Car Trouble - Hard Start

asechrest

asechrest

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asechrest
Requisite background info:

The car: My significant other's 2005 Chevy Malibu V6. 130k miles. She has not kept up with maintenance, and I haven't done a good job of helping her do so.

Me: Very inexperienced working on cars, but trying/willing to learn. I have a floor jack (Costco sells a great one for less than $100) and a nice set of regular tools. The most I've done on my own car (2003 Corolla) is oil changes, tire rotations, break pad replacement (still working up the guts to do the rear drum brakes), and installing new front struts.

The issue: The car frequently has trouble starting; once a day at least. I believe the classic term for the issue is "hard start." It's not a battery issue (recently replaced) and the engine turns over fine. It just has difficulty "catching." Pumping the pedal while cranking seems to help, but it's possible I'm tricking myself into thinking so. The engine will always start after cranking a bunch of times. Occasionally, the engine will die right after starting. Giving it gas after starting seems to prevent it from dying. If you let it die, it always starts right back up again. It never dies during regular use.

So...I know a bunch of you are real sharp with engines, and it's decidedly not my forte. Anyone care to come up with some ideas, and perhaps an order in which I should try them? As I mentioned at the top, we've not kept up with maintenance, so I'm fully prepared to hear "change the damn original spark plugs" from a bunch of you. :D
 
First thing, plug into it and see if it has raised any codes. You're seriously wasting your time if you don't start with that. Plenty of places can do it for you for free.

If that turns up nothing I would be throwing a pressure gauge on the fuel rail to see if it is coming up to the spec and to see if it's holding that value. Sometimes a slow leak here will cause those hard starts. If it isn't holding I'd probably start with yanking all the injectors to put new o-rings on them.

Once again though -- start with looking for codes.
 
Start with cleaning your injectors, mass airflow sensor, and throttle body
 
Start with checking for codes, as Jesse suggested. The car may already know what's wrong with it, so you may as well ask.

That being said, there are many, many reasons for hard starts, especially on a car with 130K that's been less-than-perfectly maintained. Here are a few possibilities off the top of my head.

Fuel problems in general (weak fuel pump, clogged fuel filter, dirty fuel injectors, leaky seals around injectors...).

Ignition problems in general. Change the spark plugs, for crying out loud! Also look carefully at the wires. Bad wires will usually cause some sort of code (misfire, etc.), but not always.

Dirty air filter.

Clogged cat.

Maybe I can think of more after coffee...

-Rich
 
Good suggestions up front. You have to read the codes, as everything that engine does is controlled by the computer which, in turn, requires good data from the various sensors, including mass airflow, coolant and air temperature, throttle position, crank position, and many more.

Do the spark plugs - a no-brainier, never wasted time.

How does it run, once started and warmed-up? And, how is gas mileage? That car should easily yield high twenties on the highway, probably thirty, and around Twenty mpg in reasonable city driving.

One thing for sure- that engine is a rock-solid unit, and if it is operating reasonably normally, you should expect it to start at the touch of the key, hot or cold.
 
I agree. Read the codes, but do NOT take them as gospel. They are a hint -- in a post 1996 car, a specific hint, but nevertheless a hint. Always confirm faults before replacing stuff.

Hard starts don't often trip codes without setting the MIL, but they can. Once you find out the codes are either absent or don't tell you much (like misfire on #4), check the following:

1. Pull each spark plug in turn and inspect carefully under a bright light and hand lens. Are they carbon fouled? Oil fouled? Bright white? Green? A light tan color on the insulator is normal. Bright white squeaky clean indicates a coolant leak into the cylinder (not necessarily a head gasket on a V6). Check the gaps as well, and look for cracks or evidence of arcing (black ash tracks along the insulator). Disable the injectors by disconnecting their harness, run a jumper wire from the loose spark plug threads to a grounded surface, and crank the engine to see the spark. Should be nice solid blue/white. Red/orange is weak. I prefer not to hold the spark plug by hand against the intake manifold just in case the wires arc. That kind of spark isn't dangerous (very low current), but it's unpleasant to get zapped. Something else I like to do is run a grounded probe (held by a nonconducting pliers!) around the spark plug wires while idling. If that makes any change to idle, you have bad wires. Do the same thing with the ignition coil pack.

