Help - running rough, new plugs, wires, cap and rotor

SunlitComet · Dec 10, 2010

gulleyman · Dec 11, 2010

Those look better than all three sets I pulled out of my Yukon sunlitcomet :signs8:

The new mechanic called me today a couple of hours after I dropped it off. Said that the compression is bad in cyl 6, said he wonders how the other two guys missed it unless they didn't really check...
Possibly bad valves or head, about to start weighing options and spending money. I'm so ready to get this behind me and get my truck back on the road again.
Maybe I'll drop a 383 in there if I end up just replacing the motor

SunlitComet · Dec 11, 2010

could you get the pressure reading from him?

---------- Post added at 09:54 AM ---------- Previous post was at 09:49 AM ----------

or more specifcally how that 6 cylinder is building pressure?

gulleyman · Dec 12, 2010

Yes'r, I'll try to get it out of him tomorrow.
How's your project coming?

SunlitComet · Dec 12, 2010

I think when I move my truck back here on the first of the month I can get the pitman arm replaced first on the way. It is dangerously close to breaking off the relay rod any second. Then off to a car wash where the bottom end is going to get steamed and degreased. I hope to get my software and hardware for for diag so I can start doing analysis on the vehicle systems.

gulleyman · Dec 17, 2010

Man, I thought I posted this earlier in the week but here goes:
Nearly "150" on all holes except 6, it was "0"
Guess we know now that neither my first mechanic or the dealership REALLY checked the compression!

So anyway I've been wrestling over what to do as far as replacing the engine all week. After looking around on several forums it seems that the best and likely most cost effective option for me is to pick up a late model 5.3 engine and swap it in. At first glance it looked like that would be too much of a PITA but after looking a little harder it seems as though others have already done all the hard work; custom mounts, harnesses and adapters can be had online or even locally.

As an added bonus I've read that the 5.3 will be more efficient and is capable of over 400hp with just a mild cam and performance tune. If I can find one that comes with a 4L80e attached to it even better. I found a couple of low mileage 5.3's for less than $500 right away.
Check out this write-up:
http://www.hotrodlane.cc/PDFFILES/Lisa Tahoe.pdf

What do you guys think?

SunlitComet · Dec 17, 2010

I just choose to do all the diags myself from now on I am tired of relying on others. Nobody makes an effort anymore as long as the get money. I still seem to be on track with getting my pitman and software done next month so far. I will read it and get back to you. Thanks

SunlitComet · Dec 17, 2010

Harness $926+
Mounts $115+
computer programming $260+
Fuel line and regulator if needed $220
5.3l drivtrain ?
plus adapter and other bracket ?

I find no numbers to back up power gains, mileage, or emmisions gains. What happens when you need to run diagnostics and you have two computers. I think the scanner will be a little confused.

I like the idea but if I did i should be getting a better and bigger block and the rest of the drivetrain to go with it. Also to get the newer engine but not all the rest of sytem upgrades the vehicle has just sucks to me.

I think there are too many unanswered questions for me.

The dollar amounts I listed already is a remaned long block from atk engines and I have used about 6 of them in aviation equipment running 16 hr days with no trouble.

I think I will stick with a stock engine with upgrades like ignition, exhaust etc.

Do you have the means to at least strip you head off to look into the problem yourself or do you not have another vehicle to use for driving while doing so? Would save some money And might just be a valve job. If your already to be willing to pull it out any way it could not hurt to look.

oldsalt · Dec 18, 2010

"0" sounds a little odd to me.

Got to be honest here. If it was me I would either pull this stock engine and have it rebuilt or purchase a new one and swap it out.

You've already spent 2 months and a bit of money chasing down this problem. I'm with sunlitcomet here. I would get back to a stock set up and start enjoying your car again then make changes to that as time goes on. At least you have a good reliable baseline to work off of.

If you want to spend your time tinkering and chasing problems buy a british car.

99Yuk · Dec 18, 2010

oldsalt said:
...If you want to spend your time tinkering and chasing problems buy a british car.

LMAO!!!!!
I've been watching BBC Canada's Top Gear UK, and I just came to the same conclusion this week!

Is it my imagination, or does '0' compression speak to one or two bad valves for that cyl, while the heads are probably ok? Couldn't he just pull that one head, repair the valves and pop the head back on, and be back on the road for cheap, relatively speaking vs. buying a new engine?

Help - running rough, new plugs, wires, cap and rotor

SunlitComet

OBS Jedi-Do Good

gulleyman

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SunlitComet

OBS Jedi-Do Good

gulleyman

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SunlitComet

OBS Jedi-Do Good

gulleyman

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SunlitComet

OBS Jedi-Do Good

SunlitComet

OBS Jedi-Do Good

oldsalt

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99Yuk

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