240 84 242 turbo misfire

84 242 turbo misfire while accelerating

I have been searching for a while on here now. All the misfire cases on the other 240?s seem to be a rough idle situation and mine doesn?t have a rough idle but when you are in third or fourth gear and step on the gas there is a constant misfire but the engine light does not come on.

The previous owner put in a IPD Turbo cam and set it at 2.5* retard. (No clue why for a daily)

But, I can?t tell if the problems are related because there is 0 power from idle to 3800 rpm even though it has boost before that. The ignition timing is 12* like it should be and I have replaced everything on ignition other then the distributor. (Plugs, wires, coil)

Would changing the cam timing to 2.5* advance help this problem or does anyone know how to solve this.

It is a 84 B21FT kjet

I would first verify the cam timing without any advance on the gear. It may be that someone that would do that cam timing like that may have put the cam in with the timing off. If it is good then yes advance the cam timing. I use two degrees on my engine but would recommend four or even six for a bit better daily driver enjoyment.

Have you also made sure things like the plug gap and boost enrichment are working? With a worn plug the engine can miss when boosting or likewise without the extra fuel from enrichment it can cause misfire when boosted.

Does it smooth out after a certain rpm? Is there a certain psi threshold that the missing begins at?Sounds like spark blowout to me. Try switching to colder plugs and gap them at .028 to start. Ngk brp7es is a good one for turbo cars.

Also grab a k jet pressure gauge (no point in owning these cars without one) and throw it on to see what you system and control pressure is.

Ha! Check engine light....

Start with inspecting cap, rotor, plugs, and wires. Spray them with water at night and look for arcing.

"constant misfire" Do you mean pinging?

Check that your timing belt is aligned correctly on the cam gear -- the distributor/aux shaft could be correct, which would show proper timing with a timing light, but the cam being off a tooth, or more, could cause pinging and lack of power.