My diagnosis...

Hello all!

Had some real issues starting the Hijet recently, only when it's sat overnight and got really cold though. I had a bit of hunting idle a couple of times, but that seemed to clear up. I think it was some air trapped in the idle control valve. Hasn't done it for a while now. Finally got round to bridging the diagnostic connector today and found what I believe to be the cause of my morning woes!

Diagnostic mode video - 4 flashes then 2

I got a 4-2 flash code: Coolant temperature sensor.

Seems fairly logical, once it's started it's fine for the day, so I suspect it's okay at most temps higher than really cold!

Going to order a replacement in a moment, hopefully early next week it should be all sorted.

Cheers guys

Oh and also feel free to move this to the cooling system section, I wasn't too sure as it was a sensor problem, so I stuck it in the general workshop bit!

You need a proper offset 19mm ring spanner for the 1lt as its too deep for a deep socket and too buried for a normal spanner don't know where it is on a 1.3 but I broke mine forgetting to unplug it before strip down and it was a proper git to start from cold and it only gets worse until you replace it.

This is the one I went for (mine's the 1.3 Rich):

Coolant temp sensor from MicksGarage

Looks like it's a 17, I'm going to have a proper look at it Sunday when I get a chance. Been meaning to replace the coolant anyway and flush the oil once again. I've done around 1500 miles since I got the hijet and put the new head on it. So far so good it seems - except morning starts recently. I do wonder how long the sensor was duff for, and whether sitting in a field for 2 years without any coolant or water on the sensor could have oxidised and potentially damaged it.

Hopefully it'll be sorted next week. I still need to properly seat my lower rad cap as I think there may be a tiny air leak sometimes when it cools down after a hard day.

It's not the same as mine I think it had two conectors but there is two on the 1lt the one for the ECU and one for the dash.

That makes sense... Hmm hope I got the right part, I've bought stuff from MicksGarage before and it's been good. Ah well I'll check it out and see, I seem to recall it's reasonably simple (fingers crossed) to get to on the 1.3, but it's been a while since I had a proper look. I struggled to find one on ebay or my local motor parts place.

I had to order mine from a Piaggio dealer in Norfolk I think either that or Motoquip I've had stuff from both over the past few years.

Well if the photo is anything to go by that isn't the right one But I doubt the photo is of the part!   

The one you want has 3 pins, with a plastic triangular connector.

I sell alot of coolant sensors, yet I have never seen a faulty one.... which always makes me wonder!

I have about 3 in a tin in my workshop if it turns out you need one.

If anything, the wires sometimes fail just where it joins onto the connector.

The other fault is the sensor is not properly submerged in coolant due to an underlying coolant system issue.

Hope this helps or not!

I have also published full test data for the coolant sensor here:-

https://hijet.forumotion.com/t1794-test-your-suspected-faulty-sensors#16125

Also your hunting is caused by the same issues, improper coolant system integrity. It sounds like you have an underlying issue. I would recommend dropping all the coolant out of it, pressure testing the system with air. Then see if you can actually hold air pressure. I would guess not at the moment.

Resolve your minor leaks, then refill with coolant using the pressure fill method. Then see how it goes.

Looks like the cheaper one from Euro?
http://www.eurocarparts.com/ecp/c/Daihatsu_Hijet_1.3_2001/p/car-parts/engine-parts/fuel-and-engine-management/engine-management-sensor/?224810030&1&c9ef3f807f56073f14e26ebfa1d0d97684ac6240&000572

Cheers for the info guys. I shall see what turns up. HJ - I've been meaning to pressure test for a long while now, but I'm committed to work 6 days a week so I can really only do stuff on a Sunday, unless I fiddle around in the dark which is a pain. I'll send the part back if it's not suitable, what Rich was saying about the pins on the connector is totally logical, it's payday today though so I just ordered it anyway (fool).

I think I def have an air leak somewhere in the system, I am almost certain it's around the filler cap, but without pressure testing I'll have no idea. So that may be a job for Sunday. I will have a look at my connector, it may well be shot. Some good leaded solder and a decent flux pen should fix it though.

Aaaarrrgh I just need 2 days or so to absolutely fix this little van. Still pleased it's actually running though.

HJ - if the battery disconnect and bleed doesn't come up trumps (i.e. error code still present) and the part is wrong I'll take one of your sensors for sure.

Cheers guys will keep you posted

nc30 wrote:HJ - if the battery disconnect and bleed doesn't come up trumps (i.e. error code still present) and the part is wrong I'll take one of your sensors for sure.

Test what you have first - its easy peasie.

My repairs methods follow a sort of philosophy:- Only replace what I prove is at fault. Prove faults through testing.

Buying and changing parts on a hunch or hope is nonsense.

Target your efforts in a strategical methodical approach.






Feel the force NC.

HJ I agree with you 100% and the great thing about this group of people on here is the advantage of being able to cross referance data I once ended up buying a car (£20) just because I could not find the information I needed to diagnose the fault I had in an ignition booster box to then find car had different system fitted but I got my money worth out of it and ended up having to buy a £35 little black box to prove it wasn't that part but fortunatly that time it was and I could not have proved it was as it was inaccesable and breaking down due to heat, Had a forum existed at the time I might have not wasted so much time. Long may this forum go on.   

Right, so the van wouldn't start at all on Saturday - not a good day!

Drained all the coolant from the system and pressure tested at 20psi and voila! Found 3 leaks, 2 of them fairly major! One was the bottom passenger side radiator clip (which SOMEONE had replaced with a jubilee clip and not tightened up enough - oops!) and the other was the clip between the bottom hose and the metal pipe with the fan sensor switch thing in it. These were leaking pretty badly under pressure. Another small leak was the small pipe between the filler cap and the header tank.

So with those all sorted, bled the coolant system using HJ's watering can method, got plenty of flow from the brass hex nut thing and the rubber pipe, so I don't think there's air in the idle control valve. Put the battery back in and the error code has disappeared - definitely not the coolant temp sensor then!!

Ran it yesterday until it got nice and warm, then let it cool and topped up a few cc's from the header tank. Had my fingers crossed it would start this morning and it did, but not nicely. It hunted for a bit, the gauge went all the way up to the H mark, no hot air from the heater matrix, then gauge sudddenly dropped back to normal and hot air started blowing.

I'm at a loss as to what this could be, is it still just air locks in the system somewhere? The system hold pressure perfectly now, and the van runs lovely once it's run for a few mins.

Thanks for all the help guys, I'd have given up long ago without this forum!!!

So you bled out the heater matrix, the head, the radiator and the idle control valve yeah?

Yep, and the little t-piece

How did you bleed out the heater matrix....

Actually describe how you did all the bleeding.

Got a watering can, connected a hose pipe (about 5 or 6 feet of it) to the spout. Put other end snugly in filler cap hole after using insulating tape to get a tight fit.

Filled the can up and put it right on top of the van with spout pointing down to generate the pressure head. With the front panel removed and rad cap still on disconnected the bleed pipe (for the heater matrix) on the right hand side of the rad cap and water flowed out. Twiddled the heater controls, plenty of water coming out. Plenty of water coming out of the other bleed points too.

I'm praying it will start in the morning!!

Did you take the front rad cap off under the grill?

No, front rad cap was still in place. Just took the little pipe off the side of it. I'm going to bleed again tonight but this time with the engine running, then let it cool down with the watering can still in place so hopefully I can encourage some air out of it and allow it to draw the coolant from the watering can as it cools.

You have to take the rad cap off to purge the air out of radiator.