General backfireing punto 85sx

[zlawlaw]

hi there i have a punto mk1 85sx sporting just re-done the head gasket and the other gasket like the cam cover and so on. the problem is when i start to accelerate up in first it backfires popping so you lose power but just because its backfireing.... its had new spark pugs set at 0.7mm and the ht leads are 8 mouths old but i did have to keep pulling the one on and off a lot befor i re-done the head. so i dont no what the problem is ????? it mite be the lambda senser, mite need new HT leads. coil pack. just dont no. plz help me

 

[alexbpl]

hi there i have a punto mk1 85sx sporting just re-done the head gasket and the other gasket like the cam cover and so on. the problem is when i start to accelerate up in first it backfires popping so you lose power but just because its backfireing.... its had new spark pugs set at 0.7mm and the ht leads are 8 mouths old but i did have to keep pulling the one on and off a lot befor i re-done the head. so i dont no what the problem is ????? it mite be the lambda senser, mite need new HT leads. coil pack. just dont no. plz help me

I have the same problem. If I accelerate hard at the start of a gear I just get bogging and spluttering for a few seconds before the power kicks in.

My HT leads are about 5000 miles old, and my ECU has been decoded and tested about a week ago so you can cancel those out as causes.

 

[DaveMcT]

If its backfiring into the inlet manifold you risk blowing a hole in it. Check the cam timing is correct.
Backfiring down the exhaust will quickly wreck the catalyst again check the timing but also the coils, plugs and leads. Any recent work on these makes them top suspects.

 

[zlawlaw]

If its backfiring into the inlet manifold you risk blowing a hole in it. Check the cam timing is correct.
Backfiring down the exhaust will quickly wreck the catalyst again check the timing but also the coils, plugs and leads. Any recent work on these makes them top suspects.

hi thanks. no just out the back of the exhausted i asked a gargae and he said no the timing ok just check the ht leads and the coils. but i was reading some info on lambda sensers and i fink it mite be that but no no because a new ones like £60 ..

 

[alexbpl]

Well tomorrow I'm going to seal all my exhaust gaskets with 'fire putty' or a similar exhaust sealant.

I also have a coil pack gasket to replace so will see if that makes a difference.

I don't have another lambda sensor to try, but if the mk2 8v lambda is the same as the mk1 16v lambda I might try it as there is an 8v mk2 punto at my local scrappies.

Throttle position sensor has also been noted as a possible cause, but I don't know how to test it without swapping for another which I don't have.

Blowing a hole in your manifold is pretty unlikely though, unless you hit a roadside bomb on the way to work.