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  #1  
Old 08-27-2004, 12:59 AM
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603 Turbo has no boost, need help!!!

Now that I have better understanding about my injectors, it's on to my next repair!

Since I've owned my 87 300d, the turbo has never produced boost. Here is a short list of what I have done so far to investigate why..

#1. I have tested the electro switch valve that operates between intake and alda, it works!

#2. I have bypassed the switch and direct to alda from manifold, nothing!

#3. All hoses connecting switch, alda, and manifold hose fitting are unclogged, open and clean.

#4. I have connected a pressure/vacuum guage between intake manifold and alda, no boost pressure is evident.

#5. I had suspected a frozzen waste gate in open position, but it is not frozzen.

#6. I have inspected the turbo fan for play and it is firm and spins easily by finger.

#7. While I had the head off last week, I looked it over and couldn't see anything amiss, but then I'm not knowledged about what I should be looking for!

#8. I did move the push-rod between vacuum pod and waste gate and it moved all the way, but with much spring resistance from the pod.

#9. I removed the only 1/2 in dia. rubber hose that is affixed and it was not clogged, cracked or broken.

#10. I disconnected and plugged all vacuum hoses from the tee, located front of engine, that went to the EGR, located front below air filter.

While I have adequate power to maneuver in traffic, and it climbs hills without dying too much, I generally have to give it all it has, near pedal to the floor to do so! I get better than 30 MPG on average.

I would like to understand what I can do to get it working, but at this stage, I need some advise.......


Steve...........................


Last edited by sarafin; 08-27-2004 at 01:38 AM.
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  #2  
Old 08-27-2004, 01:39 AM
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Location: Evansville, Indiana
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Sounds like the wastegate control spring is shot and the wastegate is open all the time. The link between the boost control servo and the wastegate should be sprung fairly stiffly towards "closed" (I think that is toward the front of the car, but I'm not sure).

Make sure the fitting in the intake manifold is clear -- if it it plugged, you willl have boost but it won't do anything without extra fuel, and you won't get extra fuel unless the boost signal line is intact (white plastic between intake in the center and ALDA -- note that it goes through a switchover valve on the firewall and to the vac amplifier for the tranny shift controls).

Blow through this line after detaching from the intake. If it won't hold pressure, find the leak. Most likely is a blown overboost protection switchover valve -- it must not vent out the top when unplugged. If it does, replace it. If it does any time the ignition is on, the pressure switch is bad, replace that.

Otherwise, look at all the connections (the boost line has clamps everywhere) to check for broken rubber connector bits or cracked lines. Don't ignore the tranny amplifier, it must hold pressure too.

The wastegate control servo can be fixed by a competent diesel injection service, this shouldn't be too much.

However, it is possible that the turbo is bad -- if you feel intermittant resistance while spinning the turbo compressor wheel, the bearings are shot and it isn't making much if any boost even though it turns. It has to go pretty fast to make boost, after all!

Peter
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  #3  
Old 08-27-2004, 07:16 AM
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psfred

Thank you for pointing out several thoughts. It was several months ago that I tested the switchover valve and overload protection switch.

I have not tested the wastegate control servo yet, will do today!

I have a service manual printed for everything related with the turbo and will test everything I can.

I didn't notice anything you mentioned about "intermittant resistance" with the turbo compressor wheel, it turned freely.

I'll report back my findings tonight.............Steve
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  #4  
Old 08-27-2004, 05:24 PM
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Spent the morning inspecting and testing most all componants that could be tested of the turbo and have found no faults with pressure switch, switchover valve, or charge pressure control valve. The alda is probably ok but I could only produce 6 psi @ 4000 rpm. You can feel a bit of boost so I do think the fuel is being enriched but only up to 6 psi.

I had the crossover pipe off and reved the engine until the turbo started blowing lots of air, not as much as I expected, felt like an air hose blowing 100 psi in your face!

