Quick Questions...

[Frankenstein86]

Okay, so I have a 86' Ranger 4x4 with a cracked head and/or block (water in oil top to bottom, it's a real mess). So I decided to swap the motor out, and to keep from dealing with an onslaught of wiring issues I just went back with another 2.9 out of 1990 Bronco 2. My questions may seem somewhat random but here we go...

1) Do I need to take the EGR Valve System (including driver side exhaust manifold) off the 86' motor and put onto the 90' motor? Do I HAVE to have it to run properly?

2) On the 86' motor I have a sensor that just screws into the block under the driver side exhaust manifold, the 90' motor has no such sensor. It was easily swapped out but just for future reference can anyone tell me the formal name for this sensor? I have been told it is a knock sensor, is this correct?

3) Are the TFI Modules interchangeable between these two motors?

4) Is there anything I should know, anything that might keep me from just being able to basically plug and play....

Any help would be greatly appreciated

 

[RonD]

1) yes, you want the EGR system, it will keep your engine from knocking/pinging
The Exhaust Gas Recirculation(EGR) system is used only when engine is under load.
When an engine is under load the cylinders heat up, as they heat up two things happen, the NOX emissions go up and the heat causes Regular octane gas to pre-ignite(pinging).
While you may not care about the first thing, you will care about the second thing, because you will lose power and over time pinging will knock out a piston.

2) yes that is the Knock sensor, because this engine will be prone to pinging the knock sensor was added in case the EGR system wasn't working correctly.
The knock sensor will cause spark timing to retard(Before TDC) so spark happens before pre-ignition can in the hot cylinder, this causes a power loss, but much better than a hole in the piston.

The computer in your '86 is setup for the EGR and the Knock sensor, so it's fuel and spark settings are more aggressive than with an engine that doesn't have them, and without these your engine will not run as well.

3) from what I remember there are 2 different kinds of TFI modules, not sure what the year differences are.
I would look up an '86 module and a '90 module, see if the part numbers are the same.

TFI is a self contained ignition system, it does sends PIP pulse to the computer for fuel injection timing, and computer does send TFI spark advance/retard info based on throttle position changes and MAP levels.
So you could swap the whole system from one to the other, distributor and module.
A coil is a coil......... is a coil, lol.

 

[adsm08]

The TFI will work. Ford made one 6-cyl TFI, it fits all 6 cylinder engines that used the system.

If you retain the 86 computer you do want to keep the EGR and knock sensor, like Ron said. On the other hand, both systems could be somewhat problematic. The EGR can fail and cause issues, and the knock sensor can confuse noise from the 2.9's noisy valve train for engine knock.

My advice, personally, would be to go back to your engine donor and grab it's computer too.

Beyond that the only thing I can think of that might even be remotely an issue for "plug and play" in 88 the shape of the Y-pipe flange at the cat changed, so unless you plan to use the later Y-pipe you should be good to go.

 

[Frankenstein86]

Thanks for the info and quick response, you guys are awesome... Everything is looking good at the moment, although I will be sure to check the manifolds out to make sure they will fit up properly. The EGR system has already been swapped except for having to go find some replacement bolts for that drivers side mainfold.... Also I would go and get the computer but the guy claims he doesn't have it. Anyways I appreciate it fellas...

 

[arizonadirtslinger]

Isn't the 4.0 swap plug and play with an 86 ?

 

[adsm08]

Isn't the 4.0 swap plug and play with an 86 ?

No. It's a lot of wiring, and the 4.0 will eventually kill whatever trans you have in an 86. It usually doesn't take that long.