turbos help! think i have a bad 1
04-03-02, 10:53 AM
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turbos help! think i have a bad 1
i have noticed that the 93 i have seems to have lost power. still runs fine but it doesn't pull as hard as it has in past.it also was smoking bad when i would first start cold.my motor is a pettit rebuild with 30k on it.it is not smoking bad now when cold help please any ideas?
04-03-02, 01:03 PM
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Do you have a boost gauge? Do the boost test and let us know your readings. (3rd gear, WOT from 35 mph)
If you don't have a boost gauge, get one. If you just want to check your boost for cheap, you can get a vacuum/boost gauge from an auto parts store for about $20-25. You just run some vacuum tubing from the passenger side nipple on the upper intake manifold to the gauge. Get long enough tubing to run under the hood and into the passenger compartment.
If you don't have a boost gauge, get one. If you just want to check your boost for cheap, you can get a vacuum/boost gauge from an auto parts store for about $20-25. You just run some vacuum tubing from the passenger side nipple on the upper intake manifold to the gauge. Get long enough tubing to run under the hood and into the passenger compartment.
04-04-02, 09:43 AM
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turbos
i have a boost gauge i will check to see if i am losing boost. should be about 10 on the gauge? what kind of reading should i have with the 35mph 3rd gear wot. thanks i will check back later after i get a reading.
04-04-02, 09:07 PM
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This is a good way to start. You have a boost gauge so you need to do a 40-70 run in 3rd gear. Cruise steady at 35 mph floor it have someone watch the boost and note the boost pattern.
You should get:
rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)
Let me know what your numbers are.
Have you checked the usual boost leak culprits?
Y-pipe
Y-pipe coupling
1" diameter hoses
Primary Turbo Inlet
Couplers To/From Intercooler
You may have multiple issues.
1. Give a FULL report on your boost behavior based on the "chart" above. How it builds, drops... everything.
2. Do you have a vacuum/pressure test gauge? If not see if you can find one to borrow. They cost less than $20, but hey thats still $20. We will use this later.
3. We need to get the primary working. The Secondary Turbocharger requires the Primary Turbocharger to generate more than 8 psi to operate actuators that control the Secondary Turbocharger. So we will need to get the primary boost where it needs to be.
These are the easy ones to check:
Y-Pipe connector hose, (coupling)
* This is a very common failure part. This short hose, (coupling) will split and vent boosted air in copious amounts. The trick with this one is that when just looking at the part on the car it will look just fine. You need to remove the 90 degree plastic duct on top and completely remove the rubber coupling, then examine the rubber coupling by gently stretching it to see if there are any splits. Typically costs about $47 at dealer.
Check ~1" diameter hoses for leakage
* If you can rotate these hoses while attached, then the clamps are too loose. Get properly sized screw-clamps if the stock ones are not up to the job. New hoses will also help, but usually tightening the hose clamps is enough. A sign that there is air leakage is the presence of oily dirt on the aluminum casting around the hoses. New hose-clamps will set you back about $10 maximum for good ones. Note, clean up the oily dirt around the aluminum so that you will be able to see if these hoses start to leak again, (carburetor-cleaner works great).
Primary Turbo Inlet
* Typically collapses under high volume air through air cleaner into Primary Turbocharger. When the engine bay is hot the rubber is more prone to collapsing. Typical symptoms are having good boost at lower RPMs and then a loss of boost at higher RPMs, this is aggravated when engine warms-up softening the rubber allowing for easier and more complete collapse of the hose. Typically costs about $90 at dealer.
To/From Intercooler
* Same symptoms as the Y-Pipe coupler. When under boost, the hose-clamps prevent the hose from expanding due to the air pressure inside the hose. Do not under-estimate the force of 10 psi or more on 3" diameter hoses, what looks OK with engine not running may not work under boost conditions.
Giving me the full results requested above should help narrow the problems down. If it is a loud whoosh coming from the passenger side it cloud be a cracked Y-pipe.
You should get:
rpm psi
3,000 10
4,500 8 (as 2d turbo comes on)
4,500+ 10 (recovers almost immediately)
6,000+ 8 (and holds to redline)
Let me know what your numbers are.
Have you checked the usual boost leak culprits?
