98.5 3500. 10lbs boost max?

kino_fab

kino_fab

KTPA Tech Official
Joined
Aug 19, 2007
Messages
2,244
I have been fighting a lack of boost problem with this truck since day one. When I bough it, it a HX40 turbo with a 18cm exh housing. At that time it would make about 20lbs of boost and didn't lit the turbo till around 2400rpm. So I traded it for a stock 02 turbo. With no box the truck would make only about 15lbs and 18lbs with a Quad. Adr. The boost has slowly gotten worse. I now have a Smarty running it on 8, trq 4 timing 2 duration 2. The truck will only make 10lbs of boost now and that is it. I have been tearing my hair out trying to figure it out. I have had the turbo apart and everything looks fine, no boost leaks, boost guage works fine, and it will blow quite a bit of smoke on take off then clear out once it hits about 8lbs. Although it is halfway strugling to even make the 10lbs it is making. The truck runs too smooth to be injectors or injector pump to me anyways. Could be wrong on that one, but..... I'm at a loss here. Anybody have any idea's?
 
Map sensor dirty? Huge exhaust leak before turbo? Or boost leaks...
 
Stock IC boots, no exhaust leaks and no boost leaks. I guess I'll try the map sensor, but I figure if the map sensor wasn't working it wouldn't make any power at all. I had a bad wire on the Adr. harness at one time that wasn't getting a signal from the map sensor and the truck wouldn't do anything power wise. Once I had that fixed it had loads more power, but still wouldn't make but 14lbs of boost at that time. It just acts like something gradually going out or down on the truck, just can't figure out what it is
 
Is the wastegate actuator rod attached to flapper? Possibly shorten the rod and see if that helps...how did u check for boost leaks? Possibly the o ring in the outlet vband is fubared... Just throwing things out there
 
I made a home made tester using a large PVC end cap with an air fitting, shop air regulator, gauge, and regular shop air. I loaded it up to 15lbs (all it would handle before blowing the rig off the face of the turbo). I used a bottle of soapy water and sprayed it around anything and everything that had to do with the air side of the engine. I only found one leak and it was a small one around the passenger side intercooler boot. I fixed it and rechecked other places and found nothing more. The boost would still only go to 10lbs.
 
The waste gate is also hooke dup and working fine. I even dis connected the boost line to it to make sure it wasn't trying to open. still no change in the boost on the truck
 
does it run bad? possible the gauge is bad or line running to the gauge is leaking?
 
Just a thought could the intake plate bowed or the gasket has a chunk missing i know mines a 12 valve but mine had the same issue and that was the culprit. Also on another instance when it was still a ve the afc banjo bolt came loose and couldn't find it for the life of me took me a couple hours of searching over that motor and i finally found it it was also limiting the truck to around 15 psi. I no not your same motor but just some ideas to ponder.
 
I checked the valves a few days ago. They were out of spec horably. At that time I was making about 12lbs. I adjusted the valves back to 10 and 20 and now it only make 10lbs.

Like I stated before there are no boost leaks at all.

The boost gauge is working fine too and no leaks on the boost line either.

The truck runs smooth, no missing or strang noises, but its just some what week in power. On the stock tune a VW beetle could out run this thing with fouled spark plugs and a clogged air and fuel filter.
 
kino_fab said:
I checked the valves a few days ago. They were out of spec horably. At that time I was making about 12lbs. I adjusted the valves back to 10 and 20 and now it only make 10lbs.

Like I stated before there are no boost leaks at all.

The boost gauge is working fine too and no leaks on the boost line either.

The truck runs smooth, no missing or strang noises, but its just some what week in power. On the stock tune a VW beetle could out run this thing with fouled spark plugs and a clogged air and fuel filter.
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Have you had the air horn off? Could be a bad gasket there or the intake plate like suggested.

Call Richie......its got to be something simple if you've checked all this stuff.

If you can't get anybody to answer the shop phone txt me I'll give you his personal cell #.
 
