01 SSEi I need vacuum numbers
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01 SSEi I need vacuum numbers
I've been chasing an EGR insufficient flow DTC for awhile now. In the past, when I had this, I was always able to find a small leak in the emissions vacuum line and/or fittings. I can't find one this time.
So, I humbly ask other members since I only have one Bonneville, to help me with some normal readings. I have measured at the test port with a gauge, have monitored with scan tool to see what the MAP was reading, and, pulled the MAP sensor and bench tested it. The readings were about what they should be on a 2 Torr sensor. Reading about 2.25 at atmosphere, and close to the numbers for 5,10,15, 20,25 inches applied with hand vacuum pump. I have a variable bench DC supply that I metered to 5.00 volts to set the reference voltage when taking readings with the multimeter.
The PCM uses a series of readings taken by commanding the EGR full open during deceleration from normal road speeds to monitor a rise in MAP pressure. If the average pressure delta isn't enough, you get the Insufficient EGR flow DTC.
I also pulled the throttle body and stove pipe to check EGR passages. Found no restrictions whatsoever. The only thing I didn't check, and should have, was the stovepipe itself. Hairline cracks in corrugated steel tubing are often hard to see visually.
I just came back from a road test after it set the DTC again. At idle my boost gauge is sitting at -7. If my memory serves correctly, that needle should be buried at -10 under normal vacuum conditions. Scan tool shows the MAP indicating -8.5 to -10 at idle, while analog gauge on test port shows about 24 in. HG>
I'm kind of stumped. Mileage is around 139K, so I suppose I could have some slightly leaking intake valves, but the engine is running smooth.
Like I said, I've been down this path before with this car, and it'* usually always a leak in one of the small lines or fittings running from MAP, to tee under SC snout, to FPR, to BCS.
I haven't gone on to the brake booster and connecting hoses.
Wondering about having the PCM reflashed to current SW. It'* stock PCM. The whole car is stock as it'* the missus' daily commute car.
I swear, the SES light on this car has more bulb hours than any of the exterior lighting. Grrr...
So, I humbly ask other members since I only have one Bonneville, to help me with some normal readings. I have measured at the test port with a gauge, have monitored with scan tool to see what the MAP was reading, and, pulled the MAP sensor and bench tested it. The readings were about what they should be on a 2 Torr sensor. Reading about 2.25 at atmosphere, and close to the numbers for 5,10,15, 20,25 inches applied with hand vacuum pump. I have a variable bench DC supply that I metered to 5.00 volts to set the reference voltage when taking readings with the multimeter.
The PCM uses a series of readings taken by commanding the EGR full open during deceleration from normal road speeds to monitor a rise in MAP pressure. If the average pressure delta isn't enough, you get the Insufficient EGR flow DTC.
I also pulled the throttle body and stove pipe to check EGR passages. Found no restrictions whatsoever. The only thing I didn't check, and should have, was the stovepipe itself. Hairline cracks in corrugated steel tubing are often hard to see visually.
I just came back from a road test after it set the DTC again. At idle my boost gauge is sitting at -7. If my memory serves correctly, that needle should be buried at -10 under normal vacuum conditions. Scan tool shows the MAP indicating -8.5 to -10 at idle, while analog gauge on test port shows about 24 in. HG>
I'm kind of stumped. Mileage is around 139K, so I suppose I could have some slightly leaking intake valves, but the engine is running smooth.
Like I said, I've been down this path before with this car, and it'* usually always a leak in one of the small lines or fittings running from MAP, to tee under SC snout, to FPR, to BCS.
I haven't gone on to the brake booster and connecting hoses.
Wondering about having the PCM reflashed to current SW. It'* stock PCM. The whole car is stock as it'* the missus' daily commute car.
I swear, the SES light on this car has more bulb hours than any of the exterior lighting. Grrr...
#3
Bumping this as the boss' wife'* car (03 SSEi) is giving me the same grief. We've gone through 3 different CEL codes, and I've fixed most. I've removed the EGR and cleaned, as well as the stovepipes (the corrugated and the hard pipe from exhaust manifold). The only thing I can think of is either the MAP sensor, or vacuum lines. I noticed that most of the vacuum lines under the hood are plastic, and not standard rubber tubing.
Anyone got any suggestions? Do the MAP sensors fail that often? I haven't gone into in-depth troubleshooting as I don't have access to a diagnostic machine (Snap-On Solus Pro) until Thursday and Friday during the week.
Anyone got any suggestions? Do the MAP sensors fail that often? I haven't gone into in-depth troubleshooting as I don't have access to a diagnostic machine (Snap-On Solus Pro) until Thursday and Friday during the week.
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Originally Posted by cliffp
I noticed that most of the vacuum lines under the hood are plastic, and not standard rubber.
#8
I noticed that the boost/vac gauge on the instrument cluster shows around 10inHg +/1 1inHg at idle, and the idle isn't rough or hunting. Thus, I didn't think to trust the gauge. I'll run a vac gauge inline at idle though and see what pops up. I've got tons of excess vacuum line laying around the garage so that'* a free diagnosis.
That'* a pretty cool handout, though. Thanks!
XDHD - I had figured that these lines are likely the culprit, but ran out of time before I could literally start yanking them one by one. I'm a huge fan of pressure testing the entire system (turbo guy) to determine where there are boost leaks which by nature also become vacuum leaks behind the throttle plate. I had thought about pressurizing the system to around 5~7psi to see if I hear anything hiss in the engine bay. If it'* something I hear, it'* definitely something allowing unmetered air into the cycle which obviously means that the MAP doesn't see the drop it'* expecting, and triggers the EGR CEL.
Clear as mud, I *'pose. Thanks. Will report back my findings after the evap canister comes in and I have a day to install it and remove/replace all the cheap plastic line with silicone line.
That'* a pretty cool handout, though. Thanks!
XDHD - I had figured that these lines are likely the culprit, but ran out of time before I could literally start yanking them one by one. I'm a huge fan of pressure testing the entire system (turbo guy) to determine where there are boost leaks which by nature also become vacuum leaks behind the throttle plate. I had thought about pressurizing the system to around 5~7psi to see if I hear anything hiss in the engine bay. If it'* something I hear, it'* definitely something allowing unmetered air into the cycle which obviously means that the MAP doesn't see the drop it'* expecting, and triggers the EGR CEL.
Clear as mud, I *'pose. Thanks. Will report back my findings after the evap canister comes in and I have a day to install it and remove/replace all the cheap plastic line with silicone line.
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