Engine stalls

Welcome to 2CarPros.

It could be an ignition related issue. The most common cause of what you described is associated with a crankshaft position sensor going bad. Take a look through these links. They describe what the sensor does, symptoms of one that is bad, and in general how one is replaced.

https://www.2carpros.com/articles/how-a-crank-shaft-angle-sensor-works

https://www.2carpros.com/articles/symptoms-of-a-bad-crankshaft-sensor

https://www.2carpros.com/articles/crankshaft-angle-sensor-replacement

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The easiest way to identify if this is the problem is using a live data scanner. If the sensor fails, the rpm signal will also stop on the scanner.

If you determine this to be the cause, here are the directions for replacement specific to your vehicle. The attached pictures correlate with the directions.

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PROCEDURES
Removal and Installation

1. Raise and support the vehicle.


pic 1

2. Remove the bolts and the right front lower splash shield.


pic 2

3. Remove the crankshaft position (CKP) sensor.
1. Disconnect the electrical connector.
2. Remove the bolt.
3. Remove the sensor.

4. To install, reverse the removal procedure.

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Let me know if this helps or if you have other questions. Also, if the problem is related to a low idle or something different, let me know.

Take care,
Joe

Thanks for the fast reply. Now here's what else I found. Tried to start it today but it didn't even fire. It turns over but no start. So I started checking voltages and found the fuel pump is only getting 6.8 - 7.0 volts. I went back to the cut off switch and it to has only the 7 volts. I swapped the relays around twice and no change. The fuse has 12 v and after pulling the relay it to has 12 volts to it, I believe on terminal 87. I don't know where to check it from here except I found a fuel system diagram some where and it looks like the voltage should be coming from pin 40 of the PCM. I'm not sure if I should unplug the PCM connector to check it there. I not sure if there's some thing else making it put out that low voltage or if that may be normal. I'm don't know where to go from here. Thanks again for your fast reply. Oh I'll change the crankshaft position sensor tomorrow if I can get the chance. Thanks again. Jim

Welcome back:

If you have 12v to the relay and out of the relay, and only 7v at the cut off, there is a wiring issue between the two. And yes, you are correct with the pins.

Here is a link that shows how to check a relay:

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

As far as a power drop, the wire itself can have excessive resistance to a partial break, grounded (insulation rubbed through), and so on. The fuel cut off switch may be the cause too. I attached what I believe you already may have. The pics show where power goes. You know, I wonder if there is a weak connection where the power from the relay and PCM join together before going to the cut off. You are checking power into the cut off, correct?

Let me know what you find.

Joe

Sorry Joe, I had a few meetings yesterday, but here's what I did so far. I made sure battery was fully charged. I can't start the engine in step 12 of testing relays, so I went on to step 13 with the relay out of circuit and jumped 30 & 87 got 12 v until I turned on the ignition and blew the 20 amp fuse. Before I jumped pins 30 & 87 I checked voltage on both & found 12 v on 87 not on 30. Your diagram says it should be on 30. I put the relay back in and put my Fluke 73 DMM on pump connector across pin 1 & 3 which should be the P/B & B wires to motor. Turned ignition on got 12 v for 2 seconds the it dropped to 6.8 - 7.0 v. I still don't get a service engine code. I'm using a Micro Mechanic Engine Light Check and is says no problems. A little about me. I'm a board level electronic tech. I repair PA Systems, power amps, musical instrument amps, LED light fixtures and systems. I'm not an auto mechanic but know how an engine works except for electronic engine controls and computer systems in the auto world. With that in mind, guild me thru your testing ability. I added an image of the diagram I'm using. Most of my voltage readings are to ground.

If you had 12v for a short time and then it dropped off, that's normal. The PCM will prime the pump and then not power it until it see ignition. Did the pump turn on at all? In addition to checking the relay, did you try switching it with a known good one?

I don't know if the pump ran. When I turned the engine over, I don't think the voltage came back up. I'll check that again. I switched the fuel relay with 2 other relays. There are 6 relays with the same part number in the battery junction box. I swapped it with main fan and add fan relay, no change. Maybe I should be sure the pump is still working. How would I do that? Maybe hook up another 12 v source? I have adjustable DC power supplies rated up to 30 amp. Or another battery from my Jeep. Just take it out of the car and hook it to the pump motor wires. I'll try that next, I guess. Thanks for being so patient with me. I'll let you know what I find. Jim

Welcome back:

You could run power to it to see if it works. Also, when you checked power, did you have the pump connected? If so, disconnected the power supply and then check it.

