cambelt jumped a tooth.

[grass hopper]

Originally Posted by lou

i dont have any warning lights on the dash, they come on and go off, i used a flah code reader, the the codes i got all related to the cornectors that i unpluged to do the pcv system, reset the codes and retested and it was all clear. sorry but whats the ecm??
also its the blowing from the joint back of cat to nxt section, ie where the bracket is.

HI Lou,the ecm is the engine control module,it can save intermittent or permanent codes in the memory.

if blowing at the back off the cat it should not alter fuelling.

does the car run ok,but sound only noisy on overrun etc.

remember mentioning the car run on when switching off ? i remember if a few years ago dependant on model/year there was a electronic valve that cut of the air bleed in the inlet manifold area,worth checking with Volvo on this but im sure we had one with this problem

[lou]

Originally Posted by grass hopper

HI Lou,the ecm is the engine control module,it can save intermittent or permanent codes in the memory.

if blowing at the back off the cat it should not alter fuelling.

does the car run ok,but sound only noisy on overrun etc.

remember mentioning the car run on when switching off ? i remember if a few years ago dependant on model/year there was a electronic valve that cut of the air bleed in the inlet manifold area,worth checking with Volvo on this but im sure we had one with this problem

starts and runs ok, just the missing sound when ticking over, just doesnt have the get up and go now,
ok gunna call it a night on this for now, and would like to thank all who has put there views comments into this. thanks again andy.
will keep you all updated.

[Oly.850]

Have we done a compression test? That would rule out a valve timing problem and some other things too.

[scr8pdo]

Hi Andy, I found this this morning, does it sound like your symptoms? http://realbig.com/miata/1997-10/379.html
This is just an example of a twin cam engine still running sort of ok, one tooth out on the intake, Ive seen this many times and its frustrating because the car can seem to run ok condradicting the fact its out a tooth, if it were a single cam, both the exhaust and inlet would be out and the problem more pronounced, all the best Steve

PS in that article it describes him altering his ignition timing to try and make his car run better, as this cannot be done on a 850 the ECU will try its best to alter the timing to suit automatically, so when you turn it back a tooth the timing will re-adjust itself automatically and should work fine

[lou]

Originally Posted by Oly.850

Have we done a compression test? That would rule out a valve timing problem and some other things too.

hi m8, yes 230-232-across all 5.

[lou]

Originally Posted by scr8pdo

Hi Andy, I found this this morning, does it sound like your symptoms? http://realbig.com/miata/1997-10/379.html
This is just an example of a twin cam engine still running sort of ok, one tooth out on the intake, Ive seen this many times and its frustrating because the car can seem to run ok condradicting the fact its out a tooth, if it were a single cam, both the exhaust and inlet would be out and the problem more pronounced, all the best Steve

PS in that article it describes him altering his ignition timing to try and make his car run better, as this cannot be done on a 850 the ECU will try its best to alter the timing to suit automatically, so when you turn it back a tooth the timing will re-adjust itself automatically and should work fine

thanks ste, will look into it, im also told if i run the timing gun on the bottom crank i should get an idea if the timing is out, picing up the strobe gun in the morn.

[scr8pdo]

Originally Posted by lou

thanks ste, will look into it, im also told if i run the timing gun on the bottom crank i should get an idea if the timing is out, picing up the strobe gun in the morn.

This will only tell you if ignition timing is out and because the car has no manual adjustment, the ECU will compensate some what ie move the ignition timing to suit and will give you a false indication, if the car had a distributor you could manually adjust you would see it out straight away if it was but with ECU it will adjust automatically mate

PS: If the cam sensor is on the Exhaust cam the ignition timing will be spot on, as will the crank sensor as all this looks to line up ok, if the inlet cam is out a tooth and there is no sensor on it the ignition timing will be as it should

[lou]

Originally Posted by scr8pdo

This will only tell you if ignition timing is out and because the car has no manual adjustment, the ECU will compensate some what ie move the ignition timing to suit and will give you a false indication, if the car had a distributor you could manually adjust you would see it out straight away if it was but with ECU it will adjust automatically mate

PS: If the cam sensor is on the Exhaust cam the ignition timing will be spot on, as will the crank sensor as all this looks to line up ok, if the inlet cam is out a tooth and there is no sensor on it the ignition timing will be as it should

hi ste, ok got the crank lined up spot on the exhaust mk is spot on the inlet is still a tooth ok, anyway run a mark on the crank pulley and the raised line.
run the timing gun on the crank and the strobe is showing the crank is advanced by one tooth.

[scr8pdo]

Originally Posted by lou

hi ste, ok got the crank lined up spot on the exhaust mk is spot on the inlet is still a tooth ok, anyway run a mark on the crank pulley and the raised line.
run the timing gun on the crank and the strobe is showing the crank is advanced by one tooth.

Ok so its wrong then, at least you know now, the sensor must have been on the inlet cam after all, Right, get the crank lined up and them two marks as best you can, make sure the belt is tight on the straight between cam and crank and the slack on the tensioner side and do what I said PM mate, good luck and PM if you need help, all the best Ste

[lou]

thanks ste, got a friend coming over in the morn to give me a hand etc, as it to dark now, kinda volvo mini meet