83Toyota88

iTrader: (1)

Did a compression test and the results (engine cold) were 153, 170, 155, 158. The plugs looked good except for #2, it was black. Also have a some weird crap blowing out my tail pipe:



feels like water with black soot in it. #2 plug also seemed to have some oil on it. Ideas? Getting about 10 mpg right now too. Carb is new and tuned within specs. I also have a can of restore in my engine oil too.

gillesdetrail

iTrader: (1)

Your results aren't worth very much if you did a cold compression test

1) warm engine up to full operating temperatures
2) block fuel suply to carb
3) open throttle all the way
4) check number

and on the picture that is nothing more than just condensation from the exhaus heat and carbon soot.

If a spark plug has oil on it it's because that cylinder burns oil, it may be showing higher compression because there are more carbon deposits in that cylinder because of the oil burning.
Here check this out:
http://www.4secondsflat.com/Spark_plug_reading.html

http://www.dragstuff.com/techarticles/

That 10mpg is real bad, but it's possible it's not because of the engine.

83Toyota88

iTrader: (1)

I did steps #2, 3, and 4. Just not #1. I will try again when I get a chance.

gillesdetrail

iTrader: (1)

It is said however that a cold compression test can exagerate compression problems because you are testing them at their worst condition, when hot the ring gap tightens and so does the piston to wall clearance showing ''real world'' results for the engine, but a cold test can be a way to diagnose compression problems.

83Toyota88

iTrader: (1)

I honestly have no idea what to do. #2 is sparking I checked that by removing the plug wire. I may have to take it some where and a let someone see if anything is wrong.

gillesdetrail

iTrader: (1)

But, why? Does the engine run rough? Those cold numbers are quite good, they should raise and equalize in a hot test. If you had a dead cylinder you would barely be able to drive the truck.

83Toyota88

iTrader: (1)

Well the bad mpg is one thing, high end power is kinda lacking, and a couple times on the interstate a have got on the gas and the rpms jump but the truck doesn't accelerate. Something just seems off to me. Maybe it's the carb, but all my screw settings are within tolerance and judging by spark plug color the 1,3,4 are ok but 2 is fouled.

Y8rodo

If it was me I would do a leak down test. It is a lot more informative. With a comp test, The difference shouldn't be more than 10% this will definitely cause a rough run. May just need a valve job that is where a leak down could save you a full rebuild. Also there is a slight possibility that a de carb such as sea foam could buy you some time, but be warned that Toyotas can have a tendency to accumulate carbon to the point that a decarb may break off in large chunks and tag a valve

gillesdetrail

iTrader: (1)

Well if the carb is tuned withing specs and the spark plugs look good, I don't see how bad mpg is caused by the motor. It would be if it was running rich, but your spark plugs would be black and sooty. High end power...have you driven another 22r for comparison? There is not much going on past 4500rpms, maybe by comparing you can see an anomally or not. And the third thing you are mentioning about the rpm jumping without the truck accelerating, well you'll have to elaborate on that because told that way it sounds more like clutch slippage than anything.

How sure are you that your ignition timing is good? webers seem to like around 8*.

83Toyota88

iTrader: (1)

I have never driven another 22R, I can't get past 80mph but it takes a while to get to 80 also.

As for the timing it is set to whatever the sticker on the hood says. I believe that 5*. What's benefit to running at 8?

Rowdydudeman

You can't get past 80? do you really want to drive a 30 year old 4x4 truck over the national (average) interstate posted speed limit? My 82 will go faster than 80, but I have yet to need to go faster than 80. I get pretty good mpg with my 32/36 weber and working vac advance diaphrams (usually about 18 city, 22-23 hwy) but once I get over 65 there is no semblance of anything approaching "fuel economy." most of the issue (mpg wise) is from the far right pedal and the brick like aerodynamics of these trucks. XD the faster you go the worse mpg you will get. It drops off, drastically, past 65.

