Engine Dies at 40mph 1500rpm and 140 degrees...

[GreenBravada]

2003 Bravada 110,000 miles
Driving along soon after starting and before the engine is up to temperature. Two times, the engine has just died showing no warning lights or error codes. Pull over and it immediately starts and runs fine. Only about 1/8 of a tank of fuel when this happened.

Today, it did the same thing but I got off the gas and it restarted. Seems like a fuel issue. This time the engine service light came on.

Error 1: P0440-FF This is a known fault that pops up at long intervals. I have a solenoid to install.

Error 2: P0340-09 Crankshaft position sensor

I am thinking at this moment that the crankshaft position sensor may have been the effect of the engine shutting down rather than the cause because it didn't show up in the first two incidents when the engine completely shut down.

Could this be a fuel pickup issue or weak fuel pump?
Why does it seem to happen when the engine is on its way up to normal operating temperature and doesn't occur when starting the engine when it has warmed up and cooled down to 160 degrees?

Additional notes:

I removed and thoroughly cleaned the throttle body just under a year ago.

I the past month, the truck has seemed to stumble just a bit starting from a dead stop. Not sure what the engine temp was when this happened. Seemed to go away.

I think I changed the fuel filter less than a year ago, but I'll have to confirm that. I might be thinking of the Buick. If it's old, that will be the first thing I do.

That should be enough for you hungry geniuses to chew on! Any ideas?

 

[Mooseman]

P0340 is not for the crank sensor but for the camshaft sensor. This might be the cause of the stalling. I would tackle this first to eliminate it as a possible source. Pull it out, clean it and check the wiring. It has a tendency of breaking right at the connector due to the sharp right angle bend.

If that doesn't fix it once that code is eliminated, then definitely check the fuel pressure. This could be one of three things; fuel filter plugged not letting enough fuel through (quite possible if running it so low in the tank and picking up junk at the bottom), pressure regulator failure or the fuel pump is failing and unable to keep up with fuel demand at higher RPM.

For the P0440, check that you don't have an actual tank leak. The filler neck on these older trucks are starting to fail, cracking on the tank and leaking. This was a problem on the 2002-03 EXT/XL trucks with early failures but the older trucks are also starting to show this same issue. Also the filler pipe can rust through and/or break. Looks for evidence of leakage around the neck. Of course there's also the cap that could be faulty.

 

[Mooseman]

And the metal top of the fuel pump also tends to rust through and cause a leak. A smoke test would likely be needed to confirm.

 

[GreenBravada]

And the metal top of the fuel pump also tends to rust through and cause a leak. A smoke test would likely be needed to confirm.

P0340 is not for the crank sensor but for the camshaft sensor.

My mistake. Typo. Brain fart. I'll check this as you suggested

"If that doesn't fix it once that code is eliminated, then definitely check the fuel pressure. This could be one of three things; fuel filter plugged not letting enough fuel through (quite possible if running it so low in the tank and picking up junk at the bottom), pressure regulator failure or the fuel pump is failing and unable to keep up with fuel demand at higher RPM."

Happens at low rpm, not high. Will check filter. It's either new or ancient.

Is there a port on the fuel rail for checking fuel pressure?

For the P0440, check that you don't have an actual tank leak. The filler neck on these older trucks are starting to fail, cracking on the tank and leaking. This was a problem on the 2002-03 EXT/XL trucks with early failures but the older trucks are also starting to show this same issue. Also the filler pipe can rust through and/or break. Looks for evidence of leakage around the neck. Of course there's also the cap that could be faulty.

I replaced the filler neck with a new one within the past year. It attaches to a rubber hose. Not sure of condition beyond that. Will check. The Bravada was never sold as an EXT.

I replaced the evap solenoid in the rear. New cap. I have the other solenoid for the side of the engine. I'm thinking that's probably it. I have a smoke tester. Evap error has been popping up for some time at LONG intervals.

1. Check fuel filter
2. Check camshaft sensor
3. Check fuel pressure

Thanks, Mooseman. In general, truck has been running really well and replacing all the front suspension parts and new tires have made it really tight and quiet. Well, sure, there's an exhaust leak up front that makes it sound "sporty" but I'll get to that.

 

[budwich]

Two times, the engine has just died showing no warning lights or error codes.

what does this mean? no dash lights at all or no specific lights associated with some system (ie. fuel level, brake, battery...etc).

