Intermittent limp mode issue 1999 Toyota Hiace Super Custom

Hey Everyone,

Long time lurker on this forum, I've read lots of really informative posts and it's great to see such an active supportive community, So thanks everyone for your info.

A bit about my story, I purchased a 1999 Toyota Hiace Super Custom Auto Diesel 1kz-te engine  about 10 months ago, and have been having limp mode issues with it pretty much ever since I got it.

Originally it was about 50% of the time on start up having no power and going into low power mode (about 50km/h max) and would intermittently go away while driving it. These appeared to be more frequent when on the motorway doing over 100KM/h

I took it to an Auto electrician after it refused to start completely one day, He fixed a fuse and it was going again but the issue remained and even after leaving it with them a month and having them remove my immobilizer and check my ECU for issues with quality of capacitors and leaking said that ecu was fine and couldn't identify the issue or reproduce the fault.

I got van back and  the problem persisted and was advised to go to a diesel specialist which I did.
They managed to reproduce issue and reported knocky engine, timing control covered in oil and pins corroded.

They then replaced timing control valve connector and reset and said that if the issue re-occurs they suspect it to be injector pump and that would need replacing.

After that I had no issues for 2 months and I thought I was in the clear.

However van started going into limp/low power mode with check engine light on intermittently, could happen 3 times in a 30 min drive or not at all for 5 30 min drives. However this time the max speed it would go to is about 20km/h and turning vehicle off for 30 seconds and on again would clear code and it would drive fine again.

So I took the vehicle back diesel specialists who had car for 1 month and were driving it every work day but could not replicate the issue. They then advised that they couldn't be certain that it's a fuel pump issue and were hesitant to replace it as were quoting around$2000AUD.

I've now got vehicle back and feel a bit defeated by it. Would really appreciate any advice?
I've had the transmission serviced and general service and it came back fine.
I've also read on forums that this issue could be related to fuel filter or air filter, so thinking maybe I'll get that checked next.
The vehicle also takes 4-5 seconds to turn over if it hasnt been driven a while (1 week) or its a cold day. and then when it starts it lets out some white smoke.

All mechanics have reported that they can't read the codes as there is no tei terminal in diagnostic plug.
Is it possible for me to read the codes on this? It doesn't look like ODB or odb 1 port, could anyone tell me what it is and if its possible to read it?
I saw on a post that someone read their 1kz-te with a 2017 Vgate V1.5 ELM327 OBD2 OBDII Bluetooth CAN Scanner for TORQUE Android phone

Any advice or support much appreciated. Had this Van 10 months and it's been in mechanics for 2.5 months of that and still not much closer to resolving this.

It sounds like you have ECU issues, this is your thread!!
https://hiace-super-custom.forumotion.com/t3391-ecu-capacitors

If you are SURE your caps are correct I'd look for a tank pickup blockage (When it stops see if the primer pump button has been pulled down with a vacuum (in the pickup pipe!).

And clean up the turbo pressure sensor filter with brake cleaner (It's on the inlet manifold plugged into a pipe to the manifold near the primer pump. If it's yucky think about checking the pipe to the manifold allows air through.

That generation of vehicle had the Toyota diagnostic system that predated odb from memory. I had one too great van

From memory, to read the codes you needed to short pins te1 & e1
in that connector your have a photo of (I can't make out the photo clearly). And read the engine cel light flashes. This is just general to all Toyota's predating odb. Its worth a shot and it may pinpiont the issue. Sounds like whatever the diesel specialist did the first time to fix it is where the problem persists.

Not sure if this will help but worth a look and cheap to fix. We had a 2001 Supercustom with very similar sounding issues. Tried overhauled timing belts, transmission and checked turbo. On and off the same.
After some months finally found another thread from a guy in NZ and resolved our issue. Turbo pressure sensor was getting incorrect readings due to a filter close by being cracked and leaking stuff onto it. Filter cost $52 from local Toyota dealer - done! I’ll send through pics.

