Hello all so I had a code come on last week it's p0401 low flow to the egr. I have a egr delete and a few other things done to the truck. I started monitoring the map ebp and boost so map and ebp are within one or two most of the time but when I get boost up to 22-27 psi the map will drop to 0 or 1-8 psi. So I'm trying to figure out why this is happening. Any ideas? Thanks in advance!

 

combine all three Map, Baro, ebp .MAP look at the Nipple in the Intake the little hole gets clogged

 

Wait I'm confused so why do I add up all the readings? And so your saying I'm getting a low map psi when boost psi is high because the whole may be clogged?

 

Wait I'm confused so why do I add up all the readings? And so your saying I'm getting a low map psi when boost psi is high because the whole may be clogged?

 

Low Map is from plugged at the Intake or hole in the hose are you getting any codes?

 

Yes po401 I think it was. It's for low flow to egr valve. I did do some research and founded that it might be from a leak in the system but from the readings I'm getting from my map you think it's a clogged port to the map sensor?

 

It could very well be , That threaded nipple down at the Intake gets sooted up , I take the hose off the sensor then use it to help un thread it after I loosen the nipple, while your in there clean up the IAT2 sensor that will be sooted too. also look real close at the Map Hose it's been known to split and leak from there too

 

So I got this correct the map sensor is the one off the intake manifold right next to the heater hose? If so I have replaced that hose before with a hydraulic reinforced hose so it doesn't break. Now when I did my egr I cleaned out the manifold the best I could but I do understand diesel and soot from it could re clogged it so I will give that a shot tomorrow and see if that works. Now the iat2 sensor where is this located?

 

Yes the Map sensor is bolted on the heater box via 3 nuts, follow the hose down to the intake. the IAT2 is right behind the upper fuel bowl be carful the clips are brittle and most likely to brake off mine sits in snug so haven't had problems with that if they do. use carb cleaner and a plumbers flux brush.
ware your safety glasses that stuff burns like

 

Ah I see I remember that sensor behind the fuel bowl always wondered what it was when I was cleaning that hunk of aluminum lmao. And yes why does every clip I ever take off on this truck always crack. When I removed my bed both of my rear tai light clips broke and are now held on with electrical tape. God bless that s*** lol. thank you for your help I'll keep you updated with my progress/praying after this cleaning is completed.

 

Ok, continuing on with what has been said here... if you can help me with some similar things.... On my monitor of the engine... when the boost psi goes above about 22-23 psi... it drops out to zero and stays that way until it drops below that.

So, is this somehow related? What should I be looking at in this regard? And is it a problem?

Thank you

 

Your MAP, EBP and Baro all should be within 3 psi of each other, look at the readings cold koeo ( key on engine off) Low ( Idleing) Engine warm High ( 2500 rpm ). By the sounds of it you might have a leak in CAC tube or a crack in the Map hose . you may want to take the EBP sensor off and run some weed eater line through the tube just to make sure it's not being restricted. before you try to loosen up that hard line spray some wd or penetrating oil on it first. Does the turbo spool up?

 

If you're using a ScanGauge, the standard boost gauge just does that. There is an "extended" boost XGauge for the 6.0 diesels. If it's another brand of gauge, it may have similar issues.

My '06 has a boost gauge in the instrument panel so I don't monitor it with SG. Flipping through my gauges the other day I came across boost and left it up just to play with. Under high boost (20 something psi) it flipped to low numbers just as you described. Nothing wrong with the truck, just need the extended boost XGauge.

 

So I checked the map nipple clean as can be. So I searched on a few forums and one told a guy with same issue to unplug the ebp sensor and drive around witch I did and came up with a huge change the truck had some ***** with high boost but low boost it felt like there was an issue but with high boost the map still dropped but with even a slight tap on the throttle there was a weird type of chopping sound after you let off I noticed this when I had the ebp plugged in but it only happened when I stepped peddle to the floor. But it's much worse with ebp unplugged but three out throttle it would have a swooshing sound. I checked the exhaust manifolds and up pipe bolts and the bellows and everything seemed intact so what's my next step do you think it's cac issue because I checked my hot side and everything is great there but I can't really check the cold side as things are in the way. I did see on YouTube diesel tech Ron check for cac leak and wondering if I should do that. Any help is greatly appreciated! Thank you.

 

Oh to add I checked with koeo map is 16.5 ebp is 15.0 I do not know how to check for baro I'm ising scan gauge 2