Reduced power at low RPM after driving in hard rain and mud

Hello,

I have a 1999 Daihatsu S210 Deck Van GX with manual transmission.  I use it primarily for off-road hunting purposes, with occasional small highway use.  It has been relatively trouble-free for the first 4 years of ownership.  Then, about a year ago, after driving it during a heavy rain and splashing somewhat aggressively through mud puddles (although none were deeper than 6 inches or so), it suddenly began to lose power- particularly at low RPM.  In first gear on relatively flat ground it would have just enough power to accelerate, but it lost so much power at low RPM that I would have to run it to nearly 5,000 RPM to successfully shift from 1st to 2nd, 2nd to 3rd, and so on, in order to prevent it from "bogging down" and eventually stalling.  I have noticed that if I can keep it above 4,000 rpm at all times while driving, it seems to have nearly normal power.
Climbing hills is now very tricky, particularly from a dead stop or at slow speed, so that creates big problems on my usual dirt road travel, and is tough on the clutch.  

Ever since that night, when I crank the truck it barely idles (very low RPM) and sometimes will die and will sometimes eventually "find itself" after a few minutes and start idling somewhat normally although often surging.  Lightly tapping the gas pedal while it is in that very weak idle state will sometimes help it find idle, and too big of a tap will kill the engine immediately.  I have noticed that if I disconnect the MAP sensor, the engine always cranks immediately and with a strong idle (sometimes around 2,000 RPM) and when I plug the MAP sensor back in while idling the engine will either immediately die or go back to that very weak, extremely low RPM idle.  Usually once the engine warms up for a while with the MAP sensor unplugged, I can then plug it back in without the engine dying.  Once the engine does warm up I can drive it around either with or without the MAP sensor plugged in but it continues to have the lack of power problems described above.  It blows excessive smoke now, particularly when the MAP sensor is unplugged, but also while it is plugged in.  I have replaced the the spark plugs and MAP sensor.  I have taken out and cleaned what I believe to be an O2 sensor near the exhaust manifold but I haven't replaced it.  I have checked the air intake and filter for water.  I have looked for vacuum leaks and replaced some vacuum lines, although I am not confident I know where all the engine related vacuum lines are, and I am not sure I know how to find a leak with any degree of certainty.  I am not a mechanic, I am relatively ignorant and stupid, but I don't mind turning wrenches and following instructions.  I have a strong feeling this problem is something super-simple, but just not sure how to figure it out.  Hopefully somebody can help.  The Ninja Warrior has been out of commission for over a year and I really want to get it running again.  Thank you!

Is the clutch okay? Is the throttle body or air intake filled with gunk?

-edit- Just saying what comes to mind first; things I'd check myself... And what is it with Americans and camo?

I've never seen this model before, but I guess the thing has a single point injection?

I wonder if it's another cat problem?

PFM wrote:I wonder if it's another cat problem?

Ah yes... Very hot cat being dipped in water... I don't think that's a good combination, check the cat.

Ahhhh I cannot wait to try this. Thank you for the quick replies. I will post the results. Is the cat the thing on the exhaust that looks like it is made of wire mesh? or would it be something else? Thank you!

If you can see mesh it's well and truly f*****! Google 'catalytic converter' and see images.

could the oil breather pipe be blocked?

Question- unlike Raggy, I do not have a spare cat or exhaust system so when I go to remove the cat and inspect it, can I also run the engine while the cat is disconnected and take it for a test drive to determine if the cat (and/or other part of the exhaust system) is the problem? I know it will be unusually loud, but should the engine function normally if the exhaust is disconnected at the cat or will the various O2 sensors and other stuff go crazy and send false signals to the computer and thus affect the engine function?

You should be able to run it without the cat as a test, you will at least be able to see if the revs are any different to what they were before.

Ok, so i disconnected the entire exhaust including the cat, took it off the truck and inspected it the best I could without breaking welds or cutting into it. The honeycomb inside the cat appeared intact and did not appear to be clogged (i could only see the front side). I hooked up a blower to the exhaust and airflow did not seem to be restricted and there were no rattles. I started the truck without the cat or any of the exhaust pipe hooked up and the symptoms were the exact same. I also did a compression test and the compression was similar to what it was when i bought the truck (125,120,95). Any other ideas?

With the Bi-Metalic Gauze Mesh that this model would likely have, you should be able to see right the way through the removed Cat.

