Stu
Posted a lot
Posts: 2,913
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Aug 30, 2020 11:00:06 GMT
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Hi all,
Any tips on this appreciated. My Mum’s Seicento (2002 1100cc, not ‘sporting’ model) hasn been cutting out occasionally for probably a year now, usually at low rpm putting out of a junction or slowing to a halt and dipping the clutch. Always restarts fine and idle is stable.
I had a look at it last year, checked the fuel pump under the back seat looked clean and functional, the wiring to it was ok, throttle body was clean, couldn't find any vacuum leaks. It didn't seem to be related to fuel starvation, as there was plenty in the tank. I can't remember now if I found the fuel filter, but I checked the tank breather was ok.
I did try some computer diagnostics on it with limited success using a generic OBD lead and some free software but couldn't see anything obviously wrong. My brother has since replaced the spark plugs and had a look over it too, as has my Dad, again we can't really find what's up.
Some googling suggests it may be a cam or crank sensor fault, which seems plausible, but I was hoping someone on here knows their small Fiats and could point me in the right direction based on the symptoms, or to some Fiat specific software if that exists, which could identify the issue electronically? I can find out the engine code and other specifics.
Any help appreciated, my Mum loves the car but it's getting a bit unpredictable for her to use so I want to fix it and am happy to spend some time and money on parts to do so.
Thanks Stu
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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Aug 30, 2020 12:42:06 GMT
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Hello Stu
Crank position sensor (cps) is a good bet.
One key characteristic is that it fails when car has got to full temp. In the past I have identified a failing cps by spraying it with something cold, brake cleaner or similar will suffice. The cooling effect temporarily bringing back the cps into life.
Typically no fault codes will throw up from a failing cps
whilst I'm not normally an advocate of throwing components at a fault, for the relatively low cost of an aftermarket cps it would at least rule that out.
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Stu
Posted a lot
Posts: 2,913
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Aug 30, 2020 13:17:44 GMT
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Thanks, that's useful info - much appreciated! I will dig out the VIN number for the car and make sure to track down a suitable CPS to swap. I've also ordered a new VAG-COM cable for £6 via eBay as I can't find mine and need one for my VW T4, but also because I think it's compatible with the Fiat too so could help diagnose what's going on if there are any faults logged.
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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goldnrust
West Midlands
Minimalist
Posts: 1,872
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Aug 30, 2020 16:54:32 GMT
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The Fiat diagnosis software you want is MultiEcuscan, there is a free version. www.multiecuscan.net/It does all the Fiat / Alfa group cars. If you go on the website you can see what connection type you need. I’m not sure with the Seicento, but with some of the similar era Alfa’s I’ve had a Vag-com Type cable will only get you into some of the functions, and an ELM type reader will get you into more. Fiat also transpose some pins in the OBD connector, so you need adapter cables (bought or DIY made) to access some ECUs, for example on my 166 to read fault codes on the automatic gearbox I had to get an adapter cable. All the info is on the MultiEcuscan website as to what functions you can access. Regarding the actual fault, I think this apples to all the Fiat FIRE engines, but certainly on the 1.2 versions I’ve had, theres a hose that’s part of the crank breather assembly that connects under the air box. This can split with heat/time and cause some rough idling type issues, might be worth checking out?
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Last Edit: Aug 30, 2020 16:57:48 GMT by goldnrust
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Stu
Posted a lot
Posts: 2,913
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Aug 30, 2020 17:23:05 GMT
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Sounds good - I’ll download that software and checkout the website for connection details tomorrow and what’s needed for this car. I have the VIN and engine number now so should be able to narrow down the specifics.
Noted on the breather - I’ll check it out, much appreciated.
Stu
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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Stu
Posted a lot
Posts: 2,913
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Aug 31, 2020 13:58:47 GMT
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Hi All, I got the car round this morning and started investigations. Firstly, I can't find any air leaks, perished hoses or anything like that. The symptoms are that it drives fine on a 1 mile trip to the shops, always starts first time hot or cold, but any longer trips, when it's fully warmed up, cause the engine to cut out when you slow down or come off the throttle at a junction or to park. Again, always restarts. No EML light on while the engine is running, just that it comes on with the battery light when you first turn the key, and back on when it cuts out. I removed the crank position sensor, noting it's a Magneti Marelli branded one (could be original?) and unplugged it. Checking it's resistance I get 1250 ohms across the two pins that give resistance, this drops by maybe 100 ohms if you pass a non metallic piece of metal near it. I tried warming it gently (at a safe distance) over the hob in my campervan and the resistance increased as it warmed up, to around 1550 ohms, but didn't lose resistance with the heat as I expected it might if failing? Cooling down it returned to around 1250 ohms. I cleaned it up, refitted it and had a look at the camshaft position sensor, this gives around 600 ohms resistance, not sure if that's correct or not? I believe it's a hall effect sender rather than magnetic? I've installed Mutliecuscan on my laptop and await the VAG-COM cable to see if that can throw any light on the subject. As it is, I still suspect the crank position sensor and am inclined to try replacing that next. Any more input much appreciated! Stu
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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TessierAshpool
Club Retro Rides Member
Posts: 507
Club RR Member Number: 168
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Sept 3, 2020 16:56:39 GMT
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Euro Car Parts have a HAAS crank sensor for £7.49 before discounts. I'm not usually a fan of throwing parts at a car until the problem goes away, but for that price...
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Stu
Posted a lot
Posts: 2,913
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Thanks, I’ve ordered that crank sensor - worth a gamble as it was under a fiver with discount code, pick it up tomorrow. I believe the car has been behaving itself a little better since I cleaned up the crank and cam sensors, so hopefully I’m on the right track.
My diagnostic cable arrived too so I’ll see if I can find anything out via that.
Thanks again :-)
Stu
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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Phil H
Posted a lot
Posts: 1,448
Club RR Member Number: 133
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Euro Car Parts have a HAAS crank sensor for £7.49 before discounts. I'm not usually a fan of throwing parts at a car until the problem goes away, but for that price... ..the fault could come back before you think you’ve fixed it. Sorry, Haas is on my “never again” list like a lot of stuff they sell. New coil pack didn’t last until I got home before expiring - luckily the faulty (just working) original carried on working for long enough to get one from elsewhere and return the shiny new one..
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Stu
Posted a lot
Posts: 2,913
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Sept 6, 2020 19:17:27 GMT
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Hi,
I wasn’t sure about HAAS either, and it certainly wouldn’t be my brand of choice but in terms of chucking £5 at a new part to eliminate it, worth a go as the alternatives were around 10x the price.
I scanned the ECU yesterday and found no DTCs, and my Mum reported that the car hasn’t cut out since I’d first cleaned up the cam and crank sensors a week ago. I swapped in the new crank sensor, drove it around for a while up to full temp and repeatedly tried to get it to cut out, and it wouldn’t. Scanned again, no DTCs so left it at that and put the old crank sensor in the boot for a spare just in case.
My Mum has since used it for a few local journeys on which it would cut out previously, and so far so good...! Fingers crossed :-)
Thanks Stu
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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Stu
Posted a lot
Posts: 2,913
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Sept 22, 2020 13:41:49 GMT
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Just to update this topic, the car has behaved itself since I swapped the crank sensor around 2-3 weeks ago so hopefully that's it sorted! Thanks again for the replies, much appreciated.
Stu
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'89 BMW E30 325i Sport, '04 MINI Cooper S, '09 Volvo V70 D5
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