 

[GreenBravada]

The blue line of LEDs remained on because the key was in the run position. In this case, it was reading instantaneous mpg. No warning lights of any kind ( no fuel level, no ABS, no nothing). No service engine light. Looked just as it would when driving down the road without incident.

 

[TJBaker57]

FWIW, I suspect something electrical. Perhaps something like a PCM ground or similar critical circuit without which the engine cannot run.

I had an 86 TransAm, bought new, It sometimes would stutter after say 10 minutes of driving from cold start. Never showed any issues on a scan. Eventually I found the issue. Power to the ECM came through an inline fuse tucked up into the upper radiator support. A blade type fuse in a weathertight fuse holder. At the factory they missed when installing the fuse. It slid up alongside the terminal sockets instead of inside the sockets. When I discovered it the fuse body was cracked and partially deformed from the heat generated by the poor connection. There must have been a time during warmup when the temperature of the messy connection was just right to cause a loss of continuity through the circuit. And being the power to the ECM of course there could be no code set without power to the ECM.

 

[budwich]

No service engine light.

I think you have an electrical issue... potentially powering of the PCM. The "check engine" should be coming on. As tjbaker57 has stated, check powering and grounds going to the pcm.... maybe some focus on the ignition switch also.

 

[GreenBravada]

FWIW, I suspect something electrical. Perhaps something like a PCM ground or similar critical circuit without which the engine cannot run.

I had an 86 TransAm, bought new, It sometimes would stutter after say 10 minutes of driving from cold start. Never showed any issues on a scan. Eventually I found the issue. Power to the ECM came through an inline fuse tucked up into the upper radiator support. A blade type fuse in a weathertight fuse holder. At the factory they missed when installing the fuse. It slid up alongside the terminal sockets instead of inside the sockets. When I discovered it the fuse body was cracked and partially deformed from the heat generated by the poor connection. There must have been a time during warmup when the temperature of the messy connection was just right to cause a loss of continuity through the circuit. And being the power to the ECM of course there could be no code set without power to the ECM.

All very good points, TJ. It does "feel" like an electrical issue when it happens. What gets me is that it seems to happen only when the engine starts cold and then warms up and also at low rpms. Starts right up immediately afterwards. I also figured that it could not store because of loss of power. The time it did store, the engine had stumbled before it died.

When you say ECM, I assume that the the computer on the side of the 4.2 engine. I will probably have to unbolt that to install the evap solenoid I have that goes behind and under it. I'll check all of those connections. I'm not aware of a separate inline fuse going to that.

Thanks for the input.

 

[TJBaker57]

I'm not aware of a separate inline fuse going to that.

Correct. The inline fuse I mentioned was only for the sake of of explaining the issue I had with the TransAm. And how a bad connection can cause an intermittent loss of connection during a warmup cycle.

I have never had to replace an EVAP purge valve/solenoid so I cannot say if the PCM will need to come out for that. I would suspect not but cannot say for certain.

If I were to need to replace an EVAP purge valve/solenoid I think I would also at a minimum, closely inspect all the ground points that are down there on that side of the engine block. I think there are perhaps at least 3 grounds down there.

The blue line of LEDs remained on because the key was in the run position

Here's something to watch for. If it happens again, if you can safely look for the underline marker beneath the PRND321 display, see if it is there. It is the PCM that sends that information to the instrument cluster. If the PCM loses power or ground I would suspect that the transmission range marker might disappear.

The PCM supplies the ground for the CEL. I suspect that a loss of PCM power or ground might mean that the CEL would not turn on.

 

[GreenBravada]

Correct. The inline fuse I mentioned was only for the sake of of explaining the issue I had with the TransAm. And how a bad connection can cause an intermittent loss of connection during a warmup cycle.

I have never had to replace an EVAP purge valve/solenoid so I cannot say if the PCM will need to come out for that. I would suspect not but cannot say for certain.

If I were to need to replace an EVAP purge valve/solenoid I think I would also at a minimum, closely inspect all the ground points that are down there on that side of the engine block. I think there are perhaps at least 3 grounds down there.





Here's something to watch for. If it happens again, if you can safely look for the underline marker beneath the PRND321 display, see if it is there. It is the PCM that sends that information to the instrument cluster. If the PCM loses power or ground I would suspect that the transmission range marker might disappear.

