I'm starting to go off turbos!

[blu_s2]

I suspected that I still had a small air leak so this weekend I took the bumper etc. off to have a proper check through.

I found two loose clips (outlet from turbo and the infamous i/c Mark H mod). BTW That now makes three clips that have worked loose since the samco's fitted. I would suggets that after a couple kmiles anyone who has fitted should check the tightness, it *may* be something to do with the silicone hoses.

Once that was all done and put back together I now have overboost protection kicking in I suspect the marginal leaks from those two clips was masking another problem elsewhere.

BTW, The boost guage was steady at 1.25 bar when overboost protection cut in.

I've now had three leaks that did not appear to cause overboost protection (outlet from turbo, i/c inlet and i/c outlet) and one leak that did (i/p to ECU).

Does anyone know where leaks occur on the pressure/vacuum line that do cause overboost protection and which points do not? so I can narrow down the search.

Cheers Jim

[pjeast73]

my car was showing all the signs of an air leak - overboost protection kicking in all the time - but after searching for a leak it turned out to be a faulty MAF. just a thought.

[Ski]

same here.. but mine turned otu to be the waste gate :/

[Crawford_S2]

I have had bother with my ABY since i got it on and off and the only thing that cures it every time is contact cleaner on the the MAF plug and throttle position sensor. Try this every time now first and cures running faults straight away.

[blu_s2]

If its another MAF gone then even Doug will hear my scream in Scotland.

MAF contacts and element have been cleaned but I'll give it another go.

Question for you Motronic techies out there (you know who you are). If the ECU has been running for a long time with leak(s) does it have to relearn once they dissapear and during this period could it trigger overboost cutout?

I did pull the motronic fuses, is this enough ?

Cheers

[audiman]

Pulling those fuses would clear its memory, sounds like you have another leak somewhere else Jim. The overboost condition, is caused by the MAF seeing too much air flow, either 1) you have a leak somewhere or 2) the MAF limit set within the chip itself is set too low.

I found the same thing with the clips on my new samco hoses, after 2k of heat cycling the clips had loosened off a bit, some of them did up a further 2 turns or so. Worth double checking evry few months or so.

[Doug_RS2]

I doubt it is the MAF - I think most of the high power guys, which some are high miles never have problems with their MAFs.

[audiman]

My car is original MAF and has 160k on the clock!!! It also works fine even when caked in oil vapour ffrom the breather system.

[blu_s2]

I'm going to go over the small bore tubing this weekend. Luckily I've now found out that another member lives just around the corner from me so I can borrow a MityVac to test them.

Having said that the car drove well last night and this morning after cleaning MAF and other contacts (though never had a chance to boot it for a very long time to be 100% sure of no cut-out)... we'll see

[blu_s2]

Checked out all the small bore today and all of them held up to MityVac with no problem.

No overboost protection at the moment though.

Definitely not holding boost above 1.25bar so will have to resort to sorting out a proper leak test with compressor and bungs.