I recently finished installing my project but everything is never easy. Before i give up and just go Carb i want to see if you guys know what can do it. I have a HSR 58mm TB and 36lbs injectors. and my timing jumps. My mechanic times it perfect and then we drive it and after 1-2 blocks of driving we test it again and it changes timing by itself. Not just that but after like 2500rpms there is a sound that sounds like sucking of a valve. My car is a 1992 Camaro tpi before and now its a 383 stroker gen 1 block. I heard something about the knock sensor doing that, or distributor being bad, and ecm going bad and trying to adjust to timing. If you guys know something that might do this please let me know as if not i will change it to carb. I want a good performance car.

What ecu are you running so I have a better idea of where to start?

Sorry I dont know the name but I do know that the ecm and all were stock from my 1992 camaro. The only other thing is that I installed a pcmforless chip but besides that everything is stock as for ecm.

When timing it, did you unplug the esc connector on the dizzy? Is the hold down bolt tight on the dizzy? If the above is good, it could be a bad pickup in the dizzy causing the issue. Unplug the esc connector and set base timing and drive it a bit. Dont get too carried away at higher rpm because there will be no advance timing. See if the timing stays the same or changes. If it changes, then definitely the dizzy.

I am so sorry but I'm not use to the term dizzy. Or esc connector on the dizzy. Sorry thanks.

I had a similar problem with my HSR and I bought a new distributor, 350 knock sensor and aftermarket fuel pressure regulator (kirban) and it cured several bugs mine had.

Thanks abray1 I hope mine does. What type of distributor did you buy and I have to buy the knock as I already have the kirban. But I hope .

I have a MSD 2345 (I think thats the number) distributor on mine and Ive had the timing retard on me 2-3 times. One way to tell if the distributor is moving is to put some whiteout on the base of the distributor and see if its slowly retarding itself.

How are you determining that timing has " changed" ?

You have what is commonly known around here as a '730 ECM ( computer)

You need to know what base advance was programmed into your custom pcmforless chip
as you must set the engine base timing to that same figure

Dizzy /dist = Distributor

There is a connector (ESC connector) on the wiring going to the distributor.
If you do not disconnect this 1st before setting the base timing with a timing light then you will never be able get the timing correct

Should be a connector on a tan wire that has both wires coming in and out of the harness somewhere around the A/C or blower box.