Digsy

MKIV.com doesn't specifically mention the pistons being forged, but it doesn't say they are cast either, so your guess is as good as mine at the moment! Since this thread has moved off in its own direction, I've started a new one in Techincal where we can discuss slap to our heart's content...

Its the thing that goes "langa-langa-langa". Its something to do with the side loads on the piston reversing at top-dead-centre & bottom-dead-centre. Piston pins are usually offset by about 1mm towards one side of the cyinder bore (the "thrust side" on the power stroke) to help rememdy this. (Getting to the limits of my knowledge here. I need to talk to a Development Engineer at work for a full description. They have much bigger brains than us ignorant Designers! ) I'll post more info on Monday if I remember.

If its a "langa-langa-langa" kind of noise that goes away after a couple of seconds after you first key on then it could be a touch of piston slap - a tad annoying but nothing to worry about unless it gets really bad or prolonged. There was an espisode some months back when a few people were reporting strange noises from their PAS pumps, but to my knowledge no-one ever go to the bottom of what it might have been. I have noticed that mine makes a slight while from cold, but it dissappears after a while - at least it isn't whining any more when I get to work (25 miles away from my house).

Its right at the front of the "metal part" of the engine, sandwiched between the back of the crank pulley / timing sprocket and the oil pump at the front of the cylinder block. You won't be able to see it directly because of all the bits in the way, but if there is any wet oil around there then chances are its coming from the front crank seal. You will have to take the undertray off to see anything at all. I'm not implying that there will be anything wrong with it. Mine is leaking a tiny bit but I don't leave puddles of oil around or anything. In fact I don't even notice and loss of oil at all (for how often I check it). I just happen to have had my timing belt changed first. If it had happened the other way around I would have definitely got them to change the front seal at the same time because the amount of "pulling about" is virtually the same for both jobs.

Visual inspections of any kind are very hit and miss with timing belts. They can get cracked to h*ll and still run fine, or look like they just came off the shelf and suddenly let go. If you are at all worried then I would get it changed (I did - at 27000 miles). At least you know you are starting with a "clean sheet". Might be worth pricing up how much extra it would be for a front crank seal replacement at the same time. I've got a very slight weep on mine and I wish I had had it changed while they had the front end apart to change the timing belt. Oh, and given Rob's experience, make sure you take it somewhere that doesn't have to use a blowtorch to get the crank pulley off!

Sorted it this afternoon. Thanks for the input guys.

If we can't laugh at ourselves...

...if you want to find out more about the Supra engine, I can thoroughly recommend reading the New Car Features documents on MKIV.com I work with engines every day, and I enjoyed reading it immensely. Its an excellent resource.

I've been looking at the wiring diagrams on MKIV.com and I think I know what's wrong. I've been having a look at my alarm wiring and I know the earth wire from the "tailgate open" switch is joined to the earth side of the ignition barrel light by a long length of wire, and in turn to the earth sensing wire from the alarm. The light delay on the ignition barrel works by allowing the earth side of the bulb to stay connected to earth for a while after the door has been closed. Because the earth from the tailgate switch is linked to this wire, it thinks the tailgate is staying open too, and hence the dash light stays on until the delay circuit trips and disconnects everything from earth. Trouble is, i am *sure* it didn't do it before! Hopefully I've answered my own question. Looks like I'll be trying to sort it out tomorrow. Cheers, Syed & Ian.

Hi Syed. In my car the main light on the ceiling goes out instantly, but the orange symbol on the dashboard to the left of the steering wheel stays on for about 5 seconds. I'm sure they both used to go out instantly.

I've just been mesing around with the wiring on my car again and I think I may have b*ggered something up slightly. When I open either of the doors (not the hatch) the courtesy light comes on, the ignition switch barrel lights up, and the "doors open" telltale on the dash illuminates. When I close the doors, the courtesy light goes out srtaight away but the telltale and the ignition barrel lights stay on for about 5 or 6 seconds, then go out together. I'm sure that pre-messing the telltale used to go out immediately (with the courtesy light) and only the ignition barrel used to stay on, but its one of those things that you don't check out regularly... The annoying thing is that after tonight's exploits I put everything back to how it was at the start of the evening, when I'm sure everything was working OK. Can one of you guys do an idiot check for me please?

Ian C has done this for his FMIC. Not sure what components he used, but I would have thought washer jets would deliver the water in too big a "clump". Better to have a finer spray. I think that's what the Scoobynet guy may be getting at when he says a "higher density" spray.

