Turbo doesn't work

[scooter]

My 96 Suburban K2500 4x4 6.5L TDiesel has 3 symptoms that are driving me crazy:
1) Constant SES light
2) Lack of power - probably turbo in-op
3) Overheats in mountains

1) My membership just expired, so I can't look up how to read the SES codes on my 96. The instructions on Kennedy are for Pre-96 ARGH!! No way to get it renewed on a Sunday night I suspect

2) I've done some basic troubleshooting on the Turbo, and can't figure it out.
a) Vaccum fom Pump to Wastegate solenoid is a solid 24 inches
b) Vaccum at the Wastegate Actuator is 0
c) Wastegate solenoid is brand new (well...two months new)
d) I connected the vaccum pump directly to the wastegate actuator and went for a test drive...it didn't seem any different for power...so it's hard to tell if that makes the turbo work better or not. Maybe I overboosted on the first hard acceleration and it turned off?
Is it possible that the new wastegate solenoid was bad from the factory? Or is there something else going on. I obviously need to get a boost gague so I can see what's going on...How hard is it to use my vacuum gague tool to see what boost is producing?

3) It runs fine around town, starting and stopping, running in 110 degree heat...but it's very flat here in Fresno...It also runs fine on the freeway, but we just occasionally go for a drive in the mountains, and whenever I have to climb a decent hill, it begins overheating...even when the weather is only in the 90's (cool for Fresno). Any link to the turbo problem? It's certainly dog slow climbing with no turbo boost to help out.

Thanks for any suggestions. Any clue about how to read the SES code would be great. I will renew my membership this week, but don't want to wait....

Thanks,
Scott

[a5150nut]

Yes you can use your vacuum gage for a boost gage. I put mine on for a check and it's been hanging in the ashtray ever since.

Have yo got the vacuum lines in the correct position on the solenoid?

For a couple quick Sunday night answers................

[scooter]

Hey, good idea...I thought it only fit one way, but I just reversed it, and sure enough, it fits backwards too. But, I didn't have any better results, so I switched it back. However, I thought, maybe I should check out the electric connection...make sure it's not backwards. It really does fit just one way, but after re-plugging the electrical plug, the line to the wastegate had vaccum and had pulled the wastegate up!!! What the heck? Maybe my plug is corroded or there's a short somewhere?? I didn't take it for a test drive tonight, maybe tomorrow my wife will report that she's got power back...we'll see.

I just put two new batteries on today...the old ones had 53 months on them, and were not able to hold charge anymore. Costco gave me 50% back...cool. The weak batteries should be unrelated to the turbo, right? It didn't work just after changing the batteries...

Out,
Scooter

[hayhauler69]

Yes, the electrical connectors to the solenoid are funky.
I had a bad wire going to the solenoid (think it was the brown one)and the turbo didn't work. Had to take the connector completely a part. Amazing enough it works fine now.
I love to hear the turbo whine.
Some don't, but I do. I drive with the pax window down quite a bit:D
How long has it been since you flushed the cooling system?

[scooter]

Ok...I'll check out the wires...I think it's definitely something electrical. I got it working shortly after replugging the wires, but then it stopped working right after that. I'll try disassembling and cleaning the plug.

Ok...well, I, ah, well, you see, I've never flushed the cooling system. :( I'm a little embarassed to admit it. I guess that sounds like a really good place to start....Going to be towing a trailer in a couple of weeks, and don't want to overheat.

I don't quite understand how to hook up a vaccum gauge to read boost pressure. Maybe my gauge is different that what you guys are talking about. The tool I have is a little hand pump to create vaccum, and a gauge to read how much vaccum is being maintained by the feeder tube. Isn't boost a positive air pressure? Wouldn't it just push my needle down to zero? The needle doesn't have any readings for negative vaccum.....(ie: Positive pressure).

BTW: The SES light has gone out since I replaced the batteries...maybe it was just trying to tell me the voltage was low or something...

Thanks,
Scooter

[daustin]

If your going to flush the cooling system, i'd highly reccomend taking the upper fan shroud off and look between the radiator and A/C condersor and clean that out as well. It's a well known area to collect leaves...etc.
Don

[scooter]

Good suggestion...I'll check that out and clean it up as well.
Thanks,
Scooter

[a5150nut]

Instant tea (unsweetened) works real well to clean out the insides of your radiator. Drain the coolant, replace with water and a small jar of generic instant tea. Run it around for a while getting it up to operating temp. Then drain and flush with clean water and fill with your favorite koolaid.:D

[joescj5]

Check your wastegate actuator to rule that out. Go ahead and bypass the wastegate solenoid and make sure you have vac at the actuator. Once you have vac at the actuator put on a pair of gloves and grab a hold on the wastegate actuator rod. At idle you should not really be able to move the rod at all.

If the rod moves easily with verified vac at the actuator then it is probably time for a turbo-master (more cost effective). If the rod does not move then your problem is now isolated to the vac line coming from the solenoid, the solenoid itself (new doesn't always mean good), or the wiring to the solenoid.

Good luck, having the turbo spool up and feeling how these things are supposed to run is a pretty good feeling.

[scooter]

Hi joesc5,
I checked the Actuator, but forgot to mention it in my first post. I was not able to move it with the vaccum pump hooked directly into the actuator (Bypassing the solenoid). I also put my hand pump on the actuator with the engine off, and it takes very little vaccum to raise the wastegate. In fact, it starts coming up before I even get to 1 psi. I haven't tried to pump it while at idle....that would be interesting to see how much psi it takes to hold the wastegate up against the pressure of the turbo....

Does anyone know what I should expect to see? Maybe 5 psi? It's supposed to be getting 14 psi from the solenoid at idle, right? That should be more than enough to keep it closed.

a5150nut: You have a strange recipie for making hot tea, but I prefer kool-aid cold :D I suppose I have to use the AC compressor for that?? LOL...

Thanks guys for all the tips. I hope I can get this burb running up to specs soon...it is nice to feel the whine of the turbo!!