2,9 EGR? (split from other topic)

AllanD said:

It is Legal to "update" to a newer year engine IF and only if ALL the emissions controls from that engine are swapped with it.

The interesting thing on 2.9's is that while the '86-87 2.9's have EGR the later 2.9's made from 1989-92 DO NOT.

You'll need the computer from the later engine (it plugs right in)
and you get the happy job of removing the EGR system.

The "thing" about EGR on the 2.9 is that the system is failure prone.
/Not so much the EGR valve itself, but the metal tube that feeds exhaust to the valve and especially the vacuum lines that the system is controlled with.

ANY sort of "failure" of the system and the relatively stupid management
decides that the situation is not good and runs the engine full rich.

The one "ugly" part that might be overlooked is that the '86-87's use a different Y-pipe and a different style mating flange to the catalytic converter.


AD

Click to expand...

oh my god, i think this is whats wrong with my motor!!! Ive been wondering for the last 3 months why it drinks so much gas. I have an '88 though but it had the metal tube comming from the exhaust to the intake, so its EGR right? is there any way to remove this?

edit: sorry didnt mean to threadjack but ive never heard of this possibility before

mikhail,

The '88 computer isn't even looking for the EGR system.

And FWIW even if I kept all the EGR plumbing on an '86 or '87 engine
transplanted into an'88 or later Ranger/Bronco2 I'd keep the later computer
so that the system would NEVER be activated by the computer.

Trust me an '86-87 engine runs quite well on an '88-92 2.9 computer.

And if you want it to LOOK like the system is there and functioning even though you are using a later computer that isn't looking for the system to be there get a few air rifle BB's
and shove them into the rubber ends of the "spagetti" vacuum lines to prevent those lines from causing vacuum leaks, which is actually THE common problem with the 2.9 EGR system.

AD

AllanD, for CA smog ckech would my 87 still pass running this ecm? Sounds like this ECM is programmed for more performance? What would be a good upgrade ecm for my 87 CA truck to get more performance? I thought the egr was good cause you can run more ignition advance without pinging?

The 1986-87 PCM is slightly higher performance than the 1988. Not that you would notice. Along with that EGR, you have a knock sensor, which allows for slightly more aggressive timing.

You will NOT pass a CA smog check with a disabled EGR regardless of how the engine runs without it. Except if you have a door sticker for a complete 1988+ retrofit. All CA smog checks include functional EGR tests under idling and driving conditions, where the vehicle came from the factory with EGR. I suggest you watch your next sniff very carefully, and read the checklist.

It would be a good idea to call your BAR smog ref, rather than take advice from well informed but out of state sources. There is no substitute for the horse's mouth.

Interesting thread . . .

I have an '87 B2 that has the EGR tube removed (rusted away) and capped at both ends. I was easily able to pass Maryland emissions testing (once a faulty O2 sensor was disconnected). Almost all my emissions vacuum lines have been removed and plugged. (Not to the MAP though.)

AllanD. A few questions?
Just to confirm, when you say "Trust me an '86-87 engine runs quite well on an '88-92 2.9 computer.", what does "quite well" mean? As good or better than with the '87 part?

Is the 88/89 part (the TFI unit on the back of the distributor?) a simple remove and replace proposition?

What difference in performance (power) and/or gas mileage have you documented?

What I'm getting at is is this a real, inexpensive modification that can improve engine performance and/or mileage?

I don't know if CA and other states have this, but after my last emissions test, and after my vehicle was officially 20 years old, I was able to re-register it as a "historic vehicle" in MD. No more emissions testing.
Thank you.

CraigK

Quite well in this case is perfect.

Think of it this way, what will run better:
a)an engine with a computer that overreacts to a minor fault that
is really irrelevant to the operation of the engine
b)a computer that doesn't even look at that system regardless
if it malfunctions or not.

Hell with an '88 computer you could simply CUT all the lines in the egr system and except for having to reset base idle to compensate for the vacuum leak you'd have to do nothing else.


NO changes to the basic engine were made.
the change to the throttle body was because the
engineers MISCALCULATED and used TOO LARGE of
a throttle body on the '86-87 2.9.
But that can be played to our advantage, if you run the
bigger TB with the later computer and TPS the computer
can be fooled into staying OUT of "open loop" operation.

In open loop (triggered by 100% throttle) all that really happens
with the bigger TB is that the engine runs pig rich.

Truth be told on the '86-87 the last 30% of the throttle doesn't
really do all that much.

AD

AllanD

Pardon the repeat question, but I'm sorta slow . . .

Is the 88/89 part (the TFI unit on the back of the distributor?) a simple remove and replace proposition from an '87 B2?

Your last post talks about making a change to the throttle body, "fooling the TPS", and even cutting all the EGR lines and resetting the idle.

Can I go to the auto parts store, buy a TFI (the unit on the back of the distributor?) for a 1988 Bronco II 2.9L V6, unscrew and disconnect my '87 TFI and screw on and plug in the 88 TFI and have a performance improvement (either power or mileage)? The reason I ask is that if the answer is YES, with no other mods, I might make the investment. If I have to modify and adjust other stuff, I'd rather not bother.

Thanks again for sharing your knowledge.

CraigK

CraigK said:

Is the 88/89 part (the TFI unit on the back of the distributor?) a simple remove and replace proposition from an '87 B2?

Click to expand...

The TFI is sort of a translator between the PCM and the pick up in the distributor. It basically sends data from the pickup to the PCM, the PCM signals back to the TFI when to spark.

What AllanD is basically indicating that it's better to have a PCM that doesn't look for a particular sensor, than to have a PCM that does look for a sensor and it's not there. Even though it's timing curve might be a little more aggressive.