Keep me in the loop.

Take care,
Joe

Using the battery in the car, I checked the volts at the pump and got 12.74 v when I turned the ignition on. Then it dropped back to 6.8 v. then I tried to start the engine and it came back up to 10.48 v. I don't know if the voltage drop is normal or not. Then I put a hose on the bigger output connection to a bucket and tried it again and I didn't get any fuel. I tried that with the smaller output connection and didn't get any fuel there either. A friend brought over an other fuel pump from a 2004 Mazda Tribute V6 and put it in and I get the same results. He says his pump came out of a running engine that the trans was bad. I don't know for sure if his is really a good pump. What do you think I should do next? Again thanks for being so patient we me.

If I can jump in here. the computer will not turn the fuel pump on if it does not see ignition activity which brings us back to the crank angle sensor. did you install a new one?

No, but I will do that and try it again and get back to you with the results ASAP. Thanks and I do hope that fixes it. Jim

Welcome back:

As Ken mentioned, if the computer doesn't see ignition, it won't pump gas. However, I don't like the voltage drop. It's almost as if there is a bad switch that can't handle the load. Does it start with starting fluid? Also, were you able to check the relay?

Let us know what you have found so far.

Take care,
Joe

Yes, it starts with starting fluid, and the relay checks good and has been changed with others of the like. The 20 amp fuse is good and shut off switch checks OK in the tripped and reset position. I changed the crankshaft position sensor with a new one and tried it again. Turns over but no start, but will with starting fluid still. I bet I'm a pain in the, and again thanks, Jim. PS I'm learning a lot though. Lot different from transistors, bias circuits, o/p drivers and op-amps.

Welcome back:

If it starts with starting fluid, then the ignition isn't the issue. Since you are getting 12v and then it drops off, I have a feeling either the splice between the inertia switch is weak or the inertia switch itself is bad.

Just to reconfirm. If you run power direct to the pump, does it run? I know a different pump did the same thing, but something doesn't seem right. The motor getting 12v at first and then dropping off still should run the pump to prime the system.

Let me know. I attached a pic of the schematic for you to see the two things I am suspecting are bad. If the splice is good, I would try a different inertia switch. It may not be able to maintain the draw.

Let us know.

Take care,
Joe

I ran a long cable (14 ga) from the positive post of battery to the pump and put a pin test lead through the PNK/B cable and it didn't run. I took the negative cable off the battery and clamped a long cable to it (not the post) and checked the ground from there to the pump. It showed .3 ohm. I did the same thing from the relay pin 87 to the pumps PNK/B wire got the same thing, .3 ohm. I'm using a Fluke 73 DMM for a meter
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I understand that's not under a load, but I don't know how to test it any other way but check the voltage drop when it's running which it not. The voltage drop I got before could have been caused by a shorted motor, I guess. Could the pump have started failing at first and finally gave it up? I guess now it's time to get a new pump?

I couldn't find where the splice was but I did check the resistance of the switch in the open and closed positions and got .02 ohm closed (test leads) and OL in the open position. Let me know what you think.

I;m prepared to purchase another pump and if that doesn't do it then I'll replace every thing including the high $ switch and low $ relay and fuse and finally run new cable from the relay to the switch and then to the pump. Anyways let me know what you think now. I'm sorry for being a pain but you sure are great at helping me. I sometimes get customers like me too, and what a pain they are.
Thanks again, Jim

Hey Joe,
Thanks for all your help. I figured we spent enough time on this project, so I broke down and bought a fuel pump and varoom off she went. I also got a couple of connectors to replace a few tore up ones.So far it's idling sooth. I haven't been on the road yet, but I will be soon.

I can't thank you enough for your time but if there is a way, let me know.

Put Ken on line -----

Hello, Ken? I want you to know you have one great mechanic. Joe's the kind of employee I wish I could find in my business. Thanks for having a company that's for the DIY'ers. Let me know how I can help promote your business. Thanks again and warning, I'll be back if I have more problems. Jim

Welcome back:

Wow. I'm glad it's running again and you are very welcome for anything I was able to offer. Thank you also for the compliment. It's appreciated more than you realize.

