Project Tomcat, Boost and High Stop

I just can’t help myself, I needed to dig further into the Tomcat and see what was happening.

So the issue I had was although the car was running OK on the one drive I took it on around the block, it ran really flat and there was no boost.

I had read about the diagnostic tools available for the MEMS 1.6 ECU, and it was quite limited. I could either spend hundreds of dollars on a dedicated scan tool for it, or make a cable myself and use the free software available. The choice was obvious, DIY.

Three parts are needed,

• Housing – 571-172201-1
• Pins x3 – 571-170280-1-LP
• FTDI USB Cable – 895-TTL-232R-5V-WE

Some crimping and soldering later, we had a proof-of-concept cable.

Once the cable was assembled, and the drivers are installed, it is just a matter of plugging into the car and opening the software. In this case in using the fantastic piece of free software, MEMSFCR.

I reconnected the battery, set the COM port on the software, started the car and the software connected with no issues.

A quick check of the error codes and showed that I had one, the O2 sensor was reading out of spec.

I changed over to the dials screen, and sure enough, the O2 sensor reading was off the scale

And the short term fuel trim was trying to pull a large amount of fuel out

But what bothered me was the MAP sensor reading. I noticed the needle pegged at 96KPA and sat there, even if the engine was revved. That’s not right.

This was also where I noticed the car was running like a bag of rubbish, popping and farting when giving it throttle.

So I shut the car off and started hunting. Clearly there was an issue with the map sensor, so let’s check that first. On the MEMS 1.6 units, the map sensor is inside the ECU and fed via a vacuum hose.

Well, clearly I didn’t get the memo, but it seems we have advanced to wireless map sensors now.

In that image, the hose (orange arrow) should be connected to the black hose nipple (green arrow), but instead, it’s hanging free, causing a vacuum leak and not feeding any data to the sensor.

I removed the unreliable wireless connection and reverted to good old plugging it in.

I fired the car back up, connected the diagnostics and instantly the car was already running better. Much smoother at idle and revved cleanly. The diagnostics were all suddenly back within range now too, with the O2 sensor, MAP sensor and Fuel Trim all perfectly within range. The MAP sensor was now changing with the throttle position as it should.

The amount of detail and information that can come through those three pins was quite astounding.

It was a bit late at night to take the car for a test drive, so I waited until this morning.

Before heading out though I needed to fix another minor issue. My Wife has noticed yesterday when I parked the car in the garage that the taillights appeared to be on when the car was running, but the headlights were off.

Turns out yes, there were lights lit, but they were actually the brake lights (although the high stop light wasn’t working, as shown in the above photo).

The switch on the brake pedal is adjustable, so a quick couple of turns of the switch, and the lights were back to working properly, but I still had no high stop light. Regardless, I embarked on a sneaky trip to the nearest petrol station with the sweet high octane fuel.

40 litres of 98 went into the tank, which in a tank that takes 55L from dry, means it was quite low. The pump certainly sounds a lot happier now. No idea what swill was in the tank, but I bet it wasn’t 98.

And the result? Well, we certainly have a lot of torque steer now, which also means we have boost again. I need to get a boost gauge on the car to see what we are actually getting, but I suspect it’s not the full 12PSI and it does taper off quite quickly, so a smoke and boost leak test is on the cards.

The main thing is that it runs really well, drives smoothly, and makes great noises. The temp stays steady, and the fans came on as they should. The brakes need a good looking over as they are spongy and have a bit of a wobble.

One thing I knew I needed to fix before trying for a WOF check was the high stop light that wasn’t working.

They aren’t the greatest designed light, and it was an afterthought slapped onto the boot lid of the JDM cars, as the UK cars never had one. It was made by L.E Perei, who appears to make lights for… trailers.

Two screws hold the lens on, and then the actual light unit slots into the housing. Inside the boot are the two wires, with bullet connectors attached. Disconnect them, and pull the light unit out through the boot lid. All bulb holders and bulbs were present, one was removed before the photo was taken.

The reflector was filthy, so that got a clean, but putting power to the wires resulted in no light from the bulbs.

On the back of the unit is a basic circuit board that links all the bulbs in parallel. The bulbs work by just touching the contacts of the bulb holder onto the metal strips on the circuit.

I tested all the bulbs one by one to make sure they worked, cleaned the contact areas up with the fibreglass brush, and fitted the bulbs back into the unit. A couple of bulbs only worked after some wiggling, but I got all of them working.

The unit got refitted, and a bottle of oil was placed on the brake pedal to test.

I reassembled the light, slammed the boot closed a couple of times to latch, and bam, suddenly only 4/5 bulbs worked. Oh well, good enough for a wof.

Thinking of the substandard design, I’m going to look for a nice surface mount LED board to fit into a 3D printed housing that works inside the existing light. Do away with that rubbish circuit board completely.

Speaking of slamming the boot, this is why it needs to be. My catch looks like this

But it should look like this, with a plastic section on the catch, which would change how far the striker needs to go into the catch to latch it. The orange arrow shows what is missing.

So I need a new boot catch. Yay. Until then, it’s slammy slam time.

That is where I’m at for now. I still need to reassemble the back seat, and then work on sealing everything that could leak so the car can live outside again.