Running like a dog!

[Zuffen]

I've just finished wiring an Sc400 (40/40/40 plug) engine into my 5 speed manual Rover.

This is the 4th 1UZ in this car ( 1 stock and 2 supercharged engines and now back to basically stock) so I have a good idea of how they work.

The current engine has the plenum turned around, headers plus a CAI/BFI, otherwise unmodified.

The symptoms are a CEL showing 22 - Coolant Temp Sensor Signal a rough idle (hunting from 1,000 to 1,200rpm and no power and smells like its running rich. Also isn't starting all that well either.

I've replaced the Temp Sensor but still have the CEL. Yes I did reset the ECU.

Of interest if I press the CEL activation button (it earths the appropriate wire from the ECU) the idle is smoother but still at 1,000rpm.

I've checked the ignition side and its firing on all 8 cylinders. In my car I can reach in and feel the headers to see if the cylinders are firing.

I've replaced the ISCV and before fitting the replacement I checked the bearings are running free.

If I choke the air line to the ISCV it will drop the idle depending on how much I choke it off.

The o2 sensors are fairly new 3 wire Bosch units running as single wire.

I've spent two days on this and its doing my head in.

I'm starting to think leaking caps in the ECU.

I'm open to suggestions.

 

[cribbj]

Hey Rod, good to see you back.

Couple things come to mind in addition to swapping ECU's:

1. Any chance you could've swapped around a couple of HT leads and she's firing out of sequence?

2. TPS set right?

3. Try unplugging the MAF and see if she smoothes out?

 

[Zuffen]

Hi John,

I've dropped in most days to keep an eye on things for David but everyone has played nice so no dramas.

Firing order is correct and TPS hasn't been played with.

I've had a few interesting CEL codes pop up (such as vehicle speed sensor) which don't make sense, considering it isn't connected to the ECU, which leads me to the ECU.

The current CEL 22 hasn't gone away even after re-setting the ECU and this suggests it's in the ECU as well.

Unplugging the MAF/AFM doesn't have any effect.

I think I'll send out the ECU to have the caps replaced (I don't trust my electronics qualifications, none!) to working on the circuit boards.

I may try and borrow a working ECU to try it out.


I noticed the vehicle has now covered almost 1,800klm in the last 6 years so it would be good to get it running with acceptable power and some sort of reliability so my son's can drive it.

The 1UZ has almost twice the power of a standard 3.5litre Range Rover and 50% more torque across a flatter curve so I should just accept it won't fry the tyres in the first few gears.

 

[gloverman]

Hello Rod

It is pretty normal to get a speed sensor code in the SC400/soarer ecu when the speed sensor is not present. They do not present a CEL with this code but it sits in the background. It will not effect the running of the vehicle. If I have a suitable signal avaliable I wire it it but this will also introduce the speed cut on the ECUs with this function. Fun when the converted vehicle has a different diff and the cut happens at 130km/h.

As for your coolant temp code double check the wiring and operation before hitting the ECU. Check continuity from the sensor to the ECU and the earth circuit of the sensor. Then check the voltage at the ecu and watch it change as the vehicle warms up. I normally use my scanner for this as well as manually. A multimeter will work fine and if you have a resistance wheel then that will allow you to complete the job without starting the engine. Voltage should range from around 0.5 volts up to 4.5 volts.

If this work then ECU work is required. I have 5 sitting at work which have been repaired as I do bulk runs of them now. I sell most to factory cars as the soarers need the correct ECU to run the car correctly. In some conversions I can swap in other ECUs without an issue , especially when running manual.

Cheers

 

[Zuffen]

Kelvin,

Checked continuity of coolant sensor to ECU and all good and the brown lead is showing a return to ground.

Now the car has decided to only spark on one coil and not start.

After swapping igniters over I know they are both good.

I have continuity from the appropriate igniter plug to the non-working coil and the ECU.

I've replaced the non-working coil with a known good one and no change.

I have 12volts at the coil.

I've also replaced the main coil lead for that coil for another.

