without a way to start the car, and it didn’t seem to help at all. You can hear the pump prime and it sounds healthy when you do this.

Cold starts requires considerably more gas be injected than warm start. The computer gets the air intake and coolant temp from its sensors, and uses that to determine how long to pulse the injectors during cranking. It assumes the fuel pressure is correct, and the injectors spray as much as they should for a given pulse interval time (i.e. they are not clogged). Cold starts also require a healthy spark, good compression, and robust cranking.

Where to begin, who knows? But something is wrong with something in that list. Since a faulty temp sensor usually throws a code, I’d probably take a look at the spark quality first, then check the fuel pressure. After that, check the compression.

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For what it’s worth . . .

I’ve worked on vehicles which wouldn’t start without ether

yet once running, they’d stay running. You could leave them running all day and they wouldn’t stall. You could drive anywhere under any conditions, and they wouldn’t stall

But they wouldn’t start without ether

A fuel pressure gauge key on engine off confirmed the fuel pressure was a tad low, just below minimum specs. Not enough to start on its own, but enough to keep the engine running.

And the fuel pressure while running was so close to normal, that there were no driveability problems, and no fuel trim issues.


So I tested the fuel pressure after letting the car sit overnight, and when I turn the key on, the pressure jumps right up to spec, but then it slowly looses pressure (I’d guess 30-45 seconds to reach 0). Again this morning, similar to what @db4690 was describing, once it goes, it goes just fine.

The residual fuel pressure should take 15-20 minutes to bleed down to zero.

If it only takes 30-45 seconds, there’s a problem with the anti drain-back valve on the fuel pump.


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With that being said, is that a major problem that means I need to replace the pump soon before it totally fails, or does it just mean I’ll need to start the car with starting fluid until I replace the pump?

This is just me.

But when a component begins to fail where it becomes doubtful, I replace it before it leaves no doubt.


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Sounds like this one is solved, more or less. I remember the garbage pickup in my mountain village showed a coolant temperature of -40, though in this case it would seem it would run richer not less rich. But, yes, in cases like this get a real time scanner on it and check the temps to see what they are doing. The problem is most folks don’t have a real time scanner.

That garbage pickup, where the coolant temperature showed a value of -40 . . . that sounds like the sensor was either unplugged or open circuit

In many situations, the pcm is programmed to recognize certain values as irrational, and use default values instead

For example, “surface of the sun” and “north pole” would in many cases be rejected as irrational by the pcm, and default values would instead be used

That is the problem with not having access to software. On military self-test, we had the software and it helped a lot. Of course, the car stuff is protected as proprietary, and I guess that makes sense in a commercial environment.

The pickup does start and run, though not well, but it also had a second faiure, something to do with crankshaft timing, but I forget now.

I told the driver that it could be a bad connection or broken wire, or a bad sensor. But, the town doesn’t have enough money for repairs. Funny how the town fathers and mothers (in this case since a woman is president this 6 year cycle) always get paid but can’t find money to fix the garbage truck…

When I was in the apprenticeship, decades ago, we did have engines on test stands, but they were removed from very old vehicles which were being scrapped. We welded the test stands and the exhaust system very robustly, but the engines themselves were “yesterday’s news”

The exact opposite of modern technology

That said, auto technology wasn’t evolving very rapidly at the time

Some of our instructors were very sharp, but it was literally impossible from them to teach us anything more than the very basics, because there literally weren’t any modern vehicles for us to learn on. It’s a long story . . .

“Town fathers and mothers” . . . is that something like an elected council?

The muncipio (much like our counties) president is elected. Now, since there is a lot of money coming in, it is very competitive. My wife’s grandfather many decades ago was president (each term 6 years, I think) three times. In those days, there was no money so if he wanted a project he dug into his own money, so they loved him as president. A descendant of the Moctezuma Emperors, he has in those days a lot of land so there was money.

They call the whole leadership body the Ayuntamiento, but I am not sure if more than the president is elected. The rest may be appointed by the president, not sure. I need to ask someone.

Speaking of old technology, some years ago someone posted a magazine article on an electronics test station. A high school automotive instructor knew someone with an old 1924 car, I think it was a Buick. He wanted to show his students how much cleaner the new cars are, so he borrowed that old car to show them.

To his total surprise, IT PASSED SMOG TESTS, just tuning it up by ear as folks used to do.

The explanation they came up with was the old, slow moving pistons had time to burn it all up. I sure cannot speak with any expertise. But, we couldn’t go back to that technology, because it simply was not efficient enough for modern rules.

@irlandes post reminds me that I need to resume listening to my Learn Spanish audio CD’s. I was gung ho after listening to the first 3 CDs, thought I was pretty much beginning to become a Spanish listener/speaker. I was sure I could speak and listen well enough to meet people, ask them where they are from, which way to the bar, etc. Then I decided to test how well I could understand real life Spanish, so I switched to a Spanish language station here that was broadcasting some kind of competitive athletic program. I couldn’t understand a word the announcers were saying … lol …

I had a classmate in high school; a judge’s daughter. She studied French in college. Then, she went to Paris to practice her French, and could not understand anyone. :smiley:

I also have a hard time understanding radio or TV Spanish. One on one with Mexicans, I can get along really well. I also have stopped going with my wife to her church. I do not understand the sermon, so I sit there admire “Bathsheba”. Sorry but I am not going to explain that. :smiley:

I know I’d have difficulty in Paris, my French teacher in high school was from Quebec, so I learned Quebecois French as opposed to Parisian French…

So I replaced the fuel pump, and I’m still experiencing the same issue…

As an addendum, now when I hook a pressure gague up, the pressure drops much slower (probably would take 5 or so minutes to drop all the way), but it does still drop, and I still have the same issue with starting.