Topic: The all-new 1990 Daihatsu Rocky

[emsvitil]

Just fill with water for now.

[LittleSteve]

I had one of these... called a Sportrak over here.. not a spot on the Fourtak. It was the biggest rusted turd ive ever had the idiocy of buying. stuck it back on ebay and let someone else have the pleasure of discovering it was turd with a different owner...

[Lewis Hein [OP]]

Took a test drive this morning, to some steep hills. Here are my impressions, both from today and accumulated.

On-road:
First off, this thing is LOUD. So loud that I need to wear earmuffs at highway speed. This is probably due to the aftermarket intake with an "open" style air filter, combined with two or three big exhaust leaks. Meanwhile, for all the loudness, getting above 60 or driving above 3rd gear is impossible. The engine just can't pull it, unless I'm going downhill. It also likes to be revved up above 3000, which I don't like. Like some people I know, it's noise to useful effort ratio is quite high.

Off-road:
For a short-wheelbase rig with IFS, it's pretty capable compared to my expectations. That said, it's no rock crawler. It'll go many places in 4low, although my truck is much better. Driving in serious snow or mud, though, is not possible. I purposely tried to drive through a small puddle with a mildly sticky bottom in 4 high and nearly stalled the motor. I can only imagine what it would be like trying to bust through an 18" deep packed snowdrift. On the plus side, it can turn around in places that my Toyota could never dream of. That's a big plus for me.

General:
This thing feels like driving an old rattletrap chevy. Much more so than my Toyota, which has twice as many miles and is 5 years older. The doors cannot be locked or unlocked with the key. The ignition switch is so sticky that I have to make sure to turn the starter off when the engine starts rather than just release the key. The back door won't lock. Every door rattles, all at once on the slightest bump.
Note: I believe some of my troubles with lack of engine torque may have more to do with the tires than the engine. Some dummy is running 29" tires on there, whereas factory spec is 27s. There is exactly one way to find out...

Am I disappointed? Not really. With all the faults listed above, it's still a fun little vehicle. Besides, I'm learning, and have already learned much. Plenty of learning, tweaking, and puzzling remains.

[THK Matt]

2' taller tires i highly doubt would make your engine so sluggish. you have way more issues than a tire size. fix the exhaust (u have like little to no back pressure from the sounds of it) which can cause issues, replace PCVs, fuel filters, normal maintenance stuff. id bet that help a lot.

with that fixed, your on and offroad behaviors will change with a smoother running engine. wont be no race buggy.

[Lewis Hein [OP]]

Thanks for the wisdom. I roughly calculated out the difference in performance due to 2" taller tires, and, like you said, decided I need more engine tuning if it's going to run well. I am 90% sure the O2 sensor is bad. Burning coolant is supposed to do bad things to them, right? And I haven't the foggiest idea when it was last replaced. I need to look at timing and check plugs, too. But the fuel filter is new. I already replaced it and made a big difference. The PCV valve is shot but inaccessible and unavailable -- some invention will be needed there.

Would someone mind educating me me on back pressure? I know nothing except that vehicles always "feel" more zippy when they don't have exhaust leaks.

Tune, tune, tune! learn, learn learn!! I won't be happy until I can shift to 5th at 40 like the manual says.

Lewis

[THK Matt]

Thanks for the wisdom. I roughly calculated out the difference in performance due to 2" taller tires, and, like you said, decided I need more engine tuning if it's going to run well. I am 90% sure the O2 sensor is bad. Burning coolant is supposed to do bad things to them, right? And I haven't the foggiest idea when it was last replaced. I need to look at timing and check plugs, too. But the fuel filter is new. I already replaced it and made a big difference. The PCV valve is shot but inaccessible and unavailable -- some invention will be needed there.

Would someone mind educating me me on back pressure? I know nothing except that vehicles always "feel" more zippy when they don't have exhaust leaks.

Tune, tune, tune! learn, learn learn!! I won't be happy until I can shift to 5th at 40 like the manual says.

