I recently had to e-check one of my kids 1995 Taurus 3.0. It is from Florida, so it is in pretty good condition body wise and drives pretty well. It failed the e-check for NOx, CO and HCL were very low. I checked the egr system and it seemed to work correctly. Apply vacuum to the egr valve and the engine runs rough and almost dies. I then drove it with a vacuum gauge connected to the egr valve line and it applied vacuum when warmed up and accelerating and lost vacuum when at idle. There is a small exhaust leak somewhere in the front exhaust between the manifolds and the converters. I don't think that would affect NOx because I believe they are only 2 way catalyers in 1995, but I am not sure. Any help would be appriciated
1995 Taurus NOx fail
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THere is no smog test required in Florida. The emissions system may not have been serviced in many years.
How much vacuum did you apply to the EGR valve? If you apply too much you could get it to open, but it still won't open under normal conditions. I think EGR valves usually only need less than 5in. of vacuum to open.
A lean mix will raise nox, perhaps an 02 sensor gettting slow? I still think its egr related.
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^ What spasm3 said, take it to a shop where they can watch 02's and such on a datastream to get the whole scoop.
Did Ford use DPFE or backpressure sensors back then? If they did, those sensors might not be accurate any more.
If the EGR valve doesn't have such sensors, it may open at a fixed rate set by the computer, and that can't compensate for EGR passages that are dirty. Clean the EGR passages if they are dirty.
Since it is a 1995, I don't know if it used OBDII or EEC-IV. Most places have OBDII diagnostic tools, but not nearly as many have EEC-IV tools.
If the EGR valve doesn't have such sensors, it may open at a fixed rate set by the computer, and that can't compensate for EGR passages that are dirty. Clean the EGR passages if they are dirty.
Since it is a 1995, I don't know if it used OBDII or EEC-IV. Most places have OBDII diagnostic tools, but not nearly as many have EEC-IV tools.
Originally Posted By: HerrStig
THere is no smog test required in Florida. The emissions system may not have been serviced in many years.
The Taurus has been in Ohio for about 6 years and passed e-check every 2 years until now.
THere is no smog test required in Florida. The emissions system may not have been serviced in many years.
The Taurus has been in Ohio for about 6 years and passed e-check every 2 years until now.
Originally Posted By: jsfalls
How much vacuum did you apply to the EGR valve? If you apply too much you could get it to open, but it still won't open under normal conditions. I think EGR valves usually only need less than 5in. of vacuum to open.
I applied 5 in. of vacuum which caused rough/almost stalling running. The valve holds 5 inches vacuum and does not leak.
When I drive the car with a vacuum gauge connected to the EGR line it applies 5 in. vacuum once warm and throttle applied. When the throttle is released so is the vacuum.
How much vacuum did you apply to the EGR valve? If you apply too much you could get it to open, but it still won't open under normal conditions. I think EGR valves usually only need less than 5in. of vacuum to open.
I applied 5 in. of vacuum which caused rough/almost stalling running. The valve holds 5 inches vacuum and does not leak.
When I drive the car with a vacuum gauge connected to the EGR line it applies 5 in. vacuum once warm and throttle applied. When the throttle is released so is the vacuum.
5-6" of vac is the spec at which the EGR should be fully open.
If it isn't spitting EGR codes (OBD2) look around for another cause. OBD1 run a KOER with a vac gauge hooked between EVR/EGR and verify vac when idle speed increases during test. Well you seem to have already driven it with a vac gauge hooked up. Verify base timing.
Odd it has an EGR as most Vulcans with fed emissions didn't even have EGR systems (just a factory blockoff plate near the throttle body). I remember Cal and Mass were 2 states that required EGR on that engine.
Not sure of the CAT status on that year and its effect on NOx. No lean codes/trims? I never really dealt with NOx or EGR problems on these in TX. I would take a drive with a scantool hooked up checking long term trims, PFE/DPFE voltage, coolant temp, TP and SPOUT timing. See if anything is wigging out of spec. Kind of clutching at straws a bit. Good luck.
If it isn't spitting EGR codes (OBD2) look around for another cause. OBD1 run a KOER with a vac gauge hooked between EVR/EGR and verify vac when idle speed increases during test. Well you seem to have already driven it with a vac gauge hooked up. Verify base timing.
Odd it has an EGR as most Vulcans with fed emissions didn't even have EGR systems (just a factory blockoff plate near the throttle body). I remember Cal and Mass were 2 states that required EGR on that engine.
Not sure of the CAT status on that year and its effect on NOx. No lean codes/trims? I never really dealt with NOx or EGR problems on these in TX. I would take a drive with a scantool hooked up checking long term trims, PFE/DPFE voltage, coolant temp, TP and SPOUT timing. See if anything is wigging out of spec. Kind of clutching at straws a bit. Good luck.
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