1.6 Misfiring Problems, In Need Of 205 Boffs

[ricky1.9 0]

Hello chaps.

 

I'm stuck and in need of you 205 nerds out there.

 

What i have is a 1.6 which doesn't seem to be firing on no.4 cylinder.

 

The car starts but runs lumpy and when I remove the ht lead from no.4 plug makes no difference as when I do this on the other plugs the engine coughs and stalls as expected.

I have done nearly everything I can think of and don't seem to be getting anywhere, was wondering if anyone had similar problems. Proberly something obvious.

 

What I have done so far:

 

New Plugs.

New leads and am getting good spark on all jumping good half inch.

New dizzy cap.

New rotor.

have checked injectors, removed and swapped around and am gettin fuel ok to all equal pulses.

have drained fuel and put new stuff in as had just filled up when problem occurred but no change.

rotated dizzy to check timing to see if this would improve which might suggest cam belt slip but no luck.

Measured voltage on injectors roughly same but hard to tell as pulses but looks good.

Also checked compression and seems bit low 130psi but put this down to the cylinder been washed down with fuel as not been firing therefore lost bit of the oil sealing.

 

in the morning i'm going to check belt timing by dowels but can't see it but best to check everything.

 

Anymore ideas would very helpful.

 

The answer would be even better cheers

 

Rick

[Super Josh 4]

What are the compression figures for each of the 4 cylinders? And how does the compression build up? Does it rise up in one go? or does it increase in stages with each rotation of the engine?

 

 

 

Josh

[steve@cornwall 100]

Time for a compression test

[Arahan 4]

Said this on a recent topic, but check for fluid in the plug holes! Thats what was up with mine when it went like that! Once it was soaked up with some kitchen roll on the end of a screwdriver all was good! You might have to blow in the holes to see the movement of the liquid to know its there as it can be quite hard to see!

[ricky1.9 0]

What are the compression figures for each of the 4 cylinders? And how does the compression build up? Does it rise up in one go? or does it increase in stages with each rotation of the engine?

 

 

it builds up in a few cranks like the others

No.1 = 175

No.2 = 170

No.3 = 160

No.4 = 130

[ricky1.9 0]

Said this on a recent topic, but check for fluid in the plug holes! Thats what was up with mine when it went like that! Once it was soaked up with some kitchen roll on the end of a screwdriver all was good! You might have to blow in the holes to see the movement of the liquid to know its there as it can be quite hard to see!

 

Will have a look at this but but I have had the plugs in and out a few times and have seen no sign of liquids

thanks

[ashlee205gti 1]

it builds up in a few cranks like the others

No.1 = 175

No.2 = 170

No.3 = 160

No.4 = 130

 

30 psi (2 bar) difference is not a good sign. Are you losing water?

[Richie-Van-GTi 70 2 Cars]

it builds up in a few cranks like the others

No.1 = 175

No.2 = 170

No.3 = 160

No.4 = 130

 

 

looks like a blow between 3 and 4, other figures also look a sghade low but can be down to batrtery health, equipment used, starter strength etc. Id normally look for 180's on all 4.

[zilog 0]

Instinctively I find 130 psi enough for ignition of fuel - have you checked/made sure that there isnt any problem with the cables from the ECU to #4 injector? I think you can measure the resistance of each injector from the ECU connector. I would be looking for roughly the same resistance value for all injectors here.

 

See http://hem.bredband.net/thedagger/16V_Bosch_SM1288.pdf for pinout on the Motronic unit.

[Bonez 0]

have you taken the plug out of 4 to see if its even getting a spark??

[ricky1.9 0]

Woopty do I have found the problem.

What it was was a dislodged collet on the exhuast valve.

 

one collet had slipped off the stem, fallen down and got it self wedged down between the spring and stem.

This then caused the valve not to be able to close properly which is why it wouldn't fire and had low compression. It also jacked the follower up a bit so that there was no clearence and has worn the follower. Also roughed up the ccam lobe a bit buut not not bad.

 

Put it all back together and seems to be fine now although compression a bit low still at 155 but will see how it goes.

 

Thanks though for the suggestions and hope this don't happen to anyone else.

cheers