08 Tahoe Hybrid no start/ no crank after AFM valve replacement

[kenny-or]

Well guys... She is alive!! I went out today and removed every plug and ground that I had to remove during the lifter replacement. I blew out each plug and reattached it. I used a wire brush to clean the grounds and used sandpaper to clean the contact points on the battery disconnect. I put the negative and positive terminals together on the 12v accessory battery and left them there while working through the plugs and grounds. After reattaching everything I turned the key and she started up. I'm not seeing any leaks so am feeing pretty happy about that of course. During the test drive the car entered and exited Hybrid mode flawlessly and the charge system was showing 14.2V on the scanner.

So now that its running I have some bugs to work out it seems. I took the car for a test drive and am getting misfires still on cylinder 8 (had this prior to the rebuild) as well as a multiple cylinder misfire code. I'm thinking that the misfire on 8 is from the injector possibly being plugged as it has a new spark plug and I ran my timing light on the plug wire and am getting steady flashes confirming that the coil pack and wire are likely not the culprit. I'm guessing that I may have some other injectors that need cleaning as well which is possibly the intermittent multi-cylinder misfire. I got some Lucus fuel injector cleaner that I just added to the tank. I have sea foam as well but have never used it so am a bit leery about it. The rockers seem to be ticking a fair amount which I am a bit surprised by. I did a 24hr lifter oil soak to fill them prior to install. The rockers are nonadjustable and just required the torque (I would have to look it up but I think it was 18 ft/lb). During my test drive I noticed the car did not once go into V4 mode which is controlled by the solenoids on the underside of the VOLM.

Any suggestions on cleaning the fuel injectors?
Any thoughts about why the lifters would be so noisy outside of the fact they are all new?


Thank you guys for all of your help and suggestions so far. I greatly appreciate all of the input and time!

 

[j91z28d1]

that's very good news. wonder what it was.


it never hurts to clean injectors. especially with today's fuel and that there's not really a fuel filter in these trucks these days. just a sock over the pump intake.

there's some good videos of testing and cleaning them yourself on a bench at home using 12v battery and carb cleaner hooked to spray thru them. the good way is to have them professionally cleaned thou. I don't have much faith in the can in the tank stuff.

I did this to a set of injectors I had setting on a shelf for a few years before using them, and some where really plugged up. they opened up after a few sprays. it worked better than I thought it would. only thing I did different was I spayed cleaner thru both ways while open. but the engine ran smooth after install.

as for the missfire, I've seen coils that will fire at idle, but not under load. if you did plugs, I'd swap the coil pack and wire to a cyl that isn't misfiring now and see if the code follows it. you can do the same with the injector, but if you get them out to change position, you may as well test them yourself.


the tapping lifter, I don't know. standard lifters I've been around usually quiet up pretty quickly after starting up and getting oil up there. what brand of lifters did you use? when I was researching before I picked my truck up, it was recommended to use oem, or one other brand, maybe millings? others were considered made in China and may have issues with quality control. I read about a guy doing the job twice over it. I've not changed mine, so I have no first hand knowledge, just stuff I've read. guys on this forum outside of the hybrid sub might know more but I think most people go back with a delete kit and not replacment afm style here. I don't believe there's a delete cam grind for out trucks. might be, but I haven't seen a listing. ours have a grind unlike a normal truck.

the volm controls the oil going to the lifters to deactivate them, but the ecm decides when to go into v4 mode. if it is sending power to the volm solenoid and they aren't working, it will run rough and set a code. because it turns off those injectors too. so if your truck is running smoothly and not going into v4, the ecm isn't meeting the parameters for tuning it on. your misfire codes might be stopping this. you'd have to dig deeper into what action the ecm takes when that specific code is set

you could ask about the tick in this forum, this is where I saw about what brand is recommended. it's a bit of an odd forum lay out to read the threads in the right order, some times it put the newer post first, so it's like reading upside down backwards lol at least on my phone.

09 Silverado HYBRID.. Disable DOD w/ HP Tuners. | Crazed Performance R

So I have an 09 Silverado Hybrid with Alum 6.0l LSM Engine. I'm wondering if I disable the DOD using HP Tuners, would the VLOM plug still be required? So my question is really this. If you disable the DOD in the ECU, then what is the purpose of the plug after that? Could I just disable the DOD i

www.crazedperformancerepair.com

hopefully you don't have bad replacement lifters. but personally would do a old school compression check, just to be sure nothing is mechanically causing the miss fire, and go from there. coil pack then injector.

 

[kenny-or]

@j91z28d1
Thanks for all the info. The lifters I ordered were supposed to be new OEM replacements. I actually ordered them a couple years ago when I was having an aux trans pump issue and mistook it for the AFM. I’m planning to pull the valve covers to check and see if any of the rockers are floating which would be a sure sign the new lifters compressed and didn’t come back up. Hopefully that’s not the case but at least the job would be a lot cleaner for round 2 if needed.

I did consider doing the delete but from what I read you can’t do that on the hybrid as there isn’t a program to tell the computer you deleted it. They apparently used a different code base on the hybrid or I would have dropped the factory cam and AFM. I may consider attempting to write a program for that in the future if I find the time.

Love the video on the injector cleaning. That’s gonna be a must I think. Of course 8 is at the end of the rail so I’m sure junk builds up down there.

