nb with hesitation under load

StanTheMan · Postby **StanTheMan** » Mon Sep 19, 2022 9:06 pm

in m y case with a BP4W conversion on a NA6 chassis been wiring of either
COPS wired upon for a NA6 chassis
Dodgy COPS
Crank angle sensor itself

that's it

twice its been the Crank position sensor where the wiring got damaged by the timing belt... because=e I had not secured it correctly

hamx5ter · Postby **hamx5ter** » Wed Sep 21, 2022 8:20 pm

well, i drove the car today and the hesitation is definitely gone... so it WAS the AFM

@greenmachine - that's a bit hard-core tearing up a perfectly nice AFM for curiosity. Remind us not to leave you unattended at home! Although i didn't expect to see such a big circuit board

Anyway, did the pink slip, car's fine, hesitation gone... hoping to do some more driving and kinda keen to do a camshaft + ecu at some point. The rest of the car is quite nice, except for the utterly gutless engine. Will have to go read the forums again

StanTheMan · Postby **StanTheMan** » Wed Sep 21, 2022 9:51 pm

where are you thinking of going with your cams ?

greenMachine · Postby **greenMachine** » Wed Sep 21, 2022 11:49 pm

hamx5ter wrote: that's a bit hard-core tearing up a perfectly nice AFM for curiosity. Remind us not to leave you unattended at home! Although i didn't expect to see such a big circuit board

For science! It will form the basis of my PhD thesis, so it has been sacrificed in a truly noble cause, in fact it was screaming out from the shelf 'pick me, pick me'!

Well when you invite me around (Australia Post seems to have misplaced the invitation :roll:

, better send another), you had better not leave me in the garage :wink:

hamx5ter · Postby **hamx5ter** » Thu Sep 22, 2022 3:41 pm

Well I haven't been in the track years now... Probably last in 2018/19 .. now Wakefield is closed too and so options are really just Marulan and SMPS.

I'd like to stay naturally aspirated, but quite aggressive cams for fast road / track... But not race.

I know nothing about the cam profiles, lift etc so I'll have to read the various threads on the cams as well as what ECU to go for.

StanTheMan · Postby **StanTheMan** » Thu Sep 22, 2022 7:08 pm

start a new thread & I'll start talking of my experience

ive had 3 different sets ..... alll a little different

hamx5ter · Postby **hamx5ter** » Thu Sep 22, 2022 7:35 pm

lol... i will. I'll just read up what's on already and then start a thread with my travails.... i mean travels...

Nevyn72 · Postby **Nevyn72** » Fri Sep 23, 2022 9:53 am

hamx5ter wrote:Well I haven't been in the track years now... Probably last in 2018/19 .. now Wakefield is closed too and so options are really just Marulan and SMPS.

Don't forget Luddenham, I haven't been there but the boys from MCM use it as their default track these days...

https://luddenhamraceway.com/

hamx5ter · Postby **hamx5ter** » Wed Jan 25, 2023 7:37 pm

Well, i'm back!!

After my drive up Putty turned to poop i went and purchased a Panasonic AGM battery from Mania on Monday... Battery holder bolt was stripped so it was back to Mania for a $6.50 Mazda replacement bolt and fitted the battery.

Cranked it but it spluttered and died. Doh! Remembered that the car was surely out of fuel by the time i drove into the carport (and then the wall)... put in 10 litres of fuel, cranked and the engine misfired and make clunking backfiring noises when it died!! tried cranking a couple of times and it still wouldn't run with or without throttle, just choke and die. On one try it died with a clunk and there was some smoke coming from under the bonnet. Popped the bonnet; nothing on fire but i thought i saw some smoke coming out of the cold air intake?? :oops:

https://photos.app.goo.gl/u5YuckqnGb36aPEp7

Unplugged the maf, tried again and it started up and ran but the engine sounded rattly and LOUD. Miscellaneous whine and quite rattly. Definitely didn't sound healthy. Apologies for the revving. I didn't think it was actually going to ever catch. I think there's also a leak in the exhaust manifold.... could it be the reason and / rather than the MAF? That said, it ran and idled without the MAF. When i plugged it back in, it wouldn't start up again...

https://photos.app.goo.gl/ubrqo2427uoNjUAw5

Of course, the previous times i drove it i thought the intake sounded loud and now i can see that there was smoke coming out of the engine bay!! that's got to be the exhaust.... wonder if it is broken or if it has just come loose. Although when the engine was actually running, i didn't see smoke pouring out the manifold... The smoke is from loose / cracked header? That whine could be intake whistle (or something worse??)!!

