LB7: It's all over
- Thread starter KEVINL
- Start date
wow the more timeing/less fuel, more fuel/less timing and some in between agrument came up... 
yet everyone seams to forget no 2 truck tune alike
if the heads are comeing off good time to check protustion of the pistons as well... will give you a idea how short hte rods are
BTW H/G change can be done for less then 400.00 if you do the work
yet everyone seams to forget no 2 truck tune alike
if the heads are comeing off good time to check protustion of the pistons as well... will give you a idea how short hte rods are
BTW H/G change can be done for less then 400.00 if you do the work
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I tried to live by that motto.... cost too much damn money
By the way, "smile, bitch" made me smile....:rofl::rofl:
so this is a common problem on the 3.4s??
Sorry to derial the thread but I have a 95 monte carlo 3.4 loosing coolant and overheating all the time
What table is it B1001?
I tried that and was scared out of my mind truck would barely idle and was smoking like crazy.
Rail pressure held though?
Have you checked to make sure your intercooler is not cracked at a seem.I was getting 40 and spiking 44 lbs with that turbo.
maybe try doing a compression test just as another thing to add to the list.
If you dont have a compression gauge and the adapter for the duramax, go to the dealer and ask to borrow thiers. They dont use it much and usually will let you have it for a night or over the weekend if you have a good relationship with them.
Remove your front tires and fender liners
Then remove the glowplugs and thread in the adapter and clamp on the compression gauge. The pass side is a breeze, drivers side has a lot of junk in the way.
remove the IGN 1 fuse and have a buddy crank the truck while you read the gauge.
The GM manual says you should let the cylinder compress 6 times.
There should be no more than a 50psi difference between cylinders IIRC it could be less im not 100% sure on that number.
GM states around 400psi is normal but that is a rough number, the biggest thing is that they dont vary fcrom cylinder to cylinder.
Also watch how it ramps up if it builds up slowly and such. Others could add more info to this to determine what is wrong. Im not looking at my manual now and dont remember off the top of my head.
Usually low compression in one cylinder will show up in the balance rates, but all trucks are different.
My #2 cylinder had a balance rate of +8.5 on average. The compression test showed that cylinder 120psi lower than the others. which i later found out to be a really short rod and the rest were all short too. I was running 50psi of boost but a lot of timing and pulse width.
If you do the HGs, to save time just order C gaskets. Youll want these anyways to bump the compression ratio down a few points. Studs are a good idea as the factory bolts will run you a little under $200 for all of them and they arent reusable, the ARP studs initial stretching will wear you out but after that its done and they can be reused again and again. Only bad thing is they find the next weakest link, rods.
and since your in there, you might as well check the injector cups and loctite them again and reinstall them to be safe.
hopefully its something simple.
If you dont have a compression gauge and the adapter for the duramax, go to the dealer and ask to borrow thiers. They dont use it much and usually will let you have it for a night or over the weekend if you have a good relationship with them.
Remove your front tires and fender liners
Then remove the glowplugs and thread in the adapter and clamp on the compression gauge. The pass side is a breeze, drivers side has a lot of junk in the way.
remove the IGN 1 fuse and have a buddy crank the truck while you read the gauge.
The GM manual says you should let the cylinder compress 6 times.
There should be no more than a 50psi difference between cylinders IIRC it could be less im not 100% sure on that number.
GM states around 400psi is normal but that is a rough number, the biggest thing is that they dont vary fcrom cylinder to cylinder.
Also watch how it ramps up if it builds up slowly and such. Others could add more info to this to determine what is wrong. Im not looking at my manual now and dont remember off the top of my head.
Usually low compression in one cylinder will show up in the balance rates, but all trucks are different.
My #2 cylinder had a balance rate of +8.5 on average. The compression test showed that cylinder 120psi lower than the others. which i later found out to be a really short rod and the rest were all short too. I was running 50psi of boost but a lot of timing and pulse width.
If you do the HGs, to save time just order C gaskets. Youll want these anyways to bump the compression ratio down a few points. Studs are a good idea as the factory bolts will run you a little under $200 for all of them and they arent reusable, the ARP studs initial stretching will wear you out but after that its done and they can be reused again and again. Only bad thing is they find the next weakest link, rods.
and since your in there, you might as well check the injector cups and loctite them again and reinstall them to be safe.
hopefully its something simple.
I want to do a compression test but I am afraid of glow plugs breaking. If the heads do not have to come off that would suck to break one
I was a little worried too. mine came out with no issues at all, it was a breeze, 103,000 miles on mine at the time.
I got the compression tester pulled the glow plugs inserted the adapter cranked the engine and the gauge didn't move
What am I doing wrong?
What am I doing wrong?
Remove all the injectors?
I cranked it over about 6 times and the gauge stayed on zero
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Yeah I am not sure what the problem is It should hold the pressure right till I push the release