Help needed with 05 Impala 3400

[Hannibal]

Hoping one of you folks is a Chevy tech.

I have an 05 Impala with a 3400 V6. Driving home from work yesterday. Car was running fine. Exited the highway and stopped at a traffic light. When the light changed I realized that the engine had died. Odd thing was, NONE of the idiot lights came on. No check engine light, alternator, nothing. Tried to restart it. It would fire strangely but never came close to starting. Got it towed home. Checked the fuel rail pressure. 50PSI. Plugged in my cheap code scanner and checked for codes. No codes. Overnight I completely recharged the battery as it was nearly dead after all the cranking attempts.
When I got home this evening I cleaned the chassis and frame grounds because I know occasionally those will cause weird problems. Tried starting it again and it's the same as yesterday. Fires strangely but never comes close to starting. Checked codes again. No codes.

I suspect that either the ECM or PCM has failed, but I'd really rather not open up the 'parts cannon' on this thing and electrical parts can't be returned anywhere.

Anyone familiar with Chevrolet products have any ideas about what options I have?

Thanks for looking.

[Recycled bullet]

If you spray gum cutter into the throttle body while an assistant cranks the engine and then if it starts up you know you have a fuel delivery or air-fuel mixture problem.

If it then does not start, check fuses inspect wiring with a bright flashlight always check the easy stuff first etc out is it one failure or multiple issues does it have spark compression timing etc.

[Hannibal]

If you spray gum cutter into the throttle body while an assistant cranks the engine and then if it starts up you know you have a fuel delivery or air-fuel mixture problem.

If it then does not start, check fuses inspect wiring with a bright flashlight always check the easy stuff first etc out is it one failure or multiple issues does it have spark compression timing etc.

I'm certain it has fuel and spark. I suppose it's possible the timing chain jumped but I'd think there would be at least one code. If it weren't fuel injected and electronic ignition I'd immediately suspect the timing chain based on how it acts when cranking. However engines routinely run well over 200K miles without timing chain issues even with only minimal maintenance anymore. I don't think it's a mechanical problem. IE-timing chain or dropped valve. Particularly since absolutely no warning lights came on when it died.

[Recycled bullet]

Do the supplemental fuel test. Just because you have fuel rail pressure does not mean you have fuel Volume being delivered into the cylinders.

[Hannibal]

Do the supplemental fuel test. Just because you have fuel rail pressure does not mean you have fuel Volume being delivered into the cylinders.

Point taken. Time change means it's dark here at 6 now so I'll try your suggestion tomorrow. Thanks.

[Recycled bullet]

When you test it tomorrow pay particular notice if the tachometer is not working crankshaft position sensor failure is very common on that engine.

[Hannibal]

When you test it tomorrow pay particular notice if the tachometer is not working crankshaft position sensor failure is very common on that engine.

Unfortunately, this particular vehicle did not come equipped with a tachometer. Base model.
The only gauge it has is a temperature gauge. That at least appears to work fine.

On a whim I disconnected the MAF sensor and no fault code was logged. But I don't think this sensor is monitored during cranking. Perhaps I'm mistaken about that. I'm not intimately familiar with open loop and closed loop functions.

[MaryB]

Compression check each cylinder... those engines were notorious for head gasket issues...

[rancher1913]

because of the suddenness, i would lean towards the crank sensor took a dump.

[Hannibal]

because of the suddenness, i would lean towards the crank sensor took a dump.

Any way to check it apart from just replacing it?

[Finster101]

because of the suddenness, i would lean towards the crank sensor took a dump.

This would be my bet.

[45DUDE]

I don't think timing chain. If it jumps motor will turn faster than normal and compression will be lower. If you can spray an ounce of carburetor cleaner into the motor before the throttle body and it cranks and dies That would indicate a fuel problem. The computer stores hard codes. If you just fueled up maybe water in the tank. If you knew a mechanic with a scanner that would solve a lot of problems before you started unplugging stuff. The computer is going to show a problem with things unplugged with the key on and show false codes.

[45DUDE]

Any way to check it apart from just replacing it?

You can check an electrical part with an ohm meter on the car and wright it down without removing it. Your local parts store should let you test ohm a new part at the counter before you buy. Mine do. Maybe test more than one. The service engine engine light should have come on driving unless a fuel problem. You can go to the net to see what the suspect part is supposed to ohm.

[Hannibal]

I don't think timing chain. If it jumps motor will turn faster than normal and compression will be lower. If you can spray an ounce of carburetor cleaner into the motor before the throttle body and it cranks and dies That would indicate a fuel problem. The computer stores hard codes. If you just fueled up maybe water in the tank. If you knew a mechanic with a scanner that would solve a lot of problems before you started unplugging stuff. The computer is going to show a problem with things unplugged with the key on and show false codes.

