Help please... engine cuts off after about 45 minutes

UncleWick · Jul 27, 2017

2001 Dodge ram 1500 4x4 w/ 5.9l engine.

I can drive or idle engine in driveway for same result.

Start truck and wait, engine cuts off after about 45 minutes. Check fuel pressure port and there is a lot of pressure, not sure how much but it has to be well over what it should be.

However, if I drain the rail (takes a minute not a couple seconds) and turn key or even try to restart there is NO fuel sent to fuel rail. No sound from fuel pump. If I try again in 10 minutes still no fuel.

Wait an hour (engine is cool) and start right up.

What would be telling the fuel pump not to pump? Even when just turning the key to on (not hitting the starter).

Thanks for looking.

(only drained the rail once, just to see if pump was running)

SportRam00 · Jul 28, 2017

Sounds like you are having a heat related failure.

You checked the fuel, now how is the spark?

Any check engine lights or any other messages on the cluster?

Does the truck just shut off, or does it kind of sputter out (ie. shut off from fuel starvation)?

UncleWick · Jul 28, 2017

Thank you for the reply.

No Codes. I did watch live display and found it needed a TPS (stuck at 12%) and replaced it. Had a slight miss and RPMs dropped below 400 when would rev it up and let off gas plus the shutting off, took a chance and replaced the Distributor Pick-up (not missing but still shutting off.

Shut down is sudden, no warning. Will check for fire after shutdown. If none, what would it be?

SYKRAMMAN · Jul 28, 2017

Sounds like a relay thermal shut down to me. Anyone else?

Ballistic308 · Jul 28, 2017

Clean the throttle body.

UncleWick · Jul 28, 2017

SportRam00 said:
Sounds like you are having a heat related failure.

You checked the fuel, now how is the spark?

No spark after shut down either.

got a few temp readings after it shut down this time.

Upper radiator hose at thermostat 156.9
Lower radiator hose at water pump 151.2
Water pump Outlet 151.6
Right head rear 251.0
Right head front 246.3
Intake 156.7
Fuel Rail 151.1
Upper radiator at hose 198.2
Lower radiator at hose one 114.1
Left head front 199.0
Left head rear 236.6
Water pump behind pulley 172.4
Catalytic converter 354.5

Connected scanner to check Temp Sensor and unable to connect (after shut down) "No Bus" displayed in odometer.

... The hayfield just got bigger.

Yeret · Jul 28, 2017

UncleWick said:
Connected scanner to check Temp Sensor and unable to connect (after shut down) "No Bus" displayed in odometer. ... The hayfield just got bigger.

"No bus" is key here. This means there's a communication failure between the ECU and gauge cluster. If this happens but the engine will run, there is a plethora of possibilities. However, if "No Bus" appears with engine running issues, it generally means an issue with the ECU. If you're lucky, it's as simple as a faulty ground. If you're not so lucky, it's a fault in the ECU and you'll have to replace it.

In regards to the fuel pump, the ECU directly controls it. When you turn the power on, the ECU energizes the pump for a few seconds to prime the fuel system. Then the ECU opens the circuit and will not close it again until you either crank the engine over or turn the power off and turn it back on again. A fault in this circuit would either cause the ECU to randomly open the circuit while running, which cuts off the fuel supply, or flat out not close the circuit at all.

UncleWick · Jul 28, 2017

Yeret said:
If you're lucky, it's as simple as a faulty ground. If you're not so lucky, it's a fault in the ECU and you'll have to replace it.

I've only run into a no bus issue once before and it took me 3 days to track it down. This has me stumped because it's not constant nor is it random, you can almost set your watch for when it's going to shut off.

If it was a ground wouldn't it be less predictable? (brain storming, not questioning your reasoning. you have a very good point)

After reading your post I'm thinking there might be a portion of the circuit board overheating and that's why it doesn't happen until around an hour later, and maybe resets after it cools down.
Could this be a possibility?
Any recommendations for testing this Theory?

Thanks for your reply.

