I have a 2008 Chevy TrailBlazer with 160,000 miles. I had to replace the engine and now I'm having problems. I would drive for about 30 minutes cut it off come back and it would not start. cranks fine but will not start wait about 20 minutes and cranks and starts fine I have done the fuel pump test, change the ignition switch, and now I am down to the fuse block. I have checked my fuses with a multimeter with the ignition switch is in the Run position and it looks like fuse number 10 is dead I have swapped fuses and no help. I got the codes from AutoZone that said I had P0 201 through P0 206 injector open circuit And a PO230 a fuel pump primary circuit open. anyone have suggestions? I have been working with this for about 3 weeks now. Thanks for this site as it seems that I have read most of it and has some valuable information.
SOLVED! Cranks but won't start after driving.
- Thread starter GBOfan
- Start date
'06 Envoy 4.2: Crank but will not start
I am looking at a co-workers 2006 Envoy XL SLT 4.2. He filled up with gas on Wednesday and before he could get home, the truck stalled and would not start again. He pushed it into his driveway and it fired up but quickly stalled again. After this it would not start again, only crank. I looked...
gmtnation.com
No power to the PCM B fuse and fuel pump relay.
You guys have the best posts I've seen online for trailblazers! You've saved me a few times. Than you all! Initial issue was that my vehicle would crank but, not start. I almost pulled the fuel pump, but went through electrical testing. I'm getting no power to the pcm b fuse for those 2...
gmtnation.com
SOLVED!-04 Trailblazer LT 4.2 L no crank - no start
Hello everyone - I am a brand new member on this site and am thankful that it exists. This is my second try at posting this thread (although similar to many already posted). I lost all my previous typed text due to veering away from this site momentarily. It was actually a quite lengthy text...
gmtnation.com
Last edited:
Mooseman
Moderator
There is obviously something going on with wiring or power to the injector and pump circuits. Download the manuals from the link in my signature and look at the schematics for these circuits to see what is common to both.
Thanks for your reply. I already downloaded and am going over them now. Love my TB had one since 2001. I will become a supporter after I get this repaired. Thanks again for your help.
Hello again
Well I am back asking for your help again. I have since changed the fuse block and it cranked and run fine. then I drove it for about 20 minutes and went dead while I was driving it. I came across an article on trailvoy that had this exact problem that I am having and it turned out to be the PCM. Could this be the problem? I have been experiencing this problem since I changed Motors. my mechanic had to go back and have the PCM reprogrammed. When you reprogram one of these do you have to include a VIN number? my thought was which VIN number do you need to put in. is it the one that is on the TB I am driving, or should it be the one that the working engine came out of?
Thanks for any help you can give me on my ongoing situation. your help is greatly appreciated.
Well I am back asking for your help again. I have since changed the fuse block and it cranked and run fine. then I drove it for about 20 minutes and went dead while I was driving it. I came across an article on trailvoy that had this exact problem that I am having and it turned out to be the PCM. Could this be the problem? I have been experiencing this problem since I changed Motors. my mechanic had to go back and have the PCM reprogrammed. When you reprogram one of these do you have to include a VIN number? my thought was which VIN number do you need to put in. is it the one that is on the TB I am driving, or should it be the one that the working engine came out of?
Thanks for any help you can give me on my ongoing situation. your help is greatly appreciated.
Mooseman
Moderator
Not really but you do have to do a security relearn, which takes about 30 minutes.
huge problem after PCM update / calibration (PCM Security Relearn)
You could just pick one up from a same year truck, throw it in and do a security relearn. You could also try communicating with the PCM with a code reader to see if it's responding.
huge problem after PCM update / calibration (PCM Security Relearn)
You could just pick one up from a same year truck, throw it in and do a security relearn. You could also try communicating with the PCM with a code reader to see if it's responding.
gmcman
Member
- Dec 12, 2011
- 4,656
Does the security light illuminate when your problems show itself?
This almost sounds like a failing crank sensor. I remember quite a few different engines that would experience this phenomenon.
Before you go removing the crank sensor, you have to understand the PCM will need a Crank-Angle-Sensor relearn (CASE) procedure done by a dealer or a shop with an programmable scan tool. The engine will run, but will throw a CEL.
What happens is there's a small wire in the sensor that sends the signal from the magnetic pulse to the end of the sensor where the wire harness connects. If this wire breaks, then when it heats up it may lose contact with the broken lead. Then when it cools off, you can drive it again.