2. If you can, get a SMALL flashlight and crank the open cylinder to TDC by hand, and inspect the top of the piston. A little carbon coating is OK (but wind the thing up to high RPM a bit more). An oil spot in the center with clean edges is bad news (blow-by). Sparkly clean all over is bad news (coolant burning).

3. Check the FUEL PRESSURE REGULATOR. Hard starts accompanied by reduced (not necessarily poor) mileage can be caused by a blown vacuum-powered fuel regulator. This is an extremely simple test. Run the engine for a bit, then stop it. Pull the vacuum line off the regulator. If it drips liquid fuel out of the line or regulator, it's very definitely bad. It's also really common! It will likely disable only the cylinder or two right under the regulator, as the fuel doesn't evaporate much. On a V-6, it may not screw up the idle much.

4. Check the entire starting system. Disable the injectors by disconnecting the electrical harness. Measure the voltage drop across each part of the starting system -- battery, each wire, solenoid, and starter. Do this while cranking, as you'll get different answers when it isn't (you'll need an assistant -- I don't recommend a remote starter because it disables safety interlocks and I really want someone on the brakes). The voltage drop across the battery and starter should be equal. Any significant voltage drop across a wire condemns the wire. This is a VERY COMMON problem, and it can be fixed for $20.

5. For basic engine condition checks, run a vacuum test. You want a steady reading at idle around 20" (minus 1" per thousand feet altitude), that momentarily lowers when the throttle is opened (until the engine speeds up; after that, the vacuum should be higher up to the torque peak -- you'll need very little throttle to do this with the transmission disengaged) and raises momentarily when it is closed rapidly.
 
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jesse said:
First thing, plug into it and see if it has raised any codes. You're seriously wasting your time if you don't start with that. Plenty of places can do it for you for free.

If that turns up nothing I would be throwing a pressure gauge on the fuel rail to see if it is coming up to the spec and to see if it's holding that value. Sometimes a slow leak here will cause those hard starts. If it isn't holding I'd probably start with yanking all the injectors to put new o-rings on them.

Once again though -- start with looking for codes.
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Best answer
 
After a code check - and assuming you find nothing. . . .

Engines don't start for three reasons: Air - Fuel - Spark.

If it runs once started - its not Air.

So we are down to fuel and spark.

1. In an unmaintained car with 130k miles - I'd look at whatever passes for a distributor - may be an olde-fashioned cap, may be a place where the wires come out - but there will be that point - and check something there for wear. Then pull a couple of plugs - if they are worn replace them all - they are cheap and due.

2. Fuel/Air mixture- if there is detonation or rough idle there no fuel. Period. Clogged fuel filter - something that acts as a choke - after 2002 its pretty much all electronic - so your issue is basically electronic - at some level.

The most common issues are bad plugs, bad wires, bad distributor panel arc'd or something, clogged fuel lines, injectors or etc .. . . unless you see a code for something like a bad crank sensor which has replaced points these days =

Cars still have the equivalent of a coil to generate the voltages needed to spark - replace that as well since poor spark quality will make an engine hard to start . . .
 
jesse said:
First thing, plug into it and see if it has raised any codes. You're seriously wasting your time if you don't start with that. Plenty of places can do it for you for free.

If that turns up nothing I would be throwing a pressure gauge on the fuel rail to see if it is coming up to the spec and to see if it's holding that value. Sometimes a slow leak here will cause those hard starts. If it isn't holding I'd probably start with yanking all the injectors to put new o-rings on them.

Once again though -- start with looking for codes.
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Another free check. Listen for the fuel pump hum as soon as you turn the key on. These GM fuel pumps give up between 8 and 10 years it seems like. If you dont hear the hum (pump is in the gas tank) it's not building any pressure in the fuel injection rail. The pump should run for 3 seconds or so went you turn on the key. If it's not working and your car won't start, lay on the ground and beat of the bottom of the gastank. The pumps start getting sticky and intermittantly fail before giving up alltogether. I've never had good luck with aftermarket ones so I buy OEM fuel pumps.

Do not just start randomly taking things apart and cleaning injectors etc. You may induce a hole new problem and then have two issues going on at the same time making it more trouble to figure out.