83Toyota88

iTrader: (1)

No I do not want to drive past 80, I have floored it a couple times just to see how fast it would go. I drive at 65-70 mhp on the interstate.

gillesdetrail

iTrader: (1)

I'm seriously scratching my head over this, you have 33'' tires and 4.88 gears, which is pretty much the same as me with my 31 and 4.37 gears, which is about the same as the stock 28'' tires and 4.10 gears. The only time I checked my fuel economy was on a roadtrip I took where the truck was fully loaded (weighted in at 3600lbs on a scale, 800lbs more than when I'm empty with me in it), did about 150 km of highway driving at 55 mph (I have a 4 speed), and another 150km of country roads and mountains. I have a weber 38, 20r head, o/s valves, porting, stock cam, header, and a very worn block (it consumed 1.25 quart of oil during that 300km roadtrip). I still managed to average 19 mpg on that trip, and I'm lifted 2.5'' too, no skid plates. So either your carb is not tuned as good as you think it is (can you post close good quality pics of your spark plugs?), or you have un-economical driving habits, or you are not doing your mpg calculations correctly, or something else I can't think of / don't know.

To answer your question about timing, I can't give you the answer as to why webers like a bit more advanced timing, because I don't know for sure, but I'm guessing it is because of fuel atomisation, and slower flame travel, therefore it may benefit from the spark lighting up the mixture a bit earlier, but honestly I don't know. But you should try it to see how the engine responds. On the spark plug reading tutorials I posted above it shows how to check if the timing is correct according to your setup just my reading a spot on the ground strap. Also, how sure are you that your mecanical timing advance is working on the distributor?

moroza

I started reading this to know what compression numbers you got and what to expect when I do mine soon, but I gotta say this about your terrible fuel economy:

I think we've found the biggest problem here. You're taking a 32-year old truck with an underpowered 1960's tech engine, Malaise Era smog equipment (might not apply to you), the aerodynamics of a brick, modifications that make the aero even worse, big soft tires, and you're trying to do 80?

Your expectations of speed and economy are what, exactly?

Aerodynamic drag gets exponentially worse the faster you go - the increased consumption between 65 and 80 is a lot more than between 50 and 65. And it gets linearly worse with higher drag coefficients and frontal area. A typical car has a Cd of about .32; a typical truck, somewhere around .45; our trucks, worse, maybe .50.

10mpg is a bit surprising, but not very surprising.

gillesdetrail

iTrader: (1)

Well it's all relative, I can ''easily'' take my truck to 85, and if I had the balls it could do 100 I'm sure, but the highways here are awful so I didn't try. And I find a big fuel consumption difference between 55 and 65, but remember I'm 4 speed.

jimbyjimb

iTrader: (1)

Common wisdom is to run your timing advance as high as possible until you start pinging. LCE recommends no more than 10 degrees advance at idle, which I use to good effect. You can run more if you have good fuel, but 8-10 is usually sufficient to see a noticable power gain.

RPM jumping and no acceleration is a clutch or drivetrain issue, not an engine issue.

If your screw settings are within Weber's suggested guidelines your idle circuit is probably well tuned. Have you tried tuning the main and air jets?
Main and air jets take over at freeway RPM. I believe the idle circuit drops out of the picture somewhere from 1900-2200 RPM off the top of my head...

How is plug two fouled? Wet with fuel? Oil buildup? Soot buildup?

Your compression isn't awful, but your engine could be getting tired and starting to suffer blow-by if it is high mileage. Or, cylinder two could have a bad or going bad oil ring. It would be odd to see a single fuel-fouled plug and it would certainly be an ignition system issue or spark plug issue if that were the case as the carb isn't going to foul one plug over three others generally speaking. It might foul two plugs, but generally not one.

83Toyota88

iTrader: (1)

Late follow up but I had a professional mechanic check my timing today and it was at 0 and I had him change it to 8. He also pulled plug #1 and verified TDC was 0 on the timing mark. So guess I'm a retard when it come to changing the timing because I swore it was at 5.

It drove a little better on the way home had more guts in the accel. When I got home I put the idle jets back to the stock size (I had lowered them) and retuned it per weber instructions and all screw settings are within tolerance and it has pretty good acceleration now. I will have to check my mpg later and see how that was affected.

83

I'm with Jim, though...the one thing that jumped out at me was the increasing rpms without increasing speed. That's a slipping clutch.

83Toyota88

iTrader: (1)

Here is the video for it

gillesdetrail

iTrader: (1)

Yup,that clutch is gone, and you can fix the header leak at the same time