Only 4 bar of boost on turbo

[AZ88Turbo]

Hi,

Does anyone have any idea why I only read 4 bar of boost on my 88 turbo? Does it mean the turbo is on its way out or could it be something else?

[superdave]

Hi,

Does anyone have any idea why I only read 4 bar of boost on my 88 turbo? Does it mean the turbo is on its way out or could it be something else?

I take it you mean 0.4 bar.
Yes, get the car hooked up to a calibrated reading. That way you'll have a beeter clue what's wrong with the car. I'm getting over 1 bar, my service engineer reckons it's a faulty gauge.
Does the car perform the same? Have a look at previous thread under not enough boost and too much boost, Iam sure this will help you.

Cheers,


Dave Walters

[AZ88Turbo]

Hi Dave,

It's hard to tell if there is any difference in performance, there doesn't seem to be any noticeable difference.

I'll read throught the other threads per your suggestion.

Thanks for your help,

Mark

[cnh1990]

Uhhh....You probably mean .4 bar of boost right?
Your car is supposed to get only about .65 without a chargecooler. With my car boost is limited unless I reach 82c then I get full boost, it will go to 1 bar and hold depending on what the ECU decides is best.
Calvin 90 SE

>> Edited by cnh1990 on Tuesday 8th April 17:40

[AZ88Turbo]

cnh1990 said: Uhhh....You probably mean .4 bar of boost right?
Your car is supposed to get only about .65 without a chargecooler. With my car boost is limited unless I reach 82c then I get full boost, it will go to 1 bar and hold depending on what the ECU decides is best.
Calvin 90 SE

>> Edited by cnh1990 on Tuesday 8th April 17:40

Hi Calvin,

Yes, I do mean .4 bar of boost, sorry. The thing that bothers me is that it was boosting to around .6 (just over half on the gauge) up until a few days ago, now it's down to .4. This makes me think something is failing but it still seems to drive ok (after it warms up- see other post for that problem).

Mark

[lotusguy]

AZ88Turbo said:

cnh1990 said: Uhhh....You probably mean .4 bar of boost right?
Your car is supposed to get only about .65 without a chargecooler. With my car boost is limited unless I reach 82c then I get full boost, it will go to 1 bar and hold depending on what the ECU decides is best.
Calvin 90 SE

>> Edited by cnh1990 on Tuesday 8th April 17:40

Hi Calvin,

Yes, I do mean .4 bar of boost, sorry. The thing that bothers me is that it was boosting to around .6 (just over half on the gauge) up until a few days ago, now it's down to .4. This makes me think something is failing but it still seems to drive ok (after it warms up- see other post for that problem).

Mark

Mark,

Assuming that your cold start problem and low boost are unrelated, and I don't necessarily make that assumption, I think your problem w/ boost may be fairly simple.

Check the tension on your throttle cable to insure that the 'butterfly' valves on your throttle bodies open fully when you press the throttle pedal to the floor. These cables are known to both slip and stretch. If either of these occurred, your throttles aren't opening all the way and this will limit your boost as volumetric efficiency is not achieved. Take up the slack in the cable and check to see that the throttles are opening fully. I suspect this may solve your problem. Hope this helps. Happy Motoring!...Jim'85TE

[az88turbo]

Boost is down to .25 bar now on the gauge. Anyone have anymore ideas please?

Thanks,

Mark

[lotusguy]

az88turbo said: Boost is down to .25 bar now on the gauge. Anyone have anymore ideas please?

Thanks,

Mark

Mark,

Remove the Turbo Inlet Hose and run your finger around inside both the hose and the turbo inlet. If you have any liquid oil at all coming out on your finger, the bearing seal is gone on your turbo and the turbo needs a rebuild. It's possible that your finger will be oily, an oily coating inside these surfaces is not unusual, but if you get liquid oil, it's turbo fixit time. Hope this helps. Happy Motoring! Jim'85TE


>> Edited by lotusguy on Monday 14th April 09:20

[cnh1990]

More important than what the gauge reads. Do you have a noticable loss of power or are you just telling us the gauge only reads .25 bar? Is it just a transducer problem?

Calvin

[lotusguy]

cnh1990 said: More important than what the gauge reads. Do you have a noticable loss of power or are you just telling us the gauge only reads .25 bar? Is it just a transducer problem?

Calvin

Calvin,

No transducer on the '88, it's a mechanical boost gauge. Could be a split or leaky supply tube to the gauge though. Happy Motoring!...Jim'85TE

[AZ88Turbo]

I had the inlet hose off a few days ago and didn’t see much oil then, I’ll check it again later this week when I get time. I have noticed that my car is using quite a bit of oil (about ½ pint every hundred miles or so), there are a couple of very small leaks but nothing that would lose that much oil in that time so maybe it is the turbo seals. There doesn’t seem to be any major loss of power but it does seem a little slower than when I first got it. That could be just me getting used to it though.

Does anyone have any idea what it costs to get the turbo rebuilt? And where I could get it done over in the US? Is it something I could do myself if I have the parts?

