2.8 to 3.1

[ForcedFirebird]

Also with TBI, could he keep his stock carb fuel pump?

[jeep2.8]

What year S10's should I look at? Also is the computer wiring hard to get off? What I am concerned is that if I don't have all the sensors that donor S10 has, can I get the computer doing it's job. For example my truck has no O2 sensor.

I remember reading somewhere on the internet about similar project and there they installed new high pressure fuel pump near the gas tank. Although the brand and parameters of the pump where not available.

[geoffinbc]

You wont be able to use your mechanical pump. It has a built in regulator that will only deliver 5 PSI or so. You will also have to plumb in a return line for the TBI system. A junk yard is a great bet for a tank and lines. You can also try the junkyard fuel pump but may want to buy new. I highly recommend against an external pump. They fail alot, run hot and do not perform nearly aswell.

Any 86 to 93 S-10 will have TBI. It never changed through the years except the TPS sensor. You will need all the sensors in order to make it run. O2 sensor included.

[jeep2.8]

Yes, I remember reading somewhere that fuel delivery unit on my gas tank may not be easily swappable with internal fuel pump. If someone has experience regarding that please let me know. That means I have to change tank. Unfortunately truck is in Europe and I live in Canada - i visit Europe for a month each year. So changing fuel tank is not ... the first option as the junkyards there rarely have cherokees.
It think there is a place for O2 sensor, right on the exhaust collector, so that may not be a showstopper. What other sensors I may need to look at, that need to be added/replaced?
In other words I am trying to figure out, is it reasonable to think of rebuilding to EFI. I have problems with the current carb and gas mileage is also an argument.

[geoffinbc]

EFI will make the vehicle so much more drivable. You will never have to worry about a Carb going flaky. And EFI (especially TBI) rarely every has a hickup.) I have over 200,000 KMS on mine and nothing has been changed. My old EFI still runs my new motor and it even uses a 4.3L junkyard TBI unit. You can easily have a shop weld in an O2 sensor bung if need be. You can use an external pump by all means if necessary. Just be sure you get it as close to the tank as possible. And buy a good one. It is just that in tank pumps typically perform better.

[jeep2.8]

What may be the difference in gas mileage with TBI compared to carb.
Thanks

[geoffinbc]

Not too sure could be 2 to 5 MPG

[jeep2.8]

It seemes that intake manifold has to be replaced as current one does not have Crankshaft Position Sensor (CPS). Correct me if I am wrong.
Thanks

[geoffinbc]

CPS for what? And what does the intake have to do with a CPS?

[ForcedFirebird]

CPS for what? And what does the intake have to do with a CPS?

x2, the CPS is in the block, the reluctor wheel is on the center of the crank.

Might be thinking of the cam timing lobe for SFI?

[geoffinbc]

Still it has nothing to do with any intake manifold. They all stop short of the Cam sensor hole.

Maybe it was posted in the wrong thread.

[jeep2.8]

Sorry, I didn't know exactly where this sensor is located. I thought it may be close to camshaft and detachable with intake manifold.
The question is, do I have to replace intake manifold when rebuilding to TBI? I don't want to start rebuilding only to figure out that some of the sensors mandatory for the computer are not available.
Thanks

[geoffinbc]

Yes you need to use the TBI manifold.

[jeep2.8]

Your truck likely does not have vacuum advance on the distributor. So I may also need to replace distributor.
What are the sensors that the computer uses to get crank-/camshaft position data?
Is there a place on TBI or intake manifold to plug vacuum line to drive front axel vacum motor and climate controls?

Thanks.

[geoffinbc]

The computer does not know the crank or cam position. It simply has a magnetic pickup in the distributor that signals the ECM. This signal is used for spark and for fuel delivery. There are a lot of vacuum locations on the TBI system for anything you may need.