I am having this work done right now to my truck. P0302 Cylinder #2 misfire. The GMC dealer is replacing the entire cylinder head. They said it shipped in peices, the mech has to assemble it. 20 hours book time, actual 30 to complete it. Well that is what they said anyways. Keep us informed of any new information on this!!

 

What timeframe of Colorado does this happen to? I have an '05 built in 6/04. Is this something I have to look forward to?

 

This is fustrating for me. I can feel the truck misfiring but I can't get it to throw a code. I've checked for codes several times and nothing, yet it continues to stumble. I even spent the money and put Denso's into it.

 

I am not saying this will work for you, but this is exactly how I got mine to throw a code EVERYTIME. Start up truck and let it sit and idle upto 40 minutes.
I bumped into this by letting my truck warm up in the morning during 0-10°f nights... Lazy man's de-icer! :wink:

 

What timeframe of Colorado does this happen to? I have an '05 built in 6/04. Is this something I have to look forward to?

Whats the number on the bulkhead to look for? Is it easy to get to it?

 

Well, that is scary. I have never had my truck show a check engine light, but it did have the exhaust valve springs replaced due to rough cold starts. On top of that the dealer told me the tires are crap and that I should put good ones on there. I'm getting sick of this truck.

 

This stuff still bothers me a little. I'm not a high mileage driver, and it makes me wonder if I'm facing a problem like this after the warranty expires, when I finally reach 20K or 30K miles. On the other hand, there are a lot more trucks on here that don't have problems then do, so it's hopefully worry about nothing.

 

OK guys, sorry for the wait. I must clarify my findings. The exhaust valve spring TSB still stands and you basically get new exhaust valve springs and seals ONLY on first diagnosis. The head replacement is only if the leakdown test shows intake valve leaking. At this point the exhaust valve springs get updated as well.

Speaking of this, a second Coly came in the next day after i posted this and same thing, number 2 cylinder intake valve leakings and this time it was a 4 banger. And this one also had 23,000 miles. 23,078 to be exact.

The exhaust valve springs TSB is 04-06-04-081C.
The cylinder head replacement PI is document ID PIP3748E.

*Rememeber, the exhaust valve spring is a TSB, the head replacement is NOT a tsb, it is an informational tech tip....... right now. I see it becomming a TSB soon tho, watch.

Updated Exhaust Valve Spring TSB:

Subject: Check Engine Light Illuminated, Engine Misfire, DTC P0300 Set (Replace Exhaust Valve Springs and Seals) #04-06-04-081C - (08/18/2005)



Models: 2004-2005 Chevrolet Colorado

2004-2005 GMC Canyon

with 2.8L Inline 4 Cylinder or 3.5L Inline 5 Cylinder Engine (VINs 8, 6 -- RPOs LK5, L52)

*For Engines Built Before and Including VIN Breakpoint 58261313 and Build Date 04/13/2005



*This VIN should ONLY be used in conjunction with the Dealers checking the Engine Unit Number (EUN) (label date reads T050880001 or lower) if they think they have a truck exhibiting the issue.




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This bulletin is being revised to update the VIN breakpoint and Engine Unit Number. Please discard Corporate Bulletin Number 04-06-04-081B (Section 06 -- Engine/Propulsion System).


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Important: The bulletin may apply to vehicles with a VIN breakpoint of 58261313 or lower. If the last 8 of the VIN is lower than 58261313, the engine unit number (shown in SI # 889181) will have to be inspected to determine if the bulletin applies. If the engine unit number is lower than 050880001, the bulletin applies to the vehicle. If the engine unit number is 050880001 or greater, the engine already contains the updated valve seals and springs that are mentioned in this bulletin, so the bulletin does not apply.

Condition
Some customers may comment on a Check Engine Light On or that the Check Engine Light is flashing. An actual engine misfire may or may not be felt . Typically this occurs during engine warm up or on deceleration after the engine is at operating temperature. Additionally, some customers may comment on a light engine knocking noise or misfire during warm up or on a deceleration after the engine is at operating temperature. Upon investigation, the technician will find a misfire code P0300 through P0305 and possibly a P0420.

Important: If a DTC P0420 is stored along with DTC(s) P0300 through P0305, the catalytic converter diagnostics in Service Information (SI) must be followed to determine if the catalytic converters are operating properly.

Correction
Perform the diagnosis for the P0300 DTC as found in the appropriate section of Service Information (SI). If no concerns are isolated through the diagnosis, then replace all of the exhaust valve springs and seals. It will be necessary to remove the intake and exhaust camshafts. Refer to and copy all of the appropriate section(s) of Service Information (SI) repair procedures referenced below before attempting this repair. Refer to the parts information below to determine what bolts, valve springs, seals and gaskets will be necessary during reassembly.