This is just a hunch, this condition may or may not throw a code. The old GM DIS ignition systems with the coil packs attached to the ignition module had issues like this....even the old Plymouth K cars with some of the 2.2L motors.
Look down around the LH side of the motor, find the harness to the crank sensor....will be near the rear of the block. Look for any stretched or stressed wires, could have happened with the engine swap. This part of the broken wire is not what I'm referring to, that would be internal of the crank sensor, but check for the wiring for being pulled from improper routing of the wire loom.
Do you have a CEL on?
I see you said it was injector related, so the above mentioned is only a guess. I would look for any wires that could be rubbing against something. Also, check the fuel injector harness, ensure its clean and the weather seal in in the connector.
This almost sounds like a failing crank sensor. I remember quite a few different engines that would experience this phenomenon.
Before you go removing the crank sensor, you have to understand the PCM will need a Crank-Angle-Sensor relearn (CASE) procedure done by a dealer or a shop with an programmable scan tool. The engine will run, but will throw a CEL.
What happens is there's a small wire in the sensor that sends the signal from the magnetic pulse to the end of the sensor where the wire harness connects. If this wire breaks, then when it heats up it may lose contact with the broken lead. Then when it cools off, you can drive it again.
This is just a hunch, this condition may or may not throw a code. The old GM DIS ignition systems with the coil packs attached to the ignition module had issues like this....even the old Plymouth K cars with some of the 2.2L motors.
Look down around the LH side of the motor, find the harness to the crank sensor....will be near the rear of the block. Look for any stretched or stressed wires, could have happened with the engine swap. This part of the broken wire is not what I'm referring to, that would be internal of the crank sensor, but check for the wiring for being pulled from improper routing of the wire loom.
Do you have a CEL on?
I see you said it was injector related, so the above mentioned is only a guess. I would look for any wires that could be rubbing against something. Also, check the fuel injector harness, ensure its clean and the weather seal in in the connector.
Last edited:
gmcman/mooseman
Thank you all for replying so fast. after replacing the fuse box I crank the vehicle and had no lights on. after I drove the vehicle for about 15 to 20 minutes it went dead and then the CEL came on. It restarted and I was very close to home so I went back and check the codes. The codes were po201 through po206 . it was like someone just turned off the fuel I will take your advice and check the wiring on the crank sensor and see what I can see. I have chased all the grounds and clean them so I am sure they are good.I will also look into finding another PCM and do the swap and see if that helps
Thanks again for y'all's help
Thank you all for replying so fast. after replacing the fuse box I crank the vehicle and had no lights on. after I drove the vehicle for about 15 to 20 minutes it went dead and then the CEL came on. It restarted and I was very close to home so I went back and check the codes. The codes were po201 through po206 . it was like someone just turned off the fuel I will take your advice and check the wiring on the crank sensor and see what I can see. I have chased all the grounds and clean them so I am sure they are good.I will also look into finding another PCM and do the swap and see if that helps
Thanks again for y'all's help
gmcman
Member
- Dec 12, 2011
- 4,656
Well, don't disturb the crank sensor as of yet. I would just check the wiring. I don't know if this PCM will show an open circuit related to the firing of the injectors to the crank sensor. I would think it would be crank sensor specific.
I would first look at the injector wiring harness, check for any signs that it was chewed on.
I would first look at the injector wiring harness, check for any signs that it was chewed on.
Mooseman
Moderator
Hey guys,
Well here we are again. My security system is OEM. I cleaned the throttle body out Wednesday and while I was doing it. I checked the wiring as good as I could wiggle it, looked at it. sprayed compressed air at it, but still the same thing. the vehicle runs great especially after cleaning the throttle body. I drove to a friend's house took me 23 minutes. that was driving at 65 70 miles an hour and had to drive through town starting and stopping. I had some things to do that took me about 20 minutes. came back and would not start. it looks like this engine has a new fuel line going to all the injectors it is nice and bright and shiny as I checked to see if I had fuel to that point. I happened to be at a quiet place this time when it quit and can hear the fuel pump turn on and has pressure all the way to the injecting line.
This is quite confusing because my TB is running great. it idles fine with the air conditioner on it never missed going down the road there is no CEL at this point in time even after it finally cranked still no CEL.
I drove home the exact same way and when I got home I'll let it set for 23 minutes and it started fine. I waited different intervals throughout the rest of the day and it never fail to start.
As always thanks very much for your help and suggestions. I am determined more than ever to find out what is wrong.
