In 1998 I bought a Triumph Herald 13/60, here you can read about it's restoration and share in a few photo's from it's travels. Please feel free to leave comments to any of the posts, of even email me if you want to.

Saturday, August 19, 2017

Converting a Triumph Herald to EFI (Part 7 - IAC Valve Update)

Back in an earlier post I mentioned that I was having trouble getting the Bosch IAC Valve to function correctly, not wanting to be beaten by this I started re-reading all the articles when the penny finally dropped as to why I was struggling.

The valve I was using only has 2 wires, one a 12v supply the other goes back to the ECU so simple enough, but I had missed the instruction which said that I needed to put a 1N4001 diode across the 2 wires, once this was done the valve started to operate as I'd expected.

These valves only need to open a very small amount to make fairly large differences to the amount of air coming into the plenum, so I decided to restrict the airflow by inserting a short piece of rubber hose on the intake side as I figured this would give me more control, I also fitted a small cone filter.

To control the valve you need to work out at what Duty Cycle % it is fully closed and fully open, mine seemed to be at around 33% for closed and 75% for open, once you have these figures you can start to experiment. There are 2 ways to set up these valves, Open Loop (Warm-Up) which is based purely on coolant temperature or Closed Loop where yo can set a target RPM. Most people start with Warm-Up only as it's much easier to set-up, so this is where I started.

With all these things it involves trial and error, but after a couple of days I ended up with with the settings below, which work pretty well. This provides an idle speed of around 1100rpm during warm-up, with a gradual reduction in the duty cycle, then I tail it off quickly just before it's fully warm.

Idle Air Control / Warmup Duty Cycle

I may revisit the settings and experiment with Closed Loop at some point, but for now it's working well so I'm going to leave it alone.

Thursday, March 9, 2017

Converting a Triumph Herald to EFI (Part 6 - Fuel Tank & Pump Update)

The initial tank/pump set-up has worked perfectly, but the pump is a little exposed on the boot outrigger, so does get more than its fair share of mud and water spray from the rear wheels, plus it's quite noisy. Not when you're in the car, especially when driving, but noticeable if your outside.

After reading many article on how people have approached this area, I decided to revisit the set-up. The plan this time is to modify a Vitesse tank to take an internal pump, the pump of choice is one that fits a classic Range Rover.

First thing was to find a donor tank to modify, condition was not too important as it was going to be cut up anyway. A local TSSC Devon member had a few, so a deal was done.

First thing was to cut one side off to give full access to the inside of the tank, it was then given a very hot jet wash to remove most of the gum and surface rust within. If you've ever wondered what the inside of a Vitesse tank looks like, here it is.

Fuel Tank with the side removed
Whilst the side was off it was an opportunity to increase the capacity of the tank. I cut a couple of strips of steel, joggled both edges to allow an overlap and tack welded it on to the main body. With my very rough calculations I reckon the band will an extra 2 gallons, I could have gone more, but wanted to retain some boot space!

Banded to add extra capacity
I knew of another Triumph owner who had used the same pump and had made a flange for it to mount to, so I approached him to make another and he kindly obliged (Thank you Roger). The flange was mounted centrally and near the back of the tank so that the pick up would be in the lowest part of the tank. I had to extend the length of the pump slightly and then created a baffle around its pick-up to help when the fuel is low.

Pump, Flange & Baffle
After some modification to the main baffles within the tank, I slipped the side over the edge of the banding and tack welded in place. Once I was happy everything was in the right place, it was fully welded along with the flange for the pump.

Tank fully welded
I used some car body filler to smooth out the welded areas, the taped up areas you can see in the image below are in preparation for a Frost Tank Sealer treatment. With the amount of welding that was needed and the fact it was done with a MIG, there was no way it was going to be fuel tight. I have used these sealer kits many times to good effect.

Cleaned up and filled
Even though the tank was solid it was still covered in surface rust, so it was initially brush painted with POR-15 Rust Preventative paint. It was then sanded back smooth and painted with a 2K black gloss. To minimise the new pump resonating through the tank, I used several self adhesive bitumen sound deadening pads.

Ready to Fit
There are several advantages to this revised set-up, the pump is quieter, kept cooler by the fuel, the main filter is now be in the boot rather than engine bay, it tidies up the underside of the boot area and the extra capacity increases the range by 60-70 miles.

Tank fitted
I did have minor panic before fitting, I have to admit to completely forgetting about the spare wheel and whether I'd be able to access it with the tank in, fortunately I can remove and refit quite comfortably.

Clearance for spare wheel
Apart from revisiting the Idle Control Valve at some point, that is the conversion complete. If you'd like to see all the images you can see them here: https://tinyurl.com/jyk8u9w.

