Ok.... Here i go again. I had finally cleared all possible codes on my ECM when just a few days ago my car started acting up again. I can be cruisin down the freeway and i feel the engine change RPM but not speed. Everything on the road is passin me (im doing the speed limit) so i also think the speedo is off. and then after a couple of minutes the "SES" turns on. Spits out the egr code. I dont know what it could be but every stupid sensor on the car is new. Now for my question... Could this be a VSS problem. I also noticed that my cruise control works...well it works when it wants to. All the problems i have seem to point to this but i just wanted some feedback before i go jacking the car up and just wasting time and money.

305 tbi, 700R4, no catalytic converter, open air element, everything else is stock.....

 

have you read this yet??

https://www.thirdgen.org/newdesign/t...diagnose.shtml

it might help...

 

Is the EGR solenoid operating?

Maybe you could run through the diagnostic again:

 

vader...could you PM me and send me the TPI EGR flowchart?

 

actually i am not an idiot...i should just pay more attention when Grandpa works on the car with me. My codes are coming from the 160 degree thermostat HE put in Its cool though...gives me a reason to finally buy a modified compter chip for the car Thanks for the help Vader, it actually helped me diagnose my Dad's Suburban...Made me look smart for a second at least...haha...anyways thanks again Also if anyone has any info on tbichips.com i would greatly appreciate it....

 

How about you cut-'n-paste?

 

works for me...thanks man

 

One other thing that can set the EGR code when you are driving. If the ECM commands EGR and doesn't see the voltage signal from the feedback switch it will set the code. Those little wires on the feedback switch like to break off easily, and the wire terminal just screws into the switch, so if you loaded the wire when installing it, it could back out a ways and not make enough contact to send the signal.

 

what switch are you talking about and where is it located??

 

On the front of the EGR valve there is a little metal thing that looks like a plug, it screws into the EGR and the single wire screws into that.

 

so you are saying that the wire may be loose causing the SES light?

 

Could be, it did that on mine a few years ago. When you are driving steady state and the light comes on it means that the ECM has requested EGR but did not get the feedback signal saying that it opened. The switch is just an immersion thermocouple that generates a small amount of current when heated. If the EGR fails to open it won't heat up and send the signal and if the wire is broken or backed out of the switch...the ECM thinks the EGR didn't open, even if it really did.

 

mine does that...i will be cruising down the highway at 75 and the light will just pop on, usually codes 34 and 32. cant seem to track either of them down. i received a EGR flowchart from vader and i will try that out to see if it helps. as far as the 34...i dont have a clue. but i will definately check that wire. do i have to remove the plenum..or can i access it another way?

 

For the code 34, what year is your car?


That switch is a royal pain to get to but you should be able to grab the wire terminal where it goes into the switch with some needlenose pliers and see if it is loose. Also follow the wire back to the back side of the engine and make sure it is still hooked up, along with the solinoid connector.