Is it the petrol or diesel model?

A learned source once told me that if your clutches are burned out, as well as the fluid being dark, it should stink! He didn't say exactly how it would smell, but if you sniff the transmission dipstick and go "URG, BL**DY HELL!" or something like that, then it means your clutches are on the way out, or they have left already. I've sniffed my dipstick, and it just smells oily.

Yeah, I should have been more clear on that. The retainer is designed to be still held by the connector body while "disengaged" from the pins (I did remove mine, however, just because I like to live dangerously ) The clips felt strong enough to hold the pins in should something untoward happen. I was more worried about sneezing and losing the pin once it was out!

If you want to tap into the MKIV harness, either to add some extra gubbins or to redo a bodge job MPH / KMH conversion etc. there is an easy way to connect to an existing wire without having to cut anything. 1) Trace the wire to the nearest connector. 2) Unplug it and lever the retainer out of the connector body, (they are all slightly different). Use a small screwdriver or stanley knife blade (you may want to get an adult to help youi with this bit ). 3) Look at the "business end" of the connector. Above each pin you should see a small plastic clip moulded into the connector body. Depending on the size of the connector pin, carefully put a small tool (I used a needle) in between the connector pin and the plastic clip, and gently lever the clip upwards while pulling carefully on the wire. The wire and pin should slide out of the connector body. 4) You can now prize open the crimp on the pin and either remove the wire, or add one of your own. If you piggy back another wire onto the pin, be careful to do it over the original crimp location and not to use too much solder, or you will find that the retatiner clip in step (2) will not go back into the connector body. 5) Slide the pin back into the body. It sould click home as the clip re-engages. 6) Replace the retainer from step (2).

Where the h*ll do you get those smileys from, Martin? That's the best one yet!

Lots of stuff in here about it. Use the search function and you should turn something up.

Ar*e!! I had that in my hands yesterday! Next time, little nuisance, your fate is sealed. Soon you shall beep no more. (Cheers, JB!)

Does this win the prize for the biggest gap between posts? Next time my dash comes out this little s*d is going in the bin. Can anyone tell me where it may be found? Please???

Hi Matt. I did a quick websearch during my lunch break (so as not to take up useful work time when I browse the BBS) and reminded myself about all the diode specs. Forward voltage drop, breakdown voltage, leakage current, etc, etc. Even that s-shaped current v voltage graph. Brought it all back to me, happy student days breathing solder flux, jumpers for goalposts... Anyway, you are quite right, its nothing too bewildering after all. It will probably cost you more than the parts are worth in postage and time, and I'm off to the electrics store this week anyway, so I won't bother you just yet unless they don't have the goods. Thanks for the kind offer though! PS. I've sent you a PM about something else.

Alex is right, there was an in-depth discussion about what were the limiting factors for revs in the 2JZ a while back. Taking valvetrain in isolation, a longer duration / higher lift cam will allow the engine to breathe better at higher RPM (a'la Honda VTEC). The valve spring, however, will only have been engineered to prevent the follower from floating up to a certain engine RPM. Going significantly higher will probably require a new spring pack. As for running in (harking back to the start of thr thread), this is a new one on me because cam lobes are ususally hardened (either by induction of remelting), so they shouldn't wear much when new, and any kind of wear on a follower is a bad thing. I have, however, seen top ends built up with a blob or two of molybdinum (sic?) grease on the cam lobes to help with rotating the cams when setting the timing, and for protection on the very first run.

Calling all electrical boffins. I need a diode, but I've forgotten almost all my college electronics so I can't remember how they are defined. I need one that will stop a current of 2A flowing in the wrong direction in a 12V circuit. What do I need to ask for at my local Maplin's?

Cheers, Pete. Will do.

Hi all, Despite my grandiose plans to mount the tell-tale for my rear roglamps inside the instrument cluster, I have decided I had about as much fun with wiring as I can stand for one weekend. Therefore I will be going the "easier" route and using the rear bulbe fail warning lamp as my rear fogs tell-tale. As I understand it, you need to snip the purple / violet wire and simply route it to earth to make the blub come on. Looking at the diagram on Pete Betts site, it looks like there is also a yellow wire that you have to snip at the bulb fail unit itself. However, the diagram is a tad unclear (no offence meant, Pete)because it hops straight from the front of the car (where the warning blubs is) to the rear of the car (where the blub fail unit is). It also says you have to cut both ends of the yellow wire, but only shows it being cut at the "rear" end. If someone has done this mod already, please can they advise?