I have 2002 Impala with the 3.4L going passed 210k miles. New fuel pump and fuel filter 5 years ago. I've never had the fuel injectors out. Never any ignition problems. But what you decribe sounds like a fuel pump problem
 
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Thanks for the responses. I'll check the codes on Saturday. I forgot to mention a known issue: failed fuel sending unit resulting in a non-functioning gas gauge. We decided to forego fixing it until the fuel pump died, because it requires dropping the tank. Seems like that shouldn't be the cause of the current issue, though.
 
asechrest said:
Thanks for the responses. I'll check the codes on Saturday. I forgot to mention a known issue: failed fuel sending unit resulting in a non-functioning gas gauge. We decided to forego fixing it until the fuel pump died, because it requires dropping the tank. Seems like that shouldn't be the cause of the current issue, though.
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See post #9. That is part of the fuel pump assembly BTW.
 
Another quick easy free check is to pull the vacuum line off of the fuel presure regulator while the car is running. Wait a minute or two and if gas starts coming out of the nipple, the regulator is bad. Google that or youtube it to find out where to look.

Edit. I see MakG suggested this already :lol:
 
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bnt83 said:
Another free check. Listen for the fuel pump hum as soon as you turn the key on. These GM fuel pumps give up between 8 and 10 years it seems like. If you dont hear the hum (pump is in the gas tank) it's not building any pressure in the fuel injection rail. The pump should run for 3 seconds or so went you turn on the key. If it's not working and your car won't start, lay on the ground and beat of the bottom of the gastank. The pumps start getting sticky and intermittantly fail before giving up alltogether. I've never had good luck with aftermarket ones so I buy OEM fuel pumps.
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The other functional test after that is to take the fuel line off the regulator where it comes from the tank, stick it into a mason jar and to have a helper turn the ignition key. If you get hum without fuel or just a couple of drops, the pump is just stirring in place.

Does that years Malibu have an in-line fuel filter. If yes and it hasn't been changed, change it.
 
asechrest said:
Thanks for the responses. I'll check the codes on Saturday. I forgot to mention a known issue: failed fuel sending unit resulting in a non-functioning gas gauge. We decided to forego fixing it until the fuel pump died, because it requires dropping the tank. Seems like that shouldn't be the cause of the current issue, though.
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Seems like it might be.

Pull the electrical connector and check the resistance. Don't drop the tank until you've confirmed a fault. And drain it first if you do need to drop it. You'd be amazed how many people try to drop a 100+ lb tank, when empty, they are maybe 10 lb (including "unusable fuel").

MANY cars have an access panel under the back seat cushion or in the trunk. This is a lot easier to deal with than dropping the tank.

Does it jumpstart with cables connected to the solenoid and intake manifold? If it runs normally once started, that's where I'd look first (well, after code checks, but those may be unrelated). If that works, suspect battery or cables. Avoid the "new = good" assumption and let the data steer you. If it doesn't work, check battery charge and measure system voltage while cranking. If it's below 10V, pull the starter and have it bench tested (a good auto parts store will do that for free).
 
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Fuel pump assembly (sending unit included) is a frequent part request for the Malibu's at my salvage yard.

Average sale is $125 with 90-day warranty, $165 with lifetime warranty.
 
AggieMike88 said:
Fuel pump assembly (sending unit included) is a frequent part request for the Malibu's at my salvage yard.

Average sale is $125 with 90-day warranty, $165 with lifetime warranty.
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Yes, apparently a common problem. Cost to repair at a shop is mostly labor because there's no under seat access for the fuel pump assembly so the tank has to come down.
 
Pardon the ignorance, but you lost me on the jumpstart post. :D. Haven't needed or tried to jumpstart. Is this a jumpstart as a diagnostic test?

MAKG1 said:
Seems like it might be.

Pull the electrical connector and check the resistance. Don't drop the tank until you've confirmed a fault. And drain it first if you do need to drop it. You'd be amazed how many people try to drop a 100+ lb tank, when empty, they are maybe 10 lb (including "unusable fuel").

MANY cars have an access panel under the back seat cushion or in the trunk. This is a lot easier to deal with than dropping the tank.

Does it jumpstart with cables connected to the solenoid and intake manifold? If it runs normally once started, that's where I'd look first (well, after code checks, but those may be unrelated). If that works, suspect battery or cables. Avoid the "new = good" assumption and let the data steer you. If it doesn't work, check battery charge and measure system voltage while cranking. If it's below 10V, pull the starter and have it bench tested (a good auto parts store will do that for free).
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asechrest said:
Yes, apparently a common problem. Cost to repair at a shop is mostly labor because there's no under seat access for the fuel pump assembly so the tank has to come down.
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That's not terribly difficult to do yourself (letting the tank down)

Just get a 2x4 (or better 2x6) and your floor jack. Have someone operate the jack while you undo the mounting points. Then easy the tank down until you have access to the top.

