New guy with a '97 K1500 Z71 [Archive] - TheDieselPage.com Forums

Itsnotme1988

06-28-2013, 16:33

greatwhite

06-29-2013, 05:37

Just picked up a 1997 GMC Z71 with a 6.5. New to the world of medium diesels (last was a 2003 Jetta TDI) and still very green on diesel to begin with. Truck has 189k miles and runs alright. Have some odd flutters and intermittnet issues to figure out. Vac line broken from pump, waste gate actuator removed and has a spring with 2 washers to hold open (showing no boost on gauge.) Pickup for boost gauge pressed into rubber hose from turbo to upper manifold. PMD was relocated to a heatsink but is just laid in the inner fender well in the engine bay, not sure of the brand. Thinking this could be the issue...Also has a leak at the filler neck...will be looking for some parts soon to get it right!

http://i123.photobucket.com/albums/o318/trashfile_bucket/GMC%206%205%20Z71/phone116_zps2e4cc926.jpg (http://s123.photobucket.com/user/trashfile_bucket/media/GMC%206%205%20Z71/phone116_zps2e4cc926.jpg.html)

Think I did alright for $4k

Supposedly has upgraded injectors and new transmission but nothing to prove when or what. PO said it was done by the owner he purchased from a year ago.

Things to do so far:

Wastegate Acutator
Replace line from Vac pump
Clean VSS
Turbo to intake hose
New filters
Replace/Clean CDR (looks original)
Possible PMD
Flush brake fluid
Replace M/C grommets
Replace/rewire stereo
Tires
Bulbs in dash (no SES light, glowplug light, etc)

While I do like the OEM vac system (IE: prefer it), it can be rather "nickle and dime" once it gets miles and age on it.

You can convert it to a mechanical wastegate controller for about 110 bucks (heath diesel) or you can make one yourself out of hardware store parts for around 10 bucks (Google for DIY turbomaster).

I have the Heath until on my truck right now as my vac pump was going out and I had a Turbomaster sitting on a shelf. I like the turbo master over the home made one becasue it a simple bolt on procedure and you know what you are going to get. Looks neat and clean too. But you pay more for that convenience over a DIY one. It's a personal call (or budgetary call) that's different for everyone on which way you go.

For reference: turbo master ~ 110 bucks, vac pump ~ 130-150 bucks.

You will also need a new serpentine belt as removing the vac pump requires a shorter belt.

The other issue you may run in to if you go that way is that most 1500 6.5's were L56 RPO engines which means they have an EGR valve. This valve requires the vacuum pump to function. You can convert to an L65 (HD version of the 6.5) calibration and remove the EGR valve, but that's more money again.

With your wastegate held "open" no boost makes sense. It's bypassing all the drive pressure. With it held shut you should have lots of boost depending on the strength of the spring you have installed (what is essentialist a turbo master). If the wastegate is held closed and you have no boost, there's something wrong with your turbo. No drive pressure would be an exhaust leaks and fairly obvious from the noise it would produce.

Also, if you're got "0" boost, you should be laying down one heck of a thick black cloud when you stomp on the throttle pedal. If the truck only makes a light haze when you tromp it or are climbing a hill, then I'd bet money on your boost gauge either not working or the "boot tap" is leaking. You should be hearing a fairly high pitched whistle if it's leaking though...

"Upgraded" injectors makes it sound like they dropped in a set of marine injectors. While some may disagree, these are pretty much pointless on an otherwise stock truck. Fuel delivery is essentially determined by the PCM through the fuel solenoid, not the injectors and pump springs like a purely mechanical diesel. They're not going to hurt you (at worst they may drive your egt's up a bit if towing high and heavy or at full throttle application since they are optimized for fuel delivery at WOT like a marine engine is run), but they're not really going to help either other than being new (er) that a set of 100,000+ injectors.

The boost gauge tapped into the manifold boot isn't the best way to do it, but it will work just as well as a "boost bolt" (google for it if you don't know) or tapping into the upper manifold. It's just a PITA to get a reliable seal unless you do it right.

I tapped my manifold and used a Digital gauge:

http://i40.photobucket.com/albums/e235/gr8twhite/Private/1998%20GMC%20private/Interior/gauges/DSC03844-1.jpg

And then used some fiber braided fuel return line to connect to the 3 bar map sensor that runs the gauge.

A rebuilt or New transmission most likely has a label or tag on it somewhere from a rebuilder. If it's not that old, you can probably still find one if you have a look in, under and around the transmission. No guarantees there is one under there though.....a local shop doing a "bench rebuild" with the original core won't be likely to have their ID on it somewhere.

These are old trucks but there's lots of quirks and oddities to learn about them. You're in a different world than the modern Di engines.....

Cheers

:)