Jump to content
The mkiv Supra Owners Club

please help - loud bang, now car won't start


Guest chris t4

Recommended Posts

Guest chris t4

firstly hello to everyone i i wasnt expecting to ask for help so soon:(

 

i have just bought a 95 tt with a big single turbo (t4) and its been to tdi in lakeside and it came out with a perfect bill of health

but just yesterday i started it up and drove 100 yards, and once the turbo started spawling up it made a loud bang from under the bonnet and the engine died on me, now it wont start at all, it turns over fine but backfires every 5 seconds or so. the biggest problem is that i live in spain!!!! i had it bought over on a transporter last week and up untill yesterday it ran perfect.

please help with any idears of where to start

thanks chris

Edited by Gaz6002 (see edit history)
Link to comment
Share on other sites

  • Replies 82
  • Created
  • Last Reply

Top Posters In This Topic

What sort of level are you at mechanical wise? The reason I ask is that this will most likely not be a quick easy fix. You might get lucky but it sounds like something has failed quite badly. The loud bang that you heard, could that have been a misfire? If so then that would point towards an ignition problem.

 

Take the intake off of the turbo and make sure the compressor spins free, if all seems good there then...

 

The first thing I would do would be a compression check, just to rule out any major and obvious issues with the engine itself.

 

From there I would be checking the spark of each plug and the fueling.

 

 

Doing the above is fairly straight forward if you know what you are doing but if you have no experience then I would probably suggest to you to get the car towed to a garage.

Link to comment
Share on other sites

Have you tried yours with a boost pipe off Scott? I've seen them at Jurgens not run with it off.

 

Saying that, logic would dictate that it "should".

 

Yeah, I started mine with no boost pipes at all, intercooler completely removed lol.

 

That's when I was trying to figure out what the issue with the turbos was, I started up the car with all the pipes off so that I could watch the turbo.

Link to comment
Share on other sites

If it's in Spain it may be MAF based so blowing a hose would cause huge overfuelling. Also, if it's singled up it's probably running bigger injectors so any cocked up fuelling issue is magnified. My money is on a popped hose as well.

 

The fact that it's a single was where my uncertainty was lying regarding the car idling.

 

I didn't think it would overfuel massively at idle/start though as the turbos surely put more of a strain on the intake draw than what not having a turbo would?

Link to comment
Share on other sites

I'm not quite sure what you mean about the 'turbos putting strain on the intake draw'?

 

If it's MAF, the sensor is up by the air filter, pre turbo. Popping an intake hose is going to be post turbo. So the engine draws in unmetered air when trying to start or idle, and the MAF sits there saying "nope, no air flow at all". Which means I meant to say "underfuels massively" and didn't quite think it through, but the not-starting result is the same :D

Link to comment
Share on other sites

This is what I'm thinking ronttuk & Scott M. If it has adjustable pulleys, one might have slipped just enough to upset things. Backfiring is most easily caused by poor ignition timing and has only got to be a tiny bit out to really cause havoc.

 

The hose blow off scenario is just as likely though, if not more so.

 

I think he's done a runner so we may never find out. :(

Edited by Morpheus
Forgot how to multi-quote and it didn't work! (see edit history)
Link to comment
Share on other sites

i had similar sitaution, in fairlady Z TT,

 

driving down the road, bang and pop and backfiring, then died and woudnt start.

 

it was the crank angle sensor, the wire had simply come off it.

 

 

check all connectors are secure, on everything. (dont know if or where there crank angle sensor would be on supra)

Link to comment
Share on other sites

i had similar sitaution, in fairlady Z TT,

 

driving down the road, bang and pop and backfiring, then died and woudnt start.

 

it was the crank angle sensor, the wire had simply come off it.

 

 

check all connectors are secure, on everything. (dont know if or where there crank angle sensor would be on supra)

 

Sounds like a plan. Could be the cam position sensor in this car? Maybe some oil contamination even?

Link to comment
Share on other sites

Guest chris t4

lol im still here, ive only got internet at work sorry boys.

ok its got standard pulleys and a hks head gasket, no oil leaks smoke or noises. ic hoses all on and not split also i cant see any vacume hoses etc off, no plugs have poped off and all the sensors plugged in. the cam belt it self seems like its been rubbing on the back edge!! but i havent checked timming yet, the last owner told me it had been done not long ago! the only odd thing i could see is the idle control valve on the inlet has no pipe on it, ive looked everywhere but there is no sign of ever being one on it. ill check the turbo but the turbo is brand new (ap70 t4) what ever that is. so should i start with the maf then and should i put it on the diagnostic

thanks for all the responses

Link to comment
Share on other sites

Guest chris t4

i forgot to mention, i think the copression would be ok because its running standard boost and hks headgasket so there really isnt much strain on the internals, its prob only running 400 bhp so not piston killing power lol im deff thinking more of a sensor issue

Link to comment
Share on other sites

I'm not quite sure what you mean about the 'turbos putting strain on the intake draw'?

 

If it's MAF, the sensor is up by the air filter, pre turbo. Popping an intake hose is going to be post turbo. So the engine draws in unmetered air when trying to start or idle, and the MAF sits there saying "nope, no air flow at all". Which means I meant to say "underfuels massively" and didn't quite think it through, but the not-starting result is the same :D

 

It's hard to explain as I don't know all the technical jargon relating to cars, I know what I mean in my head though :D

 

I understand what you mean by if it's on a MAF, I would be surprised if it hadn't been converted to MAP at the same time as going single though... what with an ECU running the bigger injectors etc. I was taking the 2 points from you as seperate so I bypassed the MAF point without mentioning it, sorry for the confusion.

 

To try and clarify where i was coming from....

 

Obviously in an N/A you get a negative pressure at the manifold due to the engine trying to pull the air into it. Not that many people do it but you can see this from a vacuum gauge. On a turbo engine exactly the same can be said at idle, just thinking about it I assumed that was because the exhaust flow wasn't high enough to spin the turbo to the level required to even atain atmospheric. With the throttle wide open enough flow is given to see round about zero (atmospheric) so from that I assumed that with a pipe off... it would still idle just the same and even if it wouldn't, you would still be able to start it by giving it a little bit of throttle.

 

As I say, that's in my head though (as that's where I tend to live most of the time :D ) so it could be wholy inaccurate but I just don't see how the car won't start with a pipe gone, other than if MAF related of course.

Link to comment
Share on other sites

lol im still here, ive only got internet at work sorry boys.

ok its got standard pulleys and a hks head gasket, no oil leaks smoke or noises. ic hoses all on and not split also i cant see any vacume hoses etc off, no plugs have poped off and all the sensors plugged in. the cam belt it self seems like its been rubbing on the back edge!! but i havent checked timming yet, the last owner told me it had been done not long ago! the only odd thing i could see is the idle control valve on the inlet has no pipe on it, ive looked everywhere but there is no sign of ever being one on it. ill check the turbo but the turbo is brand new (ap70 t4) what ever that is. so should i start with the maf then and should i put it on the diagnostic

thanks for all the responses

 

dont worry about the idle control valve, you can just put a filter on it.

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.

Guest
Reply to this topic...

×   Pasted as rich text.   Restore formatting

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...

Important Information

We have placed cookies on your device to help make this website better. You can adjust your cookie settings, otherwise we'll assume you're okay to continue. You might also be interested in our Guidelines, Privacy Policy and Terms of Use.