78' Scout II 4 cyl. issues?

Do you have a tach connected to the vehicle or a handheld unit you could hook up? Just curious to know what the actual idle speed is at full operating temperature. Another consideration is the throttle return spring. If you've got some stretched out job on there now, it May not be returning your throttle to the fully closed position on a consistent basis.
 
Yes I am setting the idle speed with a hand held actron(?) meter. It is set at 550. I do have a question on this though. The rpm guage has 2 diff readings one for 8 cyl and one for 6 cyl. It has a note that says double the 8 cyl scale for 4 cylinder engines, but that is way way to high. I have been setting it off of the six cyl setting bc that is what sounds correct. So its at 550rpm on the 6 cyl reading. I figured this way I would atleast stay consitent. My return spring is new and the accelerator pedal is smooth and seems to return normally. Good spring stength another words.
 
I've recently had my own experiences with a handheld meter of potentially questionable accuracy. 8x2 is the correct method for determining idle speed on a 4-popper. The readout you are seeing on the 6cyl sweep is meaningless. I imagine there is some mathmatic conversion, but doubling the 8 cyl figure seems easier. Are you sure you have the test leads connected properly?
 
Pretty sure, its just 2 wires. One to the coil(side that feeds the distibutor) and the other is a ground. When I set it at double on the v8 setting that would be at 1100 rpm on the 8 cyl scale, if I am doing this correct? If thats right it sounds like its at 1100 rpms and not 550 rpm's. One thing I was curious about was the fact that this particular 4 cyl is in all actuality 1/2 of a 392 v8, so do you still time it at a 4 cyl setting or could it be the 8?

No had not looked at the fuel pressure

just had a thought, I wonder if I am not letting the Scout get hot enough before I am setting my carb mix and idle speed. I havent been taking it down the road, just letting it sit and idle for awhile until the temp guage is at normal operating temp

sorry for some of my ignorance here guys I am learning a little as we go. I am absolutley not sorry for some of the other ignorances I May post, lol
 
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wiggins said:
pretty sure, its just 2 wires. One to the coil(side that feeds the distibutor) and the other is a ground. When I set it at double on the v8 setting that would be at 1100 rpm on the 8 cyl scale, if I am doing this correct? If thats right it sounds like its at 1100 rpms and not 550 rpm's. One thing I was curious about was the fact that this particular 4 cyl is in all actuality 1/2 of a 392 v8, so do you still time it at a 4 cyl setting or could it be the 8?

No had not looked at the fuel pressure

just had a thought, I wonder if I am not letting the Scout get hot enough before I am setting my carb mix and idle speed. I havent been taking it down the road, just letting it sit and idle for awhile until the temp guage is at normal operating temp
Click to expand...

Ya simply must have a shop tachometer that reads correctly for the engine you are working with. Whatever it takes! I've never seen a hand-held tach that is not correct for any engine as long as it's working correctly, is connected correctly, and "zero'd" correctly (if adjustable).

The correct base idle speed for a 196 of that era is 525>575 rpm.

A "hot" engine means one that is fully operating at normal oil temperature. That means driving for at least 15 minutes at say an ambient temperature of 60*f.

That is why I suggested you totally bypass the dtm system and drive the rig and determine what happens. There are other "things" going on throughout the entire emissions/drivability scenario on any emissions engine, stuff that changes to some degree continuously. You May in fact have other issues happening intermittently also.

The big picture here is..."drivability" in it's entirety. Everything that is part of the emissions program must work correctly in order to keep everything in original condition. And each engine/transmission combo involved on these vehicles after the 1976 model year is a bit different from the previous model year. For someone who wants to keep these rigs totally original, it's simply imperative that you have a service manual to go by. The manual "set" you need is a cts-2313.
 
Good to have you back mayben. The entire dcm system is unhooked. This is what happened once it was unhooked, but I bet the motor is not hot enough when I am making adjustments. I'll readjust everything tomorrow.
My tach is just one I got from sears a while back. It has rpm, dwell, and voltage and is non adjustable. So when my tach says double for a 4cyl(550 rpm) that would be in the 1100rpm range on the 8cyl scale?
 
I haven't been "gone", I just let this stuff play out and then jump back in when it goes a bit off course! I work here, this is my job!

So yes...simply follow the instructions for the instrument! If you have doubt regarding the instrument, simply install it on some other vehicle that uses a distributor and see what you can read.

The instructions you have suggested are certainly within the norm for these types of instrumentation.
 
Just figured you had been busy. I remeber you said your busy season is coming up. I'll get back with you tomorrow
 
Ok with dsm disconected, I took the Scout out for a good drive,motor good and hot and came abck to make my adjustments. The motor being hotter put my idle speed up around 600 rpms so I put them back to 550 rpm. Rechecked timing, adjusted the air mix on the carb and rechecked the rpm's, which were still at 550 rpm. Took it back down the road and came back , killed it, and it caughed a little out of the tailpipe(light backfire). Confused!
 
So...your latest testing indicates the dtm module is punkee. Put a replacement on the list of parts to look for, that has nothing to do with actual operation/drivability of the entire machine. You will come across one at some point.

Once you come up with a complete service manual, you can go through every component/system that involves fuel/ignition/emissions and verify what is actually going on. At that point you can make a full determination of what needs to be done and what parts you will need.

As nice as that rig appears, it's still got issues you haven't found or seen yet! Stuff that you can make a difference in right now. Such as...

1) window lifts/door hardware
2) rear hatch/tailgate hardware
3) floor supports/floors
4) instrument electrical connections
5) brakes/suspension
6) lighting
7) front hub bearings
8) etc.
 
Not sure what you are refering to?

"1) window lifts/door hardware
2) rear hatch/tailgate hardware
3) floor supports/floors
4) instrument electrical connections
5) brakes/suspension
6) lighting
7) front hub bearings
8) etc."

all of these things are fine. I do have a bulb out in my dash bezel, lol
I am interested in that manual though. Thanks for all your help mayben.
 
Hey mayben I just checked out yalls service mauals and realized that I have a set of these from another Scout I had from years back. Still have that Scout as well but it's been the closet for years. I am going to make it more of a custom trail rider, one day. You know how that goes. Anyway asuming its the proper set of manuals, and I can find them, what else would I be looking for? All I can think of is points gap, plugs ect..
I wish I could ship my other Scout to you guys, thats some nice looking work yall do on the spring over lifts! Just might do that when I get back on that car, but it will probably be years from now. Too many irons in the fire right now. Did I say irons I meant kids, lol
 
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