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2G 2GB Cylinder Head build, now GST wont stay running

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MissSpyderGST

10+ Year Contributor
82
12
Mar 12, 2010
Luthersville, Georgia
So my husband and I pulled my head, while it was off, I replaced the springs with Kiggly Racing beehive Street Steel springs, replaced the seals, relapped the valves using the lapper tool, cleaned it to the best of my abilities and put it back on with my new ARP Head Studs and Cometic Head Gasket. As a surprise, he also bought me Crower 272 cams and Forced Performance exhaust manifold. I bought the new turbine housing for the 14b and we put it together. Well, he did 90% of the putting together LOL. So, I crank it, and it sounds okay, however, it wont stay cranked. I'm stock other than the above mentioned info and a cat back exhaust and FMIC. He's looked into it and so have I and we can't seem to get a real clear answer as to why this is happening. Just a few guesses. I dont have tuning software at all, and once he mentioned that the cams were too big with no tune, that it could be the answer, and I agree. I would just like to get some opinions as well, and hopefully a 100% right answer. Any and all help would be appreciated. I just wanna drive my baby again.
Thanks,
Sara
 
Does it just stall while idling or can you throttle it to keep it running.
While the tuning should probably be tweaked for open loop running/WOT the closed loop part throttle running should be able to make adequate adjustment to run ok.
If you're sure about the cam timing I would then check for possible air leaks.
 
Agreed ^^

check, verify and rectify mechanical timing, and also check that lifters are bled and not pumped up. Past that a major vacuum leak could be preventing you from running.

A compression test, mechanical timing check and BLT would be a good start.
 
Brandon, my husband, thought initially it was timing. However, everything is lined up perfectly. He got me to check as well and everything was spot on. As far as idle, when it cranks, it will rev up to 2500 rpms, then start to bog down then it will go up and down between 100 and 500 rpms, to which is finally dies. I did some checking with vacuum lines, and everything seemed to be fine.
 
Also I would like to specify that it is STOCK tuned. No DSM link or any other tuning software. I have a feeling that the tune will fix the issue... thoughts?
 
Hate to bring this thread back, but I'm still at a loss. So, I did manage to drive the car for a couple of days. At a cold start, it did great. Once I got to where I was going, the car wouldn't crank back up well, meaning it would stutter and act like it's a boost leak. I would then limp it home, and do another BLT, fix whatever leak was present, and try again. After the second time, the car did actually die quite a bit, and I had to keep it revved to make it home, and couldn't of course, drive it past 3k RPMs. After that, I kept the car at home and didn't even try to drive it again. The smell of something burning was present, and a little smoke was coming from under the hood of the car, which happens every time I have a boost leak. Fast forward, we repair all the boost leaks. I even got to the point to where I popped the FPR vacuum line off every time I do a BLT. So, I think It's safe to say I can def rule out boost leaks. I decided to try to crank it up, and now it struggles to crank. Very hard to crank, and when it does, it idles up to 1200RPMs, then bogs down to 500, and waver between 300 and 600, and then dies. After many attempts to try to get it running, I decided to pull the spark plugs and check them. They were all carbon fouled (pure black), which is why it wouldn't crank. Now it cranks, once I replaced them, and it's still doing it again, only now it will actually die, versus a rough idle at about 300 RPMs. I've been looking everywhere for answers, but I can't seem to get a clear answer. I've replaced the plugs, all coils are good (COP setup), I do have a tune now, and that doesn't help and I replaced a leaky PCV valve. I also took the EGR valve out and cleaned it, as it was caked in carbon, but that didn't help either (unless it just went bad). On a side note, The vacuum line that held the PCV valve was rock hard and I literally had to cut it out and pry with all my strength, off the IM. I also see that my vacuum at idle is at 9 inHg.
Any advice would be very helpful, as I'm running out of places to check.
 
The black/carbon plugs definitely points to you running really rich.
You should probably just do an EGR block off at his point, it's really not going to be effective with the cams anyways.
If you have access to something as basic as the torque app and a bluetooth obd2 adapter you can see what your fuel trims are doing.
Once the coolant is warm enough and the O2 sensor cycling the ECM should be able to get the fueling under control for cruising conditions during closed loop.
Cams can create issues during idle but things should clear up once rpms increase to 1000+.
You really need to see what the ECM is trying to do.
The cams would have thrown off WOT/open loop fueling and idle but if the ECM can't get things under control during closed loop driving there is probably an issue outside of something specifically tune related.
 
So, the plot thickens. My dad and I ran a compression test, and the numbers were: 0, 100, 100, 130. So definitely not good, and shocking. We ran it twice just to be sure, but it was consistant. Now, from my understanding, when you run rich, which I have for years, your fuel injector(s) over compensate and spit more fuel into that cylinder. When there's more fuel, and same amount of lubricant, the ratio is thrown off and over time, it gets worse and eventually, you have way more fuel, and since fuel is a drying agent, it can score the cylinder walls. When all this takes place, your vacuum decreases and therefore, so does the compression. Is this correct and has anyone ever had this issue?
 
