Engine/Transmission (1994 - 1998) low power

[Pdingman]

I have low power between 1200-1750rpm, low boost, and low EGT readings

1. my boost psi is 21psi (is was 26-27psi)

2. my EGTs does not get over 800* (note: EGT probe is past exhaust ebow about 2")

3. between the 1200-1750rpm range my boost was OK, know it is 10psi or less. I have to get the rpm's over 2000 to get any real power out of my engine.



What I have done up to now:



replaced supply and return fuel lines

cleaned fuel screen, replaced fuel line between heater and lift pump(it was bad)

Cleaned the K+N filter



I tried removing exhaust at the ebow to see if boost went up. And it did, about 4psi it got there quicker than before. What is the back pressure before the cat. and muffler? Can the cat and/or muffler be pluged? what other things can I check?

 

[Andy Redmond]

What is the fuel psi at idle and high rpm? Did you change the fuel filter?



Yes, a plugged cat can cause low power, but typically a gradual condition, rather than "all the sudden. "



Over oiling of the K&N might hurt the boost a tick? Do you have a clean oe filter to take a test run with?



You've checked many important things, let us know about the fuel psi, I bet its too low (less than 20 at idle).



Good luck

Andy

 

[PUMPERDUDE]

Check your overflow valve. Pretty easy to do. Just be sure to stuff some rags in the crack below it so you dont drop the washers in there. Let us know what you find.

 

[CRHardie]

Cant believe no one sugesed the easiest thing. Check all of your charge air hoses I have seen a few rub thru on fender on the right side of the charge air cooler Hope this helps

 

[1dslram]

The cat can be a problem, but I for one dynoed over 500hp with the cat in plalce and not gutted. Check all hoses and clamps if you find nothing pressureize the system to check for leaks and a possible split in the intercoller or one of the necks on the intercoller, they have a habit of splitting, because of poor welding. Keep us informed as to what you find.

Bruce

 

[Pdingman]

Today I checked the fuel pressure it is: 5 psi at idle (no load) 17-22 psi (no load) and 10-15psi driving with a load. My shop manual said 25psi. Is this correct? I switched to an OEM air filter and no change. I checked the intake hoses and clamps, OK. I have not checked for intake air leaks in the intercooler tubes. With the fuel being low I’ll start with that. Is the overflow valve rebuild-able? If not, where do I buy one? Dealer? I would like also to install a free flowing exhaust 4” system from turbo back. Any suggestions? I also would like to increase the engines hp.

 

[1dslram]

If the overflow is clicking it needs to be replaced. Piers has the valves for $55. 00. Also try replacing your fuel filter if you checked after the filter. or the lift pump could be bad. Your idle pressure should be 20# cursing 25#-27# and at high speed 30#. With large injectors and a high flow fuel plate the pressure can drop to 3-5# during a full throttle take off but this only 350hp and above.

Bruce