164 QV issue and misfire

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PETROLHEAD
Posts: 3045
Joined: Thu Sep 26, 2013 7:51 pm
Location: Nottingham

164 QV issue and misfire

Post by PETROLHEAD »

Hi all,

as you've possibly already seen from my other posts, i was in need of an Air Flow Meter for my ailing 3.0 24v QV.

the symptoms i was getting was the usual failing AFM behaviour, a rough and fluctuating idle, but then it developed into a full blown hard ignition cut.

it would reliably intrude at 2500rpm, and whilst observing the AFM sweeping contact, it would fault at an identical point in its movement, hence, diagnosis Air Flow Meter.

i was approx 10% sceptical, as i'd never known a failed AFM to create such a hard cut, but all other evidence pointed that way, so the search was on, and not an easy one, as the QV only shares that bosch part with a couple of other fiats and lancias, and the porsche 944 turbo.

an ebay item was found and bought, it was useless and metered out wrong before i even started, so a remanufactured part was ordered in. at much larger expense, but at least it measured up correctly and arrived quickly.

trouble was, it cured nothing, not a thing, zip!

no change whatsoever! Grrrrr!



Finally having enough of snooping under the bonnet, i thought the longshot of the Alfa diagnostic socket was a slim possibility for some pointers, but worth a shot. Previously, i have found the early 3 pin diag stuff a little poor, so perhaps foolishly i'd not gone to it sooner.

Now it didn't tell me what was wrong, just left me a little clue where to go next.

The ecu returned me 2 codes, cam phase sensor and ecu power drivers , hmmmm, suspect ecu then???

The diag socket is inches away from the engine ecu itself, located in the passenger side centre console, just behind the carpet trim panel, but upon inspection you wouldn't think anything was amiss, so i assumed it must be an internal error. I thought i'd better try to take a look anyway, in the vein hope it might be a simple thing, or something obvious that would at least confirm where my next money should be spent.

I didn't need to look very far!

The ecu is held against the tunnel with a formed steel bracket, with the multipin connection at the top, so easy enough to release it from its mounts, manouvre it freely into the footwell, and release the loom connector.

and i found the problem!







2016-03-03 14.14.54.jpg
2016-03-03 14.22.29.jpg



That's got to be 30 pins swimming in water, how on earth it managed to start and rev to 2500rpm is a small miracle in my opinion :shock:


it was easy enough to clean up, and the big relief was that there was no water ingress to the ecu internally. Even contact cleaner was not able to creep in through the pin seals, so water couldn't for sure.

contacts and connections purged and cleaned, reconnected, and voila!

Turn the key, instant life, and revs through cleanly, Thank God!


Ive done some more tidying and improving to enure its all futureproof, and more to do yet, but a good few miles more on the clock for test drive and she hasn't missed a beat yet.


I'm assuming that the water ingress began as the condensation i saw indie the windscreen only recently, as she's been laid up for some time, unused and parked outside, but a conversation with Tom (BLS) confirmed that this wasn't uncommon aback when 164's were current.

Apparently a £2.50 car wash could easily result in a £700 ecu job, so there must be some weakness through the bulkhead and firewall where water can run down the loom and into the upward connecting ecu connection.

Clever design that, thank you Luigi! :roll:


I'll be greasing, siliconing and sealing whatever i find, the car should float when i'm done! :lol:
SHREW

I AM the Law!


Alfasud 1.7-16v, Charade Turbo SR, & The Dirty Diesels - GT Cloverleaf, 159 Ti Sportwagon, Saab 9-3 Sportwagon

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KevJTD
Posts: 5107
Joined: Thu Sep 26, 2013 8:48 pm
Location: Lincs

Re: 164 QV issue and misfire

Post by KevJTD »

got yerself a bit of furry corrosion there mate!
Giulietta JTD 170
Lancia Delta integrale
Lancia Flavia coupe 1.8 1963
Lancia Dedra turbo
Renault Clio 197 RS

I'm bad with people things
But I should have tried more

User avatar
PETROLHEAD
Posts: 3045
Joined: Thu Sep 26, 2013 7:51 pm
Location: Nottingham

Re: 164 QV issue and misfire

Post by PETROLHEAD »

Bloody fancy pants modern cars :|




Nothing but trouble! :lol:
SHREW

I AM the Law!


Alfasud 1.7-16v, Charade Turbo SR, & The Dirty Diesels - GT Cloverleaf, 159 Ti Sportwagon, Saab 9-3 Sportwagon

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