Hesitation at 4k and over when warm

[Jojo]

update:

So I have today received my new Crankshaft sensor (Bosch). When I took off the old sensor I noticed that on the tip on the sensor was a small pile of iron filings, black in colour. I would presume that this was the real culprit of all the symptoms I was experiencing.

But since the old one was out and had a new one in hand I anyway decided to install the new one.

Had it installed and went for a drive, and till now (fingers crossed) I can see that the problem has gone. Will be more sure once I make use of the car for a few more times.

So in order to help others for any similar case:

First symptom was, car starts normal when cold and also revs up above 4500 RPM without any issues, although not recommended.

Once engine reaches its normal working temperature, the car stutters when revved above 4500, also noticed that the idling was a bit rough. When engine is still warm and tried to restart, the car needed a bit more cranking than it usually needs. I also experienced a few times of engine stalling when on idle with warmed up engine.

[WorkInProgressK]

Sorry I am coming from a different car so I can't help you with the specifics.

This sounds like closed loop issues. Probably running too rich or lean (or open I always mix them up) When cold, the car doesn't take feedback from sensors. But at operating temperature it license to all the sensors at the same time. Most likely the crank wasn't a cause. The crank sensor is a yes or no sensor. Knowing the position only give a 50% chance of knowing the point in the cycle. Most older cars run with cam sensors only or distributors.

Places to look:
Your issue sound like a false reading from temp sensor(usually two circuits) most likely to the ECU . The dash one is usually correct because it reflects when the thermostat opens.

Oxygen sensors. If you have had repairs done, its not difficult to bang one into oblivion with it still giving somewhat possible results.

Knock sensor. Where it is giving false or true concerns which the previous issues could cause.

Maf: I consider this a closed case.

Finally a short in those sensors cabling. It's dumb, But unplugging and plugging connectors might get some corrosion off the connectors and fix your issue without finding it. That is why I support the fact of taking everything apart one by one. It is going to be pain staking, but you should be able to find it.


Also, I wouldn't keep working on this without a obd2 or durametric. If you can't get any. Keep unplugging one by one. The numbers between cars aren't all too different. We fluctuate within a range. So ask someone who can data log his car as a baseline.(Sorry I can't its not running :P)

Good luck.

[Smallblock454]

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