Check engine light

[Ernie/Chico]

Hey, I have 1990 bronco custom inline six manual trans and the check engine light will not go out. Code 31 “EVP sensor below min voltage”. I’ve gotten to the point of throwing parts at it egr valve, brake booster chasing a vacuum leak I can’t find. Looking for tips to point me in the right direction or really any direction. I love this thing I’ve had it for years still under 150,000 miles but living in California I’m having issues getting it road legal

 

[ragtop69]

Isn't living in the People's Republic of California a satisfying experience? Can't someone with a test setup figure out what is wrong with your engine? I'm pretty sure a competent mech could do that.

 

[miesk5]

Yo Ernie,
WELCOME!
31 EVP circuit has intermittently failed below minimum voltage of 0.24 volts.
EVP - EVP signal is/was out of range - EVP
EVR - (O, R, M) EVP signal is/was low - EVR
URL="http://web.archive.org/web/20110704111747/http://www.tomco-inc.com/Tech_Tips/ttt32.pdf"]EVR Testing, Ford; "....check the filter on the solenoid (Fig. 4, EVR filter shown). If this is clogged it will inhibit the venting of the solenoid; "...EVR Solenoids should be 20 to 70 ohms (100 to 135 ohms for 7.5L engines). A functional test can be performed on most applications by using a Scan Tool. Enter the Output State check and cycle the accelerator pedal. This will turn all the solenoids on and off. Using a DVOM monitor the voltage at the EGR solenoid(s). They should toggle from a high voltage to a low voltage. Typically this is stated in the manuals and scan tools as above 10.5 volts to below 2 volts. If the voltage does not toggle make sure that you have system voltage on the power side of the connector. If system voltage is present and the voltage does not cycle to the low side check the connector and wiring to the PCM. If the wiring and connector are okay the problem may be in the pin at the PCM or the driver in the computer itself..." READ MUCH MORE by Tomco.[/URL]

Here are the 1990 Bronco Pre-Delivery Shop & Electrical & Vacuum Troubleshooting Manuals (EVTM), Partial by member Kingfish999 in Google Drive @ 1990 Ford Truck service manuals - Google Drive
Suggest you download for faster scrolling and to use the table of contents index.

1990 Ford Bronco Brochure, partial by El Kabong @ 1990 Ford Bronco Brochure pictures, videos, and sounds | SuperMotors.net

 

[Ernie/Chico]

Isn't living in the People's Republic of California a satisfying experience? Can't someone with a test setup figure out what is wrong with your engine? I'm pretty sure a competent mech could do that.

Taking it to a mechanic isn’t really my agenda but I’m sure they could if push came to shove but it’s not my daily or will it be anytime soon so I’d rather figure it out myself ........ yeah California definitely has its ups and downs that’s for sure but so does everywhere

 

[Ernie/Chico]

Yo Ernie,
WELCOME!
31 EVP circuit has intermittently failed below minimum voltage of 0.24 volts.
EVP - EVP signal is/was out of range - EVP
EVR - (O, R, M) EVP signal is/was low - EVR
URL="http://web.archive.org/web/20110704111747/http://www.tomco-inc.com/Tech_Tips/ttt32.pdf"]EVR Testing, Ford; "....check the filter on the solenoid (Fig. 4, EVR filter shown). If this is clogged it will inhibit the venting of the solenoid; "...EVR Solenoids should be 20 to 70 ohms (100 to 135 ohms for 7.5L engines). A functional test can be performed on most applications by using a Scan Tool. Enter the Output State check and cycle the accelerator pedal. This will turn all the solenoids on and off. Using a DVOM monitor the voltage at the EGR solenoid(s). They should toggle from a high voltage to a low voltage. Typically this is stated in the manuals and scan tools as above 10.5 volts to below 2 volts. If the voltage does not toggle make sure that you have system voltage on the power side of the connector. If system voltage is present and the voltage does not cycle to the low side check the connector and wiring to the PCM. If the wiring and connector are okay the problem may be in the pin at the PCM or the driver in the computer itself..." READ MUCH MORE by Tomco.[/URL]

Here are the 1990 Bronco Pre-Delivery Shop & Electrical & Vacuum Troubleshooting Manuals (EVTM), Partial by member Kingfish999 in Google Drive @ 1990 Ford Truck service manuals - Google Drive
Suggest you download for faster scrolling and to use the table of contents index.

1990 Ford Bronco Brochure, partial by El Kabong @ 1990 Ford Bronco Brochure pictures, videos, and sounds | SuperMotors.net

This is a treasure cove of information man thank you

 

[Ernie/Chico]

Before quarantine went into effect I had 1990 bronco just taking up space in my garage. I couldn’t get it to pass smog when I first moved to California so it eventually sat and more problems arose. She’s back running and as of the first passed California emissions. Now I just need the dmv to be considered as essential as McDonald’s.