Low boost issue w/Pics - Help? - Diesel Forum

scottyryan · 05-20-2009, 12:20 AM

I have been going back and forth with Jody at DP - He guided me toward the Manifold/Up-Pipes. Here's what is going on.

Exhaust Mainfold looks fine on both sides - I am including some pictures of what I found. Where the manifolds connect to the up pipes looks fine - The passenger side up pipe to collector looks good - The Driver side up pipe to collector connection looks like it has some discoloration. Not sooty like you would expect if it was leaking there - But almost like heat discoloration. The area I noticed soot was where the "Y" collector connects to the turbo - Sorry for the terminolgy - Under the clamp there looks like there are four halfs that are clamped between the clamp and the rubber. There looks like there is some soot coming out of one of the gaps between one of the four halves. I also noticed that the heat shield that bolts on surrounding the turbo has some exhaust soot on it - exactly where I noticed it on the turbo. Could this small of a leak be the issue?

Is there something I can do to check for another issue other then visualy inspecting everything. I left the dog house off and started the van and tried to feel for the leak where I noticed the soot on the turbo - But couldn't feel anything coming out.

I tried to experiment today - and on flat ground at a cruising speed there is zero boost on the gauge - I can get into the throttle lightly and the boost will come up - but only a few pounds. If I just accelerate very lightly it doesn's show any boost. There seems to be quite a bit of turbo lag - and the RPM's have to come up a bit before the boost comes in. If I really get into it I can get 25psi or so. But again as soon as I let the engine settle and get back to cruising speeds the boost shows zero. Should it be making a specific amount of boost while maintaining say 65mph - or is it only when I load the engine - weather it be a hill or my foot on the pedal?

Not sure if this matters - But at startup - the boost gauge doesn't move - Doesn't move if I rev the engine either.

Any help or guidance would be greatly appreciated.

scottyryan · 05-20-2009, 12:59 AM

I found an old post about having the boost line that is routed into the back of the gauge pushed into the gauge too much - and this can cause an air leak. Could this be my whole problem - Just that I have the boost line installed incorrectly? I will pull the gauges off again and check my fitting.

Here's to hoping that I'm just a bone head and installed the line incorrectly

blageurt · 05-21-2009, 12:16 AM

Stock Turbos only make serious boost with Injector upgrades like stage 1's or Hybrids along with Tuning by Jody or whoomever. Intercoolers help alot. But since the vans have no wastegate the boost is controlled by defueling so you need to spend the 3 or 4 grand to get the H2E or similar Turbo and injectors to see higher boost like the f-series.

XRACER · 05-21-2009, 11:40 AM

This might sound silly, but I always start with the obvious. Does the boost gauge work properly?

For one thing, unless you've done some tinkering......you shouldn't be seeing more than 18 lbs of boost ever. The computer defuels the injectors above 18 lbs. Also, my F250 makes serious HP and it reads 2.5 lbs of boost at a steady 65. If I stomp on it I can get over 35 lbs. Perhaps your gauge just isn't picking up the bottom end any more.

rpm1 · 05-21-2009, 07:46 PM

With stock turbo, injectors, and dp tunes I could get about 32psi. 65mph was 4 or 5 psi.

scottyryan · 05-22-2009, 01:12 PM

I just unhooked the boost line from the back of the gauge last night and cut a bit if the line off to make sure I had a clean piece inserted into the fitting - When I first put it in I had the line pushed all the way up to the back of the brass fitting on the gauge - But I read somewhere that wasn't ideal.. So I left a bit of a gap this time.. I also noticed that the Ferrell (sp) didn't have a tight fit around the boost line - So I put a bit of RTV there to make sure it seals and isn't loosing pressure there....

I'm gonna give it a shot today and see what we get....

Quote:

Originally Posted by rpm1

With stock turbo, injectors, and dp tunes I could get about 32psi. 65mph was 4 or 5 psi.

Talking with Jody the other day he had told me that at cruising speeds on the highway - with no load - I should see zero boost....

I'm confused - But that's not hard to do

scottyryan · 05-22-2009, 04:43 PM

Well - Looks like the seal job did the trick - The gauge now shows that at 65mph - the van is making about 3psi - And the gauge actually moves when I roll into the throttle....

In addition to adjusting where the boost line was in the fitting and the RTV sealant - I also threw some Teflon tape on the threads of the fitting that houses the Ferrell. The instructions only said to Teflon between the gauge and the first fitting - Which I did - But apparently it needed more then that....

I'm also gonna throw some RTV on the machined T-Fitting that is in line with the Map sensor... I am not convinced that the press in fitting that the boost line goes into is sealing as well as it should...