Thanks again
Go Vols (Ronnie)
Well here we are again. My security system is OEM. I cleaned the throttle body out Wednesday and while I was doing it. I checked the wiring as good as I could wiggle it, looked at it. sprayed compressed air at it, but still the same thing. the vehicle runs great especially after cleaning the throttle body. I drove to a friend's house took me 23 minutes. that was driving at 65 70 miles an hour and had to drive through town starting and stopping. I had some things to do that took me about 20 minutes. came back and would not start. it looks like this engine has a new fuel line going to all the injectors it is nice and bright and shiny as I checked to see if I had fuel to that point. I happened to be at a quiet place this time when it quit and can hear the fuel pump turn on and has pressure all the way to the injecting line.
This is quite confusing because my TB is running great. it idles fine with the air conditioner on it never missed going down the road there is no CEL at this point in time even after it finally cranked still no CEL.
I drove home the exact same way and when I got home I'll let it set for 23 minutes and it started fine. I waited different intervals throughout the rest of the day and it never fail to start.
As always thanks very much for your help and suggestions. I am determined more than ever to find out what is wrong.
Thanks again
Go Vols (Ronnie)
gmcman
Member
- Dec 12, 2011
- 4,656
The next time it acts up, turn the key from OFF to ON, and with the door open, listen for the fuel pump to run for about 2-3 seconds. This is when it pressurized the fuel system.
It won't do this every time, but generally when the key is off for a short time, then turned back on...it will do this....which is normal.
Try that anyway so you can hear what it sounds like so you know what to listen for. Maybe the fuel pump is faulty...hard to say since it only does this once stopped, but just something else to check.
It won't do this every time, but generally when the key is off for a short time, then turned back on...it will do this....which is normal.
Try that anyway so you can hear what it sounds like so you know what to listen for. Maybe the fuel pump is faulty...hard to say since it only does this once stopped, but just something else to check.
gmcman
Thanks. I have already put a new fuel pump on it. an AC Delco fuel pump and I know what to listen for to make sure the fuel pump is working properly. It usually happens in a place that is so noisy I cannot hear the pump. fortunately yesterday it done it in a very quiet area and I made sure the pump was operating properly thanks for the thought. Keep the wheels turning we will figure this out one day!
Thanks. I have already put a new fuel pump on it. an AC Delco fuel pump and I know what to listen for to make sure the fuel pump is working properly. It usually happens in a place that is so noisy I cannot hear the pump. fortunately yesterday it done it in a very quiet area and I made sure the pump was operating properly thanks for the thought. Keep the wheels turning we will figure this out one day!
Mooseman
Moderator
When it fails to start, right away check that there is 12V at the main injector harness as well as its proper ground. For all injector circuits to fail at the same time (P0201 to P0206), it would have to be one of those or a bad main connector. It could also be a break heading towards the injectors themselves post connector. As stuff gets hot, it expands and could cause a circuit break. this could get worse as the hot engine sits and heat soaks everything, hence the no start, and after it cools, starts up OK.
gmcman
yes it is happened several times that it cut off while I was driving it only one time has it failed to restart. it usually quits when I pull up to a red light or stop sign. I drove it yesterday through several red lights and stop signs and kept my eye on the tac and never sputtered or even tried to go dead so I guess me cleaning the throttle body help that situation. This code was in the system when it first started doing this (PO230 a fuel pump primary circuit open)But as of this writing the CEL is not on.
Moose man
All my tools and meters are loaded in my TB so the next time it happens I will try the things you said. What you say makes sense to me. Looks like another trip to my buddies house. I'll bet if I call him I can get a cookout schedule today. wish y'all could come.
Thanks again for all y'all’s help
yes it is happened several times that it cut off while I was driving it only one time has it failed to restart. it usually quits when I pull up to a red light or stop sign. I drove it yesterday through several red lights and stop signs and kept my eye on the tac and never sputtered or even tried to go dead so I guess me cleaning the throttle body help that situation. This code was in the system when it first started doing this (PO230 a fuel pump primary circuit open)But as of this writing the CEL is not on.
Moose man
All my tools and meters are loaded in my TB so the next time it happens I will try the things you said. What you say makes sense to me. Looks like another trip to my buddies house. I'll bet if I call him I can get a cookout schedule today. wish y'all could come.
Thanks again for all y'all’s help
gmcman
Member
- Dec 12, 2011
- 4,656
Ok, the stalling when pulling to a stop changes things.