There was a small puddle of fresh oil laying in the bottom of the compressor housing and with 235K on this turbo, my guess is that it is time to rebuild, or buy a rebuild.

Question: Are there expensive specialized tools needed to rebuild this Garrett TB 03, can the average backyard wrench do it himself?

$700 to $900 for a rebuild is not in my walet for a while but would rather buy the needed parts and go at it!

What tipically is replaced in a turbo aside from bearings, seals, etc.???
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  #5  
Old 08-27-2004, 07:20 PM
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You didn't say whether the wastegate is closing or not. My 87 had similar symptoms as yours and I found there was the crud built up around the flapper in the wastegate (the gate?) and it was binding - never fully closed- lots of effort to clean it paid off, I was about to send the turbo for rebuilding when I found the problem. 257K miles young and still strong!
DDH
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  #6  
Old 08-27-2004, 08:24 PM
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Quote:
Originally Posted by dieseldiehard
You didn't say whether the wastegate is closing or not. My 87 had similar symptoms as yours and I found there was the crud built up around the flapper in the wastegate (the gate?) and it was binding - never fully closed- lots of effort to clean it paid off, I was about to send the turbo for rebuilding when I found the problem. 257K miles young and still strong!
DDH
Technically, it is called a "charge pressure control valve" we call it a wastegate!

Thanks for that tip about crud clogging up the wastegate, or whatever we want to call it, I'll look into that when I do remove it sometime soon but I got a feeling that with it leaking oil as it is, I hope to rebuild it anyway.
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  #7  
Old 08-28-2004, 01:02 AM
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Quote:
Originally Posted by sarafin

I had the crossover pipe off and reved the engine until the turbo started blowing lots of air, not as much as I expected, felt like an air hose blowing 100 psi in your face!
I assume that you did this with the vehicle stationary. As such, the turbo cannot produce much boost, if any, because the engine is not sufficiently loaded. Therefore, this would be a poor test to determine if the turbo is performing satisfactorily. Your previous result of 6 psi does show that something is amiss, provided that you got that result with the engine under full load (vehicle moving) with the rpm above 2500.

In this case, I concur with the previous posts whereby the wastegate is likely to be the primary culprit. There is no need to spend a lot of money rebuilding the turbo unless it is absolutely required.
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  #8  
Old 08-28-2004, 09:12 AM
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Question

Quote:
Originally Posted by Brian Carlton
I assume that you did this with the vehicle stationary. As such, the turbo cannot produce much boost, if any, because the engine is not sufficiently loaded. Therefore, this would be a poor test to determine if the turbo is performing satisfactorily. Your previous result of 6 psi does show that something is amiss, provided that you got that result with the engine under full load (vehicle moving) with the rpm above 2500.

In this case, I concur with the previous posts whereby the wastegate is likely to be the primary culprit. There is no need to spend a lot of money rebuilding the turbo unless it is absolutely required.
I took the crossover off and ran it staionary to see if the turbo was turning at all since I wasn't sure it was.

I ran my vac/pressure guage from manifold and alda (with a tee) connecting a 2 ft. section of vac hose with guage up and back through some hols in the firewall and up and under the wiper blade so I could see it while driving. Floored it from second on a long straightaway and watched the guage and tach until the engine would not put out any more rpm and the tach read 4000 rpm, pressure guage read 6 psi.

Is my wastegate not closing all the way?

What is limiting the boost?

What causes a supposed worn out turbo to limit boost?
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  #9  
Old 08-28-2004, 10:59 AM
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Quote:
Originally Posted by sarafin

Is my wastegate not closing all the way?

What is limiting the boost?

What causes a supposed worn out turbo to limit boost?
You should have had full boost at about 2200 rpm under full load. There is certainly no requirement to run the engine up to 4000 rpm to verify boost. In fact, the boost might fall off at 4000 rpm if you lift your foot to prevent overspeed of the engine.

My suspicion is that the wastgate is the culprit.

If the wastegate is partially open, even a bit, the turbo cannot provide full boost.