Y-pipe
Y-pipe coupling
1" diameter hoses
Primary Turbo Inlet
Couplers To/From Intercooler
You may have multiple issues.
1. Give a FULL report on your boost behavior based on the "chart" above. How it builds, drops... everything.
2. Do you have a vacuum/pressure test gauge? If not see if you can find one to borrow. They cost less than $20, but hey thats still $20. We will use this later.
3. We need to get the primary working. The Secondary Turbocharger requires the Primary Turbocharger to generate more than 8 psi to operate actuators that control the Secondary Turbocharger. So we will need to get the primary boost where it needs to be.
These are the easy ones to check:
Y-Pipe connector hose, (coupling)
* This is a very common failure part. This short hose, (coupling) will split and vent boosted air in copious amounts. The trick with this one is that when just looking at the part on the car it will look just fine. You need to remove the 90 degree plastic duct on top and completely remove the rubber coupling, then examine the rubber coupling by gently stretching it to see if there are any splits. Typically costs about $47 at dealer.
Check ~1" diameter hoses for leakage
* If you can rotate these hoses while attached, then the clamps are too loose. Get properly sized screw-clamps if the stock ones are not up to the job. New hoses will also help, but usually tightening the hose clamps is enough. A sign that there is air leakage is the presence of oily dirt on the aluminum casting around the hoses. New hose-clamps will set you back about $10 maximum for good ones. Note, clean up the oily dirt around the aluminum so that you will be able to see if these hoses start to leak again, (carburetor-cleaner works great).
Primary Turbo Inlet
* Typically collapses under high volume air through air cleaner into Primary Turbocharger. When the engine bay is hot the rubber is more prone to collapsing. Typical symptoms are having good boost at lower RPMs and then a loss of boost at higher RPMs, this is aggravated when engine warms-up softening the rubber allowing for easier and more complete collapse of the hose. Typically costs about $90 at dealer.
To/From Intercooler
* Same symptoms as the Y-Pipe coupler. When under boost, the hose-clamps prevent the hose from expanding due to the air pressure inside the hose. Do not under-estimate the force of 10 psi or more on 3" diameter hoses, what looks OK with engine not running may not work under boost conditions.
Giving me the full results requested above should help narrow the problems down. If it is a loud whoosh coming from the passenger side it cloud be a cracked Y-pipe.
04-08-02, 08:19 AM
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turbos bad?
i drove car in 3rd gear boost is like u said till it gets to 4500 rpm then the car has a burp or something and the boost gauge drops from +8 and falls to 0 when i think the 2nd turbo should be coming on i checked hoses i am going to get a new short hose and long 1 coming off the y pipe something is happening at 4500 rpm in 3rd gear it is bucking at this point help?
04-08-02, 09:49 AM
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Well we need figure out why you aren't getting 10 psi on the primary first. This could also be the answer to no boost on the secondary. I suspect multiple problems though.
Your message is a little unclear.
1. When you say "burp" ...is a that an audible sound or are just referring to a stumbling symptom (same as your bucking problem)?
2. I assume your boost patern was:
rpm psi
3,000 8+
4,500 0
4,500 0
6,000 0
New hoses...so did you find some bad ones?
Do you have a vacuum/pressure test gauge? If not see if you can find one to borrow. They cost less than $20, but hey thats still $20. If you can afford it go ahead and get a vacuum pump (or borrow one) like from http://www.mityvac.com
The vacuum guage is the main tool in sequential troubleshooting. The pump will allow additional tests. Let me know when you get it so we can start narrowing it down.
Your message is a little unclear.
1. When you say "burp" ...is a that an audible sound or are just referring to a stumbling symptom (same as your bucking problem)?
2. I assume your boost patern was:
rpm psi
3,000 8+
4,500 0
4,500 0
6,000 0
New hoses...so did you find some bad ones?
Do you have a vacuum/pressure test gauge? If not see if you can find one to borrow. They cost less than $20, but hey thats still $20. If you can afford it go ahead and get a vacuum pump (or borrow one) like from http://www.mityvac.com
The vacuum guage is the main tool in sequential troubleshooting. The pump will allow additional tests. Let me know when you get it so we can start narrowing it down.
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