TOPIC: Mitsubishi Starwagon 1996 2.0l 4cyl

Here's a movie on my first groove job.



Watch it on your own risk. It's long and boring for the ones who don't have an identical throttle body. The strange sound in the beginning of the vid is from one of the dogs. He gave me mental support.

I sprayed loads of heavy duty degreaser after the groove job as there were lube all over it. Finished it off with a high pressure cleaner! Not recommended as the high pressure can easily destroy the diaphragms in the TB if sprayed in the right vent.

TracyG, I have no idea how to do a proper compression test, so all your comments are valued! Thank you so much! Just one question, you write "..to block open the throttle for more accurate results...". Do you mean I should somehow make sure the throttle plates don't close?

If I don't mount the throttle and carby, can I still do a compression test? I guess there will be a strange comp in that case, right?

You asked how far the van has gone. It's 251.623 km's.

You wrote about shaved off the plate. I already touched the plate here and there with the bit, so parts of the plate has come off, but it didn't seem the diameter has changed anywhere so it should be fine. Or?

Regarding the coil lead and plug leads, the resistance is 4000 and 6000 ohms respectively. A bit too much to indicate good performance. (can't wait until I have the resistorless stuff in place on the other cars...more on that later)

This is EXACTLY what all Gadgetmen should be doing!

I'm not talking about The Groove per se, but the action of filming it and posting it to a YouTube channel.

This is how the people we serve, to say nothing of other Gadgetmen, learn.

SALUDO, RIKARD!

Ron

Hi Rikard,

Good video, you mentioned maybe re-doing the groove.

I think that would be a good idea, fill it in will plug those holes as well.

Reshape the surface and have at it again.

I would suggest, as Ron had mentioned, to close the throttle plate completely.

Yes, it will engage the groove slightly when you adjust your idle but that is what you want with this type of carb.
Once you've got it all working you'll find you won't need to use much of the accellerator pedal to get it to go and when your up to speed just a touch will keep it there.

It will also give you more meat to work with when re-applying the groove.

I might also suggest using the original angle (bit perpendicular to the throttleplate) and the small bit for this carb. You'll find that it won't take away that extra material and help keep the shape of the bit in the groove.

When you close the throttleplate completely you'll find some fresh material to cut so taking your time would not be a bad thing either.

You picked one heck of a engine to tackle for your first groove....

Great job, stepping up to the challenge

Karl Fortner
Tacoma, Washington

Hey Rikard, Great video my man!

As usual Ron and Tacoma Karl are right...

My input: hole in right side of Groove is Vacuum port, don't know what it leads to but Mikuni put there for a reason, I would try to preserve it. Make tiny mark on bottom of carb. base to re-find it if you fill in Groove w/epoxy to try again. the hole in the depth of the Groove is the one I mean. Might put a dental pick or similar stiff metal rod that fits hole, epoxy in the Groove, wait a few min as epoxy sets. Check leftover epoxy on mixing surface, when its getting pretty stiff but not yet fully hard twist/pull out rod to have a hole. No real harm if Groove breaks back thru to hole in metal again. A hole in the bore of a Throttle body or carb. isn't a vacuum leak unless it connects to something that itself is leaking.

As long as there is still material between the bores you are Ok even if it gets shaved back.


I would go w/ small bit to keep the proper Groove shape/radius, you want the Groove so that the bit fits tightly into the Groove when you are done, at same time you want Groove cut to full depth so cutter ball goes into Groove to the shaft when you check your work.

As ron and Karl suggest I would back the curb idle set screw out fully to close the throttle completely. If concerned about resetting proper idle speed, simply record how many turns you back out screw and write it down immediately after you back it out. You may decide the med. bit will work when throttle is fully closed, only you can tell!

Keep pressure off throttle blade w/bit as you cut, lifting tool up from throttle blade SLIGHTLY will do that but try to keep angle consistent!

Get some super fine sandpaper. After Groove is cut you could Very Gently radius the leading edge of Groove where air enters from top of Groove but leave the downstream edge alone. If you fill existing Groove w/ epoxy, you will need to smooth it out to existing un-touched bore contour anyhow before you re-cut Groove.

I would forget the spacer. The closer the Groove is to the throttle blade's idle position, the earlier in RPM's and the sooner vs. engine loading the Groove kicks in. And THIS engine needs all the help it can get with off idle power!

Compression test: Idea is to have all spark plugs removed and throttle blocked wide open, with Trans. in Neutral, wheels tightly blocked with blocks, bricks, etc. and parking brake full on. This way there is no loading from any cylinder except the one being tested w/ comp. tester screwed fully into spark plug hole. And no load from pumping loss as engine sucks air past nearly closed throttle at idle/engine off position. Plus with a carburetor (that's what you have there Rikard) the choke and throttle must be fully blocked open during compression test, or the vacuum oreated at the throttles as the starter motor spins the motor over will draw raw fuel out from the idle circuit and maybe the main circuit as well. THAT would wash oil off the rings and contaminate the oil, reducing its ability to lube the engine! SO clean stuff away from the open intake manifold if you do the test w/ carb off the engine, or follow my warnings if you wait till carb is re-installed. Ya put a little oil on comp. tester threads and hand-tighten it into each cylinder as you go. Blow any accumulated junk, dirt, etc out of the spark plug wells BEFORE you even pull the spark plugs out.

