FordExcursions.com Forums
Matt Cawson
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• Caledonia, MI, USA |
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• Registered on 10/20/2004 |
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• 82 posts |
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 Posted:10/26/2005 08:56 |
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Anyone have the problem on cool/cold startups where you don't have a lick of power? My '01 PSD will sometimes have no power at all (like 25%) and I hear the air blowing out somewhere other than where it should. This will sometimes go on for almost a mile down the road, then finally it's like a valve decides to close up and whooooosh, I'm off. Then it's fine. Doesn't happen all the time either, but when it does it's cold outside and the engine is cold as well. Bound to get rear ended if I try to pull out into traffic and this is happening ! |
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CHPMustang
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• Plano, TX, USA |
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• Registered on 7/24/2002 |
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• 1,800 posts |
• 1 Vehicle
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Posted:10/26/2005 12:58 |
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It's a normal function of the exhaust system on the PSD for the Exhaust BackPressure Valve to close when the ambient air temperature is cold(under 40-45 degrees) when starting up a cold engine.
It aids with engine warm up.
Generally it should open when you tap the service brake pedal or the accelerator pedal.
Sounds like a Jumbo jet on the tarmac eh 
Bill
Bill
2002 Excursion XLT-P 4x4 7.3L Powerstroke Diesel
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Matt Cawson
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• Caledonia, MI, USA |
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• Registered on 10/20/2004 |
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• 82 posts |
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Posted:10/26/2005 13:18 |
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That makes sense, but shouldn't it do that every time then when it's cold out? Sometimes I can get right in and go. You never know when it's going to do it. I don't know how turbo works, but from my understanding there's a "compressor" that blasts air into the engine faster than it would if it had to draw it in. It sounds like the "compressed" air is being dumped to atmosphere, almost like there's a valve that controls whether or not the compressed air gets to the intake or not. Maybe a relief valve or something that's supposed to dump if pressure gets too high??? I really have no idea, but it's not a repeatable thing. |
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E. Long
 
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• Subscriber since 1/1/2001 |
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• Atlanta, GA, USA |
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• Registered on 1/23/2001 |
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• 2,229 posts |
• 1 Vehicle
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Posted:10/28/2005 09:43 |
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Matt,
How cold is it when this happens? A friend of mine has had this happen on extremely cold days with his 7.3L in his F350. It's as if the turbo is not working and you're running a naturally aspirated diesel engine...runs like a dog. I think when the engine hits a certain temp, everything goes back to normal.
Unfortunately, it hasn't happened to him regularly, either. Just chalked it up as one of those things related to cold weather. I've never experienced this on my X.
The exhaust backpressure valve will generally be engaged when it's about 30 degrees or colder, but the turbo still operates...it just feels like there's a little resistance when you're accelerating. Enough to notice that full power is not there, but still enough to pull out and cruise at highway speeds without being worried.
-Eric
'67 Galaxie 500 - 390 FE, .030" over, FE to AOD adapter, disc brake conversion. The Daily Driver.
'00 Excursion - 7.3L PSD, LANDYOT Gen-II Radius Rods, Factory Tech Valve Body, 200K+ miles and going |
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CHPMustang
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• Plano, TX, USA |
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• Registered on 7/24/2002 |
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• 1,800 posts |
• 1 Vehicle
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Posted:10/28/2005 12:19 |
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I think we have too much intake flow on our '02 as the EBPV closes at 51 degrees
Bill
2002 Excursion XLT-P 4x4 7.3L Powerstroke Diesel
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Matt Cawson
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• Caledonia, MI, USA |
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• Registered on 10/20/2004 |
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• 82 posts |
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Posted:10/29/2005 04:57 |
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Happened the other day and it was only 37 degrees. Didn't happen all summer though. I'm inclined to just chalk it up as a cold weather thing too. As long as I know it's going on it's not that big a deal. It's when you have to go somewhere quick and don't have time to wait for warm up. Yeah, it's like there's no turbo at all. You can literally step on the pedal and go 0-60 in about 5 minutes, no exaggeration!!!!!!! Once it kicks in it's like a rocket just fired off, and ooooh what a relief it is |
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CHPMustang
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• Plano, TX, USA |
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• Registered on 7/24/2002 |
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• 1,800 posts |
• 1 Vehicle
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Posted:10/29/2005 08:59 |
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| Quote: | | Happened the other day and it was only 37 degrees. Didn't happen all summer though. I'm inclined to just chalk it up as a cold weather thing too. As long as I know it's going on it's not that big a deal. It's when you have to go somewhere quick and don't have time to wait for warm up. Yeah, it's like there's no turbo at all. You can literally step on the pedal and go 0-60 in about 5 minutes, no exaggeration!!!!!!! Once it kicks in it's like a rocket just fired off, and ooooh what a relief it is |
It almost sounds like normal operation as our truck does the exact same thing your's is doing. Could unplug the sensor plug at the lower left part of the turbocharger pedestal which will prevent the butterfly from closing.
The only side effects is longer engine warm up time(5-10 mins) and on California emissions powerstrokes a DTC may be generated as well as the SES light on the dash.
Bill
Bill
2002 Excursion XLT-P 4x4 7.3L Powerstroke Diesel
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