I did swap the coil and wire already and it’s on a new plug which is why I’m convinced it’s gotta be on the fuel delivery side of things at this point. It seems that I may have a few injectors that could use a good cleaning anyhow. Should have done it while it was out ‍

 

[j91z28d1]

HP tuners will 100% deactivate the AFM on the hybrids. I've done it myself and there's a few threads on the HP tuners board about doing it. You can't do much else in the tune with drivability with HP tuners I believe there's wide open throttle fueling but no part throttle fueling. Out of curiosity I would love to know if the standard cam would run in these trucks just from a tuning aspect but I don't think I'd do all the work just to find out on my own. and I'm sure it would give up some gas mileage, the late intake valve closing cam is almost solely responsible for why these trucks get 25mpg on the highway even without afm, when 18 is good in a standard truck but would probably feel really good off the line

 

[kenny-or]

From my understanding to do the delete you have to change the cam due to duration and grind. They sell VVT cams that can retain the VVT of it that work with the delete I think. My memory is very hazy. I researched this a few years ago but couldn’t find any way to update the computer at that time because it was hybrid. I wonder how long the HP Tuner one has been out. I recall there was one that claimed it could but the customers reviews were very mixed. Maybe that was Hp. ‍

 

[j91z28d1]

yeah, that is correct. you have to change cams to one with lobes ground for 16 normal lifters. I forget which car it's from, but something did have a vvt but no afm. so you keep cam timing that doesn't seem to fail and ditch the afm. extra work and cost of the cam change thou but afm lifters seem to have gotten expensive.
I like the idea of the 4cyl mode, especially on our trucks where the battery can assist acceleration and keep it in 4v mode longer. but the failure rate if you follow the recommended oil change mileage is painful.
like you did, new lifters, new volm and keep good oil in it. I'm sure you'll get at least 100k plus out of it. if I didn't have to pull the heads to do it, I'd have went that way when I picked mine up. but it had 130k and car fax showed most of its life it got 6-8k mile oil changes at random places, so no clue on the quality of oil used either. I felt the afm was just waiting to fail haha. so I turned it off and did the oil pressure block off mod and relief cuts to bypass any built up pressure between volm and lifters that crazed performance guy sells and has a video on. with that done I have faith the oem stuff will last at least till the plastic lifter holders fall apart and let one spin and wipe out everything haha. ugh hopefully with good oil that doesn't happen till 300k.

I'm not sure when hptuners allowed access to disable the afm on these, I've only had mine about a year, found the threads saying you could do it on their board before i picked mine up and already had hp with come credits left. so hooked it up, and flashed it off. no more V4 mode. oh it will cal the speedo if you go bigger or smaller tires. mine was off a few mph so I adjusted that too. since you can't adjust for part throttle fuel trims, and mine seem good anyways. I haven't touched any other settings. I believe it's possible to change the amount of time in V4 mode too though. I've caught come comments of people doing that on non hybrid trucks, and all the settings are there on ours. normally hp doesn't display anything that's not working.

on the cam note, the dodge version of our trucks got a normal cam with just the cam phasers vvt, no late intake closing cam grind. now that I think about it, I think they still showed a epa of 20 on the highway even without it but I don't know anything about the engine they put in it. it might have been a efficient one to begin with.

either way, hopefully your tick goes away, and runs good. still handy to pick up that tech 2 when you have some spare money. with these trucks, you'll most likely need it at some point.

 

[TollKeeper]

This is just my opinion here, and one not shared by many.. Have been running this way on my Saab flawlessly now for some time...

Once you are sure that all 16 lifters are working, just deactivate it in the tune. Dont worry about the cam unless you are sure that the cam is the issue. Also be sure to Modify the VLOM and the oil passage gallery for the VLOM. Problem solved (at least for the AFM/DOD)

 

[j91z28d1]

This is just my opinion here, and one not shared by many.. Have been running this way on my Saab flawlessly now for some time...

Once you are sure that all 16 lifters are working, just deactivate it in the tune. Dont worry about the cam unless you are sure that the cam is the issue. Also be sure to Modify the VLOM and the oil passage gallery for the VLOM. Problem solved (at least for the AFM/DOD)

I didn't know saab had afm. guess it makes sense gm had them for a while. I remember saab had a variable compression ratio head they almost had in production, then gm got control and said nope, don't want that and shelved it.

but yeah, that's my opinion too, or at least my hope. that I disabled it in the tune before the lifters failed, that now they will be good for a good long time. I did the oil supply to volm block off too when I replace a oil pressure sensor. seemed like good insurance.

I do always worry a bit about the plastic holding the lifters in place, but hey. it is what it is.

 

[Rocket Man]

Awesome that you got it running. As far as lifter tick, I would double check all the exhaust manifold bolts. They have a high failure rate and after a couple of the heads have broken off the manifolds develop small exhaust leaks that sound almost identical to lifters ticking. I have had this happen to me. If you have some broken off bolts , there’s a few tricks to remove the broken studs or if that doesn’t work, there’s clamps that work well. It’s such a common problem that companies came up with this solution. There’s a couple different clamps depending on which bolt is broken. Dorman 917-107 and 917-142 are the right ones I believe and there’s other companies making them too. I have replaced all my manifold bolts with ARP on both my trucks.

 

[TollKeeper]

I didn't know saab had afm. guess it makes sense gm had them for a while. I remember saab had a variable compression ratio head they almost had in production, then gm got control and said nope, don't want that and shelved it.

but yeah, that's my opinion too, or at least my hope. that I disabled it in the tune before the lifters failed, that now they will be good for a good long time. I did the oil supply to volm block off too when I replace a oil pressure sensor. seemed like good insurance.

I do always worry a bit about the plastic holding the lifters in place, but hey. it is what it is.

Good job on that, but CrazedPerformance has seen oil pressure come from underneath, and this is why the VLOM modification is done. Cant get pressure from above or below that way.