Lewis

for S&G's run one of these in place of your PCV.
http://www.autozone.com/external-engine/performance-breather-filter

id definitely replace all of your maintenance stuff.

[redneckcustoms13]

I spent sunday up at my wifes uncles taking my son bird hunting. We ran around in his 92 model and it was quite impressive. He has 31s on it ans was running 65mph with the air conditioner on in 5th gear. It did quite well offroad. I was impressed at its capabilities being so short and also being ifs. I kind of like the little thing.

[Mudder]

http://www.gomog.com/allmorgan/exhaustbackpressure.html To help with the exhaust problem.

[Lewis Hein [OP]]

I fiddled with it more this afternoon. Here's what I found.

The distributor cap is definitely bad. As in, prone to shock people who grab it wrong. Plugs are (now) clean, and gapped. Only one needed much adjustment, two needed none whatever. The valves were not too bad, but are now adjusted properly. No perceptible improvement. Ignition timing is set, and the vacuum advance is working. Plugging in or unplugging the O2 sensor with the engine on does nothing perceptible. There's still lots of deposits on the valves that resisted my attempts to scrape it away when the head was off. This may not help.

Since the HG replacement, It will now start with only a reasonable amount of cranking. But power output is not much improved. And if I rev, it stumbles immediately afterwards.

Any ideas? It seems like this could be the bad distributor cap, unhappy injectors, a bad O2 sensor, or some other sensor gone awry. And I don't want to break the bank trying things that don't help.

Thanks!

[H8PVMNT]

Start with the basic tune up parts.

[Lewis Hein [OP]]

Those being...

Plugs (just touched up)
Wires (nearly new)
Distributor cap (possibly bad)
O2 sensor (condition unknown)
Fuel filter (replaced soon after I bought it)
PCV valve (Impossible to reach or replace)
Air filter (clogged)

What else??? SqWADoosh suggested maybe TPS last night, I haven't had time to check.

[Mudder]

I think you're on the right path. I'd do the cap and rotor first along with the tps as they can have the biggest effect besides an O2 sensor.

[Toybrota]

Have you considered a 2JZ swap? I think that'll solve all your power problems

Sent from my Nexus 6P using Tapatalk

[Lewis Hein [OP]]

No... I will have to wait to swap an engine until I have time, money, and good weather

[Lewis Hein [OP]]

More impressions from a drive to town.

I think that exhaust leak is really holding it back. You see, the manifold appears to have had coolant dumped on it while hot -- there are cracks everywhere and a couple reasonably sized holes. Also, while driving, there is a quiet mode and a loud mode -- the loud mode is when the exhaust leak gets too obnoxious from the engine having to pull hard. If I am driving down the highway, it feels pretty zippy until the engine gets just enough of a load to go into loud mode. Then I start losing speed and can hardly get moving again. It also tends to run well at the start of a drive, but badly after going at speed on the highway for a while.

What do you all think? I know I need to replace the maintenance stuff, but does it sound like the manifold is also a problem?

Thanks

[Snowtoy]

Tune, tune, tune! learn, learn learn!! I won't be happy until I can shift to 5th at 40 like the manual says.

Lewis

Part of your performance issue may be due to how you are driving, Japanese engines tend to be high revving engines, and most of their usable power in stock form doesn't start until around 3k, 5th gear at 40mph in any of them, as in most cars, would make them perform horribly.

Looking at the '90 its hp/trq #'s, you should be shifting between 4500-5k,


Based on the gearing and diff gear(5.29 stock if correct), at 40mph w/29's your rpm's are about 2100, which is too low to have any performance due to its hp/trq #'s and where its power band is,at 60mph it would be about 3100rpm's.

[emsvitil]

An exhaust manifold leak will leak both ways.   

Air gets into the exhaust and completely messes up what the O2 sensor sees.

The ECU then has invalid data and gets completely confused.