I will forward the link to Ken. Interestingly, the website was his mother's idea many years ago. I wish I would have known her. Smart woman. As far as how you can return the favor, simply tell others we are here. That's the best thing anyone can do.

Jim, you are always welcome back. Please let us know if we can help in the future.

Take care and enjoy the new fuel pump. LOL

Joe

Thanks Jim! We are truly lucky to be able to help people and ask noting in return. my Mom was a special woman :)

Battery died after using radio for over an hour without the vehicle running, got a jump and drove home. the next day it started and when my wife turned the headlights on it almost shut off and she panicked and cut it off it would not start again. I jumped it again and pulled the battery cable to see if the alternator would keep it running and it shut off immediately.

You are making two very big mistakes here.

Never remove the battery cable from a running car. That is the fastest way to fry every computer in the car.

Never jump a dead battery and drive the car to recharge it. Today's alternators are only designed to maintain a battery, not to charge one from totally dead. That overloads the alternator and often causes it to fail. Always use a battery charger on a dead battery before running the car.

At this point what you need to do is first fully charge the battery with a charger and then have it and the charging system tested. You have to have a good battery before testing the alternator.

The other issue I did not address is after a battery has been disconnected or run totally dead, the computer loses its learned memory and it may have an unstable idle until the computer relearns the idle strategy. It should do this through normal driving. If it does not, disconnect the battery and start over.

Well WAYERS87,

That battery cable trick worked in the 1970's on back, but then, still, you were putting the voltage regulator at risk with a voltage spike (so what was $30.00 back then?)

Nowadays, the alternator is the least of your worries, spiking a modern car might mean a "New Computer", "expensive modules", someone to diagnose the now exponentially more complicated problem, expensive computer stuff, and that is even before the problem at hand can be diagnosed.

Bad WAYERS87, Bad WAYERS87!

Lol!

But, I was serious about the possibilities of what can happen.

Maybe you got lucky.

Look under "Electrical" in this link on how to properly test the battery and alternator

https://www.2carpros.com/articles

As far as the battery goes, remove it and take it to a popular auto parts store for thorough testing.

This might aid you should you need a new anything. A124/ TRT30/ TRT41, still worked a week or so ago.

https://www.2carpros.com/questions/2001-dodge-neon-milage-just-want-put-fliuds-their-locations

It may just be a bad battery, It may be that the juice from the alternator is not reaching the battery.

After the battery check/ charge/ replace test the system using my first link, or again take it to the auto store to insure the alternator is charging the battery.

If it is not, I will find you a diagram on what all is in the charging system that could go wrong/ along with locations of the parts. If you do need this info, send me your VIN number, it will insure I get the correct diagram for you.

Regardless, Come back and keep us updated on the situation!

The Medic

Thanks for the replies, so I should start by charging the battery and hope life is good again? I am at work at the moment but this evening I will look at the links med posted when I have time. hope I did not cost myself more money!

Hello I have a 2002 Tribute Lx V6 motor 3.0L size of motor. The problem is every time when I put it in gear it shut off and then after I let it sit for a while it will start up. PLEASE HELP

I would start by having the fuel pressure tested.

Roy

Yes. Always perform tests on the electrical system with a properly charged battery and never try to charge a completely dead battery with the alternator.

I have already tested it and cleaned everything and it still remain doing the same thing all over again

Well, charged the battery completely, tested it, the battery tester showed the battery was still good. I put everything back together with the old alternator and it now runs and drives however idles very rough and I have no radio or interior lights. I'm going to check fuses, anything else I should do?

what is the actual fuel pressure???

Roy

I would scan the computer for both hard and soft codes. I would also see if the alternator is charging properly.

65 pounds of fuel pressure

Hi my car is acting up and it is currently in the garage with no success, we drained bad gas off it and its still bogging. We realized that before it bogs and stalls the security light comes on in the dash ( the car with the key symbol in it ) can you please tell me the cause ? thank you in advance



alice

That is the vehicle's security system turning on and shutting off the fuel pump. You need to have the system scanned to identify where the problem is coming from.

thanks , that's what the Mechanic thought it could be but the only thing the analyzer picked up was the o2 senser and we fixed that ,but it is worse now then it was before .

Further to above, if the security system is acting up to cut off the engine, it could be due to a system fault or an interruption in the power supply. Check for bad wiring connectors and the ignition switch.