UncleWick · Jul 28, 2017

Ran truck until it shut down and checked ground to computer (Ohm meter)... Still a good connection.

Looks like a trip to dodge service department for a more detailed scan before an ECU investment is made.

Yeret · Jul 28, 2017

You've got an 01, so this next bit applies. To help verify if the communcation problem (No Bus) isn't the cluster itself, run the cluster's self-diagnostic test. What you do is you hold down the trip meter reset switch while turning the power on. After a couple seconds, the word "CHEC" will appear in the odometer. Release the reset switch and the cluster will flash all of it's lights and cycle the gauges. If the cluster itself has an issue, a three-digit number will appear in the odometer display. There are several of these "codes" which can help you find the source of the problem (a few of these codes are for the bus line itself which still isn't an ECU issue).

If there's nothing wrong with the cluster, then it will return to it's normal power on state. This means your No Bus is either an issue with the ECU, or one of the other modules. Considering your running problem, if the cluster has an issue, the ECU might not have anything wrong with it. If the test comes up clean, the ECU is more likely to have an issue.

There is a relay in the fusebox under the hood called the "ASD" relay, or automatic shutdown relay. This is in line with the ECU and fuel pump and I believe this it what closes and opens the circuit between the ECU and fuel pump. You could try swapping this relay with another one in the box and see if that does anything for you. Faulty relays can switch back open even when they're actively energized especially when they get hot.

SYKRAMMAN · Jul 28, 2017

I had a problem with the ASD myself, turned out to be tipcm (fuse box) the pcm was thinking the circuit was close when it wasn't so you can put a jumper wire from the relay to a ground or it could be opposite and your not getting power so you can put a jumper from positive terminal and bypass the pcm. Or buy a new pcm.

UncleWick · Jul 29, 2017

cluster returned to normal, raining right now, will replace the relay and report back later.

thanks for all the help.

Yeret · Jul 29, 2017

Okay, your "No Bus" is likely either an issue with the ECU or a different module. However, you note that it's only happened a few times which definitely doesn't coincide with your running problem frequency/timing. ASD relay would be a good next place to start.

UncleWick · Jul 29, 2017

new ASD relay and still shut down.

UncleWick · Jul 29, 2017

Yeret said:
However, you note that it's only happened a few times which definitely doesn't coincide with your running problem frequency/timing.

?

shuts down every time. without fail.

SportRam00 · Aug 3, 2017

I can almost guarantee your ECM is bad. I would verify that your crank sensor is good before totally condemning the ECU. But it isn't promising if you see "NO BUS".

I went through almost the exact same thing with my truck earlier this summer. Same heat related shutdown issue and "NO BUS". It was the ECM. Even the "new" remaned unit I ordered from A1 was bad. Did the same thing... I posted a thread here not too long ago detailing the trouble shooting I did. Might look there for more info on testing procedures.

Next time it dies, try pressing on the connector closest to the engine and listen for your fuel pump relay/ASD relay to click. If you hear it click, I bet you will be able to start the truck.

Problem is bad solder joints in the ECU. If you are good with a soldering iron, you can resolder the bad areas.

I'll keep an eye on thread and try to help you figure it out. Just to let you know, I ended up taking the cover off of my bad ECU and started poking around it with my finger, until I found the area that caused the truck to quit running. Turned out to be the step-up transformer on the front of the ECU board had bad solder connections to the board itself. Resoldered the connections, been running fine ever since.

Help please... engine cuts off after about 45 minutes

UncleWick

Junior Member

SportRam00

Senior Member

UncleWick

Junior Member

SYKRAMMAN

Banned

Ballistic308

Junior Member

UncleWick

Junior Member

Yeret

The Village Drunk

UncleWick

Junior Member

UncleWick

Junior Member

Yeret

The Village Drunk

SYKRAMMAN

Banned

UncleWick

Junior Member

Yeret

The Village Drunk

UncleWick

Junior Member

UncleWick

Junior Member

SportRam00

Senior Member

Similar threads

Latest posts

Staff online

Members online

Forum statistics

Share this page