3.4 swap into 1985 Jeep Cherokee questions?

[Canyonero]

I guess I don't know. Like I said, you can get started without it. Make sure you don't have any more important bugs to work out.

http://www.magsensors.com/

http://www.magsensors.com/vss.html

[cardana24]

It's used for emissions and fuel trim calculations. You can drive without it, but you'll get a CEL. I just hooked up mine after a year, still don't know if it's working right (still get a CEL). I had a VSS already, built into my speedometer.

You can get a VSS that plugs into the transmission before your speedometer cable.

http://www.jagsthatrun.com/Pages/Spe...eedometer.html

Is that the only place to get one of those things they seem expensive? Are those just plug and play...plug the cable into that then plug the fitting into the tranny and hook up the electrical connections? I think I need the #2 model, since I remember reading I have a 4000 pulse per mile set up, but on their site it is only list for the 91-93 camaro engines. Well my engine is out of a 94 does this make a difference?

[Canyonero]

It's used for emissions and fuel trim calculations. You can drive without it, but you'll get a CEL. I just hooked up mine after a year, still don't know if it's working right (still get a CEL). I had a VSS already, built into my speedometer.

You can get a VSS that plugs into the transmission before your speedometer cable.

http://www.jagsthatrun.com/Pages/SpeedSensors_Speedometer.html

[cardana24]

I got to work with the hole saw last night and now the wires that need to be inside are inside. I soldered some of my connections and I plan on finishing that tonight, then I will crank it to make sure it still runs As for the vehicle speed sensor am I am going to need that? I was under the impression that is the digital speedometer, but would not affect driveability. Can someone please let me know about this?

[cardana24]

nothing is rigged for the VSS yet. What do I need to do for that?

As for lash I was just going off what everyone here was saying basically anywhere from 1/2-1 full turn past 0 lash. So I did it 3/4 or a turn past 0 lash. I did not read a manual for that I was just trusting people on the site since it seems like a few of them may have done it before.

I hope to work on it more tonight.

[Canyonero]

How many turns past zero-lash did you go? My friend just set the lash on his Trooper last night. Two of my manuals said one and a half turns. That seemed like too much, but it's what the books said so we did it...

[Canyonero]

Best of luck on the test drive! Did you ever get anything rigged up for the VSS?

[ssterlingb]

Congrats!!
I'm finally about to start my project next month, so I will probably be pestering you with tons of questions.
Hope to hear about your maiden voyage soon & post some more pics!!

[cardana24]

So I got everything back together last night and fired her up...purring like a kitten Now I need to get the ecm in the cabin and finish soldering wires and I will take it out for a test drive.

[cardana24]

Nice! I thought you'd be able to do it by just removing the valve covers, but I've never tried. Sounds like you might finally be in business!

You probably can but the method I used I needed to see the lifters going up and down. Plus I did not want to se the lash on a running engine, so this is what worked for me. Also to take the valve covers off you still have to take the upper manifold and fuel rail off so really the only extra step for me was taking off the lower...yeah it kinda made a mess but its not hard to take off at that point.

[Canyonero]

Nice! I thought you'd be able to do it by just removing the valve covers, but I've never tried. Sounds like you might finally be in business!

[cardana24]

After getting these instructions from my friend. I pulled my upper/fuel rail and lower intaking manifolds off along with the valve covers and I re did my valve lash, here are the instructions I used...they were very helpful and spell out when you set the lash for each valve. I followed the directions but once I reached 0 lash I turned each nut 3/4 of a turn since that is what is recomended here on these engines. Maybe this will help other people as well.

Valve Adjustment Procedure


1. Valves can be set on a hot or cold engine. A cold engine is a lot more comfortable to work on. Major camshaft manufacturers recommend setting valves cold, to avoid erroneous adjustments on lifters that may be "pumped up" If you are setting valves on a fresh engine that has not been run, everything should be well lubricated before you begin.


2. Remove both valve covers and remove the spark plugs to make the engine easier to turn over. Also, If you are setting valves on all cylinders, it is generally easier and less confusing to just loosen all of the rocker arm adjustment nuts before you begin. This also allows for all of the internal lifter plungers to return to their "home" position.


3. Using a long handled ratchet or breaker bar attached to the crank bolt, turn the engine over in the clockwise direction.


A. Starting with #1 cylinder, turn the engine over until the exhaust pushrod just begins to move up.


B. At this point, stop and adjust the intake valve on the same cylinder.


1) Tighten the rocker until you can roll the pushrod between your thumb and forefinger with the slightest bit of resistance.


2) At this point tighten between an additional quarter to half of a turn.


C. You have now adjusted the #1 intake valve. You will now want to turn the engine over while watching the same intake pushrod that you just set, it will go full open and then begin to close. When it is almost closed, stop and adjust the exhaust rocker arm on that particular cylinder. By following this procedure, you are assured that both of the lifters are at the base circle of the cam and that there is no additional pre-load applied to them from cam lift at this point.


D. You are now able to repeat this procedure on the remaining cylinders.


4.Re-install your valve covers and your valve adjustment procedure is finished

So after I did ^^this I ran another compression check, and they are now reading between 190-200 across all cylinders!! Tomorrow I will finish putting things back together to start it again. When removing the LIM I did not remove the coolant hoses (just to save mess) but it poured some coolant into the engine, so I am changing the oil and plugs before I attempt to start the engine tomorrow. I have to work in the morning so I left the upper manifold/fuel rail off for the night along with a few other things but it should not take too long to put back together.

[cardana24]

That's my understanding, I could be wrong. If the valve lash is excessive then your valve(s) might be held slightly open. I think. Not too hard to check.

I will try to get around to re doing my lash tonight. It was never explained very well to me, but a friend just sent me some instructions that make it much more clear as how to do it.

[Canyonero]

That's my understanding, I could be wrong. If the valve lash is excessive then your valve(s) might be held slightly open. I think. Not too hard to check.

[cardana24]

Oh, weak. Sorry man.

I have less experience with the innards, I've done most of my fighting with the wiring.

Possibly got the cam timing wrong? Incorrect valve lash (too much preload on the spring)? Those are the only suggestions I have. I recall you doing using the valve-hold fitting, so I just assumed your compression would be ok.

Suppose next I'd pop the valve covers off and back the rocker bolt back to zero-lash and see if that makes a difference.

Also with the vave hold fitting that was set ~100 psi and they all held.


I guess I don't understand compleatly but could the lash be set so tight on some of the cylinders that I am not getting compression?