Thanks for your help,

Mark

[cnh1990]

You can remove the turbo and replace it after a rebuild. But if you had to ask you have neither the equipment or the experience to do the actual rebuild. I know of very little people who can do it. Usually one takes it to a shop that does a lot turbo rebuilds on semi truck turbo diesels. If you can not find a place locally to do Jim and I know a place you can ship it to. At this time you may elect to upgrade to a ball bearing turbo.
Calvin

[AZ88Turbo]

Can you give me the information on the place you mentioned please? If you guys know this place and trust their work I will probably ship it there (assuming the turbo is on its way out when I check it).

Thanks,

Mark

[AZ88Turbo]

Ok folks, more information: When I looked at the car tonight there was oil all over the back bumper, it looks like it must have come out of the exaust pipe.

When you put this information along side turbo boost going down and using a lot of oil, does this point to the turbo bearings or something worse (like rings or something?).

Any help will be much appreciated.

Thanks,

Mark

[Gary-SPG-Moore]

try this, start the car up & let it idle for a few minutes. Does any smoke come from the tailpipe? If it does, by-by turbo! If no smoke take the car for a spin & give the car 100% throttleimmediatly & pay attention behind you to see if smoke is pouring out the back. When turbo seals go out this is a sure test to find the problem.

[lotusguy]

AZ88Turbo said: Ok folks, more information: When I looked at the car tonight there was oil all over the back bumper, it looks like it must have come out of the exaust pipe.

When you put this information along side turbo boost going down and using a lot of oil, does this point to the turbo bearings or something worse (like rings or something?).

Any help will be much appreciated.

Thanks,

Mark

Mark,

Pull a sparkplug, if it's all oily, the oil loss is occuring in the engine, if not, it's the turbo.

You need to have a leakdown test performed on the engine. Short of that, do a compression test. Then add a squirt of motor oil through the sparkplug hole and test again. If the reading goes up, your rings are not sealing well and you're getting oil blow-by, if not, it could be your valve timing or worn valves or guides allowing oil to be drawn into the cylinder and combusted. Hope this helps. Happy Motoring! Jim'85TE

[AZ88Turbo]

Well, to this point I haven't seen any smoke and the plugs are a nice tan color. The only thing I see is splatters of oil on the back bumper when I have been driving it hard. Of course it is also using oil.

If the exhaust side seal is gone, wouldn't the oil just blow by the turbo and out of the exhaust? It wouldn't burn it would it? (unless the heat in there ignited it I guess).

I'm not looking forward to taking the turbo off. I think I'm going to take a suggestion made on the forum and take a pipe off the exhaust side somewhere first to see it there is oil to be seen.

If there is no oil to be seen there, I guess I'll start the compression tests etc.

[lotusguy]

Hi,

Sounds as if you are in denial. You have oil present on your bumper. It has to be coming from somewhere.

Because any external leaks from the engine, turbo oil supply etc. would not migrate from the point of origin all the way to the rear bumper without coating the subframe, tranny case etc, the oil must be coming from the tailpipe.

There are only two ways oil can exit from the tailpipe. The first is if you have oil getting into the cylinder from bad rings, valves or guides and being expelled with the exhaust gasses, but since you have no evidence of this on the plugs, these are not the causes. The second is if the turbo seals fail and oil is entering the exhaust where the scavenge effect of the exhaust gasses are pulling it to the tailpipe and out onto the bumper.

Like it or not, all the indicators are that the turbo seals have failed requiring that you rebuild the turbo. A compression test is a good idea, but only to establish a baseline. It can wait until the turbo is re-installed. Sorry for the bad news. Happy Motoring! Jim'85TE

[cnh1990]

Well one has to remove the pipe from the muffler to the turbo anyways. If there is oil or evidence of a oil leak in there continue with the turbo removal.

After all it is one of the first steps in turbo removal is to disconnect the cat back exhaust.

If it checks out fine look else where. If it is the problem you are part way through the removal process. Be prepared to remove the turbo. It does seem to be the likely cause.
Calvin

[lotusguy]

cnh1990 said: Well one has to remove the pipe from the muffler to the turbo anyways. If there is oil or evidence of a oil leak in there continue with the turbo removal.

After all it is one of the first steps in turbo removal is to disconnect the cat back exhaust.

If it checks out fine look else where. If it is the problem you are part way through the removal process. Be prepared to remove the turbo. It does seem to be the likely cause.
Calvin

Calvin,

There are really only 5 steps to removing the turbo and you won't expose the interior of the muffler pipe until the turbo is lifted free of the wastegate adapter.

To remove you:

1: remove the turbo oil feed and return hoses

2. remove the boost control pipe

3. unbolt the turbo from the wastegate adapter

4. unbolt the turbo from the exhaust pipe

5. lift it out

It is unecessary to remove the muffler of the exhaust pipe extension to pull the turbo. At least in the 1/2 dozen times I have removed them this was the case.

As I said, there is no other reason I can envision to have oil in the tailpipe or on the rear bumper, especially with clean plugs unless the turbo seals are blown. Happy Motoring! Jim'85TE