Sunday, February 26, 2017

Converting a Triumph Herald to EFI (Part 5 - Starting, Tuning & Cold Idle)

I was more worried about the next stage of the conversion than any other part. All the research, head scratching, fabricating & wiring that I'd done and I could have been left with a non-runner. So with some trepidation I sat in the drivers seat and cranked over the engine, 3 or 4 attempts and nothing much more than the odd cough. I waited a minute or 2 and tried again, this time she seemed keener to get going, one more try and she burst into life.

Thankfully the base settings that came with the ECU seemed good enough to at least get the car running, so first target was to see if I could get a reasonable idle. I kept the revs up until she was at operating temperature and tweaked the idle control screw on the throttle body. The gods must have been smiling on me as it wasn't long before she settled down to a steady idle.

Once the idle was acceptable, the next step was to improve the starting, particularly when cold, this you can only really try once a day when the engine has been left overnight. Within the tuning software (Tunerstudio) you can adjust the duty cycle of the priming & cranking pulses of the injectors, these are calculated on increased percentages of what fuel is required when running and by water temperature.

So over the next few days, the attempts to get her started were fairly lengthy affairs, each day I gradually increased the duty cycles of the two settings until such things were better, but they were still not acceptable. Then I realised that I hadn't set some of the engine constants, particularly the flow rate of the injectors I was using and engine displacement, so these were changed and instantly the cold starting improved. A few more days of minor adjustment and she then began to start consistently right through the temperature range.

If you get the paid version of Tunerstudio, it comes with a great function called Tune Analyze Live. You basically plug your laptop in, turn on the Tune Analyze Live and drive, it will make adjustments to your fueling table through all the various driving conditions. It does need a few runs, so I just used it on every journey over a couple of weeks. This is why I fitted a wideband 02 sensor, if I'd have fitted narrowband it would have meant manual adjustment or getting the car on a rolling road to get set-up. Tune Analyze Live also works on the warm up enrichment, so a couple of runs from cold and that was working well also.

So now I had a car that started well, drove well and idled nicely when warmed up, but I still had nothing to control the idle from cold. Each cold start involved trying to keep the revs up with my right boot, whilst trying to brake and change gear without the car stalling, I needed 3 feet....

This is where the Idle Air Control valve comes in, this is a relatively simple valve which opens and closes based on temperature, allowing more air through to increase revs. Sounds pretty straightforward, but so far this has proved to be a real thorn in my side.

Bosch Idle Control Valve
Again it's something that can only really be tested when the engine is stone cold, so you get one chance per day to make adjustments. After a couple of weeks, 3 different used Bosch valves and and a brand new aftermarket version and no success. I decided that I would have to try a different approach, even if it was an interim fix.

The old choke cable was now redundant, so this was removed and a longer universal one was purchased. The Rover Throttle Body has 2 cable connections, so I fitted the new cable, made an additional mounting for it and connected it up. Simple but effective!

Throttle & Fast Idle Cables
So the choke knob doesn't look so great on the dash, but if this proves to be a longer term fix, then I will find a way of grafting the original knob onto the new cable to make it look a little more authentic.

Universal Choke Cable on Dash
I have now covered several hundred miles since the conversion and I'm very happy with the results, even on a engine that has never been right since it was rebuilt (that's another story). I have another engine almost ready to go in, so I'm looking forward to see how it performs with that.

Converting a Triumph Herald to EFI (Part 4 - Final Mods & Wiring)

You can use just a narrowband 02 sensor to save money, but if you want to try and tune the car yourself then a wideband sensor and controller is essential. I used the Spartan 2 controller which ships with a decent Bosch sensor and is well priced. I have a stainless 4-2-1 manifold, so I welded in a bung just past the 2-1 join to get a combined reading from all 4 banks. Orientation of the sensor is important, it should be between 10 & 2 O'Clock to avoid damage from condensation.

Wideband 02 sensor
With no need for the old mechanical pump, I made a blanking plate that incorporated an additional breather as my engine would definitely benefit from it.

Fuel pump blanking plate/additional breather.
The breather tube in the crankcase is normally on the carb side for obvious reasons, but that's not so great as they've now gone. I decided to ditch my alloy cover and go back to an original steel type as I could easily move the tube to the other side. I took the opportunity to increase the size from 13mm to 16mm just to aid breathing even more.

Modified rocker cover
The position of the throttle body prevented fitting a filter directly to it, so a length of ducting was used to position the filter behind the front valance. A short length of 70mm steel tube was used to connect the filter to the ducting, this had a bung welded into it to take the Air Temperature Sensor.

Air Filter
All that was left to do was to run the existing accelerator cable to the throttle body, make electrical connections to the 4 injectors, Air & Water Temperature sensors, Throttle Position Sensor & Idle Control Valve. All the sensors need calibrating, Air & Water were simple as I'd bought GM spec ones so it was just a matter of selecting from a drop down list. The TPS you just need to record values at fully open and fully closed, and 02 sensor is also an option you can select.

So with everything in place, the only thing left to do was to see if she'd start......