Code 33
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Re: Code 33
I have been doing some reading and I am beginning to think there are two different problems. The code 33 is triggered because the MAP output voltage at idle (=TP sensor less than some 2-4 %) is too high. If the MAP output is correct, it means that vacuum is too low. This could be because the throttle plates do not close completely assuming there are no vacuum leaks. This I suspect because I have been adjusting the throttle plate opening to get them fully open at WOT. Maybe I tightened the throttle cable too much.......
The other problem is the stalling at midrange which most likely is ignition related. The tach drops faster than the rpm when it stalls.....
The other problem is the stalling at midrange which most likely is ignition related. The tach drops faster than the rpm when it stalls.....
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Re: Code 33
insptech. What drives the tach? Is it the pulses on the primary side of the coil or is it something on the high tension side? I am trying to understand why the the tach drops faster than the rpm
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Re: Code 33
in most cases a mid to high rpm range stall is fuel related,
I think you are trying to over engineer the problem go back to basics, as Ted stated check fuel pressure ect
I think you are trying to over engineer the problem go back to basics, as Ted stated check fuel pressure ect
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Re: Code 33
Hi . Thanks for your input. Keep the ideas coming.
Fuel pressure is OK, rock steady through all the stalls. The tach drops faster than the rpm and if the tach is as you say GOODT driven by the primary side of the ignition that is where the problem must be. Somehow the squarewave on the primary side cuts out, taking away the input to the coil as well as the tach. I have checked the coil and the magnetic pick-up in the distributor. Most likely it is an open circuit or a short somewhere....
Fuel pressure is OK, rock steady through all the stalls. The tach drops faster than the rpm and if the tach is as you say GOODT driven by the primary side of the ignition that is where the problem must be. Somehow the squarewave on the primary side cuts out, taking away the input to the coil as well as the tach. I have checked the coil and the magnetic pick-up in the distributor. Most likely it is an open circuit or a short somewhere....
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Re: Code 33
mats,
Have you checked or replaced the ignition module? It should be mounted with heat transfer compound and it needs a good ground to the distributor.
Have you cleaned and checked the connections at the back of the module (where the magnetic pick-up connects)? That is a real trouble spot, especially with the added moisture associated with MSD ignition. I can't remember if you have MSD or not.
What type of plug wires are you using? I have heard about some strange problems due to EMI on computer controlled engines with aftermarket plug wires.
Dave
Have you checked or replaced the ignition module? It should be mounted with heat transfer compound and it needs a good ground to the distributor.
Have you cleaned and checked the connections at the back of the module (where the magnetic pick-up connects)? That is a real trouble spot, especially with the added moisture associated with MSD ignition. I can't remember if you have MSD or not.
What type of plug wires are you using? I have heard about some strange problems due to EMI on computer controlled engines with aftermarket plug wires.
Dave
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Re: Code 33
Hi Dave. well I have not checked the ignition module but the whole distributor assembly is new. Is there a way to check the ignition module or do you need an oscilloscope? The plugwires are stock. I have checked them with an ohmmeter and they seem to be OK. I have checked the connection on the back of the module and they were corroded but they seem to be OK now.
Question; if the tach wire(s) gets shorted to ground, can that bring down the whole primary squarewave?
Question; if the tach wire(s) gets shorted to ground, can that bring down the whole primary squarewave?
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Re: Code 33
Originally Posted by mats
Question; if the tach wire(s) gets shorted to ground, can that bring down the whole primary squarewave?
basicly yes and it will stall the mtr
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Re: Code 33
Originally Posted by mats
Is there a way to check the ignition module or do you need an oscilloscope?
Originally Posted by mats
Question; if the tach wire(s) gets shorted to ground, can that bring down the whole primary squarewave?
Dave
#20
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Re: Code 33
I have seen similar problems with a failing module. It may be bad, even though the dist is new, especially if it wasn't installed with the heat transfer compound. There is also a possibility that the short wiring harness off the module has a broken wire. A good shaking on all the wires around the distributor might turn up something also.