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Discussion Starter #1
OK, so my "Service engine soon" light came on about a week ago. It was intermittent at first, but now its been on for the past few days. I went through the diagnositc checks on the sticky, the lift pump checked good and I was doing the ones on the turbo. The wastegate rod was sucked into the actuator housing and I could not push it down. But I was getting a boatload of black smoke (alot more than ususal) under hard acceleration. I brought it over to a Shucks and got the codes read, yup it was tubo related.
I have the following:
Freeze code: P0236 - turbocharger boost sensor A circuit range / performance
Pending code: P1656 - Wastegate solenoid control circuit fault

This is both my first diesel and turbo equipped truck, so I'm still learning as I go along. I did a search but couldn't find this problem already posted. What exactly do these problems mean, and how do I fix them?

Thanks in advance
 

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Look for loss of vacuum or a WG solenoid bad, start from vac pump make sure it has 15" minimum vac at idle, verify no cracks in the lines, if mechanically sound then problem routinely lies with bad WG solenoid or wires to it. Sustained heavy black smoke on accel is indicative of insufficient air, working WG system has puff of black smoke going to light brown then mostly clear as turbo spools up and adds air to fuel
 

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Discussion Starter #3 (Edited)
Ok, I think I'm doing something wrong. I disconnected the hose on the vacuum pump, but not only did I not get any vacuum, I got about 2psi of pressure. I couldn't feel any leaks at the connection points to the hose, but I was a little more concerned with losing my hand to the serpentine belt while the motor was running. I hooked up the gauge to the end of the hose where the red arrow is pointed. What am I messing up? Please bear with me if I'm making a real newb mistake, I work on jets, not cars. You would think the skill woudl transfer over, but hardly at all, it's apples and oranges.
http://i30.photobucket.com/albums/c348/kaaooga3/diesel place/vacuum.jpg
 

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Sorry, but I have to ask. Where did you get the cool blue (silicone?) hoses?
 

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Guy I forgot where I got them but search the net for silicone hose, I just found these with a quick yahoo search http://www.hosetechniques.com/catalog_search.tpl http://www.stealthwork.com/
www.hosetechniques.com

Okay I found where I got mine http://www.turbohoses.com/Product.htm

Jack if you can work a TF-34, aka LM500 in my world, Diesels won't be a problem, I check mine where the white nylon line goes into the rubber hose sort of behind the alternator, I just looked at my vac pump and I don't think that is the correct one you have pointed to, I'll know for sure later in the week my vac pump literally just crapped out yesterday, no vac and unhealthy noises coming from it, so I'll probably go short belt conversion and eliminate the pump.
 

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Thanks TD.
 

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Discussion Starter #7
Gotcha. I found that line in about 2 seconds. I didn't think I was checking the right one last night, it didn't seem right at all, but the Haynes manual I have is kind of vague. The nylon line on mine is orange though. I got 23" of vacuum, so I got that going for me, which is nice. I'm going to pull of the engine cover this evening and make sure the orange line is good to go and not messed up somewhere. Assuming its good, is this the wasteage solenoid? And is the dealer going to be my best bet to get a new one, or would other shops either stock or be able to other that kind of part?
 

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Discussion Starter #8 (Edited)
I checked the connection on the cannon plug in the picture, and it seemed pretty good, bit then I was looking real hard at where the wires to the cannon pulg are spliced into the wire bundle. One was good, but the other, I could see the shrink wrap had been chaffed open and the bare wire exposed. I gave it a little tug and it came right apart. the two halves had just been twisted together and covered. They were not very secure. I soldered them together, but still no luck. I guess its probably the actual solenoid then, huh?
 

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Discussion Starter #9
I got a new solenoid from the dealer, but same problem. I've read this thread http://dieselplace.com/forum/showthread.php?t=16888 about the turbo/wastegae operation but I'm still kind of lost. The way I understand, since the solnoid is good, the wastegate vacuum servo cannister is letting all the vaccum bleed off? Or is there another more likely part at fault?
 

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Should have 26" vacuum at wastegate solenoid, 15" vacuum at wastegate at idle.

Neat warthog, Jack.
 

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Discussion Starter #11
I have 23" at the WG solenoid. Is 3" that big a difference or is there a +/- range? When I measure at the hose attached to the WG actuator coming from the WG solenoid I get 0" of vacuum at idle. This is with a new WG solenoid.
The way I understand, my next step is to put a vacuum pump on the WG actuator, and pump it up. If it leaks, it's the actuator that's bad. Correct?

BTW, That picture is of one of my old jets, the first one I was a DCC on actually - 79-0141 back at Pope AFB, NC.
 

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23" is ok - 25-6" is new.

That would be a good check - but also check the plastic tubing between the sol and the actuator - it is prone to crumbling\cracking.

