1994 Chrysler LeBaron Check Engine Light

The software programmer had to satisfy EPA standards in place at the time the
vehicle was manufactured. Those standards are much more stringent than the
testing now being done. Just because the vehicle passes the NOx test 12 years
down the road, it doesn't mean the system is working as it was designed to, so
if the computer decides it's faulty, it's faulty.

If you can't figure out how to fix it, well, that's another issue.

 

Ah yes, that's what the knock sensor deals with. Which his engine has
assuming
he's got the 3.0 at least.

If his NoX production is low the engine isn't going to detonate since
NoX production is directly related to cylinder temps. That is why I
told him to have it emissions tested.

I first attempted to order the TRANSDUCER separately since the EGR
valve itself passed the vacuum test that the service manual recommends
trying. The transducer and valve are NOT sold separately, not from the
dealer
nor from any aftermarket source I ever tried calling, at least not for my
vehicle. More FUD from you I think. And totally unnecessary since as
I already said the dealer is cheaper than aftermarket for this part - and
you could also have verified that for yourself in 5 minutes of phone
calling.

The EGR valve itself is simple and if it will pass a vacuum leakdown test
and if it will cause the engine to stumble when vacuum is applied, it's
working.

The transducer contains 2 parts and it is designed to be taken apart.
The first part is the selonoid which is sealed. The second part is the
diaphram which is in a housing that can be taken apart. One side of
the diaphram is exposed to exhaust gassses. I've long experience
with EGR and I know from experience that the parts that touch the
exhaust gas stream are generally the first to go.

When I first bought my 95 and it failed emissions I took the transducer
apart and found the diaphram was cracked, obviously long exposure
to exhaust gasses ruined it. That is why I tried to get the transducer
separately.

The selonoid can easily be tested by applying vacuum with a hand
pump and actuating the selonoid with 12 volts.

While it is conceivable that the selonoid could bind under a temperature
change - for example if underhood temps were hot - thus setting the
CEL - I've seen the same behavior with the CEL with several transducers,
new, used, and used known good. I've tried multiple egr valves as I've
said without a difference. I've tried multiple ambient air temps as well.
I've tested it multiple times under the state
IMS program. Oregon allows you to test for free if your not renewing
registration If NoX is low, then the engine is not detonating.

Anyway, back to the OP's vehicle. I never advocate shotgunning
without testing. Quite obviously the right way to do it is for the OP
to start by following the EGR valve tests in the FSM. Obviously if
his transducer's selonoid is stuck or the EGR valve is leaking, then
he needs to replace the valve. But, a emissions test would show
these as well since those would give high NoX.

But, the OP didn't indicate that he wanted to do anything OTHER than
shotgunning. That is why I told him to have it tested for emissions. If
he passes NoX then EGR is working no matter what CEL says.

Ted

 

The most common reason why the EGR valve solenoid fails is water getting
into the solenoid and shorting out or gets to the connector will corrodes
the terminals to the point they break off or just don't make contact

 

Ah yes, that's what the knock sensor deals with. Which his engine has
assuming
he's got the 3.0 at least.[/QUOTE]

No knock sensor on the 2.5 or the 3.0

NOx production could be masked by the catalytic convertor.

Partially plugged EGR passages would still yield the engine
stumble when the EGR is opened yet allow that the EGR monitor
fail.

True enough. Left to go long enough, the solenoid also suffers.

The exhaust back pressure was?
The MAP signal responded how when the EGR was commanded?
The O2 signal responded how when the EGR was commanded?

Easily handled by the Cat-Con if it's anywhere near original
efficiency.

The EGR backpressure transducer in my 3.9 Dakota leaks like a
sieve when tested with my smoke machine, the truck passes the
state IM-240 as a fast pass.