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Brad & Jacolyn

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Good Afternoon,

I left the valley on the 1st of May and the Volvo wasn't pulling like I thought she should. She was fine on the flats and downhill but when we started uphill she did not seem to have any power. The engine sounds fine, no sputters or anything just slows way down on the uphills. I have added cetane booster and I changed the fuel filter. The Davco only has a couple of inches in it. There is still 125 gallons in the tanks and I wanted to burn them down lower before adding any more in case the fuel is the problem.

 

As we were driving today and it was getting slower and slower on the uphills and I thought maybe the air filter was plugged. So when we pulled into the campground tonight I opened the hood and when I went to pull the filter I noticed that the end cap on the air cleaner had 3 stripped out screws and the cap was popped out in the bottom and sucking in air. I pulled the cap and used compressed air to clean the filter and have put everything back together. I used tooth picks in the stripped holes and everything is tight now. Tomorrow I'll unhook and take a test drive and hopes things are fixed.

 

My question is can to much air getting into the system cause the power loss problem? Maybe mess up a sensor or something?

 

More info for you:

1) The turbo would not get over 10.

2) I have no faults showing in the diagnostics.

 

If this does not correct my problem does anyone have any suggestions on what else to try.

 

Thanks

Brad

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I don't know about Volvo, but I'm pretty sure my Freighliner wouldn't be effected by that. And leaks after the turbo would certainly cause you to lose power. But I don't think on the air filter side it should. I sure hope that was your problem though.

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Brad - after our discussion, I watched the turbo boost. Low normal was about 5 psi - slight downhill - to 45 plus - long strong pull in 10 th gear (top gear) bounced to 9th and popped right back to 45.

 

As others have said, check the boots. With all the work they did in Houston, you should be in top form.

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Brad,

 

I had a similar problem a few years ago and it turned out to be a boost pressure sensor. I don't have a boost gauge, but with no input to the engine computer, it would not give any boost. Fortunately, it was an inexpensive and easy fix.

 

Steve

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The guys, as usual, are on top of it. Those are the two things I'd say right off....loose hose on the turbo/broken clamp, etc. Or a bad boost sensor. I'd focus on the hoses, since that is the easiest fix and most likely fault, from what I have seen in the past. You have to look at them really closely, since you can miss a crack pretty easily.

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The fuel filter I put in is a Fleet guard.

 

This morning I climbed all over the engine and tightened everything that I can find. Found some clamps that needed 1/4 turn and one that needed a full turn. Everything is tight. The test drive was about the same but I have not towed yet. I checked the boots and can see nothing wrong. Everything sounds good and I cannot hear an leak but that may not mean anything. I tow again tomorrow.

 

Now I have a couple of questions that are probably silly but since I don't know I'll ask.

 

1) I had the exhaust manifold replaced in Houston in Nov, 2014 and that stopped my exhaust leak and smell in the cab. Everything was working fine when I pulled into Ratama in Dec and it only moved to go to the golf course a few times. When we left and headed north I noticed the problem and it did not improve. Is there anything mechanical in the system that could be stuck and causing the problem?

2) The boost sensor was mentioned. Where is that located and is it something I can change myself?

 

Thanks for the help guys.

 

Brad

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The fuel filter I put in is a Fleet guard.

 

This morning I climbed all over the engine and tightened everything that I can find. Found some clamps that needed 1/4 turn and one that needed a full turn. Everything is tight. The test drive was about the same but I have not towed yet. I checked the boots and can see nothing wrong. Everything sounds good and I cannot hear an leak but that may not mean anything. I tow again tomorrow.

 

Now I have a couple of questions that are probably silly but since I don't know I'll ask.

 

1) I had the exhaust manifold replaced in Houston in Nov, 2014 and that stopped my exhaust leak and smell in the cab. Everything was working fine when I pulled into Ratama in Dec and it only moved to go to the golf course a few times. When we left and headed north I noticed the problem and it did not improve. Is there anything mechanical in the system that could be stuck and causing the problem?

2) The boost sensor was mentioned. Where is that located and is it something I can change myself?

 

Thanks for the help guys.

 

Brad

Howdy Brad,

 

I know NOTHING about the Volvo's, that said do you have a mechanical actuated waste-gate on the turbo, if so perhaps it is sticking. Just something else to look at.

 

Dave

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Thanks Phil that does not appear to be to difficult. Now is there anyway to tell if the sensor is bad before replacing it? Or can it be cleaned instead? I went out and looked at mine and it is in the same place but the hose does not have to come off. One of the bolts holding it is broken off so I just removed the other one but the sensor does not seem to want to come out so I stopped and put the bolt back before I broke something. I'm in a rather desolate place right now so I took no chance on breaking it.

 

Mr. Cob I looked at the turbo and as near as I can tell without crawling under the truck again (I'm all showered and clean now) there is what looks like the end of an electric motor but I saw nothing that looked mechanical.

