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Strange rpm problem, randomly

Posted: May 15th, 2009, 4:17 pm
by mendelmax
Hi guys.

Again, I have a weird problem with my stroker. Usually it starts up fine, and drives fine, with no problems. Silky smooth. From time to time however, after starting up it doesn't have power, can't rev higher than 1000, chokes and sometimes stalls. Firing it the second time gives the same result, but at third attempt it starts up just fine and stays that way. Always at third attempt the symptoms vanish and it is 100% smooth.

I thought about fuel pressure, but the pressure is fine and stable according to our manometer, so that's not it. The problem seem to have started after the battery negative was removed, so I suspect that somehow PCM could get fried (I can't imagine how could that happen). I have a spare one, that I will replace soon to verify this theory, but has anybody ever encountered a problem like this? Maybe you guys have any thoughts about what can cause it?

The ignition coil is also brand new, it has two weeks at most.

Re: Strange rpm problem, randomly

Posted: May 15th, 2009, 4:40 pm
by yuppiexj
Mine would do that after water crossings when the connector for then cam position sensor in the distributor got wet, or would get hot, or get cold.

A good cleaning on the connector and my stuttering, stumbling, stalling problems went away. (until I broke something else).

IT's a quick cheap and easy thing to check.

Re: Strange rpm problem, randomly

Posted: May 19th, 2009, 2:37 pm
by mendelmax
Cleaned all the conectors and nothing. I suspect either the CPS failure or the fuel regulator problem, because I can't see anything else that can cause this sort of problem. But as I said, on the gauge the fuel pressure seems fine, so my next bet is to check the sensor. I just have to find some distributor to swap for a test- I don't want to buy and change parts randomly ;)

Re: Strange rpm problem, randomly

Posted: May 20th, 2009, 7:50 am
by lafrad
Is it related to the "heat in the fuel rail" problem they had in the past?

Does this problem occur more often when the engine has sat and heat-soaked for awhile?