1KZ-TE Smoking and very poor fuel mileage (1 Viewer)

[oilhead]

Obviously since I said mileage you can tell I'm from the states. I just bought a 1994 Toyota Hiace imported from Japan with the 1KZ-TE motor. It has 222k km with recent timing belt done.

The problem is that it smokes black intermittently and gets horrible fuel mileage (15 mpg, if I drive it lightly). It has good power most of the time. Every once in awhile it will give great power. And sometimes it'll not have much power at all. It idles pretty smooth and starts easy every time.

I'm a gas mechanic of over 20 years by trade. Not much experience with diesels.

Things I've done:

New Toyota injectors, boost sensor and valve, glow plugs, cold air intake, adjusted the fuel to it's lowest setting (which has made it smoke less, I haven't driven it enough to know the mileage, but it still smokes), checked for clogged screens on the injection pump, adjusted the pump, put a boost gauge (shows 8-10 psi, but the gauge bounces around, so not sure how well it's working), changed all the fluids and filters, new primer pump, I have checked the EGR valve, took it off and cleaned it.

After each thing I did it made it run better. But after I changed the injectors the smoke got worse. The fuel mileage had been the same the whole time.

Please help. I'm trying to leave on a long road trip to Costa Rica soon and want great fuel mileage and better performance and no smoke.

 

[GTSSportCoupe]

Things to check:

- Possibly your ECU is bad (this generation had capacitors that leaked onto the circuit board and eat away the traces...). Although usually the symptoms are different.

- Its possible the Spill Control Valve on the injection pump may have issues. Test it according to the engine repair manual.

- Possibly your injection pump has worse issues than just the spill valve.... This would mean ordering in a rebuilt one.

- Has the timing belt been changed on the motor? Any chance the belt is a tooth out on the injection pump? May have slipped if its old, or improper installation. Timing could be retarded...

- One more thought: Have you checked the turbo? If its not boosting, it could explain your problems. Take the hose off the compressor housing (inducer). Make sure the turbo spins freely and does not have any axial play. Make sure the radial play is minimal and it's not touching the housing. Give it a good visual inspection.

Have you pulled the ECU codes?

Definitely don't drive it much the way it is. Running that rich can cause engine damage from high EGT's.

 

[GTSSportCoupe]

Want to learn more about how your diesel works? Read the .pdf I've attached to this post. It's a pretty simple system really.

 

[GTSSportCoupe]

And here is a link to the manual for your engine:

http://etoymag.free.fr/manuels2/1KZ-TE.pdf

 

[oilhead]

Things to check:

- Possibly your ECU is bad (this generation had capacitors that leaked onto the circuit board and eat away the traces...). Although usually the symptoms are different.

- Its possible the Spill Control Valve on the injection pump may have issues. Test it according to the engine repair manual.

- Possibly your injection pump has worse issues than just the spill valve.... This would mean ordering in a rebuilt one.

- Has the timing belt been changed on the motor? Any chance the belt is a tooth out on the injection pump? May have slipped if its old, or improper installation. Timing could be retarded...

- One more thought: Have you checked the turbo? If its not boosting, it could explain your problems. Take the hose off the compressor housing (inducer). Make sure the turbo spins freely and does not have any axial play. Make sure the radial play is minimal and it's not touching the housing. Give it a good visual inspection.

Have you pulled the ECU codes?

Definitely don't drive it much the way it is. Running that rich can cause engine damage from high EGT's.

I don't have a manual to test the spill valve. Can you please explain how?

The timing belt was changed about 10k ago.

By the aftermarket boost gauge I installed it shows 8-10 psi. But bounces around. Not sure if it's the gauge or something going there. Could it still be the turbo?

No check engine on. So I don't there would be codes.

Would I be able to see the damage on the ECU if I took it apart?

 

[GTSSportCoupe]

I don't have a manual to test the spill valve. Can you please explain how?

- I gave you a link to the manual above. Usually you disconnect the spill valve and test the resistance. DO NOT put 12V directly to it as you'll burn out the coil winding. Read the diesel manual I uploaded above as well!! This will help you better understand your engine.

The timing belt was changed about 10k ago.

- When did your issues start? Has it always had these problems since you've owned it? Did the problems start when the timing belt was done?

By the aftermarket boost gauge I installed it shows 8-10 psi. But bounces around. Not sure if it's the gauge or something going there. Could it still be the turbo?

- Yes, could be the turbo; your engine has about the right kms for the turbo to need a rebuild. Do the testing I recommended.... If it's toast just buy a Chinese CHRA and swap it out. They're cheap and the quality is reasonable from what I've found.

No check engine on. So I don't there would be codes.

- They can have codes even without a check engine light. You just jumper the engine diagnostic connector and the CEL flashes the codes out. I believe the manual explains it....

Would I be able to see the damage on the ECU if I took it apart?

- Yes. Around the base of the large capacitors there will be a black stain.

 

[Jroc561]

I would check the timing, I know it seems like a simple thing but it does sound like it’s needs some advancing

 

[GTSSportCoupe]

I would check the timing, I know it seems like a simple thing but it does sound like it’s needs some advancing

The 1KZTE adjusts the timing electronically (compares Ne sensor in the pump to the crank sensor). The timing marks on the pump ear just need to be roughly lined up to the motor. The only thing that'll really throw it is if the timing belt is out a tooth on the pump pulley.

