Engine Stalling

Engine running rough or misfiring can be cause by a vacuum leak these guides will help us fix it.

https://www.2carpros.com/articles/stall-at-idle

and

https://www.2carpros.com/articles/how-to-use-an-engine-vacuum-gauge

Please run down these guides and report back.

I have a 2005 Jeep Liberty, I was at work tonight and when I got off work my car just started fine. I drove it just a block away from the mall and it locked up and died. I tried starting it and it will crank over but not start. The engine light came on but that is it. I have gas in the car and it has never done this before. Can you please let me know what could be wrong. I am a woman and I don't know anything about cars at all. Thank you so much.

Many things can cause the engine to stop. If the check engine light is on, there is a trouble code in the computer which will identify the problem. Most nationally recognized parts stores will scan the computer for free, but if it doesn't run, you can't get it there to check. Call some parts stores and ask if the rent or lend computer scanners for a vehicle like yours. If you can scan the computer, chances are you will know what has gone wrong.

Let me know what you find, or if you have other questions.

Joe

My car has recently had some issues starting. It will start, but as soon as I shift into reverse, it will stall. I need to keep the foot on the brake to slightly rev the engine. Once the car is moving, I have no stalling problems at all - no stalling at lights or anywhere else. This stalling issue also doesn't happen all the time. It also is not idling nor running roughly. WHat could be causing this?

It sounds like a throttle position sensor. However that is a guess without a code. Has the check engine light come on?

My Jeep has developed an unusual set of symptoms over the last 3 weeks. Primarily, it stalls a lot. About every 2 minutes (roughly, and not consistently) it stalls. If I'm at idle, it quits. If I'm driving, it picks right back up and drives like normal for a bit. Sometimes, the gages don't even dip, there's just a quick grab.

Ok, now the background. I moved the Jeep to Minnesota from Hawaii. No problems in Hawaii. Before shipping, I did a basic tuneup (oil, filters, spark plugs). When I did this, I replaced the stock filter for a K&N. I also replaced a small section of vacuum hose that had a big crack along the bottom of it. This hose came down from the throttle body and T'd into a line coming from the purge solenoid (80% sure that's what the thing mounted off the relay box is that clicks sometimes.)

For the first several weeks, there were no engine codes. I hooked it up to an OBDII reader and verified there were no codes. There were 4 lights flashing on the reader: O2, CAT, EVA, HTR. Now, I get an engine light when I start the Jeep, until it does it's first stall, then the light check engine light goes away.

When my wife picked the Jeep up from the shipper, they drove it up to the pickup area, turned it off, and it wouldn't start again. All the stall symptoms started about a week after this. The shipper had a couple guys look at the Jeep and mess with it until they could get it started. Ever since, the alarm system hasn't worked the same. Not sure if the pickup from the shipper is important, but you never know.

Lasts week, I changed out the K&N for a paper filter to see if there was any change. It went a whole day of driving without stalling, but then went back to stalling again. I disconnected the battery, cycled the key, and let it sit overnight to reset the computer. I started it up the next day and started getting incredible gas mileage, though it was still stalling. Gas mileage in Hawaii was 13.4 avg over 4 years. Gas mileage went up after fixing vacuum leak, to about 16 mpg. Ever since resetting the computer, it's been averaging over 18.5 mpg.

After resetting the computer and driving it for a couple days, I took the airbox off and visually inspected the throttlebody. I started the Jeep and watched and noticed the throttle plate wasn't moving to adjust the throttle plate and the idle. So, I think the engine is starving of air because the IAC isn't working and the throttle plate stays closed for some reason. With the vacuum leak, it could have been drawing air in through the vacuum line via the suction drawn behind the throttle plate. With the vacuum leak fixed, there's no source of air. That means the problem could have existed in Hawaii and been part of the gas mileage problem.

But, I'm not ready to change out the IAC. It makes sense that some signal may not be telling it to open.

So, I took the Jeep to hook up an OBDII reader again with the check engine light in, and it returned a code 0601 checksum code, again with the same 4 flashing indicators (O2, EVA, HTR, CAT.)

When I had the airbox off and was watching it idle, about halfway between the time I would restart it and the time it would stall, there was a clicking that would start. I traced it to a thing that has 2 vacuum lines and an electrical connection to/from it. I believe it's a purge solenoid related to the emissions system. So, once it starts clicking audibly (about 2 clicks per second), the Jeep soon stalls.

I've been to the forums, but most help there is "Replace your PCM and see what happens." I don't like the "replace some expensive part and see what happens" style of troubleshooting that happens all to often - even at dealerships. So, I'm hoping for some insight into this complicated picture of electronics, emissions, vacuum lines, sensors, etc. that can relate these symptoms to a common component.

