[SOLVED] New Owner Looking for Direction - Top Speed 85KPH

Just landed a 1998 Sambar KS4, Carbureted ENO7 engine with 69,000 KM. Working out a few minor hiccups, did oil change, air filter, plugs and just passed inspection and now have registered. Truck is running rich on cold startup, have checked choke, vacuum lines etc. and can't seem to figure out why. Decided to fill up with fresh gas, put in a can of Sea Foam and took for a 50km run. Maybe that will clean the carb and solve the problem. Sambar ran fine and has some get up and go through to 4th gear, at higher rpms I run at 85KPH, shift to 5th gear and get nothing. Truck has no torque and will maintain at 85 - 90 KPH. I see many of you are cruising at 100k and hitting up to 135KPH. Not sure where to look next, just ordered a set of wires, distributor and rotor, that may help but I am not counting on it.

Any Ideas?? Thanks for any help.

 

Take the plugs out and see if all the plugs are the same colour. Possible misfire if as you say the engine is running rich even with you releasing the choke.

 

Thanks, pulled all 4 plugs only have 75km on them and they all looked great, not running rich when warm, will see what happens after a complete cool down. Did compression check Cyl 1 125 Cyl 2 120, Cyl 3 120, Cyl 4 125. Pulled distributor cap, its in tough shape. So new wires, cap and rotor on order.

 

I would be next changing fuel filter and then consider the knock sensor located under the inlet manifold.

Compression and plugs all look good. Carbs can run rich when cold, but as long as you are not spitting black soot I would not worry too much about this as it is not causing your speed problem.

 

Yeah, no doubt you should be able to do well over 100kph. fuel, fire compression. you'll find it.

 

Thanks everyone, I will order a fuel filter as well, once they are all in I will let you know how it's running. Hopefully this solves it.

 

Patrick, Looking into the Knock Sensor possible problem. From what I can find out the Knock Sensor was in a SC Sambar but not in a basic carb model. Am I missing something?

Thanks
Rod

 

No knock sensor on the carbies. Probably wouldn't hurt to check the cat and make sure that isn't melted down and causing restriction issues.

 

Still running at 85KPH, here is what I have done so far

New Fuel Pump
New Air Filter
New Spark Plugs
New Wires
New Distributor Cap & Rotor
Oil Change
Sea Foam in Fresh tank of Gas
Waiting on new Fuel Filter - doubt it will solve problem, but....

Coil tests at 1.5 ohm, engine is responsive and pulls through all gears until 5th. Shift at 80KPH and 5th takes me to 85 and holds at that speed. If there is a slight grade downhill I can get to 95.
Compression good across all Cylinders
Timing set at 6 degree mark

Was suggested that maybe the cat is plugged, I must be blind as I can't see a cat on this engine. Can only find a complete muffler on line. Does this 98 have a cat?

If the fuel filter does not solve the problem I have no idea as to where to look next. Any more ideas would be helpful.

Thanks

 

I just looked up the 97 and the exhaust is different from the earlier trucks. I can't tell if it has a cat or not. If it does I would guess it's under the "bubble" heat shield where the flex pipe goes into the muffler assembly.

It would be loud as all get out but you can just try driving it with the muffler off.

 

As last resort, that may be what happens

Does anyone know if a 1998 has a speed limiter on it, or if they can be added / removed? Is running as if it has one.

 

Have you checked the gas pedal; the limiter on the floor? And the cable for slack?

 

Yep, getting full travel and full throttle at carb. I am just hoping a new fuel filter solves it at this point, all out of ideas. But thanks for offering up one.

Saw a post on how to adjust the SAS Screw on the carb, did that with a tach hooked up. Didn't help, but at least I know it is set properly now.

 

whats your tire pressure at came home from getting my new winters and forgot to check what they set the tire pressure at and was really only doing about 90 top speed also having 4x4 engaged dose seem to drop my top speed a bit too

 

Interesting concept, I am in 2WD and tire pressure is 32lbs, maybe a harder tire will roll better, but not sure I would run above 36. What are most of you running for tire pressure?

Fuel Filter arrived yesterday so putting in this weekend, also going to try and advance timing a bit, 6 degrees BTC at sea level, I am at 3500 ft so maybe go 10 - 12 degrees. Will double check that vacuum advance is working as it should. Should give me a little more power.

