yella 90 Posted March 25, 2008 Share Posted March 25, 2008 my 90 has devaloped a cold recently low end power is fine, but top end, half throttle and above the engine dies off, hesitates, miss fires, u name it, it does it its not as bad for cold but when the stat opens its horrific when it comes upto 1 bar it starts playing up, it will occasionally reach max pressure at 1.5bar, but thats with it coughing as spluttering if i rev it out in neutral and hold it there ( wel if its gonna go bang it mite aswel do it in a good way ) it'll missfire and backfire ( rather awesome considering its a derv ) so the only things ive got to go off are - horrific missfire on initial start up - lack of top end, hesitation ect ect - worse soon as reaches op temp so far ive done the following then gave up on it tonight - new lift pump - new air/fuel filters - blown fuel lines, both pick up and return back - checked diaphram for splits - check pressure side of air system - intake side of system - ran of aux tank - ran with out fuel stop fitted - carbon monoxide tested coolant..ok - checked for excess breathing...its like new and something else thats slipped my mind for time being seems to me asif its fuel starvation cant be the wastegate cutting in, its never done it in the past year :roll: of running 1.5bar isnt head gasket its got me puzzled and one else think of something ? cheers dan Quote Link to comment Share on other sites More sharing options...
pigster Posted March 25, 2008 Share Posted March 25, 2008 sticky injectors?? I known my vw has suffered from this one my 90 has devaloped a cold recently low end power is fine, but top end, half throttle and above the engine dies off, hesitates, miss fires, u name it, it does it its not as bad for cold but when the stat opens its horrific when it comes upto 1 bar it starts playing up, it will occasionally reach max pressure at 1.5bar, but thats with it coughing as spluttering if i rev it out in neutral and hold it there ( wel if its gonna go bang it mite aswel do it in a good way ) it'll missfire and backfire ( rather awesome considering its a derv ) so the only things ive got to go off are - horrific missfire on initial start up - lack of top end, hesitation ect ect - worse soon as reaches op temp so far ive done the following then gave up on it tonight - new lift pump - new air/fuel filters - blown fuel lines, both pick up and return back - checked diaphram for splits - check pressure side of air system - intake side of system - ran of aux tank - ran with out fuel stop fitted - carbon monoxide tested coolant..ok - checked for excess breathing...its like new and something else thats slipped my mind for time being seems to me asif its fuel starvation cant be the wastegate cutting in, its never done it in the past year :roll: of running 1.5bar isnt head gasket its got me puzzled and one else think of something ? cheers dan Quote Link to comment Share on other sites More sharing options...
yella 90 Posted March 25, 2008 Author Share Posted March 25, 2008 i could flirt a spare set in i suppose it wasnt a gradual thing coming back from laning t'uvver night, whilst p***** around and overtaking, giving it some beans in 4th it lost all its guts and slowed down, its a push to get 65 out of it now, where as it'll pull right upto 90 normally since then it aint been the same kin thing its got a week, if not, its comeing out and another going in Quote Link to comment Share on other sites More sharing options...
upnover4x4 Posted March 25, 2008 Share Posted March 25, 2008 Have you checked fuel supply? If there is debris in tank could be getting drawn into fuel lines when engine pulling/demanding more fuel causing fuel starvation.Just read your post again & realised that youve dealt with lines etc. Also is the turbo continually on boost or is the waste gate chattering? Is it coming on boost? Can you feel any difference in the charge air pipes after the turbo. You will notice them ballooning when the turbo comes on boost. Cant be many other things as youve covered most. With regards the injectors, slightly loosen off the unions one by one on the injectors with the engine running to expell any poss air in system. You should notice a change in engine tone. Its not a surefire method of find a dicky injector but eng noise should alter comparatively for each injecter. If not start with that particular injector. I noticed you said that youve checked the stop solenoid, Its poss that the solenoid isnt opening port enough again causing fuel starvation at higher revs. Its not a definitive guide but I hope it helps. Good luck Ade Quote Link to comment Share on other sites More sharing options...
upnover4x4 Posted March 25, 2008 Share Posted March 25, 2008 Belt hasnt jumped a tooth??!!!! Quote Link to comment Share on other sites More sharing options...
yella 90 Posted March 26, 2008 Author Share Posted March 26, 2008 ive ran the engine on a aux fuel supply eliminating my tank turbo is on boost, happens from warm when engine is demanding alot of fuel and air ( 1bar and above) going double check air lines tonight and fit a primer bulb into the aux tank and prime it manually when going along to see if that helps it got no strange nocking noises to suggest theres a burnt out zaust valve and the valve clearences are ok dont understand the backfires in nutral if held at full throttle, usual causes for a derv backfire all came out fine les, help Quote Link to comment Share on other sites More sharing options...
pigster Posted March 26, 2008 Share Posted March 26, 2008 I alwas thought that backfires were causes by excess fuel -- so still could be injector - possibly dirt inside it or jamming somehow. skipping timing tooth - unlikey I would of said -- it would have a lot of trouble starting too if that was the case - - like my one did once. when I did the timing belt - oops. ive ran the engine on a aux fuel supply eliminating my tankturbo is on boost, happens from warm when engine is demanding alot of fuel and air ( 1bar and above) going double check air lines tonight and fit a primer bulb into the aux tank and prime it manually when going along to see if that helps it got no strange nocking noises to suggest theres a burnt out zaust valve and the valve clearences are ok dont understand the backfires in nutral if held at full throttle, usual causes for a derv backfire all came out fine les, help Quote Link to comment Share on other sites More sharing options...
yella 90 Posted March 27, 2008 Author Share Posted March 27, 2008 all sorted blocked spill off line on engine too much pressure the longer the engine runs causing the injectors to either not open or stay open all sorted now finally, can sort out the other jobs for next weekends tuff trophy cheers dan Quote Link to comment Share on other sites More sharing options...
Recommended Posts
Join the conversation
You can post now and register later. If you have an account, sign in now to post with your account.
Note: Your post will require moderator approval before it will be visible.