Have had some problems with my car today which is typical as its a nice day here :lol: Basically I went for a drive today and the car was running fine and then I noticed it was a bit hesistant when I stopped for junctions etc. Just as you press the pedal the revs seemed to drop for like a split second and then fine again. Anyway thought I would come home and investigate and then it would't start again. Just turning over on the starter but not firing :cry: checked connections, maf and no warning lights etc and everything seems fine. Its started now but doesn't sound right like its missing.

 

Any ideas???

 

Its a non turbo auto

Let the car cool down and try again, if after it's warmed up the problem starts again then I would say that it's probably your PTU (assuming it's a S1 PTU).

Just gonna go and try it again as it been sat for a bit and I think its a S1 PTU as the car is a 1990. If it is the PTU is it easy to change?

It depends on what you do mate. If you upgrade to a S2 PTU there may be some wiring involved unless you buy the loom adapters as well. S1 is just a case of unplugging the old and plugging in the new.

 

The S1 PTU has a known problem with over heating. When this happens you get the symptoms you have mentioned. But before you change over it may be a good idea to borrow a known working one and trying that before buying a new one, just to confirm it.

Another series 1 PTU is a straight swap, undo 4 bolts and 2 plugs. If you upgraded to the series 2 then its 4 bolts 2 plugs and the 2 plugs for the harness that comes with it.

Have had some problems with my car today which is typical as its a nice day here :lol: Basically I went for a drive today and the car was running fine and then I noticed it was a bit hesistant when I stopped for junctions etc. Just as you press the pedal the revs seemed to drop for like a split second and then fine again. Anyway thought I would come home and investigate and then it would't start again. Just turning over on the starter but not firing :cry: checked connections, maf and no warning lights etc and everything seems fine. Its started now but doesn't sound right like its missing.

 

Any ideas???

 

Its a non turbo auto

 

Common cause of hesitance coupled with poor starting is temp sensor connection or fuel damper leaking fuel into the plenum via the vacuum tube, both will cause overfueling and the problems you describe.

 

 

The ptu cannot cause hesitation, it either works or it does not, well maybe sometimes it will loose odd cylinder spark but in the main when they fail its from internal overheating caused by poor connector contact leading to high current draw, a common misconception is its the heat from the engine that causes the fault, its not its internal issues,all too often the ptu is seen as the "baddy" when if after 20 years of good service why should it then fail? usually because of issues elsewhere that have not been dealt with.

 

 

Do a real good check of the temp connector at the front of the engine (two pin yellow) give a clean with WD40 or similar and close up the small box pins with a knife blade slightly to give a better connection. The fuel damper sits by the drivers side balancer bar and has a small vacuum pipe leading to it, remove this and check for any smell or in fact any petrol, if either replace it as the diaphram has split.

 

 

Trouble codes will appear in the engine ecu diagnostic if it is the temp sensor, quite easy to check.

 

Jeff TT

Tried the car today after work and the problem has gone but im guessing its still there and will come back. Will work on it tomorrow and do all the things suggested as it can only help for the future.

 

Cheers for the help guys

Did the temp connector as it was a bit green and loose so did that and checked the AFM. The AFM was a bit loose aswell and I noticed I don't have one of those metal clips on it is this normal? Seemed to start fine today and drove fine so hopefully all good. Is there any other connections I should check just to keep the car going nicely?

 

Cheers

The metal clip keeps the plug on tight/stops it coming loose, stick some insulation tape around it for now until you get another clip, Jeff may have some lying around.