Head Replacement PI

Subject: DTC P0300 And Engine Miss At Idle Due To A Leaking Intake Valve - keywords after 04-06-04-081C CEL compression cylinder excessive head high leakdown leaking light low MIL misfire P0301 P0302 P0303 #PIP3748E - (01/31/2007)



Models: 2004-2005 Chevrolet Colorado

2004-2005 GMC Canyon

with 2.8L Engine (VIN 8 - RPO LK5)




--------------------------------------------------------------------------------

This PI was superseded to include an important reference to 06-06-01-017B and PIP3940A. Please discard PIP3748D.


The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.

Condition/Concern:
On rare occasions, a SES light and P0300 may be experienced due to a single cylinder misfire at idle that may or may not be felt. In some instances, the updated valve seals and springs from 04-06-04-081C may have been installed without success or a leaking intake valve may have been found when installing the updated exhaust valve seals and springs mentioned in bulletin 04-06-04-081C. This may be due to non-uniform intake valve seat wear, preventing the intake valve from sealing properly.

Recommendation/Instructions:
If the SI diagnostics do not isolate a cause for this concern, perform a crankshaft variation learn and follow the suggestions outlined in PIP3614A. If the cause of this concern is not found, perform a cylinder leakage test as outlined in the "Cylinder Leakage Test" procedure in SI.

Important: It is very important to hold the crankshaft with the related piston at top dead center to ensure that the valves are fully closed or inaccurate results may be obtained. If an aftermarket leakdown tester is used, the instructions of the aftermarket tester should also be referenced.

If a leaking intake valve is found, replace the cylinder head casting with the GMSPO catalog part number by following the updated replacement procedure outlined in 06-06-01-017B.

Important: The updated cylinder head replacement procedure outlined in 06-06-01-017B no longer requires removal of the oil pan, front cover, water pump, or crankshaft dampener. Before replacing a cylinder head by following 06-06-01-017B, also review PIP3940A, which contains some tips for using the lower timing gear tensioner holding tool (EN48464) that is mentioned in 06-06-01-017B.

As of 4/1/2006, all cylinder heads in GMSPO stock contain harder intake valve seats to prevent future intake valve leakage. A new part number was not issued to identify this valve seat change. The replacement cylinder head casting does not contain any valve train components so it will be necessary to follow the "Cylinder Head Disassemble" and "Cylinder Head Assemble" procedures in SI to perform the following steps before the cylinder head is installed:

Install ALL new exhaust and intake valves using the GMSPO catalog part numbers.
Notice: It is not necessary to lap the new valves. However, the valve to seat contact can be confirmed by lightly lapping the valves with fine or extra fine lapping compound. A light lap is defined as, no measurable amount of seat material is removed, but the witness marks of the contact area can be seen.

Install ALL new intake valve seals using the GMSPO catalog part number.
Install ALL new exhaust valve seals using the part number listed in bulletin 04-06-04-081C. If the updated exhaust valve seals from 04-06-04-081C were recently installed, DO NOT reuse them.
Install ALL new exhaust valve springs using the part number listed in bulletin 04-06-04-081C. It is acceptable to transfer the 04-06-04-081C exhaust valve springs to the new cylinder head if they were installed during previous repairs.
Inspect ALL of the other components from the original cylinder head and transfer them to their original locations on the new cylinder head if there is no problem found. If there is anything wrong with any of these components, replace them as necessary.

 

Well, so far so good on my truck and I'm at the 20k mile threshold. I should hit 20k in a week. I did have a rough idle until I installed the Densos, but no codes. Roughly 4400 miles on the plugs now.

 

OK so today we started tearing apart the I5's head. Didn't quite remove yet, ran out of time. MAN ARE THOSE INTAKE BOLTS NEAR THE BULKHEAD A PITA TO REMOVE. Other than that everything is going pretty smooth. But i took some pics just incase yall are curious about what our cylinder heads/cams/chain/ports look like.

OUR TIMING CHAIN AND EXHAUST AND INTAKE SPROCKETS. Plus theres the camshaft position sensor on the timing cover on the right side.

CLOSE UP OF THE EXHAUST VVTI VARIABLE CAMSHAFT TIMING CHAIN SPROCKET. Basically this drum fills with oil and as certain conditions the cam will rotate slighly inside the drum advancing the exhaust cam.

