Possible Map sensor issues, P1247 and P1248 codes
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Possible Map sensor issues, P1247 and P1248 codes
It's been awhile since i posted anything as my truck has been good to me...until a few days ago. I came up to a stop sign and the check engine light came on and I had no more turbo.. Since I was 10 miles away from home after a 200 mile trip, I decided to limp home via backroads and was thinking I hope it's not the turbo. At the next stop sign I checked codes and i got p1247 and p1248 (turbo boost low and no turbo boost. I kept on limping home and as i made a right turn onto my road, i got my turbo back! Yes, prayers answered! Nope, half a mile later, check engine light came on and no turbo and i limped up the driveway. I parked it, checked diagnostics again, no additional codes, so i shut her down. Two minutes later, i restarted the truck and all was well..for about 5 seconds and then the check engine light came on with the same symptoms.
Long story short, I'm leaning towards the Map sensor being bad or the line that leads from the intake to the Map sensor being compromised, as this is a 17 year old truck. Has anyone else experienced similar symptoms? I started looking at info on here, that's why I am leaning towards the Map sensor being bad or the line being cracked.
Long story short, I'm leaning towards the Map sensor being bad or the line that leads from the intake to the Map sensor being compromised, as this is a 17 year old truck. Has anyone else experienced similar symptoms? I started looking at info on here, that's why I am leaning towards the Map sensor being bad or the line being cracked.
Veteran/Sheepdog
Joined: Feb 2012
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From: Western AR
If your turbo went out, and you had no boost:
1. You would have seen the GIGANTIC cloud of black smoke behind you.
2. You would have had NO power to accelerate at all.
3. You would have likely heard your turbo making all kinds of racket, squealing and screeching as it died under the hood.
4. There might even have been a fine cloud of oil behind you where the oil was being pumped from the engine out the exhaust.
OR
5. You would have heard the loud "POP!" after one of the IC boots had popped off and started dumping your boost back into the atmosphere.
If your turbo goes out on a 7.3 (or you lose all your boost), you will surely know it!
1. You would have seen the GIGANTIC cloud of black smoke behind you.
2. You would have had NO power to accelerate at all.
3. You would have likely heard your turbo making all kinds of racket, squealing and screeching as it died under the hood.
4. There might even have been a fine cloud of oil behind you where the oil was being pumped from the engine out the exhaust.
OR
5. You would have heard the loud "POP!" after one of the IC boots had popped off and started dumping your boost back into the atmosphere.
If your turbo goes out on a 7.3 (or you lose all your boost), you will surely know it!
Hotshot
Joined: Jan 2011
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From: Puget Sound
Since he mentioned he limped home, this sounds like a big loss of power. If the map line comes loose or develops a large leak, you will get these symptoms. It may also be possible you have a loose/corroded connector to the MAP.
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The vacuum line going into the intake manifold popped off with much less effort than I thought once I released the band clamp. My understanding is that the band clamps lose their "clamping strength" over time. The end of the hose was cracked, so I'm hoping by replacing the line and clamps will rectify the situation. I went to the auto parts store yesterday at 4 and they were closed. I'll go at noon today and hopefully will be able to close this post with good news!
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update
Good news with a catch. It was the line from the intake! $4 spent to fix a problem!!
I guess it had been slowly deteriorating without tripping a CEL.
Now I have another (related?) issue that sprang up. My current boost at idle now reads between -.1 and .1., before roughly 1 or so? Boost on a pretty level road cruising at 60 is between 1.2 and 1.7, mean of 1.5 for a few miles, before it was 2-3. When I floored it I am maxing out at a boost of 21, before it was 24, but I have much less "coal" thickness than before and a shorter duration. I launched it at a dead spot and it spewed a quick thick cloud and quickly turned into a dark haze. I't seems to be running better, but I wonder what your boost is at idle and normal driving? I think I may have addressed one boost issue, but could my MAP sensor be "off" or does the sensor go from working optimally to dead?
I guess it had been slowly deteriorating without tripping a CEL.Now I have another (related?) issue that sprang up. My current boost at idle now reads between -.1 and .1., before roughly 1 or so? Boost on a pretty level road cruising at 60 is between 1.2 and 1.7, mean of 1.5 for a few miles, before it was 2-3. When I floored it I am maxing out at a boost of 21, before it was 24, but I have much less "coal" thickness than before and a shorter duration. I launched it at a dead spot and it spewed a quick thick cloud and quickly turned into a dark haze. I't seems to be running better, but I wonder what your boost is at idle and normal driving? I think I may have addressed one boost issue, but could my MAP sensor be "off" or does the sensor go from working optimally to dead?
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Hotshot
Joined: Jan 2011
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From: Puget Sound
Boost usually reads very close to zero +/- at idle. If you have a tail wind or are going down a slight grade, the boost can read 1-2 at 60-65 MPH. I usually read 3-4 on the flat with no wind - new MAP/EBP sensors (along with everything else new-ish under the hood). Have you done your KOEO test lately?
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