EGR valve/Gas temp. sensor Question

[ReZn]

My CEL recently came on about two weeks ago but I just got around to having the code checked yesterday. It read "#71 EGR TEMP. SENSOR"

My vehicle is a 1995 Camry 5S-FE (2.2L I4) w/ FED. & Canada emissions.

Today I disconnected both leads on my battery for 3+ hours while I worked to reset the ECM.

I first removed the Gas Temp sensor which was surprisingly clean. Then the entire EGR valve. The valve itself above the plunger was heavily deposited with a caked on (yet moist) black carbon. Below the plunger there was similar deposits, but the exhaust channel was clear. The nipple on the bottom of the valve leading the bottom of the modulator was clear as well. The actual valve plunger only opened after I clean the entire unit with brake parts cleaner and liquid wrench. Now the plunger moves up and down and holds a vacuum. (How much force should be required to manually push the plunger upward with a probe?)
Next I cleaned up the EGR Mod. and checked each nipple and and the valve with compressed air. Everything checked out fine. However I did toss out the filter and plan on making a custom replacement soon. I also probed each hose and didn't find any blockages.
After all this I put everything back together with a new EGR Valve gasket.
I let the car idle for about 20 minutes, then drove about 6 miles before the CEL came back on.
By this time the engine was up to operating temp. so I decided to check the vacuum hose that lifts the plunger on the EGR. My friend revved up the engine while in neutral and after about 30 seconds of 3500 RPM the vacuum still had not kicked in to let spents gases into the intake. Is this normal or the answer to my problem? If it is how do I fix it.

Also...getting back to the original "EGR TEMP SENSOR" code. Is there a way to rule out whether or not the sensor is the root of the problem?
Prior to writing this I did as much research on this site as well as many others. I've read that if you place a 4.7ohm resistor in the sensor input it will give a good reading to the ECM, hence turning off the CEL if infact it is the faulty part. Is this correct?

Can someone help point me in the right direction.

P.S. First person to help me solve this issue will get a 6-pack of their choice on me...seriously. Thanks

[chronoti]

the sensor could be bad. when the engine is hot disoncet the lines to it and check resistance on the sensor. 2k-4k at 302 degs f. 11k-15k at 212 degrs f. 69k-89k at 112 degs f. so if it reads back bad (mine was reading back 147k at normal temp) and if it's bad you can drop in a resistor to bypass that sensor making the car think that it's letting too much exaust (too hot). and the 6 pack would be nice but wount be in boston for a while

[profuse007]

iono if this will work for ur camry (canadian model), but resetting the CEL is simple, turn key ON then unplug the EFI fuse for 10-30 or so then plug it back in.

[ReZn]

Thanks chronoti for the advice.

This morning I disconnected the battery leads then stuck a 4.7k (1/4 watt) resistor in the sensor plug. After reconnecting the battery and driving around all day the CEL hasn't come back on. The engines seems to run great. The only thing that hasn't changed is the slight engine vibration when the car idles @ 875-925 RPM.
I tried looking for a used sensor but all of the junkyards wouldn't sell theirs since it is a key component (so they say) of the engine. Most other venders want between $110-140 for the OEM replacement.

Question is: By faking a hot temp reading what are the potential side effects of running a rich air fuel mixture all the time? Poorer gas mileage, hotter combustion, possible engine damage?

Please let me know.

[chronoti]

you would get a slightly poorer gas milage but the ecu will correct the air to fuel keeping it from getting too lean or rich, it would act more like your getting more air in.

[LATech]

What is resistance of EGR Gas Temperature sensor at normal temp (70F)?

[dtencio]

As you connect the resistance? could give me a diagram please.
Thank you

Originally Posted by ReZn

Thanks chronoti for the advice.

This morning I disconnected the battery leads then stuck a 4.7k (1/4 watt) resistor in the sensor plug. After reconnecting the battery and driving around all day the CEL hasn't come back on. The engines seems to run great. The only thing that hasn't changed is the slight engine vibration when the car idles @ 875-925 RPM.
I tried looking for a used sensor but all of the junkyards wouldn't sell theirs since it is a key component (so they say) of the engine. Most other venders want between $110-140 for the OEM replacement.

Question is: By faking a hot temp reading what are the potential side effects of running a rich air fuel mixture all the time? Poorer gas mileage, hotter combustion, possible engine damage?

Please let me know.

[rhstech]

where is the egr temperature sensor located on a 1991 corolla with a 4a fe engine
any info. would help
thanx

[Mike Gerber]

Originally Posted by rhstech

where is the egr temperature sensor located on a 1991 corolla with a 4a fe engine
any info. would help
thanx

This is something that is best to post in the Corolla forum, as this is an entirely different engine than what is used in the Camrys.

Mike

[holmesnmanny]

It would otherwise be located very close to the egr valve just inside the throttle body. It'll have a connector coming off it.

Oh, and the one time I threw a code for egr it was a vacuum hose coming off it that was slightly pulled allowing vacuum to escape. I couldn't really tell until I started fiddling around with the hoses. It moved cause I didn't tighten a nut holding a bracket to it when I replaced my spark plugs.