?s on TBI sensors and variations

[BMB]

Looking at geting a 95 truck TBI engine and wiring/computer for a swap and have some questions about it.

From what I have read, looks like the later models (93-95?) difference from earlier years was the addition of electronic control for the transmission? I want to run this with a manual trans, so will I have to do anything with the computer (new prom etc) or will it run properly as is without the auto tranny outputs hooked to anything?

That leads me to the VSS sensor. I'll be running a D300 and was wondering if I could run a factory Dodge/Jeep speed sensor like this?

AutoZone.com | Vehicle Selection | Year

I belive the threads are the same and it is an 8 pulse unit.


Or would it be less complicated to look into getting an earlier version 86-91ish.


Thanks.

[Caver Dave]

Originally Posted by BMB

From what I have read, looks like the later models (93-95?) difference from earlier years was the addition of electronic control for the transmission?

I believe this correct... later models may include some additional engine management also

Originally Posted by BMB

I want to run this with a manual trans, so will I have to do anything with the computer (new prom etc) or will it run properly as is without the auto tranny outputs hooked to anything?

Shouldn't be too hard to "tune" the auto tranny out of the picture. My earlier 1227747 (circa '89-'92) only had a few tranny related items (TC lockup, VSS, etc) that were a simple "on/off" within the binary...

Originally Posted by BMB

That leads me to the VSS sensor. I'll be running a D300 and was wondering if I could run a factory Dodge/Jeep speed sensor like this? <snip>
I belive the threads are the same and it is an 8 pulse unit.

I decided against the VSS for the simple reason I didn't get one from the donor and wanted to keep the initial cost of conversion down. OTOH, according to my sources (a lifetime of early TBI conversion knowledge) the VSS isn't a must have item... usually the lack of VSS in a manual/non-lockup auto manifests in the form of rough idle/cutoffs during sudden braking or deceleration. Haven't seen the first hint of this in my rig...

Originally Posted by BMB

Or would it be less complicated to look into getting an earlier version 86-91ish.

The 1227747 ECM (42$) is the MOST widely understood & hacked system in existance. That opens many doors for assistance & knowledge that may not exist for newer systems. That same door also swings the other way where newer ECMs/PCMs have options for things the 1st generation TBI hadn't even conceived (intake air temp [was an option on *some* early car systems], MAF, multiple O2 sensors, etc)


Regardless of what you decide, the JYs are FULL of "Cash4Clunker" rigs now. If your engine is running good and would rather *add* TBI, nows the time to snab it while they're scambling to sale parts. I got 99% of the parts I used for $100 (everything that remotely kinda/almost touched the TBI system + another bucket full of spares & junk like underhood work lights ). You should be able to get the same deal or better for the asking...

[JeepDawg]

I have a 93 5.7L TBI with the 4L60E tranny in my CJ.....

The way around the tranny issue is to get a computer that came off a truck with a manual transmission......Personally....I love the auto....I'll never go back to a manual....

Caver brings up some good points.....one advantage of the TBI is the simplicity....the change over to MPI started around 95......so some 95's are TBI...others are MPI....you might also want to look at the tranny on that truck...it could be a 4L80E....which is a much beefier ver of the 4L60E.....a very heavy duty tranny.....

Check out Painless Wiring....that may have a kit to convert an auto harness over to manual....

As for the VSS...the sensor is easy to install....and manditory for an auto....helps determine shift points....but I would also suspect it has uses in the manual setup as well....personally, I would install it....otherwise, you might get trouble codes....and if you are in a state that does smog test...you won't pass.

Otherwise....electrically....it's an easy swap....you only have about 6 wires that you really need to connect to the jeep....

[Caver Dave]

Originally Posted by JeepDawg

As for the VSS...the sensor is easy to install....and manditory for an auto....helps determine shift points....but I would also suspect it has uses in the manual setup as well....personally, I would install it....otherwise, you might get trouble codes

Only for a computer controlled auto. In a manual/non-lockup auto rig, the VSS only serves to:
- Assist with idle during deceleration/panic braking
- Drive electronic speedos
- Input the cruise control

The last 2 are stretches on a Jeep & can easily be removed from the programming by removing a checkmark in the binary (= ZERO codes). Mine runs great without the VSS or EGR and throws no codes at all!

Originally Posted by JeepDawg

and if you are in a state that does smog test...you won't pass.

While my Jeep is exempt from tailpipe sniffing & now even routine safety inspections, I plan to take it down for a sniff (for giggles) once I've had a chance to resume tuning (current chip was the 2nd-3rd iteration and no where close to dialed in... but it still runs 300% better than a carb ever did!). If my buds machine will "read" OBD I, I'll have him do that too, just to see what the analyzer says!

[BMB]

Thanks for the info.

And Dave thanks for the Binder link, I'd been looking for that.

One more question, do the earlier computers plug into the later wiring harnesses? I don't believe they do.

At this point, I'm still kind of up in the air. I can get the complete 350 engine with all the wiring and accessories for $400, which is sounding pretty good.

[JeepDawg]

$400 is a good price.....you can spend a lot more trying to piece-mill a setup together.....

Did you have a look at Painless? They have a lot of good info....

One other thing....see if the engine is a Gen II....cast iron block and AL heads....if so, it will weigh about the same or a fraction less than the 4.2....and very much worth $400....

[Caver Dave]

Originally Posted by BMB

One more question, do the earlier computers plug into the later wiring harnesses? I don't believe they do.

From what I've read, later TPI ECMs will accept early TBI harnesses (with a few [<6] wires needing to be swapped at the connectors), so it stands to reason the reverse is true. If you search thirdgen.org, you'll likely find the definitive answer, since the swap from TBI to TPI is rather common for the hotrod crowd...

I agree with JD... $400 for a running engine w/ all everything you need to drop it in place (minus any adapters for tranny) is smoking!