1kz - te Super custom Fault - loss of power

Hey guys, i have a 1996 supercustom which sometinmes (not many) runs real good and some days flat as a pancake. I first noticed when trying to cross an intersection that when i put my foot down it was like trying to start in 3rd gear. I also noticed on start up the starter motor sounds like its starting with no load - high pitched like an outboard motor. it takes a lot longer to start now too. Its weird because sometimes when i start it , it runs like a dream other times its just gutless. i took it to my mechanic who suspected timing or a stuck open valve but nothing, he is thinking maybe the ingector pump or electrics, a sensor or solonoid? sometimes when its ideling you can put your foot to the floor and it dosnt rev up straight away?

any ideas.

Gloiw plugs - cleaned and tested = ok
cylinder leak down test = ok
map sensor tested = ok
injection pump timing = ok
exhaust blockage = ok
diagnostics shows no fault.

cheers, steve

tried a full service?oil diesel and air filters then some diesel additive to clean it through.do you leave it long enough for the glowies to do there job.they start wth a high voltage then drop after a short period to help cold running/emissions.about 6 or 7 seconds is what i usually do.does it smoke a lot?

Quote :

I also noticed on start up the starter motor sounds like its starting with no load

Makes me think of compression issues....is it possible and exhaust valve is sticking open sometimes?...... ...
I'd certainly try a good injection cleaner and give it a long run.....

Vacuum circuits are something to consider too...

oil filter
air filter
fuel filter
injector cleaner

All done, my mechanic did a compression test and took the tapit/rocker cover off and checked the valves, they were fine?

the glow plug duration has always been real short, about 4 seconds but i always give it a bit longer.

Another thing i have noticed is that once it is started from cold you can put your foot to the floor and the motor will not react what so ever until it warms up a bit, can take a minute or so.

Possibly a sensor fault and the ECU stops the engine from going much above tickover. Don't know how to find the fault codes or even how to get them.

Damn, I hope it's not contagious.. I tend to lean towards Clive's idea. There is a link here somewhere for engine-ECU faults

Here ya go. I hope they help you. ( A bit beyond me )

https://hiace-super-custom.forumotion.com/members-guides-to-fixing-problems-f8/engine-managment-fault-codes-and-how-to-read-them-t439.htm?highlight=faukt+codes

looks a bit long winded but really easy.just look in the battery compartment first and bobs yer uncle

in my 1996 super custom its under the glove compartment by the passengers feet.

No code recorded, still a mystery ?

have you had the diesel tank checked i had an m.a.n. that the liner of the tank came away and was being sucked into the lines when left to idle ok on power nothing but tick over.

cheers
dave

OK so it's gone full circle - I'm having the same problem as in the first post and then I find I've given advice allready!

I've done what I've advised, to no avail.

Any ideas as the bus is becoming unusable in traffic!

Also is there such a thing as Torx socket? The studs on the throttle housing have what I think are torx heads i.e. like a torx bit, these bolt through the housing onto the inlet manifold. If there is I can get the thing off and clean it in carb spray, none of my sockets fit and I don't want to mangle them.

blocked fuel filter?
Air leak around the turbo?
Diesel pump gelled ?

Any smoke with the problem?

worth looking at fuel hoses etc. too...old rubber under suction
can suck shut........
Tank gel from the veg?
sockets can be got to suit more splines....12 spline springs to mind...
Also I'd check vacuum lines very carefully for leakage...

I can drive it by left foot braking, keeping the revs up above 1000 with the right foot. So I'm happy all is ok turbo, fuel and pump wise.

No smoke while ticking over at 500 or 1000.

Vac pipes all been checked, may be worth trimming them back?

Couldn't be gearbox could it.

Nope.

I said way back last year when I began to have starting problems that it could be the ECU. Admin said I could try his, but it is a pain to get at but looks like something to try, so I guess I'll wait until he is back AND try mine in his just in case something in mine has fried my ECU!

A bit miffed that there is no fault code shown and that the engine light does not come on when it is in low RPM.

I've adjusted the throttle stop so it ticks over at 1000, will test in traffic tomorrow how that works.

Airflow Mass mater need a clean up?

I've got an air temp sensor, don't think it is that as it can be just as hard to start hot or cold.

Hi guys, i originally started this post in may last year. since then i have had my supercustom to 4 separate mechanics and i still have a low power issue. some say computer, some say injector pump, some just have no idea. I have had it to actual toyota dealerships/mechanics and so called diesel injection specialists and they are all scratching their heads. I have had it plugged in to a variety of diagnostic computers all with big promises of results and still nothing? So i have resorted to scouring the net looking for ideas. Funny that this topic seems to be under discussion again.

Symptoms:

*starter turns over real fast / high pitched when starting.
*Once started you can hold your foot to the floor and noting will happen, it just ticks over at idle. after about 3 or 4 min it responds to pedal opperation.
*Low bottom end power, sometimes will not even pull itself from a stand still in first gear.

*Top end power is great, No black smoke, No white smoke, Not over heating, No engine check light or fault.

Done so far.

air filter = ok
fuel filter = ok
removed inlet manifold and cleaned
checked timing = ok
checked injector pump timing and spill valve operation = ok
leak down test = ok
compression test = ok

Anyone want to suggest anything else??

Almost identical symptoms.

Almost similar list of things tested.

Also no clear idea.

My thoughts point at the ECU or ECD as Toyota call it. On the Oz Hilux forum they talk about capacitors decaying on the boards. Not sure how to test - I had a look and could see no obvious burning/sweating, but that was as far as I went.

However I have not had the throttle plate off and given that a good clean yet, did you do that when you cleaned the inlet manifold?

Like I say I hope to try my ECD in Admins bus next month to eliminate that rather expensive part.

kiwisteve74, Clive

Just wondering if the fault started after you had some work done on it. Since you are having the same problem i am just wondering if there is a same cause you can identify.

One thought I had is what about the fuel injectors could they be worn. So when they are cold not much fuel can get through, but when they warm up the nozzles expand letting more fuel through?

It's a thought but I think that would also give off some smoke, we have none.

I'm leaning to electric as the throttle does nothing, the ECU is running the engine and ignoring the TPS signal.

Clive wrote:

It's a thought but I think that would also give off some smoke, we have none.

I'm leaning to electric as the throttle does nothing, the ECU is running the engine and ignoring the TPS signal.

exactly, this only happens at start up with my van. once running it responds to throttle responce but is still sluggish.

And yes, my van went great untill out of the blue it wouldnt go over 90kph. I took it to my mechanic who after trying a lot of different things found that the small filter inline with an air sensor had a split in it and was giving false readings. when i got it back it had plenty of top end but no bottom end power and turns over real fast at start up. I have no idea what exactly he did before finding the split inline filter but it seems to me he has upset something while trying to fix the actual problem. He is a good friend and has spent a total of 10+ hours on it since with no results.

As for the capacitor fault in the ecu, my take on this is that it is a problem that effects the auto transmission. i have a 5 speed.

actually, when he was looking for a fault he cut and removed the exhaust looking for an exhaust blockage. I wonder if he fried the computer while welding the exhaust back together?

Is it worth someone with the problem, swapping the ecu with a friendly local member on here, woudl at least pinpoint the problem, or rule it out....

Def sounds like a fuel starvation issue of some sort....

Yep that is what I hope to do when Admin comes back.