General GT28 Turbo

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General GT28 Turbo

Liquid Knight

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So I'm dipping my toe in the Punto pool again or diving right in without looking to be more accurate.

Thanks to the Punto GT owners page on Facebook I bought this...

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...I like to think of the car as a bit of a (very) rough diamond.

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I'm not a fan of pod filters but the car is fitted with a recently rebuilt (I have the receipt) GT28 turbo from a Mitsubishi GTO, front mounted intercooler, new brakes up front and a lot of "potential".

She drove home okay but the first thing that had to go was the straight through pipe and motorbike can exhaust. Three reasons. First the car sounded like the percussion sections of an orchestra playing inside a tank and second the engine kept cutting out a trying to stall at slow speeds. The car wouldn't idle below 1,750rpm. Finally I had to slow for a horse on the road and it was completely humiliating. No matter what I did the bloody car would not shut up. Perfect for someone who leaves for work at 05:00 some mornings h?

The plan was to fit the cat' from my Bravo but whoever did the down pipe...

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...used black silicone to stick it to the rest...

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...a pigeon to crap on the bits of pipe instead of welding it...

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...and "measure five times cut once" made it clear the drive shaft eventually.

With a classic twin round pipe box selected and the middle box from the Bravo...

Oh, yes I didn't fit the cat' as the flexi-pipe was on the exhaust not the down pipe so when I make a new one of those I'll have to cut the flexi out then and do both jobs at the same time.

...and set of Ink blue painted Coupe 20V 16's the car is already taking shape...

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...so much so that some waster of Oxygen tried to take my wheels the other night resulting in a bit of a mishap.

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The car was perfect on the way to work but when I left it felt like a wheel weight had been dislodged, then it felt and sounded like the wheel bearing was shot. I slowed down to 20mph just as the wheel came off.

The wing wasn't badly bent out of shape and took a little convincing with a hammer but it doesn't look any worse than it did before.

So that's about it.

Not quite...

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...silicone exhaust and cable tie front mount. :bang:

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At least I've mounted my Maserati Shamal horn properly.

So what are my plans?

The car is at a point where it could be a good road project or strip it out and hit the track.

The GT28 is a bit Jekyll and Hyde, nothing happens before you get to 4,000rpm and seventeen PSI kicks all the way to red. Ideal for pottering around the village and economy but a bit all or nothing for "B" roads.
 
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Shopping list.

Wings
Sills
Floor sections leading up to the sills (DIY)

Original headlights, those Halo things look gash.

Down pipe that doesn't look like it was made underwater in the 16th Century.

Suspension that suspends the car. Coil overs are all well and good but...

Exhaust that might pass an MOT in this country.

Bumpers, mirrors, spoiler all matching.

Wheels and tyres. The 16's are nice but the 205-40 profile tyres are crap on Norfolk's roads.

Paint

Interior redress or rip out?
 
woa woa woa, just a minute

someone tried to steal your wheels and left one bolt in?

is that welded driveshaft?

All the bolts on the passenger side were cracked. The front came loose and off the rear didn't. All wheels were done up tight the day before. I'm not 100% it was an attempted theft. There have been several cars with wheel nuts and bolts cracked recently. Mostly 4x4 and posh stuff. A Land Rover threw a wheel last week and the owner was mugged at the road side.

The drive shaft is original apart from the scuff mark where the down pipe was fouling it.
 
At the parts ordering stage. As soon as I collect my Spider I can take the Punto apart and take care of a few dozen issues.

The Punto GT owners page on Facebook has found me a pair of very good wings for the price of a new one. Just need to go to Birmingham to collect them. Another set of Coupe 20V wheels to slap track day rubber on.

I have a pair of bumpers ready for me to collect, shocks and lowered springs instead of the grounded coil overs and new headlights and mirrors are in the post. :)

Just need some sheet metal to make the floor up to the sills. It's always like peeling an onion when you do a sill repair. I do have metal ready for it but you never know if it's enough until you have made the car unsafe to get some more.

A sheet of metal to fill the knackered sunroof hole. Then I only need to work out how much paint I'll need and I'll be ready for a fun weekend. :)
 
When I fitted the headlights I moved the air filter and the MAF came off. I put it all back together and half way to the shop it started spluttering and was gutless. Stalling every time I stopped. I thought the MAF picked up a bit of dust or the plug worked loose when it moved. Checked it, cleaned the terminals, put it back and it made no difference. The car was lumpy, wouldn't run unless I pumped the throttle and the rev' counter was stuck on 2,000rpm.

Got the car home and fitted the spare throttle position sensor and MAF sensor that came with the car, started unplugging everything to clean terminals and followed wired and pipes from end to end to make sure nothing was snagged or split.

Nothing worked and it got progressively worse.

