'97 Fiesta 1.25 Zetec woes

Hi guys,

I'd like to pick the brains of the Zetec experts here, if I may.

My daughter has just bought a P reg Fiesta, 51000 miles, genuine AFAICT.

When it's cold it's a real cow. It starts well and will idle OK but any amount of throttle will make it cut out and stall. It can be coaxed up the rev range but only very gently. It's like this for a few minutes then it's warmed up enough to behave better. It idles fairly fast (1500 rpm) for about 30 secs initially then slows down to about 900.

When hot it's much better but still not right. At ~4100 rpm in top it starts to misfire. If you're accelerating it's like somebody put the brakes on, it happens suddenly. Again, it can be coaxed further but only very slowly. It seems load dependant - if you're in a low gear it will rev past this point easily.

Another symptom is it's hanging on to revs when you change gear, about

3000 rpm.

I have put in new HT leads and plugs (all Motorcraft) and cleaned the coil pack. I've cleaned the MAF sensor wires with carb cleaner and cleaned inside the idle control valve. The throttle position sensor is giving a continuous resistance change with no discontinuities. Nothing has helped. I don't know if it has an EGR valve. There's a vacuum pipe running down the bulkhead but I can't see where it's going. The air filter is clean but I suspect this is because the housing is only held together with one screw and therefore not closing properly! I did hold it together by hand but it didn't affect the problem. I was going to clean the throttle housing but it's got a sticker saying not to - there's a 'special coating' on the throttle plate for some reason.

I don't know what oil's in it, I understand the Zetec can be sensitive to oil type. It's getting changed tomorrow.

I would really like to read the error codes from the ECU (an EEC-V, according to the Haynes BOL). But I'm confused, since the vehicle (built in 1996, according to the VIN) has the 16-pin OBD connector in the passenger footwell but also a 6-pin connector with 5 wires and a red cap in the engine bay. It's labelled 'data link connector' on the Haynes wiring diagram.

Does anybody know which of the two is the pucker diagnostic connector? I suspect I'd just get some flash codes from the 6-pin connector, does anybody know better?

Any ideas and suggestions welcome!

Thanks in advance

John

Reply to
GEezer Nug
Loading thread data ...

Replace the coolant temp sensor (CTS) its also in limp home mode (LOS - limited operation strategy).

The inadequate fuelling when cold and 4000rpm rev limit are signs of failed CTS and LOS in place.

Tim..

Reply to
Tim (remove obvious)

Thanks Tim, I'll do that tomorrow.

Just read the BOL and it says LOS will continue until the fault code is erased. Rats, looks like I'll have to get the scanner anyway.

Anybody know if the fault code can be erased without a scanner? I've heard that disconnecting the battery for half an hour or so will clear some stuff from the ECU. Will that clear the code?

Cheers

Reply to
GEezer Nug

Again a symptom of the ECU being in LOS mode.

They are prone to this even when operating properly- fix the underlying fault first and this will probably go away.

Depending on which vacuum pipe you are looking at, it will be either for the charcoal canister, or more likely the heater recirc flap.

The air

They are PTFE coated to resist oil and carbon deposits. If it is fairly clean with no ring of carbon behind the throttle plate, just use a dry cloth to clean it. Carb cleaner will strip the ptfe from it. Brake cleaner or meths is less aggressive and can be used gently.

They can be, and only 5w-30 should be used. If it was suffering from valve stick from the wrong oil you would have a very poor cold idle, prone to stalling with misfiring, and difficulty in restarting whilst cold.

Being a 96 car i expect you have neither the IV nor the V, but what is know as the FOL ecu, which was an intermediatory variant. Treat it as an EEC IV, but use an FCR on the 16pin connector.

Tim..

Reply to
Tim (remove obvious)

Yes. NB radio code.

Allow the ECU to relearn idle strategy properly when you re connect. The handbook gives details i think.

(start from cold with no throttle, allow to warm fully at idle to a couple of fan cycles, then drive for at least 3 varied miles.)

Tim..

Reply to
Tim (remove obvious)

Yes. Although a couple of minutes should be long enough. Mike.

Reply to
Mike G

Thanks Tim.

Reply to
Geezer Nug

Cheers Mike.

Reply to
Geezer Nug

The pipe is connected to a solenoid on the bulkhead near the brake servo. Now you say, I'm sure it's the canister pipe. The wire colours on the solenoid suggest that too.

That's reassuring, thanks. The oil looks quite clean, perhaps it's 'next weekend' not 'tomorrow' urgent now!

Cool, thanks. Presumably it won't give much more than basic fault codes then? Do you know if I can get flash codes from it, like the 3 pin connector of the IV?

Thanks very much for your help, Tim. I was hoping an expert would answer

- they clearly have!

I'll let you know how it turns out and buy you a virtual beer.

Cheers John

Reply to
Geezer Nug

You can try, but as I remmeber it was abit of a hybrid, and although the 3 pin connector was present, it wouldnt work...

Tim..

Reply to
Tim..

It's all fixed and working nicely.

It was the coolant temperature sensor. 'We sell a lot of those' said the spares chap...

Haynes BOL says to drain the coolant, but a plastic bag over the neck of the expansion tank with the cap screwed back on stops much escaping.

I measured the resistance of the new one, it was 27K ohms. Just to prove the point I measured the old one once it was out. I was gutted to find it read the same. Carried on anyhow and measured it a while later, this time it was 40K, so it was an intermittent fault.

Many thanks and much kudos to Tim, who diagnosed it in one. I owe you a beer sometime!

Cheers John

Reply to
Geezer Nug

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.