Attempting to find a low boost situation, probably 15 PSI max. Used to get 30 or so. 120cc cali injectors. However, I have 3.55 gears and I added 315/75/16 tires, but also have a 1.00 housing. Up-pipes are new and not leaking.

Started looking at the manifolds, but really can't see anything. My thought was to take automotive paint and spray near the manifold ports in question. Seems easier to see black on a lighter backdrop. Any other tips?

Really frustrating chasing this problem lol.

 

On the trucks I've worked on, the rear cylinder on each side is what I usually find leaking. Doesn't mean yours are, just saying.

Have you pressurized the intake system to look for leaks?

 

Yeah that is the one I am referencing. Drivers side rear most cylinder. It has a gasket installed so I know they were worked on at some point. None of the bolt heads are snapped though. It was just a faint whisp of black. The thing is I don't know if it was grime though. I stuck my hand all around that area and it was black. I'm thinking it was grime, but starting fresh with the paint was my only real idea for testing.

Typically if I had an idea that something wasn't working correctly I'd just pull it off and r&r it to be sure. However, the manifolds are a different story. I know it is going to suck to do that job.

I've found some boost leaks prior to this job. I'll check again as I think my boost gauge tubing is leaking. IDK if it would cause this much of a reduction though?

Appreciate the reply.

 

If you have gaskets on already you're right, they have been worked on. They shouldn't be that bad to do since they've been done before. Spray with some pb a couple days before you start on it to help. The last super duty I did I broke one bolt off and had to weld a nut on it to get it out. The rest came out, and I was surprised, as they were quite rusty.

My suggestion is if you pull the manifold take it to a machine shop and have it surfaced/planed, and use a gasket. Some say not to use a gasket, but without being able to plane the head surface you need it imo.

Any boost leak, even minor, will make a difference. If you have a couple of them along with a manifold leaking you could very well be losing half your boost.

 

I'll make sure to do that if it comes to that. Is there a way to test for pre turbo leaks like there is with the intake boost leak tester? Near as I can tell its all visual looking for soot.

 

I guess I'm not sure if you can build a tester for the exhaust or not.

 

If you want to check the intake's and IC pipes, get this at tractor supply etc. This fits right into my turbo's intake hose and put the air to it. Use a soapy water solution in a spray bottle and check for leaks. Sure helped me!

 

I've got a homemade version of those. I've identified a couple of small leaks at the boots. For now I took my truck back to stock as far as intake manifold/ic goes, don't have boost gauge with that so I'll have to use MAP readings on PC or something.

Looking at the painted spot on my exhaust manifold I'm not seeing any soot. Looks as clean as the day as I painted it.

I'm thinking it could be BARO sensor although my sensor readings are not throwing a MIL, or outside of what the factory specs.

 

How old is the air filter?