Black sooty smoke from the tail pipe (rich) but then white smoke started coming from the back of the engine.

Cracked turbo?

I'll have a proper look in the morning. She could be scrap by the afternoon. :bang: :cry:
 
oh dear, started reading this thinking that poor little punto - so good its being rescued. But it is not going well is it lol.. How is the shell overall, you hunted for rot yet? no matter what happens it might well be worth saving if its not rusty.

I can't see a cracked turbo doing the smoke thing, well not black sooty smoke anyway. If anything you would get the blue oil smoke and/or troubles under a bit of load. Most turbo problems it would most likely still idle. I guess if the turbo completely locked up it might not idle.

So hard to say without seeing it, check plugs and see how they look and do compression test i think is where i would start.
 
oh dear, started reading this thinking that poor little punto - so good its being rescued. But it is not going well is it lol.. How is the shell overall, you hunted for rot yet? no matter what happens it might well be worth saving if its not rusty.

I can't see a cracked turbo doing the smoke thing, well not black sooty smoke anyway. If anything you would get the blue oil smoke and/or troubles under a bit of load. Most turbo problems it would most likely still idle. I guess if the turbo completely locked up it might not idle.

So hard to say without seeing it, check plugs and see how they look and do compression test i think is where i would start.

The sills have been bent out of shape by a jack on both sides. Parts have come away from the floor so when I cut the sills off I'll have to rebuild the floor leading up to it.

Wasn't a cracked hot side of the turbo. Turns out I found out with today's update.

Having eliminated an electrical or sensor issue I spent this morning chasing mechanical issues.

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I knew the exhaust manifold had a sheered bolt to the turbo so this...

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...was expected. I popped the manifold off to see if the stud could be extracted or drilled out only to find the manifold was cracked as well.

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It can be repaired but anyone who has ever welded cast iron before will tell you it weakens the metal around it, the weld expands and contracts at a different rate causing more crack. As the manifold is now basically scrap I turned my attention to the down pipe...

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...and quickly mocked something together...

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...for when I can get hold of a new/replacement manifold. ;)
 
i know of alot that have been repaired.. but i don't really know how long they have lasted. For the cost of replacing with tubular I would give it a go myself, worst that can happen is it cracks again.

edit: to be fair, my old turbo converted seicento just had a stock cast manifold with the end chopped off and a turbo flange welded on which if anything would be weaker than just repairing a crack. That did over 40k miles and is still ok - now been replaced with a ramhorn style tubular one but it had no crack or anything. Certainly worth a repair imo
 
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Okay two hours. ;)

Re-studded, crack welded, all put back together, up and running.

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Good news, the exhaust does not leak at all, anywhere and sounds pretty good. No more smoke from inside the engine bay.

Bad news, the old girl is still coughing, spluttering and if you don't pump the throttle the car barely crawls. Hit 3000rpm and she takes off as if nothing is wrong (unguided missile). Change above 3,000rpm and she pulls like a train but drop below and she bogs down again.

It's as if the car had a carb' and the slow running jet was knackered.

Hmmmm....
 
Interesting... injector(s) sticking open a bit maybe, so massively over fuelling when not on boost?
I'm making wild stabs in the dark I know. Can't think of a reason for it currently

Your ideas are as good as mine.

Pressurised the air system to check for leaks. Nope.

The clips that held the pipe from the MAF to the turbo were knackered (over tightened and no longer gripping) so they have been replaced.

The plugs are nearly new but I cleaned them anyway.

So, it's not a sensor issue, not a mechanical issue, not an air loss issue, not the pugs.

ECU?

:bang:

Visually inspected the ECU and there are no obvious issues, no burned out components, no dry looking terminals and no odd smells. I put it back and it has made no difference at all so I can pretty much rule that out.

I'll have to check the injectors next. Shame I sold the ones from the Fiat Coupe donor.

If not the car will be off to the scrap heap as soon as my Alfa arrives.
 
well all i can think of is injectors, maybe the coil? Or even just a broken/damaged wire somewhere. Certainly sounds like an annoying issue to track down. Always sad to see another one go to scrap but i see where your coming from. Whats the going rate for a scrap car these days, i hear its a bit crap atm. If i had the tools and skills to sort the body out i would be seriously tempted to make an offer. Sadly for me to buy such a car it pretty much needs to be a mint shell with mechanical issues - that i can fix but i cannot afford to pay someone to fix bodywork and paint for me :shrug: I guess i should buy a welder and start learning lol
 
I pulled the injectors and turned the engine over to make sure all four were working and squirting the same amount of fuel. This cured it for a while. I drove into the village. Stopped and when I came back it ran rough as ever again.

The only thing that's left is the Lambda sensor. £57 for a new one next week or see if the one from the donor Fiat Coupe fits.
 
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