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It does use voltage to send the feedback to the computer...the only real simulator for the system is to retain the sensor and just block the intake behind the valve. You can remove the tube altogether at this point, blocking it at the exhaust...if you have a visual inspection for emissions they might pop you for not having the tube...leaving the tube in tact or removing it makes no difference as long as you have it blocked between the valve and intake.
I have everything removed already, I was primarily just concerned with cleaning up the engine bay by removing what I could.
So the ECM is looking for a varying voltage signal or a constant? Has anyone backprobed a sensor to verify what the sensor is putting out? I'd check myself but the engine is out of the truck being rebuilt-again.
Correct. There also seems to be some confusion as to if the CEL due to the EGR affects fueling, so if I can fool the ECM into thinking the EGR is there that's one less thing to worry about.
It's variable, which is why it's nearly impossible to simulate. You can mount it remotely anywhere in the engine bay, in order to get your "cleanliness" taken care of.
Out of curiosity, if on a vehicle you delete only the EGR pipe and leave the rest hooked up, the EVR will still open the valve with vacuum when commanded by the ECM, correct? Could a 332 (insufficient flow) code be generated?
Correct, valve will operate and computer will see nothing wrong.
I used to block off the egr to the intake at the base of the valve where the tube goes in...I don't do it this way anymore because I couldn't get rid of an egr code in one of my trucks. It turns out the valve wouldn't move completely because of the vacuum that it generated against the blockoff....like having your finger over a straw. I realized this by taking the valve off and sucking (dare I say that) on the vacuum port with the egr intake open, then blocked off with my hand, and it obviously wasn't working. Blocked it off at the intake and it works fine.
What do you guys know about doing this on a 96' half ton, with DPFE instead of the EVP sensor?
Edit:
After some reading & YouTubing, it looks like the DPFE would detect a blocked off EGR. Correct me if I'm wrong. DPFE is not measuring valve position like on the older systems (easy to trick), but rather a pressure differential across an orifice. One side of the orifice is plumbed directly to exhaust, the other side is plumbed directly to the EGR valve (and if the EGR vacuum solenoid (EVR) is commanded to deliver vacuum to the EGR, this side of the orifice leads into the intake). The PCM is using the DPFE & looking for a pressure drop across the orifice to indicate that exhaust gases are flowing into the intake. Blocking the EGR valve would eliminate the flow of exhaust gases into the intake, and so there would be no pressure differential. Resulting in an insufficient EGR flow code. Triggering a P0401 code.
In the photo of the DPFE based EGR system below, the orifice must be in the accordion region of the EGR tube. It can't be a very small opening, as compressed air readily flows through the length of the EGR tube.
96' Ford EGR system for EEC-V vehicles.
What makes me question that explanation, is that I had a P0401 code this summer, when in fact I had too much EGR flow. My EVR was always sending some vacuum to the EGR valve. New EVR and no more EGR at idle, and no more P0401. Maybe on the 96' trucks, P0401 is the only DPFE based fault code available, and the PCM is just trying to get your attention to the EGR system?
WAG: T the the reference line of the EGR to intake vacuum to trick the DPFE into thinking EGR flow is functional, with a blockoff plate between the EGR valve & upper intake. Nevermind, this would never be turned "off" and be a path for exhaust into the intake anyway. My take away message is to just keep EGR intact on the DPFE equipped vehicles.
It's variable, which is why it's nearly impossible to simulate. You can mount it remotely anywhere in the engine bay, in order to get your "cleanliness" taken care of.
That makes sense. I'll hide it then. I just wanted to make sure I understood the system well enough before writing it off that "it can't be done".
I don't know how you'd go about fooling the flow sensor, different animal entirely. You could probably reroute the exhaust of the flow tube right back to the exhaust downstream but that sounds like it might be more work than its worth.
If the reference side of the DPFE sensor were plumbed into the vacuum line that controls the EGR valve, it would at least measure 0 flow when the PCM commanded it (because EVR is not sending vacuum to EGR in that case). That might trick the DPFE into thinking the EGR port is open when the PCM commands EGR flow. Whether it's going to see the correct pressure differential is another story. But then you're sending exhaust gases through plastic vacuum hose and the EVR solenoid, and finally into the intake anyway, so it probably wouldn't last long at all. I think I'll just leave it alone. I have two fully functional DPFE/EGR systems at this point.
Out of curiosity, if on a vehicle you delete only the EGR pipe and leave the rest hooked up, the EVR will still open the valve with vacuum when commanded by the ECM, correct? Could a 332 (insufficient flow) code be generated?
Wrong definition for Code 332 on this vintage truck. The computer has no way of measuring actual EGR flow, the EGR feedback is positional. Therefore removing the EGR pipe and properly blocking off the open port will not trigger Code 332 assuming the EGR valve itself moves when commanded.
BTW the correct definition for Code 332: EGR valve opening not detected.
Correct. There also seems to be some confusion as to if the CEL due to the EGR affects fueling, so if I can fool the ECM into thinking the EGR is there that's one less thing to worry about.
I don't believe there's any sort of different routine that gets kicked off as a result of an EGR-related CEL. The CEL gets triggered by an out-of-range value input to the PCM, which is in many ways separate from the actual strategy of running the engine.
I understand what you're trying to do; as already suggested, just find some remote tucked-away location to hide the electronics - maybe even build an extension harness to further hide it away. Then if you want at your leisure, play around with minimalizing what you really need. Junkyard parts are good for this sort of experimenting.
To my way of thinking, the reason you don't want a CEL constantly on is so that you'll actually know if/when something else throws a code that should require further investigation.
To my way of thinking, the reason you don't want a CEL constantly on is so that you'll actually know if/when something else throws a code that should require further investigation.
That's another benefit I hadn't thought of. I just hate have the CEL on in general. Any light on in the dash is annoying.
What I'll probably do is backprobe the connector with some long test leads and run them into the cab (once the motor is back together and truck running). Then when I'm driving I can have someone verify what they're seeing. Based off of that I'll know for fact if it's possible to fool the computer or not.
The truck is being used for utility and trail riding, so the simpler I can make things the better.
This is also the first 300 I6 I've built, so there's a fun learning curve
Hi guys! Im new to the forum and i have been reading multiple of your forums. Im needing a little advice on what im wanting to accomplish. I have a 95 f150 With the 300 efi. I want to throw on my headman headers going to true duel, do an egr delete, new19lb injectors, adjustable fuel pressure regulator and cool air intake. My question is will i have any performance issues with my upgrade. And can i just block the egr hole at the intake and forget about the egr and tube since i will be putting on headers? I would appreciate the input thank you in advance.