Cylinder scoring wouldn't lead to 0 compression. Pull it apart, something is wrong in the head. Could be bent valves, leaking HG, or a number of other things.
 
0 compression definitely indicates a major sealing failure, not a minor leak, you can't build enough compression to even register.
I'm guessing since this all happened during a cam swap & messing with the timing belt that dead cylinder might have a bent valve or something screwy in the valvetrain, totally just a guess based on what was recently done.
You can try a leakdown test to see if you can figure out where the air is leaking specifically, intake valve, exhaust valve, etc.
The engine would actually run fine on ~100psi and wouldn't be the end of the world.
Lifters can pump up too and keep the valves from seating but I don't think thats the case here.
 
Okay sounds good. I'd much rather it be valvetrain failure versus engine failure (rings, pistons, etc). Now, I do have another question. When we did the compression tests, it was on a cold engine (car hasn't been cranked in about a day) and we didn't do any rotating. It was my first time ever doing a CT, so I wasnt sure if that made a difference or not. When the plugs were pulled (after i changed them two days or so ago), the plugs were beginning to foul yet again... just wanted to throw that out there.
 
The cold engine wouldn't drastically change the results really, warmer engine should seal slightly better though
Generally you want all the plugs out so the engine can free spin with the starter
Throttle body held WOT to allow air into the intake manifold and fill the cylinder
Crank the engine over with the starter
Even if you had to do the bottom end of the engine it can be done rather easily in frame too
 
Yeah we removed every plug before beginning. I didn't think it mattered much... Not to mention if cylinder 4 is at 0, I doubted that doing it on a warm engine would make a huge difference. My dad suggested popping the valve cover off, and while rotating the engine, pay close attention to the number 4 valves and the impact with the cam lobes to the lifters... and that I would know if my valves are bent just by watching. It just seems to me that the chances of those valves being bent is kinda slim, considering number 1 was at the highest compression, indicating that those valves are fine (my dad strongly believes it's got to do with my piston/rings).
 
Removing the valve cover sound like a good idea. In the past I remember a couple posts where a member had a loss of compression on a cylinder. After removing the valve cover they discovered that one of the rockers came loss getting caught up in a valve holding it open enough to cause zero compression. Hopefully you're having the same type of problems after your rebuilt head. Good luck to you.
 
Thank you. That would be a terrific find, if that were the case. Guess we will find out tomorrow. I'll definitely keep everyone posted, just in case someone comes across the same problem.
 
So I took the valve cover off and there was nothing completely out of the ordinary. When I compared cylinders 1 and 4's valves, the intake valves were closed on 4 and open on 1, and the exhaust valves seemed to be the opposite of one another as well. Is that normal? I would think they would be the same, since 1 and 4 seem to work together. After all, 2 and 3 were about the same to each other.
 
So I took the valve cover off and there was nothing completely out of the ordinary. When I compared cylinders 1 and 4's valves, the intake valves were closed on 4 and open on 1, and the exhaust valves seemed to be the opposite of one another as well. Is that normal? I would think they would be the same, since 1 and 4 seem to work together. After all, 2 and 3 were about the same to each other.

While 1-4 and 2-3 are on the same stroke pattern, their valve events are different.

Was your observation with the cams in place or removed? A picture of what you're looking at would be helpful.
 
The cams were still in. I'll take a picture tomorrow to show my observations.
 
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I tried labeling them through photo grid and putting them side by side (labeling the cylinder number and if its intake or exhaust).
 
It's hard to tell but to me it looks like one of the intake lash adjusters is pumped up a little & might be holding the valve open (when it should be closed). Did you bleed the HLA when you did the cam install? Also, were the pictures take with #1 at TDC on the power stroke?
 
It wasnt taken at TDC. To be honest, I'm a little rusty when it comes to determining with stroke your at when your at TDC. How would I be able to know? I know lining up the cam gears is a great start, but idk how to determine if I'm in the power stroke, though? I can easily rotate the engine tomorrow and take pics and see. The lifters could be pumped up and causing the lifter(s) to not allow the valve(s) to close all the way... I noticed on some other threads on here that some people have had that problem with the revised lifters. I def dont mind rebleeding them, just to see if that makes a difference. All lifters were bled once or twice, and I was able to press them in between fingers easily, though it seems like sometimes that doesn't seem to be enough.
 
As already mentioned above, open/bent valves or head gasket sealing issue.
Did you check the flatness and resurface the head/block before installing the cometic head gasket?
In case if you are able to start the engine even unstable, remove the coolant cap from thermostat housing and put a half pet bottle or a funnel instead, and pour coolant/water to raise the level of coolant. And then start the engine, if the head gasket sealing is the issue, you would probably see a lot of bubbles coming up in the pet bottle/funnel.
Or try to re-torque head studs a bit one by one and see if the compression test result would change or not. If the compression test result would change a lot then you probably have a sealing issue.
 
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