Toyota Hiace Super Custom (Problem)

[Alpha Frank]

I'm going to try and lay out all the information I can about this vehicle I own and hope that someone has an idea of what could possibly be wrong with the vehicle as I have taken it to the mechanic quite a fair bit and he tells me it's the fuel pump, but I think otherwise since funny things have happened in the past. It's also my first time here so please be nice

Here it goes, the vehicle I own is a Toyota Hiace Super Custom 1996 3.0L Turbo Diesel with the 1KZ-TE engine. The van around the time we bought it was at roughly 300,000Ks and already had a problem with it (Transmission fluid leaking) I know, bad sign already and I kinda regret buying this van in the first place and most likely got ripped off at the process ($6000 for the van -_-), so I ignored the fact that it was leaking fluid and thought it was fixable (Which I later on did but I'll get to that in a second), took it out for a test drive, the van was solid, it was performing great, still going strong and could go on for who knows how much longer.

So I decided to buy it and really liked the van, large amounts of space, great comfort etc etc. I neglected the fact that it leaked fluid from the transmission, at the time I didn't have enough money to take it to the mechanic to do repairs on it. So after a couple months, i finally got the leak plugged up so it stopped leaking, but since it was in the middle of summer, scorching heat and bad transmission radiator design (Facing flat towards the ground, no air or wind hitting it, I don't understand why it was designed like that) and sure enough, the gauge would hit 100+ degrees of heat and even past it's danger zone. Sure enough one day the transmission gave up, completely fried, turned on the car but the car wouldn't move at all (Didn't know it until later when the specialist told and showed us the burned transmission).

Got it towed to an Automatic Transmission Specialist and had to replace the transmission. A 2nd hand transmission in good condition got put in (But not the OEM one, one from a Lexus if I remember correctly) as well as a crappy fan that got put onto the radiator which worked for the time being but didn't last very long, spent $3500 on the whole thing already and am already at a massive loss for the price I paid for the vehicle (Back then I didn't know much about cars). Now unfortunately I can't remember if before this all happened it had a check engine light on or not, but after the transmission got put on, worked pretty good for awhile, then it started playing up. Check engine goes on, the car accelerates and decelerates itself constantly. Driving the van for 2 years with this problem (I know I should've got it checked out by a mechanic/ the specialist but I wasn't sure or could confirm it and also didn't have enough financials to get fixed) I figured some interesting ideas and theories as to what it could possibly be.

Either, the transmission is acting up due to bad wiring (The van probably went through so many electricians as there's wires pretty much all over the place and just really messed up), the van's ECU isn't functioning properly, or the whole engine has an issue. When the Check Engine Light goes on, the RPM normalizes but the shifting between the gears becomes a bit funny and power gets lost a bit from it and the biggest thing I noticed is, once I hit 90+ Km/h the transmission doesn't go into it's final drive, but gets stuck on the 2nd last gear. BUT, when the Check Engine Light is off, the RPM starts to get higher and lower and in the middle (Normal Idle is around 800 RPM I think, but when the Check Engine Light goes off, RPM's increase to 950-1250 and stay's hovering around those ranges shifting between those RPM's.) but there's a power increase and a more sharp throttle response from the engine compared to when the Engine Light is on AND while the Engine Light is off, it goes into its final drive and functions "properly". One thing though when it does high idle, engine sounds more clanky and rattly where as when the Engine Light is off, it's a lot more smoother and quiet.

So, I hope this all made sense, I don't understand what the problem could possibly be, and I don't want to keep going around to mechanics with no results. PLEASE HELP ME!

Also, my mechanic that i go to regularly (I trust him as he has fixed and replaced a lot of parts that needed replacing as they have been completely worn out and even broken) said that it could be the fuel pump, and that I should go see a Diesel Specialist so that they can look for what kind of problems there possibly could be. I hope this gets heard, I just want to get suggestions and ideas just so I can be sure of what it could be. Sorry for the long post as I wanted to dish out as much information as possible and give you guys an idea of what it could be. Thank you for reading

[Brian R.]

Download the code the ECM is putting out to cause the check engine light to come on. The change in behavior is an indication that the ECM is causing the truck to operate in a default or safe settings mode. The timing is retarded, and other performance parameters are reduced to a safe setting to prevent engine damage.

[Alpha Frank]

Thank you, I shall try to do what you told me to do, IF i can

[Alpha Frank]

UPDATE: I have managed to fix the 2 year long issue with a simple and a very cheap method using only.....WATER. Now, I have no idea how it even worked but I can only assume it was bad sensor or something rather. I decided to clean up the engine bay, but I didn't have any cleaning products and didn't want to risk using normal soapy water. I was originally going to put it off for another week to get cleaning products to clean the engine with, anyway, I got my hose from the garden, made sure to get the dirt off the hose head and such first, then went on to spray the engine with water.

Before I go further I must elaborate some things, beneath the throttle body seems to be either carbon build up, looks like smudgy mud/oil, I can only assume that the throttle body is leaking somewhere and spraying some sort of oil/fluid. Not a lot but it builds up a little over time, and usually after every drive, looks pretty fresh and shiny like as if it recently leaked (Which it most likely probably did) and causes a little bid of a mess, like as if mud got smeared over the area.

So, I went ahead and sprayed the engine with normal water, aiming at the areas which looked bad (beneath the throttle body) and other areas for a little bit using a fair amount of water pressure (Jet stream and such) managed to clean bits of it off but not entirely as the fluid is sticky and well, greasy. Then I took it out for a drive to vaporize the water and so it wouldn't cause problems. At first i didn't notice that the van was idling normally, no high revving or acting up, worked like nothing had happened. The next day I noticed that the van was fine, no engine light going on, van idled properly, gained its power back and actually went into its final drive properly for the first time in 2 year. Now I am just shocked as to how such a simple thing, fixed this whole dilemma and to think I was going to go to mechanics, and auto-electricians to get it checked out and HOPE that they'll actually find the problem. Been about a week since the clean up and still working fine, no hic-ups or problems since, and am just amazed.

So the next time your vehicle starts acting all funny with revs spassing out and funny engine light going on and off, just spray some water and clean the engine bay as it might JUST fix the problem and save you the misery.