Technical Strange HGT engine problem, help!!

[Clunkton]

Hi all. I've had a quick speed read through the forum and I haven't seen this problem covered (sorry if it has been).

I have a 2000 Punto HGT with 130,000 on the clock. I have it serviced regularly and it's never given me a days trouble since I've had it............until now.

We were travelling back from Dorset a week last Saturday, so on the Friday evening I filled up with petrol for the journey, went straight back to the campsite (4-5 miles) and parked up for the night. The following morning it took a bit of convincing to start, it had been a damp night so I didn't really think too much about it. As we travelled home through heavy traffic it began to hesitate on acceleration and splutter a bit. Once we hit the M25 I was having to adjust my foot pressure carefully in order to be able to accelerate but in the end I was losing so much power I had to stop on the hard shoulder and call the RAC. He reckoned it was either the Cat or the injection system and we had to be recovered.

The following Monday I had the Cat checked, it's fine. I took it to a local garage and after they didn't find any error codes they did compression tests, emission tests and tested the fuel but everything came back OK. They drew a blank.

On the Thursday I took it to a Fiat main dealer. They ran all the usual tests, they drained the fuel tank and replaced it with new petrol, they even got in a load of donor parts to try fitting them individually to see if they could isolate the problem. Today (Wednesday, 6 days later) I got a call from them saying that they still have no idea what's causing it. They say they can start replacing major parts but it will be pure guesswork, they'll have to charge me for them but that they can't guarantee that any of them will fix the problem.

I'm really at a loss as to what to try next. If a main dealer can't sort it out what chance does anyone else stand?

If anybody has had a similar problem or has any idea what might be causing it I'd be really grateful to hear. It's a great car and this is the first and only major problem it's had so I really don't want to (and can't afford to) scrap it.

Many thanks
Clive

 

[Tony123]

I have a similar problem...

Can you hear a noise like "spshhhh" when it hesitates coming from the drivers side of the engine ?

 

[fingers99]

I can't see it being the CAT unless it's very obviously blocked.

That they're changing parts without a clear plan does not inspire confidence.

I think that, somewhere, there's a forum which specialises in the faster Puntos. The HGT is fairly uncommon, so I'd guess that relatively few FIAT technicians have much experience of them.

I think the engine is essentially the same as the 1.8 Alfa 155 (I'm not sure if it uses the same ECU), in which case one of the Alfa forums (or an Alfa independent) might be a better bet. You don't tell us where you are, so.............

I would check fuel pump delivery/pressure, fuel filter (if an external one is fitted), lambda and MAF sensors. And, of course, the associated wiring.

I'm not sure if the ECU fitted (or the equipment the dealer has) enable the tracking of live output from the ECU.

 

[DaveMcT]

www.puntopower.com has some information.

I think you need to look at all electrical connectors for corrosion. Any that are not 100% clean the contacts. Its not technical just tedious. I would avoid the main dealer. Because their rates are so high, they are not experienced with older cars. As Fingers suggests try the Alfa people and discussion groups. Its essentially a 1.8TS but without the 2nd set of sparks.

Also its drive by wire. The problem could be in the accelerator pedal not sending correct driver demand signals. These might not throw any error codes as the ECU would not see it as a fault.

A blocked catalyst is unlikely because you have recently done long journeys with no problem. A Lambda fault wont affect starting but does push up fuel consumptions and makes it down on power.

The fuel pump could have an intermittent fault. I dont suggest change things willy nilly, but a used lower mileage HGT fuel pump might be worthwhile.

Another thought mine is a 2001 with 80K miles. So far so good, but the coil trigger wires are now vulnerable because the corrugated wire sleeves have gone hard and cracked. Faults in there should raise ECU error codes but its worth taking off the engine top cover (6 or 8 torx screws and no gasket) to have a look. Fit new sleeves and repair any chafed wires.

 

[Clunkton]

Thanks for your input guys.

I'm going to get the car back from the dealer at the weekend and try some of your suggestions.

I know the fuel pump and sensors have been tested but they may not have even looked at the connections so I think that will be my first port of call. I'll have a look around a few Alfa forums too and see if I can find anything there.

I'll keep you posted!

 

[Clunkton]

Sorry Tony123, I haven't noticed any noise, but then I was a bit preocupied with not getting shunted from behind. If I hear anything I'll post it.

Cheers

 

[HgtBill]

As its a 2000 model it'll have a throttle cable and icv, not the drive by wire system fitted to later vehicles.

Was the engine light on or flashing when it was stuttering?

 

[Jaapje1988]

Did you ever find out what the problem was?

 

[varesecrazy]

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