General Uno turbo backfire problem

[87unoturbo]

Hey.
Have had my mk1 uno turbo for almost half a year now and never had any problems. Just a few days ago it started misfiring really badly. :bang:

It accelaretes smoothly and no problems when foot pressed to hte floore through 1st 2nd and kind of 3rd :/ but when im on the motorway and floor it in 5th when I get to around 5k rpm if will start misfiring and my sister who was traveling behind me said she saw flames from the exhaust .

Has anybody ever encountered this problem before and if so how did you fix it?
Does anybody have any tips on what i could try to do to fix it?
I really appreciate your help

 

[87unoturbo]

Just an update that i forgot to say.
My friend suggested it may be the fuel pump not supplying enough fuel causing the missfire.
I went to pick a part and found a nice external bosch pump of a jaguar for $18 and fitted it and no changee to the problem.. :bang::bang::bang:

Please help!

 

[the mk1 kid]

Hi,

I could be a number of things, i had a similar problem (although that was in any gear IIRC) and the spark plugs were to blame - when were they last changed? Have you had them out to take a look?

If you've not changed the plugs, cap, rotor arm or leads in a while i'd suggest its one of them to blame - that or perhaps even a loose/bad injector connection.

The reason 'it' happens in 5th is the engine is working hardest to accelerate due to the gearing and wind/rolling resistance etc.

One last thing - you've not got your boost limiter still connected on the side of the plemum changer have you? What boost are you running, are you using a boost controller?

Tom

 

[87unoturbo]

Hi tom. Thanks for the advice.
I have replaced plugs and inspected ignition conections and dizzy cap and rotor and seem to be fine as far as i can see. I tried getting a new cap but they arnt readily availible in NZ.. The injector plugs i havnt checked. I dont know how to? tried getting plug off but wont come. How do you?
No no no that has been removed. the problem happened all of a sudden not gradually over time so it very confusing.. head gasket or cracked pisto maybe? Running 1 bar of boost.