only 13 psi

[Benbob00]

aaaahhh. I typed out all this detailed info, and wasn't logged in so i lost it! argh.
Ok, I almost hate posting another "no power" thread, but I need a few pointers here.
2000 7.3 auto that runs 13 psi stock or with a tuner on any level.
Scantool(genisys): no dtcs besides the one the tuner sets. key on engine off the ebp and baro are both very close to 13 psi, but my map is 11.3. should I worry about this? WOT the injection pressure peaks about 2800-2900 psi. I do not have a pyrometer yet. I have one, but havn't installed it. I'm taking my boost readings from the scantool.
I have replaced the fuel filter and cleaned the 2 socks in the fuel sending unit. They weren't dirty. The turbo is not dusted and does not have excessive shaft play. I just put a new ford air filter in it. I also just replaced the ebp(KOEO it was reading 15 psi before) and cleaned that pipe out. i really though that fixed it. My truck was running MUCH better after the ebp install. I checked and still 13 psi.
My truck barely smokes any at WOT.
Before I replaced the ebp, I pulled a 28ft enclosed trailer with a car and it couldn't do it in over drive. keeping it floored it still wouldn't maintain speed. I had to turn over drive off and run 50-55. On the way to my destination it wasn't that bad, but on the way back is when it felt like I was pulling another truck the with brakes applied. I got out and felt my trailer brakes. cool to the touch.
I have read that stock boost should be around 17 psi and with a tuner I might expect 25 or less. is this correct?

Let me know if any more info is needed.
Thanks in advance!

[Benbob00]

I need to add that the truck is completly stock minus the tuner. I had already ordered my exhaust, but I wish I wouldn't have. I'd rather have spent that money fixing the problem.

[Benbob00]

I put the scantool on a co-worker's 2003 7.3 to check his map sensor reading and it was right around 13 at KOEO like it should be. I took it out and put it in my truck and it read 11.3 in my truck. aarggghhh!! He has a superchips tuner and put it on the economy tune for a test drive. his truck peaked at 17-18 psi. I looked at mine again and it's only 12-13 psi.

[Benbob00]

I put my truck back to stock for the first time after replacing/cleaning the EBP. For the first time, it doesn't make a louder diesel cackle at WOT. Someone told me that was normally fuel starvation. Any time in the past with or without the tuner, it would do that at WOT. It was just much worse with the tuner in the highest setting. It got better after replacing the EBP, but not gone. I'm going to try a different tuner today. Bullydog said I should expect 16-20 psi on the different settings with my truck.

[ToMang07]

I would guess boost leak, but here is my experience:

DIY Intake w/ Stock Exhaust: 10-16PSI at WOT.

DIY Intake w/ Stock Exhaust AND PHP Tunes: 18-26PSI at WOT.

So I would expect higher w/ a chip/programmer...but I don't know.

I'm getting a 4" MBRP exhaust installed today... but my chip is in GA right now, lol!


Anyway, heres a

[Buffalo444]

yeah, definately sounds like a boost leak, fun part is determining if its on the exhaust side or the intake side.

Check all of your intercooler boots, check both plenium boots. When mine leaked it was at the pleniums, but mines an e99 so its an issue. If they are greasy and all I'd go ahead and take em all off and wash them, do the ccv mod, then re-install them. A little hairspray can help them seat better during reinstallation (which is a pita at some points). This is how you'd check the intake side.

For the exhaust side, get a small angular mirror (like they use at the dentist office) to check for soot on your uppipes. If there is soot on your firewall you can almost garuntee its an exhaust side leak. Unfortunately if its leaking here its more of a pita all together, because you need to do uppipe gaskets, or switch to international bellowed uppipes. the bellowed uppipes solve the problem permanently (barring catastrophic failure) but are expensive, the gaskets are cheaper but have to be done ever so often.

BUT before doing both of these, how are you reading your boost? Is it thru a seperate gauge or is it electronically through the map sensor? If its thru a seperate gauge, I'd say for sure a boost leak. If its electronically thru the map sensor, I'd say it could be bad/blocked.

[Benbob00]

I have been using a genysis scantool reading the manifold gauge pressure which is supposed to be boost. It subtracts the baro sensor reading from the map sensor reading. For some reason my map reads 11.3 (I can't remember the unit of measure here) and it's supposed to match the baro and EBP sensors readings with the key on and the engine off. They both read right at 13. Since the reading is key on engine off, that takes a blockage out of the picture for this reading.
I hooked the scantool up to a 2003 7.3 and his map was reading right at 13. So I put his map in my truck and it was still reading 11.3. I'm wondering if because of how it calculates boost, I need to add 2 psi to that to get my actuall. When the ecu does the math, if my map is reading a little low, it will throw the final number off.

Anyway. I put my truck to stock last night and just put the scantool on it to read boost and it hit 15 psi. It has never done that in the past. Maybe my tuner is the problem here, or it's for a 94-97 7.3. I'm assuming they run less boost since they don't have an intercooler. I'll be trying a superchips tuner here in a few.

On the boost leak issue. I removed both IC pipes looking for large holes/splits in the couplers. found nothing. I'm not saying there isn't tiny boost leaks here or there, but nothing that's going to cause what's going on here. I also checked for exhaust leaks before the turbo. The pass side has an up-pipe leak, but it's super small. And the drivers side manifold has a small leak to. but again, not enough to cause problems. It's such a tiny amount of black soot. You can't hear either one of them.

I need to read what the ccv mod is.
On another note, my 4 in exhaust will be here today! yay!



cliffnotes: truck runs more boost without the tuner. haha

[Benbob00]

with the superchips tuner installed on the highest mode, my truck peaked around 22 psi. Which that reading may be 2 psi lower than actual. I don't know. And lots of black smoke. yyaaaaayyy!!!!

So there's nothing wrong with my truck!! It's the tuner! either the tuner is somehow faulty, or this tuner is for the pre-intercooled 7.3. I'm just assuming they run less boost.

[Buffalo444]

a tuner for an obs stroke shouldnt even have worked on your truck. thats why it wasnt working right....

[Benbob00]

I left a message with bully dog to explore my options.

I'm about to go install my exhaust.