Yes I have had the intake horn off, but like I said earlier I have checked everything to do with the air side and no leaks at all. Intake plate and horn gaskets are fine. I'll figure it all out one of these days.
 
kino_fab said:
Yes I have had the intake horn off, but like I said earlier I have checked everything to do with the air side and no leaks at all. Intake plate and horn gaskets are fine. I'll figure it all out one of these days.
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Call Richie....ask his opinion....he see's crazy $hit like this all the time that he has to trouble shoot!


eerr......wait a minute...... did you take the quadzilla off? Your only running the smarty? Smarty isn't a wire tap...only timing...without a boost elbow in the comp housing I could see that only doing 10-12psi.
 
kino_fab said:
I have been fighting a lack of boost problem with this truck since day one. When I bough it, it a HX40 turbo with a 18cm exh housing. At that time it would make about 20lbs of boost and didn't lit the turbo till around 2400rpm. So I traded it for a stock 02 turbo. With no box the truck would make only about 15lbs and 18lbs with a Quad. Adr. The boost has slowly gotten worse. I now have a Smarty running it on 8, trq 4 timing 2 duration 2. The truck will only make 10lbs of boost now and that is it. I have been tearing my hair out trying to figure it out. I have had the turbo apart and everything looks fine, no boost leaks, boost guage works fine, and it will blow quite a bit of smoke on take off then clear out once it hits about 8lbs. Although it is halfway strugling to even make the 10lbs it is making. The truck runs too smooth to be injectors or injector pump to me anyways. Could be wrong on that one, but..... I'm at a loss here. Anybody have any idea's?
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I would look really hard at a fueling issue. What are the EGT's doing?
I blew a boot on my 01 one time, and you couldn't go up a hill without the egt's going over 1200.

Of course to elimnate the simple stuff make sure the wastegate is closed, and block it close to see if it helps.
 
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I can get the EGT's up to around 1350 if I wanted to. Right be fore I shift gears at WOT it can get up to about 1100, cruising between 700 and 900.

Mark, even with this thing being stock it should still make atleast 20lbs or so. I don't think a wire tap has anything to do with it. which boost elbow are you talking about. this turbo I have has a hard line going from the compressor housing to the waste gate actuator. all I did was crimp the hard line shut to eliminate the waste gate problem. No leaks from either end of the hard line either.
 
kino_fab said:
I can get the EGT's up to around 1350 if I wanted to. Right be fore I shift gears at WOT it can get up to about 1100, cruising between 700 and 900.

Mark, even with this thing being stock it should still make atleast 20lbs or so. I don't think a wire tap has anything to do with it. which boost elbow are you talking about. this turbo I have has a hard line going from the compressor housing to the waste gate actuator. all I did was crimp the hard line shut to eliminate the waste gate problem. No leaks from either end of the hard line either.
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Sounds like an HY35 then, possibly wastegate issues? Wastegate leaking?

I think you have a fueling problem, Not a boost leaking issue. When I blew the boot, I mean couldn't accelerate at all, or the EGT's were through the roof!
 
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It's got some power as long as you have some kind of box or programmer on it. Bone stock it is weak as hell, but I can still get up to cruising speed a lil faster than most senior citizens, although pulling a trailer with it, I might as well use a 4cyl s-10 with a gooseneck plate and get the same result.
 
well I got some of my boost back today. Evidentally I didn't have the hard line to the waste gate actuator fully cripped. I hooked up my boost leak checking rig agian and when I put 10lbs of pressure on the system, the waste gate was closed but I could move the rod easily with my hand. I then wired the waste gate lever shut for the most part and took a test drive. With that I could make about 14lbs. Once I got back to the shop I removed the wires I had holding the lever shut and just cut the hard line and folded the compressor housing end shut. Now the truck is making about 17lbs. I figure the spring is week in the actuator and the drive pressure is opening the gate up now against the WG flap in the exhaust housing. I also noticed now that the truck seems like it is lower on power up top now like its leaning out. My EGT's will only peek out 1000* now aswell (probe is in the manifold pre-turbo). I'm going to try welding the lever in place completely and see what that does. If there is no change after that, then I figure I got a fueling issue aswell.
 
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