How weird that it ran out of fuel (my fault kinda), battery died (had to happen at some time) AND the MAF played up at the same time. Can they be related? It was running perfectly (apart from me thinking that the exhaust is louder than usual) until it all went to poop

I'll give my mech a call Friday and see if he can have a look at this. I was hoping to do the club trackday in Marulan in mid Feb :cry:

Wish GM hadn't smashed a perfectly good MAF... :cry:

93_Clubman · Postby **93_Clubman** » Thu Jan 26, 2023 12:43 am

hamx5ter wrote:On one try it died with a clunk and there was some smoke coming from under the bonnet. Popped the bonnet; nothing on fire but i thought i saw some smoke coming out of the cold air intake??

...think there's also a leak in the exhaust manifold... could it be the reason and / rather than the MAF? That said, it ran and idled without the MAF. When i plugged it back in, it wouldn't start up again...

Of course, the previous times i drove it i thought the intake sounded loud and now i can see that there was smoke coming out of the engine bay!! that's got to be the exhaust... Although when the engine was actually running, i didn't see smoke pouring out the manifold... The smoke is from loose / cracked header?

Some initial thoughts:
Starting issues can result in a bit of smoke from the end of the CAI.

Are you running a factory ECU only, as my understanding is NA & NB won't start with AFM/MAF unplugged, something's not right if yours is starting with it unplugged. On the NA6 at least if the AFM is unplugged the fuel is cut as a safety mechanism in the case of an accident, ie if AFM doesn't send a signal to the ECU that it's detecting the movement of air then fuel isn't supplied.

Don't think the exhaust manifold leak should be causing major issues.

Not easy with the car idling high, but for a start I'd be trying to confirm the ignition timing is correct as well as identifying why it's starting with MAF disconnected.

hamx5ter · Postby **hamx5ter** » Thu Jan 26, 2023 9:46 am

Nope the engine and ECU are completely stock.

That's weird that it started then. I didn't try starting it once i plugged the MAF because it just went back to choking and dying like it did before. There was no starting or any other issues until last Sunday. I just find it curious that those issues started right with the battery dying.

I'll have a chat with the mechanic on Friday and see if he has any idea.

93_Clubman · Postby **93_Clubman** » Thu Jan 26, 2023 10:38 am

Factory ECU - has it ever got wet? If you've the time before tomorrow it might be worth removing it from the p side footwell & opening it up for a visual inspection of the PCB for moisture, scortch marks or component leakage which damages the tracks - not that the NB ECU are known for this, but something's not right & it would seem to involve the ECU, possibly amongst other things.

hamx5ter · Postby **hamx5ter** » Thu Jan 26, 2023 11:08 am

Is it possible that the battery dying could have fried the ECU somehow?

I might not get the time this evening (maybe i can) to pull the ECU out. I'll see how i go.

bruce · Postby **bruce** » Thu Jan 26, 2023 11:49 am

Possibly. They always say to be careful when jump starting a car, so a faulty battery could cause problems.

Nevyn72 · Postby **Nevyn72** » Thu Jan 26, 2023 1:51 pm

hamx5ter wrote:Nope the engine and ECU are completely stock.

That's weird that it started then. I didn't try starting it once i plugged the MAF because it just went back to choking and dying like it did before. There was no starting or any other issues until last Sunday. I just find it curious that those issues started right with the battery dying.

I'll have a chat with the mechanic on Friday and see if he has any idea.

MAF plugged in and it doesn't run
MAF unplugged and it runs (albeit badly) when it shouldn't

Sounds like there may be a short in the wiring from the MAF so the ECU thinks it's there when unplugged but gives it unhappy values, hence the rough running. Plug it back in and the short plus other values means it doesn't run at all...

Would you say the problem has remained unchanged or become progressively worse?
Thinking a progressing wire fault may be to blame.

Here ends the rampant speculation.