Basically 87 PCM on a 88 would run rich because the PCM would be looking for input from the EGR. In other words, you would probably make things worse. An interesting experiment would be to see how well the '90 MAF PCM compares to the stock '88 speed density/MAP system. I couldn't say since I am running aftermarket cam and other aftermarket parts, so I am obviously getting lower mileage than the stock '88. That might be something to look into though.

Keep tires inflated, engine tuned, plugs, wires, cap, rotor, the basic stuff..

Pete

MAKG said:

....Except if you have a door sticker for a complete 1988+ retrofit. All CA smog checks include functional EGR tests under idling and driving conditions, where the vehicle came from the factory with EGR. I suggest you watch your next sniff very carefully, and read the checklist.

It would be a good idea to call your BAR smog ref, rather than take advice from well informed but out of state sources. There is no substitute for the horse's mouth.

Click to expand...

My 87 is still jacked on the timing, idle speed and it pings/knocks too often for my liking. I'm going to the jy today and look for computer etc to do this swap! Sounds like all I need is the EECIV unit, TPS, block off plates/plugs and a few other little parts? Any particular year 88-92 or parts that I should look for over others?

you don't even need the tps. Just the block off plates and the eec. Have fun getting the plug out of the exhaust manifold without fucking it up though. Going from an 86 computer with a nonexistent egr system to an 88 computer nets a noticeable improvement in driveability. Not really any more power just way smoother. and it doesn't ping at mid rpm like the 86 computer had it doing.
What allanD is saying is that if you swap to the 86-87 Throttle Body it will keep the computer out of open loop(when the computer isnt using data from the o2 sensor and just dumps fuel into the Motor) so you get a little bit better efficiency because the larger tb will allow more air in earler in the opening of the throttle blade. Overall power won't be affected by much if anything.

Just got back from the jy with a complete 1988 Ranger 4x4 manual transmission airbox and intake system including all vacuum lines and the heat riser hose, smaller TB w/TPS EEC, EGR block off plate, and MAP (wasn't sure if it's the same). Going to try just the computer in my truck and see how it runs. Didn't bother with the exhaust manifold plug, I'll just cut mine a bit shorter and weld it shut.

At the moment, I've got terrible drivability, pinging and my a4ld computer high idle problem. So if this new EEC fixes all that I'm going to disconnect the knock sensor, egr and all and go to the referee station to make it a 1988 smog vehicle.

BTW, I had to take the airhose from the airbox to the TB because the 88 and up airboxes outlet is alot bigger and my TB hose won't fit onto the later airbox!

Why and how does the larger TB keep it out of open loop operation?

Spoke with a CARB referee today and he said, no problem to convert my 87 emissions, efi etc to 1988 stuff....just have to make sure I get all the correct parts and hook it up properly!

I can go to any newer year and same size or larger (but not smaller) engine. Therefore I'm going to install the TB with TPS, IAC, EEC (already installed), MAP, wiring and remove the EGR (install block off plate and plug). I'm pretty sure that all I have to do with the wiring is unplug the knock sensor and leave it in the block just to plug the hole. For now I may just leave the wires for the EGR solenoid (on passenger inner fender) and the knock sensor, but will cut them out of the harness for the long term.

Also thinking about cutting out the 'low oil' level warning sensor wiring too...just more crap in the way down there next to the starter and that is what the engine dipstick is for.

Once I'm all done removing and installing the appropriate parts, I call and make an appointment with a smog referee who will inspect and test my truck. If it doesn't pass they will tell me what I need to do to make it pass (and I get one free re-test). Once it passes they put a sticker on the door jamb re-labelling it a 1988 emissions vehicle. Sounds easy right?

AllanD said:

mikhail,

The '88 computer isn't even looking for the EGR system.

And FWIW even if I kept all the EGR plumbing on an '86 or '87 engine
transplanted into an'88 or later Ranger/Bronco2 I'd keep the later computer
so that the system would NEVER be activated by the computer.

Trust me an '86-87 engine runs quite well on an '88-92 2.9 computer.

And if you want it to LOOK like the system is there and functioning even though you are using a later computer that isn't looking for the system to be there get a few air rifle BB's
and shove them into the rubber ends of the "spagetti" vacuum lines to prevent those lines from causing vacuum leaks, which is actually THE common problem with the 2.9 EGR system.

AD

Click to expand...

will putting a jet chip, on 87 ranger 2.9, that's made for a 90 ranger 2.9, increase my 87 ranger's 2.9 stock engine's performance to any noticable degree.. can I use any computer from '88-92, if I use a jet chip from a 90 ranger 2.9, or do I need to, also, use a 90 ranger 2.9 computer..

Natedog said:

Just got back from the jy with a complete 1988 Ranger 4x4 manual transmission airbox and intake system including all vacuum lines and the heat riser hose, smaller TB w/TPS EEC, EGR block off plate, and MAP (wasn't sure if it's the same). Going to try just the computer in my truck and see how it runs. Didn't bother with the exhaust manifold plug, I'll just cut mine a bit shorter and weld it shut.

At the moment, I've got terrible drivability, pinging and my a4ld computer high idle problem. So if this new EEC fixes all that I'm going to disconnect the knock sensor, egr and all and go to the referee station to make it a 1988 smog vehicle.

BTW, I had to take the airhose from the airbox to the TB because the 88 and up airboxes outlet is alot bigger and my TB hose won't fit onto the later airbox!

Why and how does the larger TB keep it out of open loop operation?

Click to expand...

did your 2.9 engine run any better, after you said you were going to switch the computer in your truck, and see how it runs..