project Saved Mazda 323

[DoctorRetro]

Just to update this thread, I'm still working on this, currently making a gasket for the carburettor. 

I'll keep plodding on, and posting updates on here, but I'm definitely getting impatient with my inability to sort it. 

[sutty2006]

Keep on it lad. Could be worse, it could be a £100 2008 Vauxhall corsa. 

[egg]

[strangeangel]

1 hour ago, TheDoctor said:

I'm definitely getting impatient with my inability to sort it. 

 

 

This looks like steady progress to me - you're doing a grand job.

[DoctorRetro]

Just using this thread to upload this pic

 

[DoctorRetro]

For anyone following this, the car is now being transferred to @BlankFrank to take over.

Hopefully this will continue to improve and be an AS regular... 

[Kiltox]

Does that mean the 416 is incoming? 

[DoctorRetro]

8 minutes ago, Kiltox said:

Does that mean the 416 is incoming? 

I doubt it. Remember I owe money on the Mazda still... 

[sutty2006]

One down...... errrrrr ...... 

[Wingz123]

I'm due in for a checkup with the quack on Saturday morning...

[DoctorRetro]

15 minutes ago, Wingz123 said:

I'm due in for a checkup with the quack on Saturday morning...

Oi, I'll have you know my Gallifreyan certificate is legitimate. ?

[DoctorRetro]

[BlankFrank]

It has arrived! Cheers Doc and Wingz. 

Might make a new topic when i make some progress on it, or i'll just update this one as it's already the go-to topic for this car. Anyone can feel free to chime in with their thoughts on whether a new topic would be better or not, also any troubleshooting/diagnostic suggestions are appreciated.

First thing i'm going to do is chuck a wideband 02 sensor on it and see what the AFRs are like. Only time that wideband was used was on another Mazda my mate used to own (a ragged-to-piss mx5). Then do the coolant leak and belt squeak, then get to the main issue of carb + general running borkery.

Might pressure wash the oil off of the engine too.

[Wingz123]

Reading > Southend, Essex > Stokenchurch > Reading - Home for 8.50am

[95 quid Peugeot]

5 minutes ago, Wingz123 said:

Reading > Southend, Essex > Stokenchurch > Reading - Home for 8.50am

Top collection/delivery again Wingz 

 

[DoctorRetro]

The coolant leak is a really simple fix, was my fault when changing the alternator. 

Just to warn you, the bolts on the alternator are a pig to get to... 

I do have a rocker cover gasket, will post as soon as I find it... 

[BlankFrank]

Cheers, much appreciated if you do find the rocker cover gasket.

How long the engine has been running with the coolant leak? Just trying to gauge the likelihood of any possible overheat damage. Also, is it just tap water in the coolant system? Will probably replace the coolant with antifreeze before winter just in case.

[busmansholiday]

1 hour ago, BlankFrank said:

 

Might pressure wash the oil off of the engine too.

 

Be careful, I did that some years ago to a Triumph Acclaim. Wiped out all the electrics, next journey was to the bridge.

[egg]

7 minutes ago, busmansholiday said:

Be careful, I did that some years ago to a Triumph Acclaim. Wiped out all the electrics, next journey was to the bridge.

Cos I don't like risk, I'm more of a fan of degreaser and an old rag...

[DoctorRetro]

3 hours ago, BlankFrank said:

Cheers, much appreciated if you do find the rocker cover gasket.

How long the engine has been running with the coolant leak? Just trying to gauge the likelihood of any possible overheat damage. Also, is it just tap water in the coolant system? Will probably replace the coolant with antifreeze before winter just in case.

It has never been run low on coolant, the header tank dropped maybe 1cm in the time I've had it, don't worry. As for what is in there, I don't know. 

It is the heater pipe behind the manifold that is the leaky one. I was trying to gently persuade the alternator out past it and I squished it with the grips. Needs the rubber pipe disconnecting and the metal bit made roughly round again and it will be fine. 

[MrDuke]

Pressure washing should be fine, as long as you properly wrap all the wiry bits with carrier bags & duck tape, and keep the jet away from them. On 80s tin, there's probably only 3 or 4 places to bag anyway.

[BlankFrank]

Cheers for the responses guys. Wall of text incoming:

Done a little bit of fiddling before putting the wideband sensor in, at cold idle it seems to only be sitting at around 550-700 rpm and doesn't idle steadily but if i hold it at around 1100+ rpm it seems to idle pretty well (with a little bit of stumbling, hopefully just caused by it running very rich). That gives me the impression that the cold start idle air needs tweaking, gonna leave it like that for now until i get WOT bogging sorted as i'd like to see it at full power, a can tolerate a funky idle on cold start but i really want to see it working at full power first so i know the engine isn't perma-borked.