Tried reading the codes, no codes present as I stated in the opening post. I also checked the pressure on the fuel rail during cranking. 50 PSI which is normal. Had approximately 100 miles on the tank of fuel before this happened.

[Hannibal]

So I've done a bit of research during lunch. There are 2 different crank position sensors. A 3x/7x CKP sensor and a 24x crank sensor. The 3x/7x sensor is mounted in the side of the engine block and is in charge of controlling spark during cranking. Once the engine speed exceeds 400 RPM the 24X sensor controls firing. It is mounted behind the harmonic balancer on the front of the engine.

Since the car died when I exited the highway and now won't start I'm thinking it's doubtful both sensors failed simultaneously. Which leaves me to suspect the Ignition Control Module or a fuel problem. I'm going to try spraying starting fluid in the air intake while cranking to prove or disprove a fuel problem when I get home. As I said before, it was running perfectly before I exited the highway.

Added : also found information for testing the 3x/7x CKP sensor with a multimeter. I don't want to replace that thing unless I'm convinced it's bad because it's in a difficult to access location.

[Hannibal]

Well. Fogged a bunch of starting fluid into the air intake while my wife tried to start it. No change. Pulled off the ICM, going to have it tested.

[45DUDE]

You said the coils were firing --Then you installed fuel--If it's in time and has compression it has to run unless someone put a potato in the tail pipe. Let us know the fix. I have had to drill a hole in the front exhaust pipe on a few vehicles. Good luck

[porthos]

OR, bite the bullet and take it to a garage.

[Finster101]

You said the coils were firing --Then you installed fuel--If it's in time and has compression it has to run unless someone put a potato in the tail pipe. Let us know the fix. I have had to drill a hole in the front exhaust pipe on a few vehicles. Good luck

If the crank sensor is kaput the injectors and spark will not be in time, if firing at all.

[Hannibal]

You said the coils were firing --Then you installed fuel--If it's in time and has compression it has to run unless someone put a potato in the tail pipe. Let us know the fix. I have had to drill a hole in the front exhaust pipe on a few vehicles. Good luck

ICM tested instantly bad at 2 different store locations. They want $250 + tax for a new one.

I can't say exactly what I think about that without violating forum rules, so I'll just say that ain't happenin'.

Going to check online first then local salvage yards.

[deltaenterprizes]

A friend had a blocked muffler that would not allow the engine to start!
Mechanic cut a hole in the exhaust pipe in front of the muffler and it cranked right up!

[45DUDE]

ICM tested instantly bad at 2 different store locations. They want $250 + tax for a new one.

I can't say exactly what I think about that without violating forum rules, so I'll just say that ain't happenin'.

Going to check online first then local salvage yards.
What's the part# I used to ride dirt bikes with two parts store owners that are getting rid of older parts. One is Delco and the other is Standard.

[45DUDE]

If the crank sensor is kaput the injectors and spark will not be in time, if firing at all.

You can pull the fuel pump relay and kill the injectors. You can get #1 piston on top and mark the balancer with a timing light with degrees and see if the timing is ok. <I can if its firing.>You have to have the vin # to get the correct part using Delco parts.

[Hannibal]

You can pull the fuel pump relay and kill the injectors. You can get #1 piston on top and mark the balancer with a timing light with degrees and see if the timing is ok. <I can if its firing.>

Well, the #1 cylinder is on the firewall side. (FWD) So I'd have to pull off a whole bunch of crap off just to remove the valve cover.

If it gets that involved I'll just post it for sale and let someone else fight it. The whole pull the plug and use an indicator thing ain't much easier. Still don't know what portion of the 4-stroke you're on. Might be 180° off.

I used to do a lot of engine work. Just not that interested in pulling on wrenches these days. It's not that I can't, I just won't. Sick of it. Over a car that's nearly 20 years old?

Been there, done that. Burned the tee-shirts.

[Hannibal]

A friend had a blocked muffler that would not allow the engine to start!
Mechanic cut a hole in the exhaust pipe in front of the muffler and it cranked right up!

I understand your points but I drove this car every day. There would be signs. It's not a plugged catalytic converter.

[Hannibal]

The reason I said it had spark was because it would fire intermittently but never run. Just because it fires a plug every once in a while doesn’t mean it's doing it when it should.

If it was a timing chain issue it should have been misfiring spectacularly when it got a snout full of starting fluid. Never did anything.

[Hannibal]

One just never knows if a problem is an easy fix or a major undertaking until you investigate.

I hope none of my comments are off-putting. I really appreciate the suggestions. Makes me think. Thinking is a lot cheaper and easier than changing parts and hoping for the best.

[45DUDE]

If you can put a plug in #1 cylinder you can find tdc. Kill power to the coils and put your finger in the plug hole<aint going to kill you>get someone to bump the engine. When it spews compression that's #1 firing position with the piston on top. What part # do you need the store said was bad? I have used Cardone lots of times for ECM'S because if you are the owner they can flash your part to the vin # when they rebuild it so your car will crank without having to spend $200 +for a flash. If out of time it will likely backfire and kick back on the starter.