THE INFAMOUS OLD EXHAUST VALVE SPRINGS

PRETTY COOL, WE GOT ROLLER BEARING CAMSHAFT FOLLOWERS, VERY COOL.

AND FINALLY, LOOK AT THE GINORMOUS SIZE OF THESE INTAKE PORTS. Also, I beleive that is our knock sensor there on the very bottom right side above the little blue and red connector. It has the bolt attatching it to the block.

Here's what the block deck looks like. Lots holes, its a holy block Batman!

Close up of the suspect vavle seats. We found unusual wear on the valve seat wasn't allowing intake valves to fully close thus causing the compression leak or missfire. HEY ITS A HEMI!

Close up of our pistons, they're domed! Not good for adding boost/squeeze. Maybe some flat tops or even dished for a build motor, lower compression.

Next pics are from the bottom end with the oil pan removed. Had to remove the front cover to access the timing chain tensioner and had to remove the oil pan to remove the front cover, geez! And let me tell you this was the biggest PITA, more than the intake bolts. And this was a 2wd!!! Imagine a 4WD. Had to drop the steering rack and use a long prybar, jack up the tailshaft of the tranny and raise the engine off its mounts slightly to pull out the oil pan. BTW: there is no oil pan gasket, only RTV.

 

Nice job there on the pics Izz. It doesn't look like porting will be neccessary with the size of those bad boys. I'm not even sure polishing will produce a great benifit as they look pretty smooth already.

 

Thanks for the compliments DB. Ill try placing a ruler next to them ports when i get the head off. But yea porting will be very minimal i guess, they're huge. Maybe like 1.5 - 2 inches wide!

Ohh, BTW: Typically in a performance application most port/polish jobs include porting or gasket matching the ports and the polishing is typically only done to the exhaust ports to promote high, smooth exhaust flow. Typically most shops will leave the intake ports unpolished as its beleived the little aluminum pits/ridges help promote fuel atomization. But come to think of it, thats mainly for carbs or TBIs and since we have port injection i guess some polishing of the intake ports couldn't hurt. But yeah they are already pretty smooth.

Oh yea also: for those who were wandering about the residual oil film on their intakes well it goes all the way down to the head. Supposedly the manual says its normal. Normal reversion.

 

just put a v8 in it

 

Nah, the V8's for my 68 C10.

 

Updated pics.

 

Something I've always wondered...what is the firing order for the I5?

 

That's alot of carbon build up for a 23k mile engine :shock: I gotta find me some BG44 cleaner!

 

Any scoring on the camshaft lobes? My repair has turned upside down waiting for replacement cams. Intake cam was chewed up.

What would cause scroing on the camshaft lobes in your opinion?

 

What would cause scroing on the camshaft lobes in your opinion?

A stuck roller that's riding on the lobes can cause that scoring.

 

Any scoring on the camshaft lobes? My repair has turned upside down waiting for replacement cams. Intake cam was chewed up.

What would cause scroing on the camshaft lobes in your opinion?

Lack of lubrication, possible bad oil path. One thing i did notice when removing the cams that, and this is pretty obvious procedure, if you dont remove the cam bearing caps in a circular order the cam can warp. This almost happened to us, i was literally watching the intake came start warping then we caught it. I wonder if they're just covering up a screwup.

Other than that anything like dirt or metal could cause scoring in cam bearings or possible manufacturer defect. Who knows. But lack of lube is a big one.


EDIT: I just reread and realized you were talking about cam lobes. Umm yeah what DBNissan said could be it or possibly some dirt/metal caught between roller and lobe?

 

Thanks Izzy, Excellent pictures.
Very Cool tell us more! :lol:

 

New pics.

 

Maybe you should have just removed the engine. Is there anything other than the crank left from the tare down?

 

Maybe you should have just removed the engine. Is there anything other than the crank left from the tare down?

LMAO, i know! Its ok though, after tomorrow when we finally finish this I5 up, we'll startup on the I4 thats waiting its turn next, ugh! And a 3rd Coly just came in today with a misfire. Didn't get to it today but im pretty sure we all know what its gonna be. :evil:

Umm gee what was left....... block, motor mounts lol? I aint pullin shiznit for a while, i just got done doing a brand new VQ40DE 4.0 new Pathfinder shortblock so no more heavyline crap for a while!!!

 

WOW that's alot of work and you make it sound so easy. Does the I-5 use gaskets? Does the I-5 use head gaskets? Looking at the bottom of the I-5, the crank caps are huge.
What is the most common problems do you see with the I-5's?