Haven't got it up to temp yet because the belt squeal is so bad that smoke was pissing out from the belt/pullys and i nearly burnt my hand on the damn thing from the friction alone. Didn't want to run it too long with no water pump spinning. Loosened the alternator and took the belt off to make sure the alt and water pump aren't siezed/grindy and left it off to shut it up. Belt squeal/slippage is next on the agenda.

Chucked an old boost gauge on to use as a rudimentary vacuum gauge and it seems to have good enough vac so i'm not super worried yet. Gonna do a plugs-out throttle open compression test sometime soon rather than relying on the plugs-in compression reading 'cos if there's a break in the head gasket between cylinders then leaving plugs in could mask that, plugs out would mean the compression would escape into the neighboring cylinder and then out to atmosphere via the plug-'oles and show up as low compression on the gauge.

Not sure if the vacuum secondary is working as i've not driven it on the road, will probably jack it up with the front wheels in the air and use the brakes to simulate load while doing a WOT run in 4th to see if the secondary is working.

This is my first time messing with a carburetted car based on less than 2 days of learning/research so if there's anything that i'm explaining/doing wrong or anything i'm missing then anyone please correct me. Some of you guys have been dealing with carbied cars for longer than i've existed so i'm gonna respect that.

 

Edit: Just gonna add, thank you very much Doc for the work you've done on it before me, saved me some time and parts costs.

[DoctorRetro]

Well, you already sound like you know more of what you're doing than I do, so that's a good start. 

There is a slim possibility the new alternator has an iffy pulley, as it didn't squeal before the change. The old one is in the boot, in case you need to make one good one out of two (if that is even possible)

Glad you are getting stuck in, I have faith in you ?

[vulgalour]

Watching with interest on this one, it'll be good to find out what the running issue/s actually turn out to be.

[BlankFrank]

Was wondering if the belt squeak was there before the alt change, cheers for the headsup, it's probably the alternator as i can hear a very slight squeak when turning it by hand (water pump has not even a slight squeak so that's good nooz).

I couldn't trust my crappy cheap boost gauge to give a reliable vac reading so i tried out a proper vacuum gauge, granted it's attached to a hand vacuum pump for bleeding brakes but it's got a much finer granularity in the dial reading and is designed for pure vacuum and also reads in inHg which helps simplify diag.

Results:

....Bums.

From what i gather, the fluctuation could mean 1 or more cylinders or valves aren't sealing properly but the high speed of the fluctuation apparently indicates worn valve guides/stem seals, could be worse. Not gonna think of anything conclusively as i'm not trusting my current level of knowledge as gospel. However vacuum seems on the low side overall. Will get the borescope and compression tester out tomorrow and take a look in the cylinders in case there's any surprises, might get my housemate to blow smoke/vape through a vac line via a leccy tyre pump when the engines off as a sort of ghetto vac leak smoke tester.

I did the above vac test at about 1 in the morning so i didn't want to do any throttle blips or anything over 1800rpm to keep the noise down so i've got that to do tomorrow (along with checking cranking vacuum).

Stuck this on the arse-end of the car so i didn't get gassed out by the thing sitting in my garage.

 

[BlankFrank]

So the latest news, to sum it up: still buggered but making some progress.

When the revs are held above 1000rpm it smooths out a bit (as you guys saw in one of The Doctors previous videos) but as you can see from my video below the car isn't running rich so the roughness is probably not currently caused by over-fueling like we initially thought. It'll run at around 11:1 or 12:1 AFR which is good to see, but when misfiring it'll totally lean out for that split second.

I've got an idea that the rough running/misfiring is caused by the intake manifold gasket leaking between the coolant passages and intake ports causing coolant to get sucked into the engine, this would fit the symptoms because the fueling seems fine, the ignition (as far as i can tell so far) seems fine and the compression is fine too, yet it's still running rough despite all of the signs pointing to it being healthy. Also the coolant doesn't seem to build pressure like a normal car, it only seemed to build pressure when ragged rather than building pressure as soon as the thermostat opened.