[Hannibal]

If you can put a plug in #1 cylinder you can find tdc. Kill power to the coils and put your finger in the plug hole<aint going to kill you>get someone to bump the engine. When it spews compression that's #1 firing position with the piston on top. What part # do you need the store said was bad? I have used Cardone lots of times for ECM'S because if you are the owner they can flash your part to the vin # when they rebuild it so your car will crank without having to spend $200 +for a flash. If out of time it will likely backfire and kick back on the starter.

Well again, #1 is up against the firewall since it's FWD. Plugs are a PITA to get to.

I don't have the part#. I'm thinking I'll try a salvage yard part and if that doesn't do it this car can go down the road to someone else.

I'm REALLY not interested in changing that block mounted crank sensor and that would be the next logical step if it's not the ICM.

I really despise engineers. It might work until a part fails. Parts are typically built by the lowest cost supplier. Parts will fail. Engineers don't concern themselves with replacing parts. Ergo, I despise engineers.

Sorry. Rant off.

[Finster101]

The crank sensor is pretty easy after removing the passenger front tire. I completely understand your point about just not wanting to mess with it much. I retired 3 years ago from 40 + years of turning wrenches. I'm done. When my truck needs something I take it to the dealership I retired from and have them do it. Granted I know the right guys in the shop to have do the work and most of the time I have diaged it before taking it in, but I ain't crawling around on the ground to do the work. Besides it hurts too much now. Good luck.

[Hannibal]

The crank sensor is pretty easy after removing the passenger front tire. I completely understand your point about just not wanting to mess with it much. I retired 3 years ago from 40 + years of turning wrenches. I'm done. When my truck needs something I take it to the dealership I retired from and have them do it. Granted I know the right guys in the shop to have do the work and most of the time I have diaged it before taking it in, but I ain't crawling around on the ground to do the work. Besides it hurts too much now. Good luck.

I think you might be confusing the 24x sensor with the 3x/7x sensor?

Perhaps I'm way off in the weeds, but that block mounted sensor.....

I don't understand how pulling the passenger's side tire will help much.

That damn thing is in a really bad place.

[45DUDE]

A new icm is only $120 from Standard products for a 2005 3400 Impala. It's common for those to go bad if yours has three coils. You said yours tested bad and wonted $250. I would change parts stores. Go to Amazon. xxxx I think some was thinking in reverse --My computer and clock are showing 8;42 PM and this site is 10'42 pm.

[Recycled bullet]

Check if you have good strong spark. Remove one spark plug wire and install the testing tool then crank and see if you can see the flashing lights.

The tool is inexpensive and can be purchased at most part stores it's called inline spark checker.

If you do not have spark then it is time to look at a wiring schematic so that you understand the power distribution and theory of operation.

I would recommend having it checked out by a shop for the diagnosis. Then if the repair is something that you want to handle you can do so.

[Hannibal]

A new icm is only $120 from Standard products for a 2005 3400 Impala. It's common for those to go bad if yours has three coils. You said yours tested bad and wonted $250. I would change parts stores. Go to Amazon. xxxx I think some was thinking in reverse --My computer and clock are showing 8;42 PM and this site is 10'42 pm.

I thought it sounded ridiculously expensive also. And yes it has 3 coil packs. At both store locations the counter guys guessed it had been at least a year since anyone had requested the diagnostic service. :holysheep

[Finster101]

Crankshaft Position Sensor Replacement (7X)
Removal Procedure

Object ID: 15969Click here for detailed picture of the image.
Turn the steering wheel fully to the left.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Remove the right front wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
Disconnect the crankshaft position (CKP) sensor electrical connector.
Remove the CKP sensor bolt.
Remove the CKP sensor.
Inspect for wear, cracks, or leakage if the sensor is not being replaced.


Direct from GM SI (Service Information)

[Hannibal]

Crankshaft Position Sensor Replacement (7X)
Removal Procedure

Object ID: 15969Click here for detailed picture of the image.
Turn the steering wheel fully to the left.
Raise and support the vehicle. Refer to Lifting and Jacking the Vehicle in General Information.
Remove the right front wheel. Refer to Tire and Wheel Removal and Installation in Tires and Wheels.
Disconnect the crankshaft position (CKP) sensor electrical connector.
Remove the CKP sensor bolt.
Remove the CKP sensor.
Inspect for wear, cracks, or leakage if the sensor is not being replaced.


Direct from GM SI (Service Information)

Good to know! I think the ICM is bad but won't know until it's been replaced.