 

Brad

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Thanks Phil that does not appear to be to difficult. Now is there anyway to tell if the sensor is bad before replacing it? Or can it be cleaned instead? I went out and looked at mine and it is in the same place but the hose does not have to come off. One of the bolts holding it is broken off so I just removed the other one but the sensor does not seem to want to come out so I stopped and put the bolt back before I broke something. I'm in a rather desolate place right now so I took no chance on breaking it.

 

Mr. Cob I looked at the turbo and as near as I can tell without crawling under the truck again (I'm all showered and clean now) there is what looks like the end of an electric motor but I saw nothing that looked mechanical.

 

Brad

If the one bolt is broke this maybe the cause of your problem/leak. I sure would in my mind imagine it being the problem. <_<

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I would add another vote for the Boost Sensor.

 

One other possible point would be the Fuel Overflow Valve.

 

Do you have a way to hook it up to PTT? (Computer with Diagnostic/Monitoring software)?

if hes coming to the west coast rally he does. i have PTT on my laptop and will be at the WCR next month... :-)

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Today is a travel day for Brad. He'll be on later I'm sure. The bolt was holding the sensor and was not in a critical spot. He just didn't want to play with it in the middle of no where west Texas. The pressure gage does move - 0 to 10 psi boost, just way at the low end of anything.

 

Edit - they are planning on Sparks - if they can make it. They are going from (currently) West Texas to San Diego to Sparks with a few side trips. So there is a mountain range or 2 in the way before they get there.

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The sensor is very tight in the hole even with one bolt broke so I did not mess with it any more at this time. Traveling to Carlsbad NM. today and then on the Albuquerque NM. 2 days later. Then we will be sitting for 12 days. Hope to get things fixed then.

Can the sensor be tested before changing or do I just have to change it. I saw the video and it doesn't look hard just needed to sit long enough to do it. In a location that they don't have to pipe in the sunshine. I'm not at the end of the world yet but I can see it from here.

 

I'll keep you informed and keep the suggestions coming.

 

Brad

 

I'll be at the WCR if I can get over the mountains.

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I have now lost all boost indicating on the gauge. We are in Carlsbad, NM and head for Albq. tomorrow. It will be a long 265 miles with no boost but the Volvo dealer there has the boost sensor in stock and is holding it for me. I'll pick it up on Thursday or Friday and I hope all be good again. I miss my turbo.

 

Brad

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Sure sounds like a defective boost sensor. Or possibly the wastegate stuck wide open? I can't imagine a Turbo completely giving up without shelling. I've used 1/8" air line to plumb a hard fitting into the intake manifold to a ordinary pressure gauge to test things out.

 

You can check the boost sensor, (its a 3 wire sensor)--I'm not sure if it will tell you a lot. I looked on Bruss's schematics, and found this:

post-9595-0-39407800-1431529406_thumb.jpg

 

Pin 1: (Green/wht) is power, probably 5 or 12V.

Pin 2: (grey) is the boost pressure. See below.

Pin 4: (Brown/wht) is ground.

 

I can't tell you readings for your sensor. But depending on the sensor it is a ratio of the source voltage. Usually the lower the pressure, the lower the voltage. A typical sensor might have a power source of 12V or 5V to produce a 0.5V-4V output. Some produce a 1-10V swing. Just a guess,but I bet your sensor should read 0.5V with just the key on, and increase toward 2-3V as the boost ramps up. Testing it is hard, other than checking the "off" voltage, cause how do you create boost?

The KEY is that it changes. If you can see a definite change >0.25V from key on-motor off to motor running a 1600rpm, you may wish to let a dealer check it out for other problems. A new sensor is a pretty cheap diagnostic, though!

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I have now lost all boost indicating on the gauge. We are in Carlsbad, NM and head for Albq. tomorrow. It will be a long 265 miles with no boost but the Volvo dealer there has the boost sensor in stock and is holding it for me. I'll pick it up on Thursday or Friday and I hope all be good again. I miss my turbo.

 

Brad

apparently the ECU will only throw a code if open or shorted but not for "wrong values"

The ECU supplies 5VDC to the sensor and the sensor returns the below values to the ECU.

 

Measurement points: EA22 (signal) — EA11 (ground)

Manifold Pressure Voltage

0 kPa (0 psi) 1.18 v

50 kPa (7 psi) 1.73 v

100 kPa (14.5 psi) 2.29 v

150 kPa (22 psi) 2.84 v

200 kPa (29 psi) 3.40 v

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There you go. Thats what you should be reading on pin 2. (note: don't disconnect and try to use resistance to check most modern 3 wire sensors. Many have internal electronics, not just a resistive slider. The only sensors to use resistance on are the type where the sensor is just one wire to ground)

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