Next thing i'm going to do will be getting the intake manifold off and taking a look at the gasket. Will probably slap some RTV on it as a temp replacement for the manifold gasket and re-assemble while waiting for a new gasket to arrive. It could also be leaking coolant into the engine via a crack or porosity in the intake manifold between coolant channels and intake port. I doubt the block or head are cracked because i would assume that would show on the compression test.

General progress/info:

-Alternator is fine, tightened the belt and all is well with the water pump, alt and power steering pump.

-Coolant leak from matrix mostly fixed, still weeps a little but that can wait until the car runs right.

-Did a plugs out compression test, seems basically the same as Docs readings (150, 160, 150, 150, engine slightly warm).

-Messing with the idle mixture screw doesn't seem to do anything about the misfire.

-There was a single red vac line causing a vacuum leak, plugged it, now there are no vacuum leaks on the engine so that's basically ruled out (only did a lung-strength pressure test, didn't use a compressor for fear of blowing out the gaskets).

-Cleaned the plugs a little, no change.

-Fiddled with ignition timing, no improvement.

-A-Framed it to a friend of my housemates private ground to drive it, definitely doesn't seem to have full 75-ish HP, if i had to guess i'd say its 10 to 30 HP down.

-The black crap coming from the exhaust was probably just carbon from the exhaust mixing with condensation or coolant to create that black muck.

-I took a look in the cylinders with the borescope, bloody scope camera was crap so it was next to useless. I got a better look by just rotating the engine until the pistons were at TDC and looking down the spark plug holes with my own eyes. Couldn't see anything worrying.

-Going to check the cam belt timing, maybe it's off a tooth or two.

-I've got a suspicion that the car was laid up for ages because it developed this fault rather than it developing this fault as a result of not being used. Not sure though.

(excuse the fact a couple of words were muffled, i was holding my phone by the microphone end)

 

As always, any input is appreciated.

Coolant passages indicated in blue, possible gasket breakage indicated in red, intake passages self explanatory.

[DoctorRetro]

It's good to see I actually improved things, as it was definitely running too rich when I got it, and I set it up as best I could. 

There is spare vacuum pipe in the boot if you need it (As well as the Audi 100 Haynes manual Wingz123 wanted, but I forgot to tell him)

[BlankFrank]

Yeah you did a good job with the carb tweaking and rebuild i think, cheers for leaving the parts in the boot too. I noticed the spare vac line and was glad to see it wasn't all used up.

Wingz is welcome to the Audi haynes manual if he's ever in the area and wants to grab it, he bagsy'd it first so it's his as far as i'm concerned.

Edit: Forgot to mention something; fueling is still definitely still on the cards for the cause of the roughness. Simply because the misfire is accompanied with a lean moment on the AFR gauge so it could still be some crap stuck in the fuel system or carb jets.

[Joey spud]

I am well impressed by how you are going about this.

The way it's running seems a bit like the valve timing is off as in the cam belt is a tooth out that would also explain the slightly low compression readings (would of expected nearer 180 psi)

Many years back i did a head gasket change on a carburetor fed twincam Sierra and it ran like a dog after i finished.

It was bogging down at idle and wasn't at all keen to rev cleanly,i even swapped the carb over from another Sierra to see if the original one had got damaged.

It turned out i was a tooth out on the cam chain.

It's got to be worth a quick look.

[BlankFrank]

Cheers

Yep, turns out it was the bloody cam belt timing.

3 teeth out on the cam pulley:

FIXED!

(bit sweary, 'scuse that)

The main issues i've got to fix for it to be roadworthy are the popped spare tyre and bald front one. Gonna take a couple of my spare corsa b wheels to the local part-worn tyre place and get them to stick the tyres on the mazda rims, doneski.

Engine definitely seems to have full power now i think, also didn't get the bogging down like before which is good. 

I've got a feeling that i'm going to have to do a complete diag on the electrical system as the headlights draw a ton of electrical power (engine revs drop from the load on the alternator and stuff starts dimming as mentioned in the original "can we save it" thread) also the washer relay/light goes on and off intermittently without asking. Worse yet when the car is moving my wideband restarts randomly so i'm wondering if there is a short to ground somewhere in the cars wiring loom.  Glad i saved this mess in the shed from an old scrapper vauxhall to re-use if needed haha

Originally i was going to wait until my current insurance policy ended before getting a new one for the mazda next year, i'm paying stupid-money for my insurance already and I thought if i changed car they would double the monthly premium but after getting a quote it turned out to only be half as bad as i was expecting so i'm going to switch over and do the tax within a week or so. Mazda should be back on the road in not-a-lot-of-days.