Thanks for your time. Jason

DTC P0601: PCM INTERNAL CONTROLLER FAILURE Monitored & Set Conditions Circuit is monitored with ignition on. DTC will set if PCM senses internal checksum for software failed and does not match calculated value. Possible Causes  PCM Internal Or SPI Testing The PCM is reporting internal errors, view repair to continue. If PCM is reporting internal errors, replace PCM. Program the new PCM. See PROGRAMMING . NOTE: For circuit identification and wiring diagram, see WIRING DIAGRAMS . In testing procedure, alpha/numeric character in parenthesis, i.e. (K4), designates circuit. After each repair procedure has been completed, reconnect all components. Perform POWERTRAIN VERIFICATION TEST VER-1 under VERIFICATION TESTS to ensure system is functioning properly.
POWERTRAIN VERIFICATION TEST VER-1 1. Inspect vehicle to ensure all engine components are properly installed connected. Reassemble and reconnect components as necessary. Inspect the engine oil for contamination. If oil contamination is suspected, change the oil and filter. If repair procedure did not include replacing PCM, or PCM has been replaced and has already been programmed, go to next step. If PCM has been replaced but has not been programmed, program PCM and clear DTCs. The correct VIN and mileage must be programmed or a DTC will set in the ABS and Air Bag modules. In addition, if the vehicle is equipped with Sentry Key Immobilizer Module (SKIM), Secret Key data must be updated to enable start. For ABS and Air Bag systems enter correct VIN and Mileage in PCM. Erase codes in ABS and Air Bag modules. For SKIM theft alarm connect DRBIII(R) to data link connector. Go to Theft Alarm, SKIM, Misc. and place SKIM in secured access mode, by using the appropriate PIN code for this vehicle. Select Update the Secret Key data. Data will be transferred from SKIM to PCM. See PROGRAMMING . After PCM has been programmed, go to next step. 2. Attempt to start engine. If the conditions cannot be duplicated, clear all DTCs. Is the vehicle still unable to start and/or are there any DTCs or symptoms remaining? If no, test is complete. If yes, check for any related technical service bulletins that apply to symptom. If repaired DTC has reset, proceed to appropriate DTC test. See DIAGNOSTIC TROUBLE CODE DEFINITIONS . If necessary, go to TROUBLE SHOOTING - NO CODES article for diagnosis by symptom. NOTE: If replacing the PCM, the correct vehicle mileage and Vehicle Identification Number (VIN) must be programmed into PCM to prevent DTCs from being stored in Controller Anti-Lock Brake (CAB) module and Air Bag Control Module (ACM). If replacing PCM and vehicle is equipped with a Smart Key Immobilizer Module (SKIM), secret key data must also be updated to enable engine starting.
You can try checking the connectors at the PCM for bent or pushed out pins, and PCM grounds.

So... replace the PCM?

Ok. You're validating that there isn't likely to be something else wrong that's causing the PCM error? It sounds like that's what the code is saying.

Thanks for posting the detailed info on the 0601 error. Hopefully it's related to the stalling problem. I only recently started getting the code, but it's been stalling for weeks.

Could it be that something else is causing the stalling, which has resulted in the internal checksum error? And it still doesn't make sense that it goes away as soon as it stalls the first time after starting.

In fact, I tested it last night by starting the Jeep - verified I had check engine light - checked the code, it was 0601 - covered the throttle body to cut off air and stall the Jeep. It stalled. I restarted it and the check engine light was out.

I'm glad I didn't go and replace the IAC. I took resistance readings on it and got 53 ohms from outside pin to outside pin. I also got 53 ohms between the two inside pins. Any other combination resulted in OL. However, the signals coming to the IAC didn't make sense. The pin resistance combination didn't match. I got 23K ohms from pin 1 to pin 3, and same from pin 2 to pin 4. Going outside to outside, like on the IAC, resulted in OL.

Without any reference on correct readings, I don't know how else to verify the IAC is working other than visually. It drives out, but I could not get it to drive in.

I'll start looking for a PCM. I just want to eliminate other (cheaper) possibilities first.

Thanks for the reply. Jason.

You can try checking the connectors at the PCM for bent or pushed out pins, and PCM grounds.

I checked all the wires I could get to. There's a bunch in the loom that are wrapped pretty good, but anything accessible I checked. Everything going into the PCM looks good.

I messed with the Jeep some more last night. When I unconnect the vacuum line that I fixed and leave it unconnected then there's no check engine light when I start the Jeep. It doesn't stall. It just seems to run fine. So, the PCM still appears to be working. I just don't understand it.

