low boost

[Stanbery]

alright now, i just picked up my second 1st gen truck. but i have come across a small problem, the boost peaks at only 11lbs, and holds there. ive pressure tested the intercooler to 30psi and sprayed it with soapy water and didnt find any leaks. the truck is mostly stock with the exception of a 4" exhaust, and aftermarket air filter. im at a loss as to what to check next, any suggestions would be greatly appreciated.

 

[Jgolden]

Air filter, fuel filter ck. Was it sitting long before you bought it?

Search "low boost" for details from the experts, one of which I am not, after you have tried the simple stuff.

 

[dpuckett]

I'd lean the direction Jgolden is sending you- filters and fuel supply. If it was sitting a while, it is likely clogged somewhere- inejctor tips, or gumming up overall. I'd change filters, and fill the fuel filter with injector cleaner of your choice and see if that helps. If not, it may be time for pump tuning or injector work.



With a CPL 1351 (91. 5-mid92) engine that had the lag king 21cm exhaust housing, 14-16psi is about all you will see in stock form.



Daniel

 

[paccool]

Mine was only 14# with a 3" Banks exhaust and K&N filter when I first got it. I don't think 11# is that far off with a stock truck. Try turning the pump up and rotating the fuel cone, bump the timing a little then see what you get.

 

[Stanbery]

all of the filters and lift pump are new. and from reading other posts on here it seems like the boost should be in the 20-24lbs range. the truck had not been sitting for more than a week when i got it. at idle the fuel pressure is 8lbs and at WOT it drops to 5-6 psi.

 

[Greenleaf]

Me thinks it time to make the treck to the "Smoke House" in Ashland OH. I'll bet you a hamburger on Tuesday that Scott can wring out a bit more boost on that old "lag dog".



GL

 

[2broke2smoke]

my '91 would make 13lbs stock ...

 

[dpuckett]

20-24psi definitely is not stock for a 1st Gen, regardless of how tiny a housing you have on the hot side.



I agree with Greenleaf- time for some tuning.



Daniel

 

[Stanbery]

where in ashland is this place?

 

[Greenleaf]

where in ashland is this place?

AKA Crestview Bus Garage. 15 minute drive due West of downtown on Rt 96