The PCM supplies the ground for the CEL. I suspect that a loss of PCM power or ground might mean that the CEL would not turn on.

I have to wonder if all of these modern bells and whistles are worth all the complication! ;-)

I started working on complex x-ray systems with a lot of electromechanical circuits. Wires relays switches in 1982 and before. Then microprocessors came along and everything was a wire dumping into a data bus that could not be troubleshooted with a multimeter.

 

[Mooseman]

Is there a port on the fuel rail for checking fuel pressure?

It's located at the fuel filter under the truck.

The Bravada was never sold as an EXT.

I only mentioned the EXT because they had early failures of the tank filler neck that SWB trucks are now starting to show the same type of failure.

 

[mrrsm]

This situation smacks of "First Principles" raising its Ugly Head by means of a sudden, instant Electrical Break in a Power Distribution Center Copper Tracing that may have -=work-hardened bend locations=- and fractured somewhere in the circuit(s) in such a way that when the At Speed Vibrations and-or *Thermal Sweet Spot* occurs ...the Copper Wires separate and cause this Shut-Down Event to occur.

FWIW... You will need a Magnifying Glass and a Decent DMM and Black & Red Probe Point Leads to check ALL of the Right Angle Turns for Continuity all over this Unit. I submit the following Link and Images to a Spot On Fuse Box R&R Thread for your research and consideration:

C

Thread 'Fuse box removal..what is next step?.'

Aug 14, 2024

I got this far along. Just can't figure out how to remove the connectors from underneath.
Any tips?

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• Forum: Vortec 4.2L I-6

 

[movietvet]

It's located at the fuel filter under the truck.


I only mentioned the EXT because they had early failures of the tank filler neck that SWB trucks are now starting to show the same type of failure.

Yea, I checked the fuel pressure, right after buying Linda's 2002 Base TB. Just for giggles. I searched and searched. Then actually did the "research" and found that the pressure is checked at the port at fuel filter. Surprised the hell out of me.

 

[GreenBravada]

It does feel like the sort of electrical problem you are describing, mainly because it is so sudden and no error code is usually stored. Also, if there are any gaps in the circuit runs, they might be open when the engine is cold and close up again when the engine is at operating temperature. Of course, those would be the hardest to find.

I have the correct tools to get down to that level and make repairs, but I hope I don't end up there. I'm going to pull that module off to make it easier to install the evap valve behind it, so I will inspect it. I'm capable of doing that kind of repair, though I've never managed to fix the instrument panel in my 93 Volvo 940. That had some circuit runs that actually burned up, but the basic problems were bad old 90's capacitors.

On the other hand, the Bravada hasn't faltered since I filled the tank up.

First thing I will do is see whether or not I put a new fuel filter in. I suspect I didn't because there's a new one in the Bravada parts box. And Mooseman say I can check the fuel pressure at the filter, as well. Hope I have the right fittings to do that.

Thanks again, everyone.

 

[mrrsm]

It is worth mentioning another Strange Electrical FUBAR- vs.-Fuel Pump Cut-Off Thread you might peruse...say... around Post #9 and dial in on the importance of the relationship between the Common Ground of The Left Turn Signal, The Left Headlight (...think DRM here) and The Fuel Pump Relay... ALL sharing a Common Ground on the Engine Block that can KILL the Engine...Dead as a Door Nail... if that Ground is Loose, Corroded ...or Missing as imaged and described in Post #9 in THIS Thread:

... comme ça...

"When All Three Blind Mice need their Poor Common Ground...The Amperage Draw elevates so much... that the Fuel Pump Relay... Suddenly Disengages... Cutting off the Fuel Pump...and thus... The Engine DIES..."

M

SOLVED! Thread 'Electrical Gremlins'

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Hi All, since I bought my 02 a year and half ago I have been battling with this electrical gremlin. It only rares its head from time to time so its been very hard to track down. I have gone through all the points I can think of going over all the manuals from Mooseman and still cant fig it out. Now I am sitting $3k into this problem with no AC due to it and its 109 out. I am hoping someone else has had these same issues and can help. Again its hit n miss when they come up but here are the issues...Driving the other night I turned on the brights and the engine stalled at 50 mph then I turn...

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