Also, vac supply goes to the center conn on the sol, the side conn goes to the wg, iirc

That shark's got a nasty bite...............

USAF '59-'67
 

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Discussion Starter #13
Both lines are on the inboard side of the solenoid. The one to the vacuum pump is the foward one and the one to the WG actuator is the aft of the two. The lines look good. As I'm looking at the actuator harder, I think something is out of whack. It's the rod on the outboard side of the WG actuator that I push down that shouldn't move. It didn't move before when I pushed it, but I think that is because it was already in the down position. I noticed this a minute ago, I was looking at it with the truck off, and then again at idle and it's the same, down all the time.

http://i30.photobucket.com/albums/c348/kaaooga3/diesel place/CIMG3110.jpg

http://i30.photobucket.com/albums/c348/kaaooga3/diesel place/CIMG3111.jpg

http://i30.photobucket.com/albums/c348/kaaooga3/diesel place/CIMG3112.jpg

I am going to get a vacuum pump in the morning and check the actuator. I hook up the pump where the red arrow/rubber hose is, right?
 

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Put a tee in line with the line to the actuator, long hose routed into cab not pinched so vac can't be dead headded, drive with gauge to see how much vac is being supplied to the actuator should modulate as PCM cycles WG solenoid.

From 2 pics of actuator at idle and off I don't see a difference of WG lever arm position, at idle actuator should be fully retracted, 15+ " vac, pretty close to what is at pump actually I don't think there is much drop across the solenoid,

Another quick check plumb vac PUMP main line direct to the WG actuator, (you can remove the red & black lines from WG solenoid & put jumper tube between them, giving 23" vac you measured earlier direct to the WG actuator, which should draw actuator rod right up and hold WG tight, if it doesn't do it the diaphragm in the actuator is bad.
 
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Discussion Starter #15
Put a tee in line with the line to the actuator, long hose routed into cab not pinched so vac can't be dead headded, drive with gauge to see how much vac is being supplied to the actuator should modulate as PCM cycles WG solenoid.
I will pick up some longer tubing first thign tomorrow and check that.



Another quick check plumb vac PUMP main line direct to the WG actuator, (you can remove the red & black lines from WG solenoid & put jumper tube between them, giving 23" vac you measured earlier direct to the WG actuator, which should draw actuator rod right up and hold WG tight, if it doesn't do it the diaphragm in the actuator is bad.
I just did that now, and as soon as the WG solenoid is bypassed, the actuator arm gets sucked up tight. So I guess this means the actuator is good, and since I already replaced the WG solenoid then it's good, that my problem lies elsewhere.



OK I put a jumper hose between the two ends of line, so it bypassed the new WG solenoid, and it did everythign ti was supposed to. The rod on the actuator sucked right in and I could not puch it down. When its going through the solenoid though, it's down. I
 

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If solenoid is new, and plumbling is good, check the wires to it make sure those are good NVMTNLION posted recently that was the fix for him, similar scenario John if you are reading post some TS tips for electrical check out as this post will probly be archived with the rest of the sticky's.

If wires are good including chasis grounds, then we need to know why PCM control signal isn't pulsing on the new solenoid, which I think only thing left are boost sensor, or PCM itself. I once had a fail on mine wherein boost sensor failed going high, falsing to the PCM I was making too much boost so I defueld but did not code. Gauge readings were only showing 9 psi vs 35 psi into the PCM, see if you can read what PCM input is, also remeber to convert kPa to psig which is what your gauge probably is.

I don't see it in signature, but do you have a fooler or fixed resistor installed, if so what is value of resistance, that could be causing problems to PCM reading input incorrectly. Anybody else got a thought I can't think of much else it could be?
 

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Discussion Starter #17
I picked up a logn peice of tube and use a T to watch if the WG actuator was gettign any vacuum while driving. It's not, so it's not a problem of it getting not enough, something is not telling the WG solenoid to let the vacum through to the actuator.

The 2 wires coming out of the solenoid are good. Should the solenoid be getting any power at idle in either wire? What kind of electrical troublesooting is due now? I will ask a friend of mine who is an electrician at work check them for me.

EDIT: Also, where is the boost sensor and PCM?
 

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Boost sensor, aka MAP sensor as it is known at the dealer, black rectangle device on intake IIRC I put a photo of it photo in photo section, PCM (computer) behind the glove box, if we find that is the culprit, now would be time for reflashed one
 

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Wasnt a photo heres one
 

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Discussion Starter #20
OK, the connection on the boost/MAP sensor looks good. which one behind the glovebox is the PCM? There's a small black plastic one (about 1"x2" square) and a larger sliver metal one. I'm guessing its the larger metal one on the right, becuase it has about a million wires going into it. Either way, they both seem to have good connections.

I can have my friend at work shoot the wires if anyone can tell me what he should check for and get from them.
 
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