Engine/Transmission (1994 - 1998) egr frustration

[budctdca]

New member here, iposted a new thread a couple of days ago and I was delightfully surprised by the immediate and helpful input. Anyways, my truck came with EGR and when i first got it a year ago, the check engine light came on. I bought a scanner Po401 came up (EGR insufficient Flow) well I decided that EGr on a diesel was pointless. So I made some block off plates. My question is has anyone done this and got the check engine light from coming back on? I am not afraid to try anything, any input would help. Thanks in advance.

Luke

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1997 4x4 cc longbed, '04 chrome rims and stock 265/70r17s, straight exhaust, deleted EGR, BHAF, more upgrades when i get my tax refund :-laf

 

[Vaughn MacKenzie]

Well you did the right thing by nixing the EGR. As for the light there must be some sensor that is causing it to trip, you could try locating it, unplugging it and shorting a wire or small resistor between the terminals to make the PCM think everything is honki dori.



Vaughn

 

[budctdca]

egr sensor bypass

well, I already tried to unplug the sensor, but as soon as i did, there was another code, something like egr sensor circuit malfunction, so i routed the sensor vacuum lines in a continuous circle, which worked for like a day, but when i was passing some bad driver today (it was fun) the light came back on at full throttle, as for shorting, is that really safe?

 

[jtwcummins]

The low EGR flow is set by the IAT. When the egr opens the egr module is looking for at least a 10* temp rise in intake air temp. If the egr has been running for alot of miles I would recommend removing the top of the intake manifold, it is probably full of soot, and cleaning it out.



I went to Radio Shack and got a 12v relay with NO and NC contacts and an assortment of small pots. I disconnected the egr solenoid and used its input to pick up the relay. I put one pot across the IAT on the NC relay contacts, after disconnecting, and using the scanner set the IAT to 80* with one pot. Then used another pot and set to 95* when egr picks up relay. No more light! The advantage is when full throttle the egr is turned of so the relay opens and the IAT goes to the lower value.



The sensors on the 12v are only there for the egr so doing away with them is no problem, the engine doesn't care what the IAT sensor thinks the temp is, love the mechanical 12v.



As a note, the ECM is the same for Federal, non EGR, and the EGR equipped engines. I have been looking for the deceptive EGR module. Dealer didn't even know where it is so I was going to open the wire loom and follow the wires but decided on the easy way.