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Juan Crespo
Juan Crespo, Tech Trainer
Category: Car
Satisfied Customers: 1513
Experience:  A.S.E. Master Technician, Advanced Level, Emissions - Asian, Domestic, & European
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Cranks won't start

Customer Question

cranks won't start
Submitted: 10 months ago.
Category: Car
Expert:  Pete replied 10 months ago.

Hi my name is ***** ***** I will be happy to assist with this today.In some cases I may need more info to assist better.I apologize for any delay.

Can you tell me the year make and model of this vehicle as well as engine size and what has been done to test or try and locate or correct this issue here?

Let me know so we can continue,thanks Pete.

Customer: replied 10 months ago.
03 f 150 heritage 4.6 L new crank sensor new cam sensor new fuel pump bypassed fuel inertia switch
Expert:  Pete replied 10 months ago.

Have you tested spark,fuel injector pulses and fuel pressure?

Customer: replied 10 months ago.
the cam sensor was the last part installed no start so while I was checking injectors and coils the battery got low so I hooked up the charger low and behold it started up and ran good for the rest of the day when I went that night to go to the powerhouse it just barely ran, real rough and wouldn't idle. next morning nothing
Expert:  Pete replied 10 months ago.

O.k.,this is a tough one for me to be able to diagnose myself here.

I will open your question up for others here to see if someone else can assist further on this as there may be others here that may have more info on what to check or do with this issue.I hope you can get this resolved with ease.No need to reply to my last post here unless it is a last resort as it will keep your question locked to me and others will not be able to view it.If you feel you want to continue to work with me on this feel free to reply at any time but keep in mind in some cases it can be difficult to fully diagnose or help repair this without seeing your vehicle.

Thanks Pete

Expert:  Edward replied 10 months ago.

Hello Eddie here, Can you hook the battery charger back up to it and see if it will run then? Could be the alternator not putting out enough voltage. Let me know what happens. Thanks.

Customer: replied 10 months ago.
Been there more than once. I am a pretty good mechanic before computers, now at sixty it's being a bit of a learning curve. After the last little running spurt when I opened the hood everything was hosed down with what I thought was antifreeze I cleaned all affected electrical connections. then I thought about the oil level being low it leaks some, but it was at least a gallon overfull fuel contamination. you now know everything I know. no that's a lie, the pcm used to show codes for random misfire now it shows nada.
Customer: replied 10 months ago.
I am in the Alaskan bush, False Pass to be exact, alternatives are non existent. Fix it or burn it.
Expert:  Edward replied 10 months ago.

Check the fuel pressure regulator or gas in the vacuum line, Where did all that gas come from? My thoughts are fuel pressure regulator.

Expert:  Edward replied 10 months ago.

I feel sure all your spark plugs are gas fouled. pull them all out, and let them dry out. it's prob. flooded as it gets.

Customer: replied 10 months ago.
I've been fighting this for a month or more I think the gas just weeped passed the rings how do I check the fuel regulator?
fuel fouled possible but when I pulled them they were fairly clean and damp changed several and still no joy. Doesn't even hardly fart. It was backfiring out both intake and exhaust a little.
Expert:  Edward replied 10 months ago.

Look on the fuel rail where the injectors are, for a round metal object that has a vacuum line going to it. then pull the vacuum line off , and see if there is any gas or you smell gas in that line. It still should fire up now that the plugs are dry though, do you have spark when cranking to the plugs? Best way to check it is with a spark tester and somebody cranking it while your out looking at it. Does the check engine light even come on in the dash with just the key ON? thanks.

Expert:  Edward replied 10 months ago.

It will look like this and be in the fuel rail, should have a red vacuum line going to it.

Expert:  Edward replied 10 months ago.

I'm not sure that is the starting problem, but with all that fuel in the oil, It might be.

Expert:  Edward replied 10 months ago.

all that gas washes the cylinders, then you don't have much compression to fire it off.

Customer: replied 10 months ago.
cant answer to th compression part no tester. I will take the plugs out again dry them and check the fuel regulator, with it disconnected is it open or closed what do u think of the pcm being void of codes
Expert:  Edward replied 10 months ago.

It's normally open slightly, when you give it gas, the vacuum to the regulator drops, and it raises fuel pressure by closing the return off slightly then. See if you have a strong odor of fuel in that vacuum line, or check it with a vacuum pump if you happen to have one, Then let me know if you have fire to the plugs. If we can get fire to the plugs, maybe spray it with starting fluid to see if it will even run a second or two.

Customer: replied 10 months ago.
no fuel in the regulator vacuum line, I have fire to the plugs. I tried starting fluid yesterday, but i'm not sure if junior had the throttle cracked or not, I think not because we got nothing which seems very strange usually ether makes something go vroom for a bit. are the two sensors in the air intake duct necessary for starting one is the MAF not sure what the other one is
Expert:  Edward replied 10 months ago.