[:)bestgen4runner]

 

[Lewis Hein [OP]]

Part of your performance issue may be due to how you are driving, Japanese engines tend to be high revving engines, and most of their usable power in stock form doesn't start until around 3k, 5th gear at 40mph in any of them, as in most cars, would make them perform horribly.

Based on the gearing and diff gear(5.29 stock if correct), at 40mph w/29's your rpm's are about 2100, which is too low to have any performance due to its hp/trq #'s and where its power band is,at 60mph it would be about 3100rpm's.

5.29 stock is correct. And it is stock as far as I know. 5th in 40 seems crazy to me. But it's what the manual says, so it should at least be possible to do. Right now, it's not.

Your comment about "Japanese engines tend to be high-revving engines" intrigues me. All I know about them is what I've learned from being around trucks powered by 22R/REs, 3RZs 1UZ-FEs, 3VZ-FEs and 5VZ-FEs, and I wouldn't characterize any of these as "high revving" from what I've seen. Also, it seems that revving high and lasting long are at odds with each other. Would you care to clue me in?

Lewis

[Lewis Hein [OP]]

Time to "fix" the exhaust manifold. "Fix" is in quotes because I can neither braze nor weld, and nobody I know who can wants to touch cast iron. That leaves me with... JB-weld. Not that I think JB-weld will work well, but I hope it will work better than a great big leak.

Before:


After:


Will it hold? Probably not, but time will tell. Maybe it'll hold long enough to tell me something.

[Toybrota]

Just get a header, and make a custom exhaust. Should work well.

Sent from my Nexus 6P using Tapatalk

[Gnarly4X]

JB WELD...LOL...... JB weld is good for 600d F... that exhaust manifold will get to 1000d plus in 5 minutes.... if it holds it would exceed the specs for JB Weld. 

Gnarls. 

[Lewis Hein [OP]]

Good, thinking, Toybrota! It appears that there is actually one guy selling headers for these things. Unfortunately, though, a header costs nearly half the price of the vehicle, and to build one myself would take some doing. I am reluctant to spend that kind of money or time until I have some reasonable hope that it will be worth it. Having the exhaust manifold holes plugged will (I hope) eliminate that variable and let me play with others to try and make the engine run well.

Lewis

[Lewis Hein [OP]]

JB WELD...LOL...... JB weld is good for 600d F... that exhaust manifold will get to 1000d plus in 5 minutes.... if it holds if would exceed the specs for JB Weld. 

I am aware of the specs for JB-weld. As per my previous reply, this is a cheap fix to remove this variable from the equation. If I can get it running well enough to deserve a good fix, I'll cross that bridge when the time comes. Right now, I'm gambling on plugging a little hole being a really low-stress job.

[Snowtoy]

5.29 stock is correct. And it is stock as far as I know. 5th in 40 seems crazy to me. But it's what the manual says, so it should at least be possible to do. Right now, it's not.

Does it say why you should do that, usually they only give max speed or rpm per gear.

Your comment about "Japanese engines tend to be high-revving engines" intrigues me. All I know about them is what I've learned from being around trucks powered by 22R/REs, 3RZs 1UZ-FEs, 3VZ-FEs and 5VZ-FEs, and I wouldn't characterize any of these as "high revving" from what I've seen.  Also, it seems that revving high and lasting long are at odds with each other. Would you care to clue me in?

Should have said higher revving as compared to their domestic counterparts, your road test, dislike of the engine noise at 3k, and the engine liking to rev past 3k, is what I usually hear from people who are used to driving domestic trucks.
 
Cruising at 3k down the highway, with shift points between 4500-5krpm(up shifting at 4500) isn't going to do anything to hasten the life of engines w/a 6500rpm redline.

[Gnarly4X]

More impressions from a drive to town.

I think that exhaust leak is really holding it back. You see, the manifold appears to have had coolant dumped on it while hot -- there are cracks everywhere and a couple reasonably sized holes. Also, while driving, there is a quiet mode and a loud mode -- the loud mode is when the exhaust leak gets too obnoxious from the engine having to pull hard. If I am driving down the highway, it feels pretty zippy until the engine gets just enough of a load to go into loud mode. Then I start losing speed and can hardly get moving again. It also tends to run well at the start of a drive, but badly after going at speed on the highway for a while.