Yes that little filter has a big effect on the engine!
You can also get a cheap generic one, anything that seals will do, e.g:

https://www.ebay.co.uk/itm/RANGE-ROVER-L322-3-0-TD6-FREELANDER-1-2-0L-D-EGR-VACUUM-AIR-FILTER-PHB000450/232632575074

Nice one GPW that looks like one of those realy cheap fuel filters on Ebay good one to remember did not realize they are for air fiter as well.

JT69 wrote:

Nice one GPW that looks like one of those realy cheap fuel filters on Ebay good one to remember did not realize they are for air fiter as well.

I think as long as you get get the pipes on and they seal (which they must!) they are better than the original: more surface area and if you put them the right way around you can see any dirt from the manifold !

It's a win-win!

Thanks everyone for your advice, Thought I'd give an update on where I'm at.

Decided to get the ECU double checked and had it removed and sent away to be checked, they changed all capacitors and couldn't find any board damage but did report a couple of dry solders which they repaired.

Got vehicle back today but still same old story, going into limp mode.

Think my next stop will be mechanics to check the turbo pressure sensor filter. I'd check it myself but I know nothing about engines and don't have a manual or anything to even know what i'm looking for

Ah, recently I checked that filter and found that the hose going to it was cracked. It explained my intermittent power issues, the last couple of months I don't think the turbo was really spooling up at all and my van was super sluggish, struggling with the slightest bit of weight in the back. Replaced the tiny hose, now its back to normal and pulls like a train again!

Brendon 13 the turbo pressure sensor is check is so simple if you can check your oil level you can do it , it is on top of the engine near the water pressure cap little square box even says pressure sensor on it with wires and a tube going into it follow the tube goes to small round filter then the tube continues to a spigot on inlet manifold just pulls of check they are clear poke a plastic rod down the spigot or blow down it ( this is were mine was blocked ) if all pipes are good and clean refit easy . Safe yourself some money.

Thought I'd give an update on where I'm at, Ended up getting the fuel pump replaced and had the mechanics check the inlet on the turbo pressure sensor, they reported that it was sooty but not blocked.

Either way replacing fuel pump improved starting off engine (it now starts up pretty much instantly instead of taking 4-10 seconds with white smoke.)

However intermittent dropping to limp mode still persists.
Replaced Fuel Pump
Transmission serviced.
Had all ECU capacitors replaced and board checked.
Turbo pressure sensor checked.

Had fuel filter checked about 8 months ago and was fine, but guess can't hurt to have it checked again and the connected hoses.
I was curious on what chances are of issue being related to a faulty sensor itself?  Any advice much appreciated. I'm still yet to find anyone that can read the computer and check the codes, which is making it even more frustrating.

Is it possible to read codes on these things at all? or any idea on what kind of reader mechanic would need so I can ask around?

Try changing the vacuum hoses connecting the sensor + filter to the inlet manifold.

This is based on a recent discovery (and fix) by our own JT69 !!

Alright so I checked out that little air filter and turned out it was cracked in exact same way as photos posted above by VincentVango, was pretty hopeful I'd found the issue and ordered a new air filter, Unfortunately issue is still persisting, however it seems less frequent now. (occurs 1/6 30 min drives instead of 5/6) main symptom is you are driving and it suddenly drops in power then check engine light comes on and triggers limp mode.

I took off and inspected both of the tiny hoses going into that air filter one coming in and the one going out up to the turbo pressure sensor, couldnt see any damage and blew through them fine with no blockages. in fact the pipes looked pretty new compared to other pipes in there. I may get some new pipes and replace them anyway.

There is a slight crack on side of the electric connector that goes onto turbo pressure sensor not sure if that is related.

I unscrewed the turbo pressure sensor to see if I could clean and gave it a blow and stuck little bit of wire in it to ensure it was clear. Couldnt notice any issues.

