I have a 88 f-250 with a 5.8 gas engine. It seems to lack power once the engine is warmed up. I scanned it, it threw a code 32. Research tells me that the EVP circuit has intermittenly failed below 0.24 volts. I think that is below the closed limit. So, what does this mean? Has the EVP sensor failed? Or has the EGR valve failed? Any help and insight here would be much appreciated.... Thank you in advance.

 

Most of the time when the voltage is below on a scan it turns out to be a bad (open) wire or a bad connection or pin.

Service Code 32 in Key On Engine Off and Key On Engine Running indicates that the EGR valve and/or EVP sensor voltage is lower than normal in the closed position. The EVP voltage is less than the closed limit voltage of 0.24 volts. Because of the preload of the EVP sensor it is very difficult to determine whether the EGR valve has malfunctioned or the EVP sensor has an abnormally high resistance.
Possible causes:
-- Poor continuity in EVP sensor harness or connectors.
-- Damaged EGR valve.
-- Damaged EVP sensor.
-- Damaged processor.

 

Thank you subford. Now the next question, what would you do to repair this if it was yours? I have a little mechanical know how, but I am certainly no ford mechanic, therefore, the simpler the better as far as advice. Thanks again.

 

If it was mine I would grab my handy Brake-Out Box (BOB), unplug the computer and plug my BOB into the computer and its plug. Then I would grab my DVM, turn on the key and check the voltage coming back from and to the EVP. This would tell me where to start looking next, wiring, pins and so on.

But it is not mine and you more than likely to not have the test boxes that I have. So you need to look very close at the plugs on each end and the wiring between them. If you do not see anything than you will have to ohm out the wire between the computer and the EVP sensor. If everything looks OK change out the EVP sensor.



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Thank you subford. I will try the ohming out the wire, and check the connection before replacing the sensor. Thanks again.

 

I have the same code 32 on my 89 F250. I pulled the codes tonight as I am getting a stumble when I drive off under load.

I have .24 volts on the EVP single line with no vacuum to the EGR valve. When I apply vac, the voltage does track up to 4.3V with the Vref at 4.7volts. With the engine running I repeted the test and the engine stalled at 2.7V on the EVP(EGR valve is functional). Out of curiosty(no BOB for me) I left the EVP disconnected, I now get the 31 code. So the wire to the ecu is good as the codes change.

Now the fun begins, I swapped out the EVP with a few I have around. Got the same with them all. Looks like the EGR valve it self is not giving the preload on the EVP or I have munged up ECU.

To the OP, try disconnecting the EVP and pull the codes again, if it changes from the 32 code to 31 code, I feel the ECU is seeing the change(wire good to ECU).

 

Thanks Eddie, I did unplug the egr valve and the truck didn't run any different. But when I did that , the check engine light stayed on, which was new. Before that, it would come on intermittently, especially at low rpms.
Being this is my old plow truck, I'm probably not going to spend a whole lot of time or money on it right now. The biggest problem is that it seems to lose some power once the engine is warmed up. Any suggestions? Thanks again.