Mk1B - Won't start

[Aitch]

Just recently, my MR2 has struggled to start after being left for a few days, and when it did it spluttered and didn't rev too happily until it was warmed up. If it was used regularly, then all was fine. Now it's been left a few more days, it refuses to start at all and just turns over and over without ever firing into life.

Any bright ideas? I've changed the spark plugs, but that hasn't helped. And I've noticed this wire is getting hot and smoking at the connector block if I turn it over for any length of time...



Which is located here...



It's doing my fruit in

[millentubby]

Hi mate,

with regards to the smoking wire - I had this problem recently on a mk1 that was destined for the scrap-heap but was used briefly for field-bashing!

The wire that's smoking is an earth lead - we just added in another wire going from the engine block to the chassis to relieve some of the load.

We had this problem after leaving the engine lid off and the engine was rained on.

The spluttering/reluctance to start could be a number of things but I'd investigate an ignition issue - first port of call would be to pop the HT leads off the spark-plugs and have a look to see if there's any water gathering around the spark plugs - this can cause the spark to arc to the block instead of going to the spark plug.

Another common problem with these symptoms is old and damaged HT leads preventing the spark getting to the plug. Examine these and if possible replace them with ones that are known to work (see if you can borrow some before you spend money buying new ones) to eliminate that cause.

Have a check on these points and let us know what you find

EDIT - just read the post again and noticed you have changed the plugs. Pop the distributor cap off and inspect the rotor arm and cap for wear/tracking/cracks...sometimes a squirt of WD40 will disperse the water but is a short-term substitute for a new cap and/or arm.

[Aitch]

Thanks for the tips

Where is the best place to get leads, rotor arm and distributor cap from - local motor factors or, dare I say it for fear of my wallet imploding through fright, Toyota?

[Tony jinxy froude]

All you need to do is to take the large earth lead off of the top of the thermostat housing, give it a good clean up with some emery paper , make sure the top of the thermostat housing where it bolts to is nice & shiney then bolt it back on . The reason for the small wire in your pic is getting hot & burning is that the small wire is taking all the load due to the poor earth on the large earth wire, do as i said & all should be ok & hopefully you wont have any more stating problems, cheers, Jinxy

[monkeymax]

Where is the best place to get leads, rotor arm and distributor cap from - local motor factors or, dare I say it for fear of my wallet imploding through fright, Toyota?

For Dizzy cap and rotor arm, I still say it's worth going to Mr T. Their prices are definitely competitive (compared to my local motor factors anyway) and you're getting genuine parts.
It does in fact sound to me like it is a dizzy cap problem - it'd be worth just checking the contacts on the dizzy cap to see what they're like - most likely they're pitted. And you should change the rotor arm when you change the distributor cap.
Check/change these first before looking at replacing the HT leads. IIRC, the dizzy cap and rotor arm I bought from Toyota cost in the region of £15 (this was over a year ago, mind so my memory may be very poor!) whereas HT leads are somewhat more than this, but should last a long while...
If you do want to try HT leads, I've heard of people buying them online a lot... (Toyotas ones are indeed a bit pricey...)

[MartG]

Like Jinxy says, sort out the engine earth before you spend any money. That small wire from the head is primarily the ECU sensor ground, and isn't big enough for the current needed to start the engine - hence why it's overheating and smoking.

To find the proper engine earth, simply follow the -ve lead from the battery down to where it bolts to the chassis ( next to the grey electrical connector fixed to the suspension turrent below the engine bay fusebox ). The engine earth wire continues on from that point, and is fixed to the gearbox by one of the bolts that holds on the thermostat housing. Give it a good clean and try starting it again

[Aitch]

The bad earth wouldn't explain the misfiring when cold though would it? Please excuse me if it does - I'm not exactly what you would call technical

[MartG]

Could do - remember that when the engine is cold, just after starting it, the alternator is trying to replace the battery charge used to start the engine - that current is flowing through the earth and if its giving a high resistance it can play havoc with the voltages the ECU sensors see.

[kevin..in]

The bad earth wouldn't explain the misfiring when cold though would it? Please excuse me if it does - I'm not exactly what you would call technical

spark plugs need a good earth to ... well spark!!

[Aitch]

You see, that's why I'm not a mechanic, because I don't know stuff like that

Always learning though

[Aitch]

Tony and Mart - thanks for your help. I managed to get the car running today and I seem to have fixed the problem and it was one of the earth connections as suggested

I've been meaning to get round to it for ages but every time I have been motivated to do it the rain has been chucking down

[Tony jinxy froude]

Glad you got it sorted Andrew, its the smallest things that sometimes cause the most trouble... especially on our cars. , Jinxy