 

I've been running 28-30 psi but I run a much larger tire meant for a truck that weighs 2 1/2 times as much.

 

im also running 28-30 ish im also at 4000ft and have trouble going faster up here it might just be altitube but its quite hilly here the only flat ish road is slightly up hill and 80kph and some times i have trouble doing that
before i moved here i could do 100kph regularly the highway is only 90kph here now so i dont go much higher then that and its quite mountains so im often at 20-40 kph below the speed limit

guess we need to look at boost eh!

 

Replaced fuel filter, advanced timing to 10 degrees and changed out all the Vacuum lines running from the intake manifold and carb. Verified that all vacuum actuated valves are working as they should. Truck is running really great, starts the second you touch the key, idles well and revs to 7,000ish rpm in all 4 gears up to 85KPH. Shift into 5th and still get no pulling power, just maintains speed. I am at a loss. I would think it was a carb problem if it didn't run so well in the first 4 gears. Not sure I will ever solve this one and may have to live with the fact I can only get the 85KPH.

If I ever get this truck to 100KPH I will post the solution. Thanks for the ideas that were shared.

 

Does your carb have a low vacuum enrichment circuit?

 

That's a great question, no idea. Guess I have some more learning to do. Where would it be and how would I check / test? I have attached pics of the type of carb I have.

 

I would possibly try jacking the car up and popping on axle stands very securely. Put the car in 5th gear and release the clutch and see what happens when you give it gas. Very strange problem you seem to have. Your 5th gear is seemingly an extreme overdrive.

 

That was fun, pulls 110 - 120KPH on the speedo - no tach but it sounds like I am passing 7000 RPM's.

 

testing fuel solenoids, top one on the carb clicks as it should and I belief is the fuel shutoff. The bottom solenoid on the drivers side down low does not click. Should It?? Also any idea what this one does??

 

Do you have stock tires/wheels? When I put the taller tires on my Hijet, it changed the effective gear ratio enough that if I have any kind of load on the truck it really won’t accelerate in fifth gear on any type of hill. With the stock tire/wheel, it would pull fifth gear and get up to about 65-mph (just past the 100kph on the speedo)

If your engine is getting tired, (evidenced by a loss of compression), you may not have enough torque to pull fifth gear.

 

Running a slightly larger tire, 1" wider and less then 1" taller, so not a big change, stayed close to original but went from the 12inch rim to a 14. I will try the stock tires and see what I get.

Compression is running close in all cylinders at around 125 PSI, Not sure if that is low, some guys are saying 180PSI others say 120 - 140PSI is where these should be at. Can't find Subaru specs. In any case the engine starts, idles and revs real well. No smoke at all once the choke opens, little rich on cold start.

I am leaning to that lower right solenoid being a contributor. Pulled the solenoid plug and ran test, Upper left solenoid is getting power and clicking, lower right solenoid is getting power but not clicking. From what I can find out this solenoid should click when power applied. So maybe it is part of the problem?? May as well order a new one and put it in, just another new part

 

Lower solenoid is the idle fuel cutoff to keep the engine from dieseling on shutoff.
125-psi is about an 8.5:1 compression ratio, if your getting an 85% volumetric efficiency. I think most of the minitrucks are closer to 10:1.

 

I have a question mainly because you've done exactly what I thought you needed to do to find the issue. Have you verified your speed on GPS and not just the speedometer?
125 on the compression test sounds good to me. If you had said 90 something I might be more of a culprit.

 

125psi is low. Stock compression is 9.8:1. I'd expect 160psi+.

 

Yep, GPS verified.

Still looking at that lower drivers side solenoid, from what I can see it is a fuel shut off solenoid, it should click with power from what I can read. So why doesn't it, and if the power is the click to open, how am I getting any fuel? Thinking it may be possible that it is stuck open but not fully open. Guess I am going to have to pull it and bench test.

Also found a micro switch in the gas peddle assembly when I was looking for a mechanical limiter on it. No idea what it is for, know that it has two wires to it and is hot (active) when the gas peddle is floored. Any idea what that may be?

 

Given it starts, idles and revs so well and does not appear to be burning any oil, maybe some seafoam in the crankcase will clean things up a bit and help. Guess it can't hurt.