Just tell the jack guy to take it slow.

And no smoking. It should be obvious, but someones inattentiveness and nicotine craving can cause unwanted excitement.
 
asechrest said:
Pardon the ignorance, but you lost me on the jumpstart post. :D. Haven't needed or tried to jumpstart. Is this a jumpstart as a diagnostic test?
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It can be.

In this case, it's to bypass the battery and cables to see if it starts better. If it does, you've partly isolated the problem.

The "right" way to do this is with the voltage drop test I mentioned earlier, but this will be a much faster test. Just be sure there is no way for the "hot" to ground out or you may make a redneck welder.

My "guts" are telling me your problem is either in this direction or the fuel pressure regulator is blown. If it were the fuel pump, you would expect it to stumble on its face when stomping the throttle to get on the freeway. Fuel pumps have trouble at high loads, and starting is not a high load.

However, don't trust guts too much, especially from some guy on the internet 3000 miles away. Verify.

In addition to asking the computer for hints, it's a good idea to visually inspect all the grounds and vacuum lines for physical damage. You can get all kinds of gremlins from those. I had a doozy on the VW when it broke a pigtail ground. It burned out the fuel pump ground, causing the engine to quit when the parking brake was off (the parking brake switch grounded it otherwise).
 
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Skylane81E said:
Quit pumping the gas, on a modern EFI car you aren't doing squat
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I beg to differ.

If things are working, you aren't doing squat. If there is unmetered air or uncontrolled fuel getting into the system, opening the throttle will help get it running just by making more of the mixture under control. It's always harder to idle the vehicle (more variables requiring control) than it is to run it part throttle.

Also, if the engine is flooded, opening the throttle will help it evaporate.

But, priming is done by turning the key to "run" (even without starting) and there is no accelerator pump.
 
MAKG1 said:
I beg to differ.

If things are working, you aren't doing squat. If there is unmetered air or uncontrolled fuel getting into the system, opening the throttle will help get it running just by making more of the mixture under control. It's always harder to idle the vehicle (more variables requiring control) than it is to run it part throttle.
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You are assuming the throttle is moving, odds are it isn't,

Foot off for a normal start, floor it for a flooded start.
 
MAKG1 said:
It can be.

In this case, it's to bypass the battery and cables to see if it starts better. If it does, you've partly isolated the problem.

The "right" way to do this is with the voltage drop test I mentioned earlier, but this will be a much faster test. Just be sure there is no way for the "hot" to ground out or you may make a redneck welder.

My "guts" are telling me your problem is either in this direction or the fuel pressure regulator is blown. If it were the fuel pump, you would expect it to stumble on its face when stomping the throttle to get on the freeway. Fuel pumps have trouble at high loads, and starting is not a high load.

However, don't trust guts too much, especially from some guy on the internet 3000 miles away. Verify.

In addition to asking the computer for hints, it's a good idea to visually inspect all the grounds and vacuum lines for physical damage. You can get all kinds of gremlins from those. I had a doozy on the VW when it broke a pigtail ground. It burned out the fuel pump ground, causing the engine to quit when the parking brake was off (the parking brake switch grounded it otherwise).
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Are you thinking along the lines of low primary voltage and/or bad cables from the battery causing a weak spark until the alternator kicks in?

-Rich
 
Skylane81E said:
Quit pumping the gas, on a modern EFI car you aren't doing squat
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Agreed..... EFI motors gain nothing by pumping the gas pedal as there is no accellerator pump...:no::nonod:....

And all the other suggestions are valid but my money is on a bad fuel pump.....

Ps.... if the fuel gauge failed and now the pump too, a bad ground / wire is possible...:yes:
 
RJM62 said:
Are you thinking along the lines of low primary voltage and/or bad cables from the battery causing a weak spark until the alternator kicks in?

-Rich
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That particular post is me solving the wrong problem. This is poor cold driveability, not slow crank.

Just barely insufficient power on battery is possible, but it's not the first place I'd look. Neither is the fuel pump. This COULD be a poor head ground, but I'd be looking over ignition secondary first (my earlier post).

The OP never mentioned a MIL. Does it turn on during the light test prior to start?
 
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