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My Ford F150 didn't pass emissions test today

Herm's Avatar

Join Date: Apr 2001
Posts: 535

05-22-02, 03:31 PM   #1  
My Ford F150 didn't pass emissions test today

My Ford F150 didn't pass emissions test today, and it was because of the high level of hydrocarbons. Everything else was within exceptable levels.

I'm not sure if I even know what a hydrocarbon is, let alone what would be causing higher levels of it. It passed a year ago.

It is a 1990
4.9L straight six - electronic fuel injected
manual transmission
I live in Illinois

It needs to be repaired B4 I take it back for a retest, but I don't want to pay hundreds of dollars to a repair tech to have it fixed.

Is there anything obvious that would be causing this that I can check myself?

Any suggestions are certainly welcome!


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davo's Avatar

Join Date: Apr 2002
Posts: 2,417

05-22-02, 04:37 PM   #2  
im failure

Did it fail at idle,cruise or both?Please post all of the exhaust gas readings including rpms.By the the way hydrocarbons are unburnt fuel,usually caused by a misfire or lean mixture.Both could be caused by a vacuum leak or low fuel pressure.Please post back with readings,without knowing hc,co and o2 readings its a guess at best.How many miles on your truck?Has your truck had a tune up lately,if not maybe its time,fouled plugs bad wires,cap will also cause an hc failure,even a tired catalytic converter.

Joe_F's Avatar
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05-22-02, 04:41 PM   #3  
I agree with Davo. Need more information to be able to have a chance to help out.

bejay's Avatar

Join Date: Dec 2001
Posts: 2,538

05-22-02, 04:54 PM   #4  
even contaminated oil can cause high hydrocarbons so it is a good idea to have your oil changed right before you have an emission test done even if you just have 1000 miles on your last oil change it makes a difference.

davo's Avatar

Join Date: Apr 2002
Posts: 2,417

05-22-02, 05:06 PM   #5  
Contaminated oil will cause high hc,but will also cause high co,that is why I need readings.To have high hc from oil it must be polluted with gas which will result in high co also.Also co does not need to be to failure level to be high.Herm do you have air injection?

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