Car not starting correctly..

[Guest Jib136]

Hey,

 

Recently just brought my supra 1994 n/a and has been working fine after this past week. Tried to start it this morning and it won't run... Turns over but I don't think there is any spark... But it bump it then it starts and idles fine... I have noticed it's got a misfire though... So if you full throttle it when you get to 3k it misfires, as soon as your past 4k it's perfectly fine...

 

Any ideas of what to check?

 

My main car is a s15 and no nothing about these engines :-p

 

Thanks :-)

 

James

[listy]

First thing to check is spark plugs imo.

[Havard]

Have you washed it or steam cleaned the engine/electrics?

 

Otherwise it's probably a plug or lead problem. I had similar on my NA.

 

H.

[Purity14]

Take off the dizzy cap and clean the contacts and the rotor arm, it will start pretty much straight away after that..

 

Your s15 has an sr20de(t) engine, does it use the old sr20 with a dizzy or is it on coilpacks now?

 

Has it been reliable for you? Im tempted by one..

[Guest Jib136]

Thanks :-)

 

Nope I havnt cleaned the engine bay at all.

 

I was also thinking a coilpack problem but don't know how to check if it's faulty...

[Guest Jib136]

Take off the dizzy cap and clean the contacts and the rotor arm, it will start pretty much straight away after that..

 

Your s15 has an sr20de(t) engine, does it use the old sr20 with a dizzy or is it on coilpacks now?

 

Has it been reliable for you? Im tempted by one..

 

Thanks man.

 

I've got a forged sr20det in mine and yeh it used coilpacks :-)

[Purity14]

Thanks :-)

 

Nope I havnt cleaned the engine bay at all.

 

I was also thinking a coilpack problem but don't know how to check if it's faulty...

 

As i posted, your n/a will be using a distributor not coilpacks

[Guest Roger NE]

I bet it's your HT Leads - they're the most neglected item on ANY engine in my opinion

 

They develop microscopic cracks in the insulation, so the high voltage (around 30 kV) which should be making the Spark Plugs do their job starts leaking to the chassis instead . . . this therefore causes all kinds of intermittent misfires (and worse when an engine is cold, because of the damp)

 

People really should replace the whole set of HT Leads every 5/6 years, but rarely do. (I always have, and could spray water over my engine with no misfires!)

 

Still worth cleaning the inside and outside of your Distributor Cap (as suggested) . . . but it's far less likely to be causing your problem than the leads

Edited October 12, 2013 by Roger NE (see edit history)

[Guest Hosky]

The sr20de(t) has coil packs

[Havard]

I bet it's your HT Leads - they're the most neglected item on ANY engine in my opinion

 

They develop microscopic cracks in the insulation, so the high voltage (around 30 kV) which should be making the Spark Plugs do their job starts leaking to the chassis instead . . . this therefore causes all kinds of intermittent misfires (and worse when an engine is cold, because of the damp)

 

People really should replace the whole set of HT Leads every 5/6 years, but rarely do. (I always have, and could spray water over my engine with no misfires!)

 

Still worth cleaning the inside and outside of your Distributor Cap (as suggested) . . . but it's far less likely to be causing your problem than the leads

 

Once I replaced mine, (£107 from Toyota) I never had a problem again.

[Big Supes]

Sounds like your ignition system could do with some TLC. Clean dizzy - clean & re-gap spark plugs - assess HT leads.

[Guest Jib136]

I know it sounds stupid but is there a certain way to clean the distributer??

 

also how do I become a paid member to be able to post in the wanted section?

[listy]

also how do I become a paid member to be able to post in the wanted section?

 

http://www.mkivsupra.net/vbb/showthread.php?82442-Club-Membership-Details-Including-Trader-amp-Hobbyist-Membership-Rules

[Purity14]

I know it sounds stupid but is there a certain way to clean the distributer??

 

also how do I become a paid member to be able to post in the wanted section?

 

Take it off and clean the contacts, use a flat screwdriver first and you will see whats happening, then if you are feeling adventurous use something like sandpaper, ensuring that you are just taking the surface off, not filing them away...

 

I have been known to use the rough side of a matchbox in an emergency, its all good.

[Guest Roger NE]

The sr20de(t) has coil packs

 

Yes but the problem is on his N/A Supra!

 

assess HT leads

 

How?! There is no way of checking if the insulation is breaking down ! (not without very sophisticated test equipment) Even if a Distributor Cap is VERY furred up, an engine will still run OK, so I wouldn't say that's your priority . . . and although cleaning/regapping or replacing your Spark Plugs is sensible, I'd still bet your problem is your HT Leads (they're probably the original ones from new!)

 

There are aftermarket ones that are way cheaper than getting them from Toyota, and just as good - just go to your local Accessory Shop and see what they can order in for you.

Edited October 13, 2013 by Roger NE (see edit history)

[Big Supes]

Don't agree. Corrosion build up on rotor arms & points, as well as spark plugs fail more often than HT leads....

 

... But, hey... I didn't realise this was a competition. I was merely offering 'advice'.

