1.6 8v running badly

[Chrisstdt 4]

New to me standard 1.6 

 

Starts great but had an annoying misfire at about 3.5k revs

 

I've changed leads , plugs, coil ,ignition module ,cleaned afm ,checked for air leaks (found a split hose which I replaced but other than visual checks what can you do ?)

 

She's now running worse with annoying power loss at around 2k revs

 

I've got an ECU temp sensor coming and will check the afm with a multimeter 

 

I filled her up with standard E10 petrol ,will they run happy on this or do they need e5 ?

[PhilNW 66]

Check the fuel pressure as well, just had a fuel pump go bad which gave similar symptoms

[Chrisstdt 4]

Best way to do that ?

[PhilNW 66]

Get your hands on a fuel pressure test kit, connect it directly in line after the pump , should get around 3 bar /45psi (mine was 2 bar!!)

 

https://www.machinemart.co.uk/p/clarke-cht713-fuel-injection-testing-kit-tes/

 

[Leslie green 159]

They will run on e10 but you are better using 97 octane e5 which is what I always put in now and the haynes does say not to use 95 octane petrol but this might just  be for the 1.9 can't remember . If it was the fuel pump id think it would get worse the higher the revs and beware there are a lot of fuel pumps advertised that don't generate enough pressure for the gti . If you can get an original bosch pump that would be best .

Edited August 16, 2025 by Leslie green

[Chrisstdt 4]

Thanks up get one ordered 

 

Remember alot being said about the new fuel when it came out but can't see it causing my running problems 

[Leslie green 159]

Phase 1 and 2 use different pumps too and they ard expensive so id get that pressure tester to check if thats the issue.

[Chrisstdt 4]

Looks to have had a new pump but I've ordered the test kit

 

Noticed an unused white wire coming from the coil (is this normal?)

 

And tested afm (jetronic( with multimeter and it's out of spec ,pins 5-7 should be 60 ohms with flap closed but reads 117 and 1 John when open but reads 455

 

Took the lid off the afm and the carbon track looks ok

Edited August 18, 2025 by Chrisstdt

[Leslie green 159]

The white wire of the coil is normal ,cant remember what it was for but usually not connected to anything .

Edited August 18, 2025 by Leslie green

[Richie-Van-GTi 81 2 Cars]

White wire is possibly the suppressor, wont affect running, just to kill feedback on the stereo.

Typically a bad or lazy pump will have a complete power loss higher up due to lack of fuel. Sometimes the cause is the rubber boot that connects the pump to the pump housing splitting.

 If its an isolated misfire around a certain RPM ita usually down to the set up, check your vac advance works and hasnt split then go back to basics, set the spark angle at idle with a strobe, make aure your throttle closes correctly and the TPS switches at idle then get a CO meter and adjust the AFM screw to get correct mixture at idle, or use a colourtune then see how it drives.

[Chrisstdt 4]

Thanks I'm fitting new breather / intake hoses this weekend to rule out air leaks and fit a new ECU temp sensor to rule that out and il go from there 

 

[Chrisstdt 4]

How would I check the vacuum advance?

[Tom Fenton 1,632]

The air flow meter would be my target.

 

To test the vac advance suck on the pipe that goes to it. If you can suck air through with no resistance then the diaphragm inside is split and it’s no good. Very common they don’t last forever, BUT, I don’t think it will cause your misfire either way.

[Chrisstdt 4]

It's on the list too but good ones are hard to come by

 

Are there firms that refurb them ?

[welshpug 1,721]

yes, https://www.atcdrivetrain.co.uk/

 

they have been the only place I've ever seen in the UK doing them, I think they no longer have stock for exchange but can still test and refurbish your own unit if required.

[welshpug 1,721]

https://www.atcdrivetrain.co.uk/p/peugeot-205-air-flow-meter-throttle-body/peugeot-205-air-flow-meter-throttle-body-afm-for-le-jetronic.html

[Chrisstdt 4]

Thanks il get onto them

[Leslie green 159]

I have heard they only retrack them (airflow meter's) not fit a new carbon track which for the price they are charging is a bit of a disappointment but I suppose they offer a guarantee.

[Chrisstdt 4]

The track looks ok on mine but the readings were out of spec 

[Leslie green 159]

I need to check mine too see how it compares although it runs mostly ok it does tend to shunt at low speed regularly and I've felt brief hesitations at higher rpm (5k) The track may look ok but the readings being out of spec says its not just right .

Edited August 23, 2025 by Leslie green

[Chrisstdt 4]

Fitted all the breather stuff and ECU temp sensor and it made no difference 

Plumbed pressure gauge between filter and fuel rail and only get around 1.8 bar with engine running and no change when I take vaccum off for

 

My understanding is it should be 2.5 with engine running and jump to 3.0 when removing vacuum from for

 

Going to try testing fpr with a tyre inflator but I suspect the fpr may be at fault 

 

She's had a new fuel pump so previous owner has been chasing this ,I removed the pump and gauze on bottom was clear

[welshpug 1,721]

is it a pre 1990 car with the black housing or post 1990 with the white housing?

 

the former can leak from the rubber joiner/adapter between the pump and the housing, the latter just had a piece of hose.

[Chrisstdt 4]

1991 car ,pump has a rubber hose ,I could put the old pump back on (it came with the car) to test but I'm off tomorrow so il try and test the fpr as it seems the previous owner tried fixing this problem 

 

Would fuel pressure if under 2.0 bar cause fueling problems ?

[Tom Fenton 1,632]

As you say it should be 3.0 bar base setting, probably the easiest test is short across the fuel pump relay with a bit of wire so the pump runs constantly, and you should see 3 bar at the rail with the engine stopped, so it removes the vacuum reference from the mix while you test.

Only thing to bear in mind is a damaged injector pissing fuel in constantly could also give you low fuel pressure, it’s not necessarily the pump or regulator.

[Chrisstdt 4]

Thanks il try that