egr delete

FirstRanger86 · Sep 27, 2013

Hey guys, got an ecu from an 88 2.9, gonna fab up a block offf plate. Havent dug in under the hood yet, but on quick glance, it looks like I might have to cap off an egr tube? Is this true? Or do I just plug the vacuum line, put the plate on, and go?

Thanks
Tom

RonD · Sep 27, 2013

The 2.9L Rangers have a Speed Density fuel injection system.
The speed density computer is preprogrammed for the desired fuel, ignition, and EGR characteristics, and it makes continuous (metering, timing, and cycling) adjustments based on those pre-mapped relationships.
Basically, speed density systems are accurate because the data within the control module (e.g. computer) is based around the specific engine configuration. For instance, the speed density computer in our Ranger contains spark and fuel tables specific to the Ranger 2.9L engine.

So the new ECU came from a vehicle that didn't have an EGR system?
If that's the case then you will be better off to remove the EGR valve and tube, and plug both holes then cap off the vacuum.
Otherwise the tube and valve will rust out and start leaking exhaust.

EGR system helps reduce pinging/knocking under load, it was first installed to reduce emissions but it also allows timing to be more advanced so stock engine running regular gas runs better with it than without it.

jhammel85 · Sep 27, 2013

The 88's do not have an egr. 86-87's did though.

If you have an 88 EECm, you can just remove and plug the system as needed That's what I did.

Or you can go the extra mile and actually block it off. The actuator is activated by vacuum so you don't HAVE to block off the EGR.

FirstRanger86 · Sep 27, 2013

Hi Ron,
Yeah the pcm is from an 88 or 89. Its running rich and I'm getting egr codes on the koeo test, so rather than replace the valve and sensor, I thought I would go the easier/cheaper route. In capping the tube, would it be best to thread a cap into the exhaust manifold?

RonD · Sep 27, 2013

Yes, cap it.
The tube, if left in place, will just build up carbon inside and eventually start leaking.

One of the by-products of mixing gasoline(H) with air(O) and then burning it is H2O(water), this is why exhaust systems drip water and rust from the inside out.
Working EGR systems rust out fast enough, if valve never opens the it would rust out even faster.

FirstRanger86 · Oct 1, 2013

OK, so installed the 1988 B2 computer, and she started right up. Problem is, once it warms up a bit, it begins smoking like crazy. Like Uncle Buck's car. Once running on the road, it wants to stall at traffic lights, so I have to keep my foot on the pedal.

With the EGR vacuum plugged (for now), and the new ECU, I ran the KOEO test, and got a 95 - secondary fuel pump circuit fault (after swapping the relay and both fuel pumps!).
The KOER test gave me just the rich 02 reading, no more EGR errors.

So it didn't change much. Should I be concerned about the fuel pump fault? And why is it running so rich? The FPR is working, when I unhooked the vacuum, the fuel pressure went up, and back down when vacuum re-applied. I did smell some fuel in that vacuum line, though. Just a trace, it wasn't dripping fuel or anything. I thought maybe I could drive a few tankfuls of gas through it.

Using a quick google search, these 2.9's smoking and running rich is very common, and I haven't found a fix, just many people who gave up! Lots of people blaming the FPR, the coolant temperature sensor, the MAP, lots of guessing. Anyone seen this issue resolved? I just don't want to guess and throw more money at it.

Thanks
Tom

RonD · Oct 1, 2013

I would warm up the engine and shut it off, then unplug the FPR's vacuum, plug the vacuum line so no air leak.
Remove negative battery terminal(5 minutes) or reset computer.
Start it back up and check O2 sensor for rich mix, see if the FPRs vacuum line is indeed pulling in some extra fuel.
You may also want to try to lean up the mix by removing a vacuum line at this time, allowing extra air in and make sure the O2 sensor shows that too lean, so O2 sensor is not the issue.
O2 sensors tend to get marginal on the Rich side, so they tell the computer the exhaust has too much oxygen(lean), this causes the computer to richen the mix more than it should.
O2 sensor is not "bad" but replacing it would get correct mix back, O2 sensors do get worn out, burning oil in older engines fouls them a bit and the breather holes get clogged up.
Good read here on O2 sensors:
http://oldfuelinjection.com/index.php?p=31

If still rich after FPR test then hook it all back up and move to MAP sensor, check the vacuum line first then electrical connection.
Good read here on the MAP sensor
http://oldfuelinjection.com/index.php?p=27

I doubt the ECT sensor in this, only reason being that in the symptoms you describe you would get a trouble code 21 or 61.

Dirty injector or injectors can allow extra fuel in after they are closed, can of seafoam in the gas tank can help with that, I do it once a year.

FirstRanger86 · Oct 1, 2013

Thanks, Ron. I will test the FPR and the MAP, just as you described. I changed the 02 sensor first, so I believe that to be OK. It's just reading the rich mixture that I see and smell!

Tom

jhammel85 · Oct 3, 2013

Definitely test out those parts as Ron described. I replaced mine (FPR ruptured and the MAP was bad at one point) and I still have that problem. Mine isn't severe and only does it when I 1st start it or if it idles for a while.

I've been at a loss for years on it and wish I could figure it out. Honestly, I chalk it up to a wiring issue for me. I have no idea where though...

FirstRanger86 · Oct 4, 2013

Thanks, JH. I fear that I will be in the same boat with figuring this out.
So what I did yesterday: cleared KOER codes after warming her up, blocked off the vacuum to the FPR, and ran it -- seemed to smoke a little MORE, still got the 02 sensor reading rich error.
Cleared the codes again and disconnected the MAP - first the vacuum, then the harness -- it ran really bad either way, and I had to keep my foot on the gas to get through the KOER test -- still rich.
Finally, I re-tested the fuel pressure for the first time since I replaced the fuel pumps, it was 33 when running, and jumped up to 40psi or so when I unplugged the vacuum to the FPR.
What's next?

FirstRanger86 · Oct 8, 2013

Any ideas?

Any good way to test the CTS?

Thanks!

RonD · Oct 8, 2013

Not sure what CTS is?

What was the fuel pressure with key off, and then 10 minutes later with key still off?
Pressure drop could indicate a leaking injector which could be causing rich mix.

FirstRanger86 · Oct 8, 2013

Sorry...coolant temp sensor.
So I should run it a while and then monitor fuel pressure, key off, for 10 mins? Is there an acceptable amount of pressure loss?
Thanks!
Tom

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