How old are the fuel injector codes that are stored?
If the engine was replaced and you have fuel pump and injector codes for every injector....we need to determine these codes are fresh.
Sounds like you possibly have a severely dirty throttle body...or had one. What did you use to clean it? Did you by chance get anything sprayed into the electronics of the TB? Maybe through the actuator arm?
Check for any major vacuum leaks, check the large vacuum tube under the intake resonator.
If the codes are in fact fresh, when it stalls, verify the FP relay clicks when you turn the key on and it energizes then stops.
If you have fuel pressure, then we can look at injectors and spark.
My wild hunch is the injector codes are old, and you maybe have a vacuum leak and or dirty/faulty throttle body.
Edited to add:
Does it act up with a full tank of fuel, or when its low...or all the time?
How old are the fuel injector codes that are stored?
If the engine was replaced and you have fuel pump and injector codes for every injector....we need to determine these codes are fresh.
Sounds like you possibly have a severely dirty throttle body...or had one. What did you use to clean it? Did you by chance get anything sprayed into the electronics of the TB? Maybe through the actuator arm?
Check for any major vacuum leaks, check the large vacuum tube under the intake resonator.
If the codes are in fact fresh, when it stalls, verify the FP relay clicks when you turn the key on and it energizes then stops.
If you have fuel pressure, then we can look at injectors and spark.
My wild hunch is the injector codes are old, and you maybe have a vacuum leak and or dirty/faulty throttle body.
Edited to add:
Does it act up with a full tank of fuel, or when its low...or all the time?
Last edited:
When I fill the tank it seams to do it worst. I used a TB/carb cleaner. I took the TB completely off to clean it thoroughly. Nothing but air sprayed near any electronics or wiring. The codes have been there since mid April. will check for vacuum leak.
Good afternoon everyone
I thought I had this problem, We had this problem fixed but I was wrong. My TB has been running very good for the last month-and-a-half and had no problems except for a random Miss every now and then I parked my TB and went to a doctor's appointment when I got back it did crank and start then went dead and would not start until I sprayed starting fluid in it and it cranked and run fine. my check engine light came on at that time with a code of P0171 said that the injector Bank was running lean. I am at a loss of what to do, so any help from y'all Will be much appreciated
Thanks again for your help wouldn’t this far along without y'all.
I thought I had this problem, We had this problem fixed but I was wrong. My TB has been running very good for the last month-and-a-half and had no problems except for a random Miss every now and then I parked my TB and went to a doctor's appointment when I got back it did crank and start then went dead and would not start until I sprayed starting fluid in it and it cranked and run fine. my check engine light came on at that time with a code of P0171 said that the injector Bank was running lean. I am at a loss of what to do, so any help from y'all Will be much appreciated
Thanks again for your help wouldn’t this far along without y'all.
Looks like it is repaired!! I think it was a dirty TB. After cleaning the TB, My head mechanic failed to replace a vacuum hose that seams to be the problem. He has been reprimanded and would have fired him but that happens to be me.
Thanks so much for your help
Thanks so much for your help
Mooseman
Moderator
Just for rreference, 05+ don't have a fuel pressure regulator. It's buikt into the fuel pump module.
gmcman
Member
- Dec 12, 2011
- 4,656
Hi guys back again. I did look on Amazon for the fuel pressure regulator and it kept telling me it did not fit my vehicle so kinda figured must be something wrong.
I went to the farmer's market this morning and once again crank but no start. I use starter fluid and still no start. after I had let it sit for about 20 to 30 minutes it cranked and ran smoothly. I have cranked it five or six times since and never failed to start. I don't know where to go now so any suggestions would be greatly appreciated.
I went to the farmer's market this morning and once again crank but no start. I use starter fluid and still no start. after I had let it sit for about 20 to 30 minutes it cranked and ran smoothly. I have cranked it five or six times since and never failed to start. I don't know where to go now so any suggestions would be greatly appreciated.
Mooseman
Moderator
You'll have to be ready to do troubleshooting in the field when it does happen (hopefully not on a highway). Carry necessary tools and a meter with you.
This thread may be of some use:
Cranks but won't start
This thread may be of some use:
Cranks but won't start
gmcman
Member
- Dec 12, 2011
- 4,656
Something to check...I would locate the wire from the crank sensor, either down at the sensor, or near the PCM.
When it acts up, use a piercing probe and meter and test the lead from the crank sensor for a signal. I've used a push pin in a pinch before, just don't bore a hole through the wire, just enough for contact.
