Intermittent limp mode issue 1999 Toyota Hiace Super Custom

brendon13 wrote:

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

Hey Brendan, any updates? Did you eventually get it working? I’m having very similar issues on my 2000 SC, I’ve now sent the ECU board to get looked at by a specialist in SC ECU but it looked pretty fine when I sent it so am not feeling too confident.

Also had two diagnostic readers connected to it that said there were no errors even though the engine light was on.

Hey,

It's a weird one, This issue happens a lot less frequently now, maybe 1-2 times in last year, Not quite sure what ended up decreasing the frequency, closest correlation seems to be keeping the filter clean and making sure I don't run the tank down low.
As I noticed that most of times it happened recently was when tank was close to empty and on a hill.

Just thought I'd post an update.

I went overseas for 13 months and left vehicle sitting idle with my dad driving it briefly every month or two.

However upon coming back looks like the intermittent limp mode issue has returned with a  vengeance.


Now it's happening on every drive after 30-45 minutes, engine starts stuttering and losing power then goes into limp mode. (Usually when it happens I'm not driving at high speeds in the 50-80km range)  Pulling over and turning vehicle off for 5 mins allows you to then manually drive it by using Low, 2 gears (it's an auto) but seems to stay stuck in limp mode unless you leave it for 30+ minutes

also no check engine light comes on anymore.

Seemed to happen more frequently when it was hotter 30+ degrees vs mid 20's occurring on 20 min drives (Or maybe that was because it hadn't been driven for a while and now I'm driving it more it's happening less, who knows)

I initially thought it was transmission-related related so had a transmission specialist service transmission and check solenoids and they all test ok. They suspect it's something to do with wiring so going to auto elec next week.

Things I've done in last 2 weeks
Changed engine oil & Filter
Changed fuel Filter (Twice)
Transmission fully serviced
Run a fuel cleaner through engine including a couple of tanks of fuel
Checked Air filter, looks clean.
Checked Map filter looks fine, and hoses are all connected.

Things I've had done to van in last few years
Completely replaced the Fuel pump
Replaced all the small hoses & Map Sensor filter
Had ECU sent away and all capacitors replaced
Dropped Fuel tank and had that cleaned and checked

Hi - sounds like a nightmare. I hope you get it sorted.

I had an unrelated issue with the van not starting when warm and dropping out of overdrive occasionally - turned out to be a faulty temperature sender. Anyway - I found out after using a Toyobd1 reader. It has a companion android app - which you can follow on a phone or an android head unit. I was able to monitor various ECU parameters and sensor signals - and watch the reported engine temp go haywire when the symptoms occurred.

It's not as good as a proper OBD2, but may help. The guy that made them has been quiet recently, and they became hard to get hold of, but he's started making DIY kits for basic versions again (OBD1READ) - you just need to solder on a plug and connect it. I highly recommend them.

https://www.facebook.com/groups/1505898572959292

https://www.facebook.com/groups/1711148342392785

Contact Jean Francois Toy on those groups to get one.

g00se That reader looks really helpful, glad to hear you got on top of your van issues, I joined the facebook groups, but looks like they are hard to come by.
I wonder whether they would fit my van as the diagnostics port is this, and can't even get it to do anything diagnostically myself even when running wire between  TE1 and E1


Ended up getting a video of what happens when driving, appears to be changing throttle when driving and slowly losing power, Takes a 3-5 mins to slowly lose power to point where feels like I'm in limp mode, but no check engine light.


I've heard there can be problems with the throttle position sensor, Will see what auto electrician says next week

Any other suggestions welcome

That diagnostic port is the sort of thing that will work with the reader - just the same as mine. On those facebook pages, the guy that makes/sells them, Jean Francois Toy, has been telling those asking for one to PM him - I think he must have some available.

BTW - that rev pulsing was near identical to the issue I had when the temp sender caused the ECU to have the transmission drop out of overdrive. BUT for you, it's occurring much more regularly and you say it's going into 'low power mode'. For me, the low revs were normal and it would jump to the high revs. Maybe it just looks similar in the video - or maybe it could be a difference between diesel and petrol engines?

Try this - when it's behaving, and you on a safe, straight bit of road in top gear, press the O/D off button on the gear lever for a second or two and then release it. Do it a few times to see if it's similar? Obviously, not too fast so that dropping out would make the engine red-line. If it is similar, then it could be OD related?

Just to add, he's got a few for sale now. https://zf-scantools.com/index.php?rt=product%2Fproduct&product_id=126&fbclid=IwZXh0bgNhZW0CMTEAAR0DwdxX7b86W-KCc2nPo-ts63IoKa5QSKqhUBldYH-XMb9y5GQZuia-3_Y_aem_Ab4b5ygObbONRIt7_2iqmXf1Omm-ouRTXBCLc_ulSsGJV3IkXvGv3piqXQV34OpI8SgGXGnIVkh3OcQxT-4T_t78