If it's got spark you should get a vroom on the starting fluid, One is MAF other is IAT. Try unplugging the MAF and see if it will start with it disconnected. Does it sound like it has compression when you crank it? Does the check engine light come on with just the key on? I wanna make sure the EEC relay is powering up the engine computer.

Customer: replied 10 months ago.
check engine light is on. I will try unplugging the MAF. my scan tool gets absolutely nothing from the pcm not even vehicle info
Expert:  Edward replied 10 months ago.

Interesting, alright, if check engine light is on, then fuel injectors should be powered up. try that and let me know

Customer: replied 10 months ago.
I believe it has good compression, I get a little sputter now and then. It's like the timing is all out of whack. I miss distributors.
Expert:  Edward replied 10 months ago.

I follow you there. Crack the throttle a bit and spray it good with starting fluid, if it's got fire and compression then I believe it should run. I don't see any reason why it shouldn't.

Customer: replied 10 months ago.
Ok tried starting fluid it would catch a little turn over a little faster than starter but wouldn't actually run. are tere any tests for the pcm im curious why the scan tool gets nothing not even basic engine info
Expert:  Edward replied 10 months ago.

I'm not sure, this will be extremely difficult for me to fix over the internet. let me opt out in case another expert has another suggestion. Thank you.

Expert:  Juan Crespo replied 10 months ago.

Hi there. Perhaps I can help, as long as we understand that all my knowledge and experience as a master technician means nothing if you don't have the necessary tools and skills to follow my instructions.

First of all, the computer is there to make sure the exhaust emissions are within the limits. After the initial start-up, it only starts taking control of ignition timing and injector pulse after the Oxygen sensors heat up and start switching - we call it going into "Close Loop". What I mean is the engine should start if there is spark at the plugs and you're spraying starting fluid down the throttle. Since it doesn't start, there must be a problem with compression.

My advice at this time is to first drain and replace the contaminated oil and filter. Second, remove the fuel pump relay to prevent fuel from going to the injector rail. Third, ensure the spark plugs are dry. Fourth, spray a little starting fluid down the throttle and try to start the engine. If it starts and runs, you'll know the mechanical part of the system is OK, then we can worry about that computer.

Once you know the engine is mechanically OK, turn the ignition off and back-probe one of the injectors. Turn the ignition back on and check to see if there is power on one of the wires that go to the injector and ground on the other. If so, the computer is bad and needs to be replaced. The reason being that it's keeping the injectors open with the engine not running which is allowing gasoline to flood the cylinders.

Please let me know if you have any other questions on this issue and I'll do my best to answer them.

Best Regards.

Customer: replied 10 months ago.
mechanical checks out. there is power to 5 of the injectors I checked. one multi-meter probe grounded, one on the back pin.
Expert:  Juan Crespo replied 10 months ago.

Thanks for that information. However, regarding testing power and ground to the injectors, either you misunderstood what I asked you to do, or I wasn't clear enough - in which case I apologize.

Power to the injectors doesn't come directly from the computer - we don't need to check power at this point.

What I need you do is check for ground; leave the ignition on and the engine off; then backprobe each and everyone of the injector connectors. If you find ground on any or all of the injectors, then the computer is bad and has to be replaced before anything else can be diagnosed.

Best Regards.

Customer: replied 10 months ago.
none grounded
Expert:  Juan Crespo replied 10 months ago.

OK. Thanks for that information.

Can you put everything back together and try to start the engine without starting fluid? If it still doesn't start, then you'll need to check fuel pressure (needs to be 35-45 psi). If fuel pressure is OK, then you'll need to check whether the PCM is opening and closing the injectors (use an LED or Noid light plugged in place of any injector. The light will flash brightly if the PCM is doing its job).

Please let me know what you find.

Best Regards.

Customer: replied 10 months ago.
Still won't start, noid light checks still trying to put something together to check fuel pressure.
Expert:  Juan Crespo replied 10 months ago.

See if it starts with starting fluid now. If it does, fuel pump needs to be replaced.

Best Regards.

Customer: replied 10 months ago.
Fuel pump is where all this started
Expert:  Juan Crespo replied 10 months ago.

I don't know what you mean by that, and I don't think is relevant. The facts still are the same; your engine needs compression, fuel and spark to start. You said the engine mechanics were good, which to me means there is good compression. Since you also said there was spark at the plugs and the Noid light checks (which to me means there is injector pulse), then the only thing missing is fuel pressure, which is the job of the fuel pump.

So, I got to ask; did you put everything back together and tried to start the engine with starting fluid? If it did start momentarily and then stalled, then the fuel pump failed to do its job. Why it failed is another story. Is the pump working? If not, is it getting the necessary current and ground? If yes, then the pump is no good.

I'm really trying to help you solve this issue, but I can only do that if you follow my instructions exactly as I post them and give me the information I need to formulate a diagnosis. Otherwise we're both wasting our time.

Best Regards.

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