LLY: Intermittent reduced/no boost problem...

[dieselpusher]

2005 truck I bought new, now has 82,000 miles. Basically stock, but does have AFE turbo mouthpiece and a slightly larger exhause. Still with stock cat converter.. When new, I had an Edge unit, booststick & fingerstick. Got rid of all that, then bought a Predator. Occasionally put on the tow program of the Predator, but mostly run it stock. Currently, no program.

Issue is: intermittently get a check engine light, and code for mass air flow. I have cleaned the MAF sensor numerous times, but the code returns after indeterminate amounts of time. Also, numerous times the turbo simply doesn't respond to throttle. I have a boost gauge & pyrometer, and closely monitor both. Getting on the freeway when towing, etc is no fun when the truck just barely limps along. It also tends to emit considerable exhaust smoke when in this state. Eventually, usually after 30-50 seconds the turbo kicks in, and responds normally.

Considering that both the MAF sensor and the turbo vane position sensors are rather expensive, I would rather not simply start replacing parts hunting for the solution. Fuel filter shows 60% life remaining, air filter shows fine, and the truck has exhibited the same symptoms after replacing both filters, so I tend to think it's not a filter restriction.

Ed

[JC1843]

Sounds like a EGR problem. You should consider blocking it, to see if that helps-Cheap from Forum supporting vendors.

[Smokinlmm]

Yep^^^ your EGR is blowing/sticking open...

[Randy_the_Hack]

Blocking the EGR is a simple chore if you get the bolts loose. Getting the bolts loose is the trick... and if you don't have an FE2 truck, it'll throw a check engine light. Do some searching in here and in the DIY section for details. Good luck.

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[dh515]

Had a similar problem on my truck that started when I removed the finger stick and Edge and went to EFI Live. Turned out to be a bent pin on the female side of the sensor located under the AC compressor. I think it is a boost sensor but don't remember as it was a long time ago. Had to use a mirror to see it as it is hard to get to. Check your sensor plug connections.

[terryk]

Originally Posted by dieselpusher

2005 truck I bought new, now has 82,000 miles. Basically stock, but does have AFE turbo mouthpiece and a slightly larger exhause. Still with stock cat converter.. When new, I had an Edge unit, booststick & fingerstick. Got rid of all that, then bought a Predator. Occasionally put on the tow program of the Predator, but mostly run it stock. Currently, no program.

Issue is: intermittently get a check engine light, and code for mass air flow. I have cleaned the MAF sensor numerous times, but the code returns after indeterminate amounts of time. Also, numerous times the turbo simply doesn't respond to throttle. I have a boost gauge & pyrometer, and closely monitor both. Getting on the freeway when towing, etc is no fun when the truck just barely limps along. It also tends to emit considerable exhaust smoke when in this state. Eventually, usually after 30-50 seconds the turbo kicks in, and responds normally.

Considering that both the MAF sensor and the turbo vane position sensors are rather expensive, I would rather not simply start replacing parts hunting for the solution. Fuel filter shows 60% life remaining, air filter shows fine, and the truck has exhibited the same symptoms after replacing both filters, so I tend to think it's not a filter restriction.

Ed

Have you checked that the inlet tube is tight at the mouthpiece? If we are getting a mass error and the mass is good, I would first check for an air leak after the mass (or at the mass.)

[dieselpusher]

How do I test the MAF sensor? It's clean and look intact...

[dieselpusher]

On the EGR, I assume I can simply make an aluminum sheet plate to block it off?

[dieselpusher]

Dug around, found I had already installed an EGR blocker plate years ago. Tightened all air hose clamps. Removed turbo vane position sensor and found it pretty grungy. Cleaned in mineral spirits, reinstalled. Truck responds very well on my test drive, but will need more miles to verify if it is indeed fixed.