Thank you Woodie. My entire 6 feet of exhaust pipe is welded together as one piece and the cat is in that first foot or so. The muffler and several feet of bent pipe are in the remainder so i was unable to get a flashlight behind the cat to see if I could truly see through it. I was going to cut the pipe just to look but i dont have easy access to a welder to put it back together. I decided not to cut it when the engine exhibited the exact same symptoms with the cat and the entire exhaust completely removed. Do you think I should go ahead and cut it to inspect anyway or does my test run without the exhaust attached confirm that is likely not the issue?

I am afraid not being able to see all of your truck I can't say that I recognise it either. I assume that as you have only given 3 Cylinders compression figures that it is a 3 Cylinder 993cc based engine.
I am thinking more along the lines of the Atrai 660cc 3 Cylinder Kei class vehicle which the UK has very little experience of and I have only seen one in the UK. The S220 was only introduced in 1999 so you have a very early one which puts out just 44 bhp or PS as abroad they seem to rate them. The turbo charged version was rated at 64 bhp to keep it in the Kei class. They did make a 12 valve turbo but once again 64 bhp (47 kW).

It gets so complicated as they also Marketed it as the Toyota Sparky which was like the Extol with a mid mounted engine and Toyota twin cam engine with chain drive cams and later I believe with belt drive.
So basically a bit - no a lot more info about your truck which looks great as a 5 seater pickup. The UK always seems to get the boring run of the mill version's of some really nice variants of the Daihatsu or Toyota or the Daihatsu/Toyota collaborations.

Never the less we love our 993cc and 1300 English style vans and pickups. Such fun to drive and turns on a Sixpence and squeezes through the most ridiculous of small gaps.

Flipping Heck!! At these prices + plus export taxes and carriage costs its a good job we don't see your models in the UK. You would have to be named Trump, or Gates or Zuckerberg or Bezos to be able to afford the spares bills. Absolutely ludicrous.
Time to put my spares prices up I think. No wonder I am still a Pauper and not living on an exotic Island.
Oh hang on - I do live on a Paradisaic Island - but I am still a Pauper - but what price happiness?? I LOVE living on this Island.

Yes, just 3 cylinders. I believe it is a 660cc. I am completely stumped by its lack of performance. I hate to trash it, but it looks like I am to that point. Thank you for the effort.

It would be a shame to give up. It must be something damaged by water/mud or impact whilst you were puddle-jumping. It seems like you've ruled out the exhaust, so a methodical check of filters, electrical connections etc should find the problem. Don't rule out things you've already checked though - I've solved many problems on the second attempt.

It definitely is a shame. This vehicle fits my purposes perfectly. I'm afraid I just don't have the expertise to track down the problem. I have a feeling it is electrical, or maybe vacuum but I don't even know which components to check or how to check them.

does anyone think it may be a fuel flow or mixture problem? I have experienced similar before in a totally different kind of car

Actually I should clarify because I do think it is likely a fuel/mixture problem. When I say I have a feeling it is electrical, I think it is something electrical (a bad sensor or bad connection) causing the computer to get bad information and thus affecting the mixture or fuel flow thus impacting performance. I just don't know how many and which electrical components are involved in this process or how to test them if I did know. One of the reasons I say this is because of the improvement that unplugging the Manifold Absolute Pressure sensor has on the engine's ability to start and to idle. This, coupled with the fact that the engine seems to have near normal power at high rpm leads me to believe it is a sensor of some sort causing a mixture/fuel flow problem. Maybe the vacuum lines are involved in this equation too, but I do not know??? I know just enough about engines to get me scratching my head and wishing I knew more.

https://hijet.forumotion.com/t1794-test-your-suspected-faulty-sensors?highlight=test+your+faulty+sensors

Worth a go, hey

Any update on the status of your Van.?

I have a Daihatsu Atrai which I believe is identical mechanically to yours. 660cc Kei class JDM. I also have a Hijet Pickup that uses the same engine as the Atrai.

Im honestly surprised how you were able to get your hands on a 1999 Kei in the US Here in Canada we are allowed to import up to a 2004 currently.

I believe I have a small stash of documents that might be of use for your engine. Both my Hijet and Atrai have the EF-VE engine. And I have a pdf for engine diagnostics and such, its in Japanese and im slowy converting it to English. Yours will most likely be the EF-SE engine. From what I could see online.


Hopefully you don't have to part ways with it, if you ever do please let me know, But for now lets try and see what can be done to get it going. I have a few suggestions.

If you can, post a picture of the engine, and if willing, the chassis number so I can do a reverse lookup and see what engine model it had. Daihatsu had single and twincam engines during that era.

Being 99, it might have OBD2 under the front dash. Also do you have an engine light on. A irregular reading from the TPS, O2 sensor or MAP can throw a code.