What do you all think? I know I need to replace the maintenance stuff, but does it sound like the manifold is also a problem?

Thanks

Hi Lewis,

What do I think? ……  I think you are polishing a turd. 

Asking if there is a problem when you describe an exhaust manifold “cracks everywhere and a couple reasonably sized holes” is strangely scary.  Based upon your descriptions of the vehicles you have purchased lately, I question whether you have enough auto mechanic knowledge to truly understand what you are actually getting for your bargain deals. 

That Rocky’s life is used up and you have purchased the remnants of a carcass that you are trying to resurrect from the dead. 

Unless you were to do a frame-off complete restore, after many hours and months and lots of money, you will still have a somewhat unique, worthless turd.  If you were to restore it (and that doesn’t sound like something you want to do), at the end of the day it will still be a historically unique, high maintenance, practically worthless, polished turd...…

..... Albeit perhaps a cute little turd. 

With that said, lots of guys out there enjoy polishing turds and do a great job of it, so I won’t hold that against you. 

I have polished a turd. 

Gnarls. 

[Lewis Hein [OP]]

The JB-weld was cured this morning, so I fired it up to see what would happen.

What happened? Well, the engine ran cooler with more power and less noise. The JB-weld held until the engine had been up to temp for about 5 minutes; then it started to burn off. As it burned off, I could hear the engine getting louder and feel it losing power. I also noticed the temp gauge climbing.

This JB-weld experiment was well worthwhile, as I now have some actual evidence behind a hypothesis I've been working on for a while. My hypothesis is that the leak in the exhaust manifold lets stray oxygen into the exhaust pipe, which is sensed by the O2 sensor. This, in turn, would cause more fuel to be injected into the cylinders, resulting in all kinds of bad things.

I also got the really good experience of sitting in a car and feeling it go from no exhaust leak to big exhaust leak in a short time. The comparison between the two floored me; I knew exhaust leaks were pretty bad, but I didn't know they could be that bad.

Next up: ThermoSteel! Supposed to be good to 2000F and direct flame contact, so even derating it by 20% it might hold okay on my 500F exhaust manifold, for a while. Nothing would beat a good, new manifold or header, but $350 will buy 35 cans of thermosteel. If each one lasts only a year, that'll keep the manifold in trim for longer than the engine will keep running.

[Snowtoy]

This JB-weld experiment was well worthwhile, as I now have some actual evidence behind a hypothesis I've been working on for a while. My hypothesis is that the leak in the exhaust manifold lets stray oxygen into the exhaust pipe, which is sensed by the O2 sensor. This, in turn, would cause more fuel to be injected into the cylinders, resulting in all kinds of bad things.

Only real issue with running rich, other than poor mpg's, is burning out the cat.

Next up: ThermoSteel! Supposed to be good to 2000F and direct flame contact, so even derating it by 20% it might hold okay on my 500F exhaust manifold, for a while. Nothing would beat a good, new manifold or header, but $350 will buy 35 cans of thermosteel. If each one lasts only a year, that'll keep the manifold in trim for longer than the engine will keep running.

Why not just try your hand at brazing, should be some how-to videos on youtube, or take it in have someone repair it for you.  The heat and cooling cycle of the manifold is going to cause any paste/glue product to fail.

[emsvitil]

Disconnect the O2 sensor.

The ECU will go into open loop mode and throw a code.    But it may be better than running with faulty information from the O2 sensor.

[Lewis Hein [OP]]

Don't get me wrong. I'd LOVE to try my hand at brazing, And I really wish this could be brazed and done right.

However, I don't know how to braze, and don't have anything hotter than a plumber's torch. Besides, given my sheer incompetence, I'd probably burn a hole in the manifold before getting anything brazed. And that would be counterproductive, to say the least.