Tip-in stumble...

[ssheen]

I had it on the car since December 2004. It is a Crane Fireball PS20. The mounting of the coil on the head may of been bad for it.

[Tony Hanna]

Yeah, I had one of the cheapie accel coils on my old Daytona. It was mounted to the engine too. Never had any problem with it, but then again it wasn't on there long. Definately sees more vibration that way though.

[gkcooper]

1. Remove your throttle body and clean it with some carb cleaner
(pay special attention to the edges of the butterfly and corresponding surfaces of the barrel)
2. Allow the engine to warm up until the fan cycles on-off once
3. Disconnect your coolant temp sensor (fan turns on)
4. Set your base timing to the correct indication
5. Adjust the adle set screw to the indicated rpms

If you still have tip-in issues after this it could be a result of a defective MAP sensor (plugged MAP line), Fuel Pressure regulator, sticky injector(s), clogged air filter, oil in intercooler, fouled spark plugs, defective plug wires, etc.

[ScottD]

What about a faulty coolant temp sensor also?

[Tony Hanna]

Thanks for the tips guys. John and I got the bottom end straightened out today, so I should be back to tracking this stumble soon.

[CSX321]

I know this is a really old thread, but I've got a very similar problem with the new engine in the '87 CSX. It had been running reasonably well for about a month, then two things changed: it got a lot colder, and at about the same time I dumped a can of Seafoam in a tank of gas. For about a week now, it's fine at startup, then at exactly the same place on the way to work it stumbles badly at tip-in for about a minute, then fine again until the next morning. I'm pretty certain it was right when it switched to closed loop. Today was different. It stumbled right away when I started it. Died several times in fact. Then, after it warmed up a bit, but not to operating temperature, it was fine, including the switch to closed loop. No codes.

It's got +40s, 3-bar, 255lph pump, S60 turbo (the one w/stock turbine side), running a cal from Rob. It's got a stock FPR on it right now, but I haven't actually checked the pressure yet. I don't know if the Seafoam triggered it, or something else.

Edit...It was fine at lunch, of course. I expect it will be fine on the way home, too, and not act up again until tomorrow morning. ¯\_(ツ)_/¯