1. Label the plug wires so they go back to the proper plugs when done.

2. For those deep plug wells you need compressed air to blow out crud, if they are clean you are cool!

3. pull out all 4 spark plugs, noting their condition.

4. Screw the oiled end of compression tester into first plug hole hand tight, needs snug dont go nuts!

Coil output wire grounded or power removed from coil, fuel pump fuse pulled (Hey ya DONT want fuel spaying or gushing out along with sparking spark Plug Wires do ya??! If the engine has a Mechanical fuel pump, get the carb. completely re-installed first. I don't like to do a comp. test w/ an open fuel line!!!

Best to do this w/ a helper, someone in the car to turn the key while you watch the comp. tester gauge and keep an eye peeled for any issues...

5. have helper turn key--engine will turn over much faster than normal (only one cyl. under load). IT will sound kinda like: rrrRRrrrRRrrrRRrrrRR. Count the changes in the sound, each pitch change is the cylinder being tested going into compression. Watch the guage you will see the reading climb. dont get tempted into having it compress too many times. I usually go about 8 times that should max the guage pressure reading. Use the same 8 times (or whatever you want) per cylinder.

Write down the first cylinder's reading, then push the release button on the comp. test. guage, unscrew from plug hole, repeat for each cylinder writing it down as you go. You need to get the spec for the compression for this engine. Main thing you're looking for is big variation between cylinders.

You did a killer job videoing your Groove job, if you video'd your compressiion test we could give opinions on that too, but that's up to you! Heck you could look up the procedure for a compression test--do that anyway, i've done it so many times I might be forgetting something.

TracyG Gadgetman Reno

Hiya folks!

I just looked to see if I could find an O2 sensor. No, it has no such. I guess this is a good thing?

Also saw that it has a hose going from the exhuast manifold into the airbox. I wonder what that is doing?

New TB gasket should come on Friday and I can't wait to see the groove in action. I want to test what I have first before I re-groove it. It's not _perfect_ as it is now, but it's fine with even a tiny improvement in this car.

Hi Rikard,

That hose off the exhaust is more than likely used to help warm the engine up.
You'll probably find a butterfly of sorts down by the exhaust manifold with a thermal spring that closes it down as the exhaust gets warmer.

Similiar item in the mid to late 60's Pontiac engines.

Hmm, No O2 sensors... aren't you the lucky one...

Karl Fortner
Tacoma, Washington

Ah HA! Just as I suspected...

It is this researchers experience that vehicles without dynamic AFR management do not respond with mileage gains beyond a minimal amount. We rely on the interaction of the O2 to help the computer re-map the trims.

Your system relies 100% on the conditions inside the intake through a MAP and/or the MAF or IAT systems.

To see what is REALLY possible, you're going to need a little something extra. I would suggest a MAP and/or a MAF Enhancer. But you will get gains in the OMG range only when you properly address the sensors the engine uses to modulate fuel delivery.

GO GET 'EM RIKARD!!!!

We LOVE YOU!

Ron

Hi there,

As I have learned, the grooved car, or a car without it as well, benefits from an ignition system in good order. Here are pics from the distributor. It's the first time I'm looking inside one, so I have obviously no clue if it looks good or not. I don't want to spend to much on this car as it's gonna be sold soon, but if you think it will really benefit from a new dist change, I would get a new one right away.










Where can I get the MAP/MAF enhancers? Please note this throttle body and carburetor are mechanical. They are not computer controlled. There's a TPS wire, but I think that's all there's to it according to the pics earlier...

Hi Rikard,

Your looking at a very warn out cap and rotor which is a big part of why the engine ran the way it did.

There should be a set of points there someplace, mounted at the base under the rotor.

The 'points' is basically the make/break connection for the coil which causes the spark.

You've got a piece of vintage hardware there sir.

Good thing you checked.

Karl Fortner
Tacoma, Washington

OMG--Holy Baked Parts, Batman! Uuhh, yeah, Rikard replace that Dist. cap/rotor, the plug wires and plugs too. Geez, that's about the Worst rotor Ive ever seen. good chance all those parts are Original! Though I bet it's electronic ignition, probably no Points to worry about.

A good tune-Up will help that Starwagon get out of it's own way, no doubt. I guess the Gov't reg's in Oz allowed Mitsubishi to make/sell something this "unusual" there/then.

In the US, you wouldn't have seen a vehicle setup like this much past the mid-Eighties. So I did a lot of my guessing about this one based on my own experience.

HMMM, you might, maybe, just maybe, be pleasantly surprised how this cargo container on wheels runs after you get it all together, At least will be better to sell!

TracyG Gadgetman Reno