Thanks for your previous answers , it s was helpful for me ,

The Engine now start normaly but when I'm driving, sometimes the engine stop abrutly itself . I can start again the engine normaly and continue to drive.

Help me please , I'm worry about this , I want to sell the car

May be helpful to know what vacuum line supplies vacuum to? If there is an electrical connector on the same location? Any chance of a picture? Or try hooking up the vac, and unplugging the electrical part. see what codes come up then.

Best way to catch this -Hook up a fuel pressure gauge and monitor the fuel pressure to rule out a failing fuel pump it will show as a sore thumb if its failing-could also be the ignition switch heating up internally and breaking contact-start here

It's the vacuum line that comes down from the throttle body and T's into the bottom line from the purge solenoid. The purge solenoid has 2 vacuum lines and an electrical connector. When I leave all vacuum lines plugged in, but disconnect electrical connector, Jeep still stalls. When I reconnect electrical connector but disconnect bottom vacuum line, letting more air get to throttle body, then the Jeep runs fine with no codes. No engine light. No stumbles. Just runs. So for some reason, it runs fine with a vacuum leak, with air getting sucked into throttle body, but will stall and get PCM code if I fix vacuum leak. Just doesn't make sense.

Purge Solenoid. Part of the emissions system. The vacuum line that had the leak I fixed T'd into the bottom one on this solenoid.

This is the section of hose I replaced. When I found the leak, the hose piece that was there was split lengthwise and wrapped around the two connections. Now that I've fixed the vacuum leak, the Jeep gets great gas mileage but I have this stalling problem.

This is where the line goes into the throttle body. When I disconnect it, the Jeep runs fine, idles a tad high, sucks a LOT of air in through here, but runs fine with no codes.

Picture of Purge Solenoid in foreground and line going to T with section of hose I replaced.

Check to see if the solinoid holds vacuum, and the same for the check valve in the vac line to brake booster, also check booster and check valve there.

Ok. I hadn't thought of that.

Do you have a recommendation on how to check those?

As soon as I disconnect anything to check, it will lose vacuum. I don't have any kind of vacuum tester.

I didn't realize there were check valves in the system.

Now that I think about it, when the Jeep stalls out, or I shut it off, there's a hissing sound - like it's losing its vacuum - for about 2 to 3 seconds. I can't identify where it's drawing in the air, but it sounds like it's breaking vacuum through the air intake. I thought that might be normal.

Hmmm... Ok. I'll see if I can figure out how to test those check valves and the solenoid.

Buy a vacuum tester, it has a gauge and pump handle, attach it to the piece being tested and pump, watch gauge, if it drops, or fails to pump up, the part leaks! Tester is only about 20.00 dollars.

I have problem with my jeep liberty , the engine refuse to start for 3 or 4 days, sometimes it's start and after 5 - 10 min , it's stop .

I check with the chek engine and the error code is P1282 , it show problem in Fuel Pompe relay Control Circuit , I want to know where this part is located ? and is there difference between fuel pompe relais and Fuel Pompe relay Control Circuit

thanks

Sweet. I'll do that. Give me a couple days to get the tester and get that done. I'll let you know what I find out as soon as I do.

Thanks again. Jason

the fuel puump relay is in the power distribution center underhood.
Fuel pump relay voltage is monitored with ignition on, and battery voltage above 10.4 volts. DTC will set if an open or short condition is detected in the fuel pump relay control circuit.


Possible Causes

? Intermittent Condition
? Fuel Pump Relay
? Fuel Pump Relay Control Circuit Open
? Fuel Pump Relay Control Circuit Shorted To Ground
? Fused Ignition Switch Output Circuit Open
? PCM


Testing

1. Turn ignition on, engine not running. With the DRBIII(R), actuate the Fuel Pump Relay. Is the Fuel Pump Relay clicking? If yes, go to INTERMITTENT CONDITION under SELF DIAGNOSTIC SYSTEM.
If no, go to next step.
2. Turn the ignition off. Remove the Fuel Pump Relay from the PDC. Check connector and clean/repair as necessary. Measure the resistance between terminals No. 1 (85) and 2 (86) of the fuel pump relay. Is the
resistance between 50 and 90 ohms? If yes, go to next step. If no, replace the fuel pump relay.
3. Turn ignition on, engine not running. With a 12 volt test light connected to ground, probe the (F1) Fused Ignition Switch output circuit in the Fuel Pump Relay connector. Does the test light illuminate brightly? If
yes, go to the next step. If no, repair the open or short to ground in the (F1) Fused Ignition Switch Output circuit. Inspect the related fuse and repair as necessary.
4. Turn the ignition off. Disconnect the PCM harness connectors. Check connectors and clean/repair as necessary. Measure the resistance of the (K31) Fuel Pump Relay Control circuit from the PDC terminal to the
PCM harness connector. Is the resistance below 5.0 ohms? If yes, go to next step. If no, repair the (K31) Fuel Pump Relay Control circuit for an open.
5. Measure the resistance between ground and the (K31) Fuel Pump Relay Control circuit at the PCM harness connector. Is the resistance below 100 ohms? If yes, repair the Fuel Pump Relay Control circuit for a
short to ground. If no, go to next step.


