89 Merc CP Stumbles or stutters 5.0

thats a nice article. Ive been able to isolate the problem, and can induce it most times when im explaining it to someone in person.

I can feel the misfire sometimes under load, and sometimes at idle, in park or in gear.

Sometimes when under load, say pulling a hill, the misfire will be present, and halfway up the hill it goes away and i have full 8 again. Being an 89 model with obd1, the availability of the scan tools the article mentions is a problem.

I know its worse with headlights or AC on, but not sure if its from the power drain, or the extra pull on the engine from the alternator. I also know it only does it in closed loop, once the computer is reading the sensors. I also know that when the orange ground wire is unhooked from the block, i dont get a misfire, but i burn lean and overheat the transmission but i dont get a temperature warning light.

 

Finally got to take the car to a friend of a friend who put it on the scan tool for free. good thing too, since there were no stored codes, and no current faults.

 

I helped a guy yesterday on the side of the road. He was traveling from Florida to southwest Canada in a 1946 Cadillac, via Las Vegas. He had similar issues but on a much simpler set up.

The coil wire was not snug in coil and the negative battery cable could be removed by hand. Correcting these was all it took.

10 minutes later that was one happy traveler.

Keep us posted

 

he was driving a 46 caddy cross country? thats cool!! did you get pics??!

i have a feeling somewhere, something isnt tight, but i just cant find it. my alternator is really loud under a load so im going to borrow a known good one and see how it does. For the thing to begin running correctly halfway up a hill seems like something turning on or off. ive been chasing this on and off for almost 3 years, so maybe one day ill find it

 

A picture of the Cadillac as referenced above.

It was high quality...

 

Nice one. In Al Capone Green too. Hope he had some A/C. or maybe hes built from better stock than I am.

 

That's beauteous! My grandfather had a 42 Cadillac(the model just prior to the 46 with the war interruption), although I never saw it of course. Maybe I'll run across some pics someday.

 

You might have a clogged converter on the right side, since your #8 fouls out the worst. A clogged converter (or a muffler, as well) will make a car run much like you've described. Since you've had two engines, and the electrical seems to check out, I'd check the exhaust system.

 

There was a tsb out for inductive crossfire between plugs 7-8 on ford v-8 from 87-93. Make sure your plug wires for both these plugs are separated as much as possible. I had a sputtering issue on mine and this and retiming the engine solved it for me.

 

I had forgotten all about that little problem! There is also the issue of the 3/4 wires being too close together. These Windsors, both the 302 and the 351, have eccentric firing orders, although they are different between the two engines. make sure you have the firing order correct for your vintage of 302 cam.

 

OK, warrantied out the plug wires and installed new set yesterday. has more power, but still has the little bogging feeling going up hill or accelerating on flat road in the upper gears.

just for giggles, i pulled a plug wire from the dist cap, and saw arcing again. it looked like all over the place, but it was only coming from the coil wire, and around the coil, it looked like little arcs spinning around the coil.

so i reconnected that wire and pulled a wire from the back of the dist, thinking th proximity was the problem and would arc other wires, but no. just the coil wire and coil again.

thoughts on this?