Alfa Romeo Forum banner

GT jtdm power restored

Tags
restored
2K views 26 replies 9 participants last post by  t3yls 
#1 ·
So, I've owned my GT for about 2 months now, and I love it! Technology is sublime with added mechless stereo, parking sensors & integrated dash cam. She's running an autodelta tuning box and all appeared OK until recently.

There was hesitation through all the gears up to about 2500-3000rpm. Now, I encountered this on my impreza a couple of years ago and it turned out I'd killed the MAF sensor...to the tune of £330 :(

My symptoms pointed at the following potenials...

MAP sensor failed
EGR failure
MAF sensor failed
Turbo actuator hoses split
Turbo actuator failed
Top/bottom hoses split

Turns out this was the problem...



...and this was half way through cleaning!!

My EGR is partially blanked at the moment, but once I have my carbon engine clean, it will be fully blanked, along with a new MAP sensor and a stage 1 remap with EGR delete.

Anyone else encountered a failed MAP sensor before?
 
See less See more
1
#5 ·
When the MAP sensors are this clogged up, its likely the rest of the inlet manifold is similarly clogged. The openings to the inlet runners particularly on the 16v & 20v engines (where there are two small runners instead of one big one) will be significantly restricted. A 2mm deep coating of the black death on the inside of a 1 inch diameter runner means a whole third of its volume is lost. That has a big impact on the engine's volumetric efficiency.
 
#7 ·
As Pud says, if your map looks like that, then you manifold probably looks like this.
Auto part Engine


This was off a 156 with 110k on the clock that I bought as it is a flapless manifold.

Took me a day to clean out, and also makes me wonder if that stuff in a Terraclean actually works and removes some of that crud, would I want that all wafting into my engine.
 
#9 ·
Allow 2-3 hrs if you've not done it before. You don't need to disturb the cambelt as the HP fuel pump pulley can be bolted to the support bracket (it has 2 holes, just for that) thereby keeping the belt in place whilst you remove the pump. Wrangling the vacuum oil separator off the back of the engine is probably the most awkward bit, but it's not too bad once you understand where the 3 mounting bolts are.
 
#11 ·
Petrol, acetone or (less good) brake cleaner, I think, from dealing with what was left after oven cleaner. I used the oven cleaner that comes with a big plastic bag and left it overnight. A big gotcha, however, is that it plated out the carbon onto the manifold alloy, leaving it a sort of matt-brownish-black, so I then had to paint it with VHT silver.

I have a 25L jerry can of petrol contaminated with diesel that my son left here, from a customer's mis-fuelling incident. It's useless for fuel and with hindsight I should have just used that to clean the manifold. Outdoors :)
 
#13 · (Edited)
I have a 25L jerry can of petrol contaminated with diesel that my son left here, from a customer's mis-fuelling incident. It's useless for fuel and with hindsight I should have just used that to clean the manifold. Outdoors :)
Nah it aint useless for fuel - you can stick it in your tank with no probs, whether you use it all in one tank or add 5 or so litres per full tank would depend on how much diesel there is in it, but its still perfectly usable. :)
 
#15 ·
Overnight it didn't take quite all of it off, there was still some in parts of the plastic plenum, but it did make a mess of the alloy.

Far the best solvent I've ever had was a 5L can of acetone I was once given. That had an amazing ability to dissolve anything, and I went on reusing it for ages as it seemed to be able to absorb several times its own volume of oily filth, and still dry off in seconds. But I think that might dissolve the plastic plenum too, given long enough.
 
#14 ·
We don't know. It came out of a misfuelled diesel Mercedes, the owner had no real idea how full the car had been before she filled up. Probably around 20% diesel, 80% petrol. I did use some, heavily diluted about 1 gal in 5 gal of petrol, in my old petrol Renault, that was OK. But that car is now long gone.
 
#19 · (Edited)
I believe that although diesels will happily run on petrol the ethanol destroys HP fuel pump seals and the lack of diesel lubricity trashes the pump and injectors. Some diesel in a petrol car normally does little harm, it's not that different from 2-stroke mix. However, more than a little and it won't run at all, I think it'll just douse the spark.
 
#21 ·
Nah, most diesels have seals that resist ethanol these days and have had for the last 20 years or so. The lack of lubricity wont be an issue with small amounts of petrol, if you were talking about a full tank youd deffo be right though, the pump would be trashed.
 
#22 ·
I've seen a diesel car written off after swarf from the HP pump got into the injectors. That wasn't misfuelling, just a crappy Delphi pump failing after 80k mls. It got piped straight to the common rail and fragments of metal at >1,000 bar don't play nice with the precision pintels and minute nozzles which were totally blocked. The return took masses of metal back to the fuel tank, which is how we figured it out. So I don't think I'll be using this contaminated stuff except perhaps for burning down Parliament or similar, but it's yours if you want it :)
 
#24 ·
Ah, no, the swarf-filled stuff was pure diesel. That went to the scrapyard in the car. A great shame, it was an otherwise immaculate Renault Clio 1.5 DCi. We think Alfa have their idiocies, but eBay is stuffed with various model DCi's with these 'starting issues', and all because Delphi didn't include swarf traps in their chocolate-alloy HP pumps. £2.5k+ in new parts to fix, and nothing from breakers can be trusted because very often that's what killed the car :(
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top