[firefly1957]

My wife had a 2001 impala and I had a 2003 Hers died at 217,000 miles I believe from a pounded cam shaft , Mine was totally by my son with 180,000 miles it still ran well at the time .
I had never seen the dash lights not come on when it was stalled . Both had the fuel sender unit in fuel tank go bad and read wrong as the pivot pin got loose . The other only real issue was the trunks in both cars rusted out under the carpet and would get wet inside while driving . Mine did have one of the ignition coil packs go bad and a water pump leak other then those few things that were very good cars . oops ! As I type I remember the 2001 did have a head gasket leak and the transmission bands go .
I hope you get it fixed used cars are hard to find now if they run at all!

[Hannibal]

My wife had a 2001 impala and I had a 2003 Hers died at 217,000 miles I believe from a pounded cam shaft , Mine was totally by my son with 180,000 miles it still ran well at the time .
I had never seen the dash lights not come on when it was stalled . Both had the fuel sender unit in fuel tank go bad and read wrong as the pivot pin got loose . The other only real issue was the trunks in both cars rusted out under the carpet and would get wet inside while driving . Mine did have one of the ignition coil packs go bad and a water pump leak other then those few things that were very good cars . oops ! As I type I remember the 2001 did have a head gasket leak and the transmission bands go .
I hope you get it fixed used cars are hard to find now if they run at all!

Yeah, and they are expensive for what you get. That's the only reason I'm working on this one.

[dverna]

I fit into the "I am not going to crawl around and fix a car" group. Did enough of that when I was younger and poorer.

But in your case, if the ICM is bad, it is worth doing IMO. New cars are too expensive. Decent used cars are too expensive. And it seems every "affordable" used car has issues to address.

Better the devil you know than the devil you don't know. Just my $.02

[rockrat]

LOL about the engineer part. At least the design engineers (my SIL is an engineer), when I am working on a vehicle. Like a lot of you, just cannot stand the crawling under the car for long.
Hope you get the thing fixed, friend of mine is having the same issues with his 99 tahoe. Tough as he lives 700 miles away and it tough to figure out whats wrong

[ebb]

My GMC had issues for months and I sent it to a friend out in the glades. He is an auto computer genius, he hooked up his lap top and tested a bunch of stuff and it was a crankshaft position indicator. Mine would start and run for long enough to get hot then shut down. Mine was a 6 liter P/U. worth looking into.

[Hannibal]

I think I'm going to roll the dice and try a salvage yard early in the morning. Before all the 'tweakers' show up. Pretty sketchy place at times.

[funnyjim014]

It's not a head gasket. It will run but spew coolant. With out a scan tool to look at data your throwing darts at the wall. Take it to a shop

[Hannibal]

It's not a head gasket. It will run but spew coolant. With out a scan tool to look at data your throwing darts at the wall. Take it to a shop

Yeah, well I'm not going to. I have a scan tool. No codes. And it ain't one if the cheap ones.

There are help wanted signs everywhere I go. Auto shops aren't immune to the lack of warm bodies that will even show up, let alone people who know how to diagnose problems. Dealerships are no exception.

I could point out a really good reason why that is but I don't want this thread to go to the pit so I'll just stop now.

[Hannibal]

As an aside, the last time my stepdaughter took her older car to the dealership to diagnose an air conditioning problem they came back with a laundry list of $3K in parts and hadn't even taken anything apart yet. I replaced the Schrader valves, pulled a vacuum overnight and recharged it. That was about 18 months ago. Less than $100 in parts and refrigerant.

Not impressed.

[Hannibal]

So the car is fixed. I bought a used ICM at the local salvage yard for $30. Installed it. Started right up and test drove it. Runs as good as it has since I've owned it.

Thanks to everyone for your input. I appreciate it.

As an aside, if you do your own work and your local parts supplier offers testing I recommend that you take advantage of that. Apparently a whole lot of folks aren't.

They'll test your stuff for free, even if you don't buy their $240 part and get the $30 one from the junkyard.

[MaryB]

So the car is fixed. I bought a used ICM at the local salvage yard for $30. Installed it. Started right up and test drove it. Runs as good as it has since I've owned it.

Thanks to everyone for your input. I appreciate it.

As an aside, if you do your own work and your local parts supplier offers testing I recommend that you take advantage of that. Apparently a whole lot of folks aren't.

They'll test your stuff for free, even if you don't buy their $240 part and get the $30 one from the junkyard.

Open up the old one... you may find bad solder joints the culprit and soldering them may get you a spare module

[abunaitoo]

No lights came on when it died????
None at all????
Did they come on when you tried to start it again????
Do they come on now with KOEF????
No codes stored????
I would start checking ground wires.
Start at the battery, check body ground wires, check ground under the dash.
If no codes, and no dash warning lights, probably a bad ground someplace.
Once with a Blazer that had a dash display problem, I tapped in to the ground wire in the dash, and grounded it.
Problem went away, and it seemed to run much better.
Just a suggestion.