I still have no spark from the new coil lead.

So I removed the ECU and one capacitor appears to have a bulging bottom (the one on the board by itself, the other board has 9 caps that I can see) but hasn't leaked onto the board.

I'm leaning toward the ECU being faulty and in need of new caps.

What are your thoughts?

 

[gloverman]

If one of the caps is leaking or bulging then I always fit a new set and test the ECU. About half of the ECUs we look at have visiable damage. If there is visiable issues they will cause issues at some point.

We see failures in most circuits within these ECUs now so the range of issues the engine can have are quite vast.

ECU is a good place to start then you know that part is good.

 

[361UZ]

A while ago, I was working on a server (computer....) and I had reached the end of my tether.
So I called the support guy.
His answer? "Jeff, if I had THAT problem, I'd be calling YOU!"
Confidence inspiring, yes?

Same thing, Rod. If I had YOUR issue, I'd be calling you!

Having said that, if you read your posts, it really looks as if the ECU thinks the engine is cold.
Maybe coolant temp sensing circuit, maybe ECU.
i know it's basic, but have you double checked all the ground connections? There is a post on this very forum wherein a guy has the same issue - idle going up and down between 1000RPM and about 1200. Can't remember what the answer was, but it WAS resolved. Maybe search?

You seem to have covered all the bases, apart from rechecking what you have done, sounds like the ECU may need some work.
At least if you swap it and it doesn't fix the engine problem, you have a reliable ECU for many years to come (if your's has swollen caps - even if it's not playing up now, it soon will!).

Jeff

 

[Zuffen]

My seemingly minor leakage turned out to be worse than expected.

I sent my ECU to Member Gloverman (Cartune Company in Hamilton NZ) for some appropriate treatment.

The news wasn't all good so a good replacement ECU was checked and sent over to me.

I collected it this morning from the Post Office plugged it in and the car fired within a revolution or two of the engine.

Yet to drive the car as I need to bleed the rear brakes as I pinched the original callipers off it a year ago for another project that uses the same axle and brakes.

Now that I can finally drive it I'm away for a month on holidays then when I get home it will be getting too cool for a car with no doors, no roof and no heater! I think I'm getting old.

 

[JustenGT8]

Good to hear the beast will live again soon How's the yellow monster going? My red thing is still failing to cooperate

 

[cribbj]

Good to hear Rod!

Wonder if it's just age that gets to these ECU's? Some of them from the early UZ's must be 20 years old by now, maybe more?

Too bad no one's come up with a PnP solution that runs well and is truly user friendly. Everyone who has run aftermarket standalones can testify to their flexibility, but they lack a lot in user friendliness and the general quality of tuning. And when I say quality of tune I mean consistent idle quality, on/off throttle transitions, etc.

I haven't purchased/tuned an aftermarket ECU in 6-8 years, so perhaps the latest generation (MSIII, Link, MoTeC M1) are much better than the ones from early 00's?

 

[gloverman]

Thanks Rod. My morning job was to check that it had arrived. We had a couple of goes at your one but as you have worked out it ended up not being repairable. I now have a test loom for these to run them in my Old surf after repair and bench test. Nothing like driving the ECU around to test it. Now go on holiday. Cheers

 

[Zuffen]

Took it around the block (iffy brakes and all) and it runs well but has a hunting idle and code 22 so I'll swap out the water temp sender and see how it goes.

Not in a rush but at least now it's driveable.

From what I've experienced anyone with an old ECU and in the throes of a swap would be well advised to either have the caps replaced or do it yourself.

In the overall scheme of things having it done professionally and knowing your ECU is good sure makes fault finding easier.

 

[361UZ]

Hi Rod and all.

Good to see you are still "dabbling".

Anyone have an idea of the cost of a "professional" check/repair of an ECU?

 

[Zuffen]

361UZ,

Sorry for the slow reply, just returned from O/s yesterday and still getting it all together.

If you speak to Gloverman on here he can advise you of the procedure and costings involved.

It isn't expensive and worth the peace of mind.