Not sure where to go next, It's been a year since i've given it a general service or had fuel filter changed so think that's my next point of call. any recommendations appreciated.

At the moment my SC is running perfectly on a blend of 80% vedg oil 10% diesel 10% petrol, this month we did 2000 miles trip to Shetland and Orkney the first two days we experienced  limp mode on a regular hourly interval, I put this down to not mixing my blend fully leading to partially blocked fuel filter leading to fuel starvation under full power after the second day running on diesel no more limp mode as I have used 3 full tanks of blend since returning home and ensuring a proper mixing of blend before filling tank I can only assume that was the problem . It costs me £8.00 to fill the tank rather than £70.00 at the pumps and it is legal. However that does not solve your problem , you may have more than one problem causing limp mode as I did turbo pressure being one and fuel starvation the other . The in tank screen was partly blocked with 23 years of debris plus a funny looking fungus type thing actually inside the screen, check the return flow from fuel pump by putting the return pipe in a clear plastic bottle about 2ltrs , the return flow is quite high on a Toyota and any air will also show .

Ah forgot to mention have not yet found anyone who has or can read fault codes on the 1KZTE however apparently what we need is a Toyobd code reader video comes up on youtube but not yet found one all suppliers are out of stock.

Ah that's interesting, thanks for your reply, never tried running it on a blend before,

think I'll get mechanic to check the return flow from fuel pump, change fuel filter and give fuel tank clean and check that screen.
Might also try a bottle of fuel cleaner/ conditioner, when next fill up

There are a number of small rubber vacuum pipes, it may be worth getting sure of the size (4,5 or 6mm ID) and buying a few metres and replace all you can see - it gets quite warm under there so the rubber ages.

Good Idea GPW, I bought a reel of 4mm Vaccum hoses today and replaced 3 Of them that I could see, I noticed that the end of the old hoses were splitting a tiny bit making them not grip super tight.

Also noticed one of the three white plastic caps that goes on top of line of three bolts had fallen off so put it back on.( not sure what the name of it is called but it's on top drivers side of engine holding a bar in place)

Will give it some tests this week and if re-occurs I'll grab the 5mm and 6mm hoses and replace those too.

Also JT69 thanks for info, I couldnt find anything online searching for Toyobd either, Guessing it's different to standard odb1 right? I'm still curious if anyone has been able to read these things.

brendon13 wrote:

Also noticed one of the three white plastic caps that goes on top of line of three bolts had fallen off so put it back on.( not sure what the name of it is called but it's on top drivers side of engine holding a bar in place)

Possibly the glow plugs and electrical bar for them - just used for starting.

Drove for 10 minutes this morning then when idling at lights back into limp mode, looks like I'll be replacing all the other vaccum hoses next.
So weird sometimes I can drive for 5 hrs and no issue other times less then 10 mins.

Also make sure the connections to the thermal sensors on the engine are clean and sound, if the ECU sees anything bad it goes into this mode.

BTW if you can buy/borrow an ODBC reader it will tell you the reason.

Ill have to find a manual to work out where the thermal sensors are and what they look like, as had a look around in engine but not sure what they look like.

I ran a bottle if diesel engine cleaner through tank and after changing those small vaccum hoses and I've got it down to only going into limp mode 1/5 30 min drives which is an improvement.

Checked on Ebay for odbc or jodb and on lots of forum posts and haven't been able to find a story of reader that works on this thing, if I could read it would make things a lot easier

The same Toyota engines were used in lots of models so you may find it easier to identify a popular Toyota model with your engine in - and then buy the OBDC reader for that.

Just wanted to give update on where I'm at, since running that bottle if engine cleaner and changing those couple of small hoses I'd say im down to issue occurring 1/20 drives which is way better, thinking I'll run another bottle of cleaner through system when I refuel again and see if it makes any further difference, think next stop will be replacing fuel filter even though it was done a year ago. Will continue my search for reader also