egr system on a 2.9l

whitebroncoii87 · May 23, 2015

Hi, I just got a 2.9l 87 bronco ii. I don't have an egr system set up, but I do see the egr vacuum solenoid on my RH fender. I want to install the rest of it. My plan is to buy the egr valve and connect from it a vacuum line to the existing egr solenoid and a piping to the exhaust manifold or y-pipe. Currently, there is no port on the exhaust manifold or y-pipe to connect a pipe/tube to the would-be egr valve. Do I have to buy a new exhaust manifold or y-pipe with a port? I've never seen an egr system so how should the port be on the manifold or y-pipe? Thank you!

alwaysFlOoReD · May 23, 2015

Some of those years didn't come with egr.

adsm08 · May 23, 2015

87 should have had EGR. Your engine has probably been replaced with one from an 88 or newer vehicle.

The EGR tube would run off the driver's side manifold, so you will have to contend with replacing that manifold, if you can find the parts to do it. You also need to make sure your intake has the provision for the valve. IIRC the 88 intake manifolds had the port, and it was just blocked off with a plate, but my 89 it was removed from the casting completely.

I'm not too sure about the availability of the tube either.

RonD · May 23, 2015

If you don't have to pass Emission tests you could also replace computer with '88/'89 2.9l computer, it has different software to run engine without need of EGR to reduce NOx and pinging under load.

whitebroncoii87 · May 23, 2015

Oh!! Suddenly, everything seems clear! I think.. So it's likely I have an 87 but an 88 engine. My intake does have an egr port but is plated up (no egr valve on it). My computer must be an 87's because I plugged an ford obd1 scanner and it mentions egr fault. Now, how do I confirm that my engine is 88? So do ya'll recommend retrofit it to egr or no?

whitebroncoii87 · May 23, 2015

and indeed my intake's egr port is partially covered by throttle plate.. I was thinking to grind that off to fit the egr valve in if necessary..

RonD · May 23, 2015

If your state requires your engine to have stock emissions system then you will need to get the correct exhaust manifold and the rest of the EGR parts, then get it working.

If not then I would source the cost of an '88/'89 computer, see which option would be less expensive

adsm08 · May 23, 2015

My advice is to leave the EGR system off, and get the later computer, unless having the EGR components present is a legal requirement like it is here in PA.

There were other changes made to the 2.9's control software in 1988 that eliminated some issues, like deleting the overly sensitive knock sensor that sometimes confused valve train noise with engine knock.

whitebroncoii87 · May 23, 2015

what if I leave it as is without egr and keep the 87 computer, will the computer still function properly without the egr signals? Can the computer still send correct calculations to the fuel injectors so I don't run rich or lean without egr?

holyford86 · May 25, 2015

whitebroncoii87 said:
what if I leave it as is without egr and keep the 87 computer, will the computer still function properly without the egr signals? Can the computer still send correct calculations to the fuel injectors so I don't run rich or lean without egr?

It will drop into limp mode and run like crap, been there, went to the the 88eec to correct it.

adsm08 · May 25, 2015

holyford86 said:
It will drop into limp mode and run like crap, been there, went to the the 88eec to correct it.

^That^. Sometimes

Technically the computer is supposed to be able to realize the system is missing and compensate. But the older EEC IV computers aren't too bright, and so it becomes a bit of a hit or miss thing. I had an 88 parts truck that I swapped computers with my 87 looking for another issue, and it pissed that 87 computer off to no end, thing barely ran, and I never even took it out of the yard.

My one buddy had an 87 with the EGR removed, kinda looked to me like your situation, a newer engine was put in, and it ran fine. I never checked that computer to see if it had been changed though.

AllanD · May 27, 2015

an '87 2.9 runs real nice on an '88 up computer with the EGR removed.

You really want to be rid of the EGR, because of how the system is actually controlled
and the enormous issues you have when the sensor that tells the EEC that it isn't working correctly, and the computer "over-reacts"

another problem is the tiny little exceptional "Christmas lines" (so named because they are red & Green) that run between the fender mounted vacuum solenoid and the EGR control valve...

the other issue youll have is that if you really do have an '88 or later engine you have
won't have the EGR valve OR the exhaust supply pipe or the proper drivers side exh manifold that the pipe connects to.

I would not want to remove and replace a driver's side exhaust manifold with the engine in the chassis.

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egr system on a 2.9l

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