This is different than mechanical rotary pumps where a dial gauge etc. is needed to setup the timing....

 

[oilhead]

- I gave you a link to the manual above. Usually you disconnect the spill valve and test the resistance. DO NOT put 12V directly to it as you'll burn out the coil winding. Read the diesel manual I uploaded above as well!! This will help you better understand your engine.

Yeah I didn't see you sent that until I had already posted. Thanks for sending it. I did test it. It tested good



- When did your issues start? Has it always had these problems since you've owned it? Did the problems start when the timing belt was done?


It wasn't very noticeable when I got it. It did have bad fuel mileage from the get go. The smoke and performance has gotten worse



- Yes, could be the turbo; your engine has about the right kms for the turbo to need a rebuild. Do the testing I recommended.... If it's toast just buy a Chinese CHRA and swap it out. They're cheap and the quality is reasonable from what I've found.


So, I pulled everything to check the turbo. It has some play, not a ton. But there is lots of oil coming from it and blowing into everything. So I went ahead and pulled it and ordered another one. Even if it doesn't fix the issues; which I hope it does, I don't want it completely failing on the trip.



- They can have codes even without a check engine light. You just jumper the engine diagnostic connector and the CEL flashes the codes out. I believe the manual explains it....


I ran the codes, nothing



- Yes. Around the base of the large capacitors there will be a black stain.

Thanks for all the help. The turbo will be here sometime next week. I'll let you know what happens.

 

[oilhead]

OK, so this is a long time for the update. But needed to do some checks and other things to try and figure this out. Plus run through some tank fulls.

Anyways, here what has happened.

I changed the turbo with a decent aftermarket one. While I was waiting for it to arrive, I went ahead and blocked the EGR and took the intake off and cleaned it really good, it was filthy. So after doing this it ran way better with a lot more smooth power. Most of the smoke is gone, unless you give lots of throttle at standstill or going up a hill with only half throttle. Unfortunately the fuel mileage hasn't gotten any better and now the engine vibrate way more when at idle. So I adjusted the fuel and timing again, and found a code for the IAT sensor (which I replaced) with no help. So then I noticed that the exhaust had a very weird sound and figured out that the muffler was clogged. So I went to a full 3" exhaust with just 1 muffler. This has made it more powerful and even smother while driving. No change to the idle vibration or fuel mileage. So then I did a diesel purge and put in some Seafoam in the crankcase and fuel tank. All which added more power and smoothness while driving. Still no change to idle vibration or fuel mileage.

Please help. This is costing time and money.

 

[GTSSportCoupe]

If the idle vibration is uneven, it could very well be a bad fuel injector. I have not re-read the whole thread, but have you had the injectors rebuilt?

 

[oilhead]

I put new Toyota injectors awhile back. Is it possible they got loose?

 

[roscoFJ73]

Is it possible they got loose?

Not if it was done properly. The torque specs are fairly high from memory. The injectors should have been added at the same time the pump was checked for pressure and the injectors should probably have been checked as well.

Still no change to idle vibration

Have you observed other small 4 cyl diesels? They do tend to vibrate or ratlle a bit. Whats the idling set at?

 

[oilhead]

I might not have torqued them enough if they are high.

It's vibration it way more than before. I've worked on quite a few VW diesels. It's set at 700.

Another thing, it is now hard to start in cold weather. It wasn't that cold before, but even at its coldest it was never this hard to start. It has new glow plugs.

 

[roscoFJ73]

At this point I would say your timing is out or you have a compression problem

I might not have torqued them enough if they are high.

High?

 

[GTSSportCoupe]

I put new Toyota injectors awhile back. Is it possible they got loose?

Did you use new crush washers to seal them to the combustion chamber properly? If not combustion gasses/carbon can get by and foul the injector nozzles. Over time this will wreck them and could give the problems you're having.

Have you tested your glow system with a multimeter? It's not that hard. Just measure voltage on the glow rail while someone turns the key to 'on' with the engine cold. Make sure you have ~11V for at least 7 seconds. After you start the engine, make sure there is around 6V on the rail for another 30 seconds or so.

You can also remove the glow rail and test the heating element (resistance) of each glow plug to make sure they're ok.

 

[oilhead]

I don't think that it's the compression. It runs pretty good once running. I tried adjusting the timing and it doesn't make really any difference.

I did not change the crush washer. That makes total sense. I think I'll get them and make sure to do the right torque on them. I think that could be causing all the issues if it's not sealing right. It's only been like 1-2k km since I changed them.

 

[oilhead]

So I just checked the power to the glow plugs. There is no power. I'm going to try and look at the manual. It's just hard to find what I need to find with the online version. Anyone know an easy way to find it out?

I'm getting the crush washers for the injectors tomorrow.

Also, the radiator is now leaking. So I'm going to get that repaired and going to change the thermostat.

 

[roscoFJ73]

If the problems go away when warmed up it could be the glow plugs. But if they persist once warmed up its unlikely to be glow plugs.
You can run a jumper lead direct to the glow plugs for about 10 seconds, if they are good , it should start easy.

Did you use new crush washers. What torque did you apply to the injectors?

 

[GTSSportCoupe]

When you pull your injectors out, inspect the nozzles to see if the washers were leaking. The whole nozzle will be black with soot instead of just the end. If this is the case you might need to get them cleaned/tested before re-install.

Also, I think the crush washers have to be installed with a certain side down....I forget which though...haha