Losing power.... continuously.... back in the game!!
Turbo Mini Forums

Hi Roy,

Thanks for the reply. I have only just seen this as I know u posted it a while back... got p'eed off with it and have been busy doing other stuff. I'll look at this tomorrow as I've just found my mojo again and decided to look at it over the next few days...

Thanks...

The symptoms you describe are exactly as mine are...

👍

Couldn't wait til tomorrow after re-reading that.. was hoping it would be loose. But it wasn't, tight as fook I'm afraid!!

So checked battery and all connections... all seems good.

Took it out for a spin tonight, the first time in weeks as I've simply been too busy for it. Also, for the first spin since I've installed a wideband too. Lo and behold same problem... well, it would have been a miracle if it had fixed itself!!

The wideband readings seem pretty normal according to my brother-in-law, he's convinced it's not fuel and more of an air issue. There seems to be some unusual hissing of air at times as if there is a leak in my system somewhere? I need to have a good inspection of all the piping.. maybe I disturbed something when I had the manifold off searching for something else (that turned out to be a kinked return fuel line).

Something else happened though... one of the front callipers seized and we couldn't get it to free up. In the end we slacked off the nipple whilst applying 'levered' pressure to the pad and it freed it eventually.
The car then started again, 15-20 mins later and managed to drive it home.

What d'ya think would be the main cause of the seizure? Dodgy seals around pistons in callipers? Grit or shite in calliper? Infrequent use? Or simply.... just my luck?

Edited by evad1980 on 17th Aug, 2017.

if its a single calliper, I'd normally assume its either calliper or the hose feeding it that has collapsed.

Given you mention it eventually released after the bleed nipple was opened would suggest to me its the calliper. If it had been the hose, the pistons should have returned easily with the bleed nipple open.

As for an air noise, may be worth checking the dump valve is not sticking open a little.

So what would you do to remedy the calliper if it is that..?

Dump valve actually looks ok and moves ok.. I'll still investigate it further.

strip it down and see. were they new/recon ones or used?

They were used, bought off someone on here..

Are you still running a dizzy and coil?

Running MJ..

It's both, still power loss and then a seized brake to add insult to injury 😂

Your problems appear to be heat related. Even with a heat shield I had heat soak fuel problems until I heat wrapped the exhaust and added an ERA style bonnet vent. Although I didn't have a brake issue at the time I wasn't happy with how hot the master cylinders were and added a heat shield between them and the turbo. Do you have a temperature input on MJ that changes the configuration?

Yes I'm sure it does have the temp input but must check it out.. when I checked this problem out before, I don't remember the master cylinder being hot. It may just be a coincidence with a sticking calliper...

Hello again...

After a break from the mini doing other shite I'm back...

Have the same problem with the mini, unfortunately it didn't rectify itself parked up in the garage...

Been doing plenty of searching on here in the background and re-read this whole post. I'm going to go through one item at a time until its rectified... and taking the advise of others.... methodically.

Just been out and pulled the plugs, and this is what I've found..



With a light scrape of a screwdriver in each bore, there is a deposit on each piston like this..



So it would seem I have 'wet or dry fouling'...

Possible Causes: "Depending on whether the spark plug is coated in oil or fuel, wet fouling can be symptomatic of a compromised head gasket, poor control from your pistons’ oil control ring, valvetrain problems, or an extremely rich condition. Dry fouling, or carbon fouling, is often caused by an overly rich condition, and the problem may lie with your air cleaner (clogged) or carburetor. Other possible causes could be low compression, vacuum leak, overly retarded timing, or improper spark plug heat range"

The plugs are NGK BPR7ES's and reading back it would seem 6's are preferred.

I've not interfered with the mixture since the rolling road but I have had the carb and manifold off.

What do you think about these?

Edited by evad1980 on 13th Oct, 2017.

Although, thinking about it....

When I have been starting it, its been with the choke and only going local/round the block.. so surely you'd expect them to be sooty.. not driving long enough to clear the soot?

Those plugs can wet very easily if things are not running right which would make the motor run awful. Until the problem is solved I would use some 6's, they are more forgiving.
I hope the valve guides are not nipping up when it gets warm, which may be an explanation.

I hope the valve guides are not nipping up when it gets warm, which may be an explanation. [/quote]

I hope that too!

I will get some 6's in the meantime...

Also, just whipped off the dump valve and found it to be a little stiff when pushing in.
Took it apart for a clean up and found the seal on the piston very loose.. i.e. too big for the piston. I can get it back on but it doesn't feel right... doesn't push up and down nicely. feels a bit shitty if being honest...

If the valve was sticking open this could cause my problems, I'm getting lots of hissing when the problem comes on.

So this is my theory... if the dump valve is sticking..

1. The dump valve should be closed with the accelerator pressed.
2. If sticking open then the boost pressure is lost and the carb is effectively normally aspirated.
3. Carb has been set up for boost pressure so therefore now has fook all air getting in.
4. Mixture is now extremely rich hence black plugs.
5. Car is bogging down when pressing accelerator and unable to drive but, is fine on tick over.

6. Am I talking utter shite or is it a possibility??

Hey.. just stepping through the steps of TurboDaves 'tee piece trick' post. It would seem that I have all the steps covered and all seems to be as written by Dave.
Took the plenum off just to check I had the right gasket (I knew it was but had to check visually to be sure, for the purposes of elimination)...



Everything is blanked off except this outlet..



Can anyone tell me what that is for?

Also, is my previous post utter poo poo regarding a sticking dump valve (if it is sticking)??

I have an AFR installed now and a temporary rigged up fuel pressure gauge that can be pulled into the cabin when going for a drive. Cant drive it just yet as I have one of the brake callipers off at the moment and need to get a new seal for the dump valve. I'll take a video of all the gauges when I'm able to drive it next and post it here... but for the moment, any help with these questions would be great.

Thanks..

Thats the dizzy vacuum advance. I'd block that off too.


Also, can you blank the dump valve temporarily to eradicate that lead completely, just don't slam the throttle shut!

Ok so getting closer..

I found one of the intercooler pipes to have moved inside one of the silicone bends, wasn't all the way out but had somehow moved past the jubilee clip. This has now been rectified and has made somewhat of a difference... car is much more drivable now but far from perfect. Still bogs down when you give it some boot but if you ease off and 'feather' the accelerator its quite drivable. I have also changed plugs from ngk 7's to 6's as recommended. Pulled one out after the drive for a look and it looked pretty decent, a bit sooty but nothing like the pics above in a previous post. Drove the car locally continuously for more than 20 mins and not once did it break down like before, completely unable to drive. I have re-set the fuel pressure at 5 psi at idle with the help of a different fuel pressure gauge and have also removed the dump valve and blanked off the outlet.. I still have the bogging down problem with the dv removed. My AFR reads between 11-15 whilst driving.

Before, it really did feel like an air issue... hissing and all the like coming from the bonnet.. unable to boost..

Since I tightened all the intercooler pipe work it now feels like a fuel issue...feels able to boost. I have not messed with the mixture at all and the oil is present in the dashpot..

I have the MJ vacuum fed from manifold 'teed' to the dump valve.

Where should I look next folks...?

I wouldn't T the megajolt to anything. Just have it separate vacuum off the manifold.