Now with regard to what caused a "worn out turbo" to limit boost, this is more complex. If the turbo is spinning freely, and if it reaches its design speeds, it is highly unlikely that it will not produce the desired boost pressure. This is true, even if the turbo is "worn out". Normally, they do not wear out. Their compressor and turbine wheels are perfectly suited to go 1 million miles and the bearings are the only thing that require replacement. However, there are exceptions. If any part of the wheels are damaged or missing then the unit will not function as designed. However, in this condition, the bearings will be taken out very quickly due to unbalance forces and you can easily feel this if you spin the impeller by hand (DO IT COLD!).

As mentioned above, I would carefully investigate whether the wastegate is fully closed, and the wastegate spring is working correctly, prior to doing anything to the turbo.
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  #10  
Old 08-29-2004, 07:21 PM
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Have inspected wastegate and is clean as a wistle! Closes all the way (visually) Spring is tight enough to take the tip of your finger off! This waste gate is sealed tight when it is closed!

Looked inside with high-tech lighted michroscope and completes a sealed close.

Pod was actuated with 3 lbs. from my shop air comp. and opens and closes as it seamingly should!

So why can I not achieve more than 6 psi from 2500 to 4000 rpm????????????????????????????
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  #11  
Old 08-29-2004, 07:42 PM
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Quote:
So why can I not achieve more than 6 psi from 2500 to 4000 rpm????????????????????????????
Cause it's not getting enough fuel? Try this. From a standing start floor it and look out the rear view mirror. If you don't see any black smoke it's probably running lean and the ALDA may need adjustment. Had same car 2 months ago with same symptoms and same shadetree diagnostics. After adjusting ALDA it took off like a bat out of hell from a stoplight. Only put out a little (acceptable) amount of smoke during heavy acceleration and still averaged almost 33mpg on a 1500 mile trip.
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  #12  
Old 08-29-2004, 09:03 PM
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I tend to think it is getting enough fuel to spin the turbo up to sufficient speed for more than 6 psi boost. Even if it was running lean, the turbo would acheive full boost, however, it might be a bit later in the rpm range.

OK, now that we know the wastegate is fully closed to start off, see if it is possible to disconnect the wastegate actuator so that it never opens the wastegate under any condition. I have not taken a good look at the 603 in this area, so, maybe Dave could chime in here on whether this is possible.

The goal is to eliminate the wastegate from the equation and now see if you have more than 6psi. Of course, you will have to be careful. If the boost climbs up over 12 psi during this test, then let off the pedal and keep it below 12 psi. If it remains at 6 psi, then we know the wastegate is out of the picture and need to look elsewhere for the problem.
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  #13  
Old 08-30-2004, 10:14 AM
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You gotta have boost

• Check or replace all vacuum lines going to the ALDA again with focus on the small rubber pieces that connect the lines. Sometimes clogs are difficult to determine. The boost signal/pressure must make it to the ALDA.

• “T” a boost gauge line and boost gauge right at the line going to the ALDA or the line into the intake manifold. The gauge is cheap and can be invaluable as you make changes. Just do a “test run” on a highway ramp or up a hill to measure boost changes under load.

• Blow out the ALDA and the line going to the intake manifold. Sometimes these get filled with gunk blocking the signal to the ALDA. GSXR has tons of photos and of the ALDA which can be helpful.

• Pinch off, or block completely the actuator hose for the waste gate. (with the boost gauge this will provide feedback so you don’t over boost) With the actuator line blocked you should get max boost out of your turbo at about 2000-2200 RPM.

• Do you see any blow by signs around the manifold. New black oil? This would indicate leaks in the crossover pipe or your manifold. This could be causing boost to “leak” out, but it would have to be a big leak.

• If you drive along a concrete divide or wall with your windows down you should be able to hear the turbo spool up. High pitched wine just like a 18 wheeler. You should be able to hear it whistle as it starts to spin up before 2000 RPM.