NOTE: Before continuing, check the PCM harness connector terminals for corrosion, damage, or terminal push out. Repair as necessary.


6. Using the wiring diagram as a guide, inspect the wire harness and connectors. Pay particular attention to all power and ground circuits. If there are no possible causes remaining, replace PCM. Program the new
PCM. See PROGRAMMING . also once problem is found make sure to clear the code otherwise pcm will make absolutely no attempt to turn on fuel pump relay.

I will be checkin in...

Well, I bought a vacuum gage. They didn't have anything with a handle. They had a gage with different fittings that can check vacuum and compression.

So, my indications when I hooked it into the line I fixed the vacuum leak on (connected to the purge solenoid and the throttle body) were this:
Initially, vacuum comes up to the middle of the green band (18/19 inches) and is steady. Once purge solenoid starts clicking, vacuum drops to the bottom of the green band (15/16 inches). Then right before the engine stalls, the vacuum goes away.

Looking closer at the purge solenoid and the fuel system, all this may be a fuel problem. I just don't understand why it would tend to stall more when I come off the gas or am at idle for a bit.

Talking to my wife, the shipping company tried to start the Jeep over and over for about a half hour before they finally put gas in it. After that, it started right up. So, it was out of gas and the fuel pump comes on every time the key is turned to the on/start position - which was a bunch of times over the half hour.

I'm thinking about dropping the gas tank and taking a look. Before I do, I want to figure out if it's possible to have a fuel pump problem with no fuel pump codes.

I'll be looking at the Jeep more again this coming week.

Thanks again for your help and patience. If you've had any epiphany's, please let me know. Thanks, Jason

Fuel pressure test it before you drop the tank, on Jeep the regulator is in the tank on the pump too...At idle the IAC(idle air control) can be a problem, it's bolted to the throttle body.

My vehicle kept shutting off after the towing comp. came out 3 time to charge my battery.

maybe the batter died. However i took it to Good Year and the mechanic said I need a new battery that would cost me 129.00, and I needed a new Radiator. He said at some point the car got hot and the radiator cracked and has been leaking water.

The hot/cold gage always remained in the middle of the gage, and I never notice the car getting hot, since I got a new water pump in June 2009.

They are charging me an additonal 750.00 for this water heater.

Can you diagnose this situation, are they just taking me for granted because we are in a recession.

Please reply: Broke

I have to start by asking if you have been adding coolant or have seen any leaks.

As far as the battery, you may need a new battery, but 129.00 seems like a lot for a battery.

My Jeep will start but runs very rough. it shakes and runs as if some cylinders are not firing. I took the gas tank off and cleaned it out as there was some foreign liquid at the bottom of tank. I took it to a mechanic and he checked the fuel pressure and it holds at 50-53. It still shakes and acts as if the cylinders are not firing, they are (mechanic checked), and after a little while it dies and I have to wait about an hour to restart it. The mechanic thinks it might be the pcm. Any suggestions before I dish out the money? Any help is greatly appreciated, Thanks

Before I would replace the PCM, there are other things to check. Have you checked closely for vacuum leaks? Has the check engine light come on? When it runs, does it have it's normal power?

Let me know.
Joe

I have a Jeep liberty that stalls when it reaches temperature and gets progressively worse. While it is running at speed it is fine besides the fact it seems as if it isn't running on all cylinders or there is a blockage of fuel delivery. I've replaced the air intake manifold, I've seen some articles about possibly having a valve spring issue. I'm at a loss any help would be appreciated greatly. I'll list symptoms:

Starts fine and runs fine while cold

When it reaches temp it begins to idle rough and eventually shuts down if idling long enough

it has trouble accelerating especially over 3000 RPM's

The check engine light is on and occaisionally blinks.

I have been told it could be catalytic convertor, valve springs, head gasket, etc, etc, but none of the above shops have been able to pinpoint the issue.

Ok well lets not guess and assume the worst. I would like you to call to your local parts stores and find one that you trust that does free scans. Take you Jeep there and get it scaned and write down the codes and then have them clear the codes. Get back to me with the codes so we can see what the Jeep trying to tell us and go from there. You may need a digital multi meter to test some sensors.