When it acts up, if it's a bad sensor there won't be a signal going to the PCM. When these sensors fail, they generally shut the motor down when hot but at any time, not usually after the vehicle was parked.
When it acts up, use a piercing probe and meter and test the lead from the crank sensor for a signal. I've used a push pin in a pinch before, just don't bore a hole through the wire, just enough for contact.
When it acts up, if it's a bad sensor there won't be a signal going to the PCM. When these sensors fail, they generally shut the motor down when hot but at any time, not usually after the vehicle was parked.
Some additional Emergency Road Side Tool Kit Supplies to consider carrying:
An Emergency Automotive Fuse Kit:
https://www.amazon.com/dp/B06XY2V532/?tag=gmtnation-20
A ”Scope-On-A-Rope” Lighted Circuit Probe:
https://www.amazon.com/dp/B014KCS1TU/?tag=gmtnation-20
Channellock Pick Set:
https://www.amazon.com/gp/product/B00RMR1X82/?tag=gmtnation-20
A “Nightstick” Fuel Leak Explosion-Proof Dual Bulb, High Intensity LED Flashlight:
https://www.amazon.com/dp/B007RKKEQQ/?tag=gmtnation-20
An Emergency Automotive Fuse Kit:
https://www.amazon.com/dp/B06XY2V532/?tag=gmtnation-20
A ”Scope-On-A-Rope” Lighted Circuit Probe:
https://www.amazon.com/dp/B014KCS1TU/?tag=gmtnation-20
Channellock Pick Set:
https://www.amazon.com/gp/product/B00RMR1X82/?tag=gmtnation-20
A “Nightstick” Fuel Leak Explosion-Proof Dual Bulb, High Intensity LED Flashlight:
https://www.amazon.com/dp/B007RKKEQQ/?tag=gmtnation-20
This is a careful Two Part Case Study involving a 2002Trailblazer 4.2L that "Just Quit Running" that the VOP (Video Original Poster) is a Professional Automotive Diagnostician and he performs a whole array of Scanner and Wiring Diagram Diagnostic Tests and an examination of the Start Circuit(s) and System Components involved that may prove worthwhile watching:
Part I
Part II
Part I
Part II
Maverick6587
Member
After you replaced the fuse block, were you still having any issues with fuse #10?
I would verify that you're getting power to the fuel injectors with a multimeter. We know fuel is being supplied to the injectors but, we don't know that it's being passed through the injectors.
If you are getting power to the injectors we need to verify the functionality of the injectors. Here's a video from Chris Fix. Who shows a simple way to check.
I know it's not related to the CEL codes you're getting but, have you verified that you are getting power to any of your spark plugs when it will not start? I ask because, it's such an intermittent issue, maybe it's not happening long enough (or not misfiring enough) for the PCM to throw a code for misfires.
gmcman
Member
- Dec 12, 2011
- 4,656
Does anyone with a service manual for the 08 4.2L know what color wire and pin location the crank sensor is?
I really feel this has a strong chance of being the issue. Would surely like to confirm though. Just dont go removing the crank sensor without checking first.
I really feel this has a strong chance of being the issue. Would surely like to confirm though. Just dont go removing the crank sensor without checking first.
Maverick6587
Member
gmcman
Member
- Dec 12, 2011
- 4,656
I'll take a look at mine a bit later, not sure if the sensor has 1 or 2 wires.... but I would be very curious if when the engine stalls, you have either a 5V signal going to the sensor and/or a signal leaving the sensor.
Just a word of caution....I would not recommend probing a 5V reference signal lead with a dedicated 12V test light. Can possibly overload the circuit.
Just a word of caution....I would not recommend probing a 5V reference signal lead with a dedicated 12V test light. Can possibly overload the circuit.
Hello guys
Thanks for all the valuable information. I am fully prepared for the next time this happens I have all my meters and everything I need to perform the task that y'all have put before me. I will keep you informed as to what is going on
I am curious why I cannot go ahead and replace the crank sensor. I Have ordered a new crank sensor, cam sensor, and mass air sensor. I had planned on replacing all of them. Thoughts please.
Thanks for all the valuable information. I am fully prepared for the next time this happens I have all my meters and everything I need to perform the task that y'all have put before me. I will keep you informed as to what is going on
I am curious why I cannot go ahead and replace the crank sensor. I Have ordered a new crank sensor, cam sensor, and mass air sensor. I had planned on replacing all of them. Thoughts please.