[Guest Roger NE]

But that's the beauty of Forums like this . . . you will get people with different experience and different opinions, offering different advice (as you say, it's not a competition!)

 

My suggestion was based on what he posted - he said the car was running fine but suddenly it isn't - the Distributor Cap or Spark Plugs won't SUDDENLY deteriorate

 

However, damp weather WILL suddenly cause poor starting and misfires IF the HT Leads need replacing

 

The other point is that his spark plugs and distributor cap will probably have been replaced/cleaned, whereas I bet his HT Leads are the original old ones.

 

You said "ASSESS the HT Leads" - but the problem is there really is no way for most people to do that. As I said before, they're the most neglected part on most engines in my experience, and for reliability should really be replaced every 5/6 years (just like you would routinely replace oil and air filters, spark plugs, etc)

Edited October 14, 2013 by Roger NE (see edit history)

[Big Supes]

No one said HT wouldn't cause issues if they need replacing and I agree that they're a serviceable part that does, indeed, get neglected. I'm all about for public forum debates, although it gets sketchy when someone dictates their opinion on something pretty speculative a fact.

 

I rule out HT leads by getting it running and popping off each HT lead until I find the missing cylinder. If the problem is across the board, I would go straight to the distributor. If it's running on 5, then I would pop the spark plug out of the offending cylinder and check the strength of the spark (if there is one)... followed by a clean, re-gap and popped back in. If it's still not firing, I'd swap the spark plug with a cylinder you know is chugging away just fine. Still not firing? Do the same, but with a HT lead. That's pretty much how I'd assess the ignition system, including the HT leads.

 

You're probably right that the leads haven't been changed so it wouldn't hurt to replace them if that's the case.

[Guest Roger NE]

Sure, if the engine's not running on one particular cylinder, it's likely to be the Spark Plug fouled up or damaged . . but that's not what he described.

 

The point is that HT Leads rarely fail completely ! Sure, the conductor CAN break inside, but that is very rare in my experience. So you rarely get an HT Lead problem causing just one cylinder not working all the time.

 

What happens most of the time is the leads develop microscopic cracks in the insulation . . . so as they lay across the engine the extremely high voltage leaks to the chassis, and causes misfires or poor starting. Given that most people replace complete sets of leads, this usually means they are ALL leaking SOMETIMES . . . . but this will be intermittent and random . . . . often dependent on how damp the air is under the bonnet, as this will make it worse.

 

That's why, in my experience, if a car runs reasonably OK once the engine has warmed up, but doesn't like starting or misfires when it's damp, it's nearly always the HT Leads that are at fault.

 

Some people even grab HT Leads and get an electric shock, and think that's normal . . . not realising that if the insulation is still perfect that wouldn't happen! Equally, I know I can spray water over my engine and it wouldn't cause it to stop, because the HT Leads are in good condition.

 

I'm not dictating my opinion . . . just stating it, to try and offer helpful advice

Edited October 14, 2013 by Roger NE (see edit history)

[Big Supes]

I never had this issue with my old NA, but it sounds like something they're starting to suffer with nowadays (ones on original leads). I take your word on it from your own experience. It's just something I haven't really come across before... although most of the cars I've owned don't run the leads across the engine.

[Guest Roger NE]

Well I know in theory the designers try and minimise the risk of Leakage by clipping the HT Leads in those little plastic holders . . . but in practice they're bound to be touching something metal somewhere !

[Big Supes]

Yeah, good for cosmetics and keeping leads away from moving/hot parts, but must be allowing contact with the engine.

 

Has the OP sorted this yet?

[Guest Jib136]

Thanks for the help everyone!!

 

Still got the problem and managed to narrow it down to the ht leads. Wanted to be sure before I spend £125 on leads.

 

Unless anyone has any for sale? Or know where I can get them from?

[Iky]

Thanks for the help everyone!!

 

Still got the problem and managed to narrow it down to the ht leads. Wanted to be sure before I spend £125 on leads.

 

Unless anyone has any for sale? Or know where I can get them from?

 

local motor factors as already stated, They might possibly be exactly the same as Lexus GS300 3.0

 

http://www.ebay.co.uk/itm/VE522708-Toyota-Supra-Twin-Turbo-JZA80-3-0-Petrol-93-96-Ignition-Leads-/400515258042?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item5d4091d6ba

 

http://www.ebay.co.uk/itm/TOYOTA-SUPRA-3-0i-24V-TWIN-TURBO-93-IGNITION-LEADS-344-/321231137005?pt=UK_CarsParts_Vehicles_CarParts_SM&hash=item4acade28ed

 

Or if your feeling flush - http://www.dcperformance.co.uk/cheap/842169/lexus/magnecor-8mm-ignition-leads/mgn-60112.html?gclid=CPXUo9fovroCFRDItAod7msAcA

Edited October 30, 2013 by Iky (see edit history)

[Ian C]

Some people even grab HT Leads and get an electric shock, and think that's normal . . .

 

That's how I "assessed" the HT leads on my friends' Astra once that was misfiring I certainly didn't think it was normal though, as my subsequent invective proved.