I had a poor performing turbo and was able to get about 8-9 psi of boost out of it with the waste gate forced shut. This boost level was also not sustainable as it would quickly fall to zero with slight release of the accelerator. The turbines were chipped and torn up and it didn’t spin freely. To get it to this level I had to check everything including leaks and cracked lines and plugged lines. I also blocked off everything under the air cleaner, eliminating it from the system. On this turbo I had to hit about 3000 RPM before any boost came on at all.
I bought a used turbo on ebay in perfect condition and replaced the old one. This made all the difference in the world. Now it boosts quickly at 2000 RPM. I have it set for 12. At highway speeds it provides constant boost at about 5 or 6 and the slightest blip of the pedal brings it to 10-12 quickly. With the old turbo, I had to "work" or force the car to boost and with the new turbo it responds like a dream and it accelerates much much faster.

The test where you strapped the vac/pressure gauge to your wiper blades and then “got on it” to 4000 RPM and only hit 6 psi of boost sounds identical to my problem above. It sounds like to me that this is all that this worn out turbo is able to give you!

There are some threads about rebuild kits on the forum that might be worth checking out.
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  #14  
Old 08-30-2004, 02:50 PM
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Quote:
Originally Posted by Brian Carlton
I tend to think it is getting enough fuel to spin the turbo up to sufficient speed for more than 6 psi boost. Even if it was running lean, the turbo would acheive full boost, however, it might be a bit later in the rpm range.

OK, now that we know the wastegate is fully closed to start off, see if it is possible to disconnect the wastegate actuator so that it never opens the wastegate under any condition. I have not taken a good look at the 603 in this area, so, maybe Dave could chime in here on whether this is possible.

The goal is to eliminate the wastegate from the equation and now see if you have more than 6psi. Of course, you will have to be careful. If the boost climbs up over 12 psi during this test, then let off the pedal and keep it below 12 psi. If it remains at 6 psi, then we know the wastegate is out of the picture and need to look elsewhere for the problem.
This morning, I clamped the hose off to the wastegate pod and nothing changed!

Kevinaw's point about the Alda not supplying fuel beyond 6 psi is possible I suppose but my thought is now, can the turbo produce 6 or the designed 12 psi at the proper rpm's wether or not the Alda is enrichening?

In other word's, is the Alda fuel enrichment totally necessary in order for the boost to develop at all? Of coarse if the Alda isn't enrichening, you wont have more power, but inspite of that, will the boost rise anyway without Alda fuel enrichment?

If the Alda is needed to produce boost, than I need to adjust the Alda.

If the Alda is not necessary to produce boost, then I may need to rebuild the turbo maybe?
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  #15  
Old 08-30-2004, 03:10 PM
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My feeling is that the ALDA cannot make up for a turbo that will only produce 6psi. The turbo spins based upon volume. If the engine is running very lean, then the volume will be down, and the turbo will not develop full boost at lower rpm's. However, once you get it above 3000 rpm's, there is now enough volume to spin the turbo up to the required speed to get full boost (12 psi).

There is a way to rig this test to determine the answer, one way or the other. If you have a portable air tank and a regulator, disconnect the ALDA from the protection valve and connect it up to the portable tank and regulator. You will need a valve in the line.

Take it out for a test and apply 12 psi to the ALDA when the engine is under full load above 2300 rpm. Monitor the boost gauge and see if the manifold pressure comes up above 6 psi. If it remains at or about 6 psi, you have confirmed that the turbo is not reaching design speed, or, has damaged impeller blades.

This test will avoid the need to mess with the ALDA adjusting screw and the inherent risks associated with that.

I'd be very curious as to the result.

I'd also be very curious as to the result of adding 12 psi to the ALDA with the power backed off, such as cruising at a steady 60 mph. I always wanted to try this to see how much smoke could be produced. This is my dream of a proper "proximity regulator", and, if successful, I just might add it to the SDL if I can cobble up the proper switching valves. Of course, I'd need to add an onboard compressor of some fashion.

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