1990 Ford Bronco



April, 5, 2010 AT 5:29 PM

Engine Performance problem. Brakes not receiving enough boost per brake installer.
1990 Ford Bronco V8 Four Wheel Drive Automatic 175000 miles

KOEO-84-EGR Vac. Solenoid Circuit Failure
22 -MAP out of range, 42-HEGO Indicates System Rich, 35-PFE or EVP Circuit above closed limit, 25-Knock Sensor.
Vacuum at idle reads 5 Hg at vacuum tree on air intake and into MAP, and 14 Hg going into brake booster.
EVP solenoid reads 3V at idle.
Recently replaced Vacuum hoses, ACT, MAP, TPS, FPR, EGR Valve, Front Rotors, Brake lines, Air Bypass Valve, Spark Plugs, Spark Plug Cables. Cleaned (and replaced gaskets)Throttle body, valve covers, rocker arms, valve springs. Also cleaned and rebuilt injectors.

Have not replaced TAD, TAB, or EVR solenoid or HGO. No cat conv. On this Bronco. Have not run WOT since changes, and have run 8 or 9 miles since
MAP change.
No knock sensor on engine, and they are no longer manufactured.


1 Answer



April, 6, 2010 AT 9:51 AM

OK first off yes it does have a knock sensor it is on the back of the manifold screwed into the top of the block, and they are available at your local parts stores. Now I do need to know a few things before taking it further. First off what engine 5.0 or 5.8 they are not the same and what problems are you having? What is the timing set at and have you checked for vacuum leaks around the upper plenum and the lower intake?

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