wcombs

high hydrocarbon readings on a vehicle emmisions test

I HAVE A 1990 E150 FORD VAN WITH A 302 MOTOR. FAILED EMMISIONS TEST DUE TO HYDROCARBONS. WHAT COULD BE A CAUSE OF THIS PROBLEM.

davo

Hi HC,S indicate a misfire from a bad wire,plug,cap,vacuum leak or burnt valve etc,what were the other readings co, nox ,co2 , o2 and your hc,s # please.

Joe_F

Davo is 100% correct. When was the last time this thing saw a tuneup?

wcombs

Re: high hydrocarbon readings on a vehicle emmisions test

Originally posted by wcombs
I HAVE A 1990 E150 FORD VAN WITH A 302 MOTOR. FAILED EMMISIONS TEST DUE TO HYDROCARBONS. WHAT COULD BE A CAUSE OF THIS PROBLEM.

I HAVE CHANGED WIRES,PLUGS.CAP AND ALL FILTERS CHANGED OIL AND EGR VALVE WITH SENSOR. ALL OTHER EMMISION READINGS WERE WELL BELOW STANDARDS. VAN WILL SHUT OFF AT TIMES DURING DEACCELERATION.

Joe_F

As requested by Davo, the test results for all three gases were?

Kill the caps, no need to shout.

wcombs

Originally posted by Joe_F
As requested by Davo, the test results for all three gases were?

Kill the caps, no need to shout.

Sorry about the caps.

Here are the gas readings from the last test.

HC= 704562 GPM
CO= 66.2590 GPM
NOx= 0.8337 GPM
CO2= 421.5948 GPM

Hope this will help. Sorry about the delay with the reply been working late.

Joe_F

Ever change the O2 sensor? How about the coolant temp?

Mileage?

davo

Check the ignition timing and possibly try cleaning the combustion chamber with top engine cleaner.Does your van have an air injection system?If so perhaps it is not working properly.

Joe_F

I agree with Davo.