High rpm limits???

I've got a 1990 Dodge Dakota with the 3.9 V6 in and have a real weird miss at high rpm. I checked and replaced the plugs,wires and coil and distributor but still it keeps showing up. I don't see it during normal driving but only if I put it in park and rev the engine up. I was trying to trace it to a cylinder by putting sparkplug test lights on three cylinders at a time but all I saw was a dimming of all three of the lights when the engine starts to miss almost like the entire ignition system is dampening. Does anyone know if there is some kind of rmp limiting programing in these engines?

Bill

Reply to
Bill
Loading thread data ...

This is a pre-Magnum 3.9, correct? Holley throttle-body fuel injection? I know the Magnums have rev limiting, but my knowledge of the pre-Magnum system is thin, at best.

Reply to
Steve

Don't know if they did things like this in that era, but the late model LH's (and probably everything else) have a different rpm limit in neutral/park than when in gear. I believe it's 4000 rpm on my '99 Concorde - certainly goes well above that when in gear - may be wheel speed vs. engine rpm limited, but not sure - never tested it and don't intend to, but it's at 110 or 118 or something like that according to the forums (to go along with tire speed ratings).

Bill Putney (to reply by e-mail, replace the last letter of the alphabet in my address with "x")

Reply to
Bill Putney

And why are you abusing your engine this way?

Matt

Reply to
Matthew S. Whiting

Got pissed at poor idling and stomped it down in frustration. The place where it seems to cut out seems to be lower when its cold outside, not the engine itself just the ambient temp. This truck has all kinds of problems and I've been working on it for a year or so now. I take back what I said about not seeing it during normal driving, I was having problems again this morning and was really paying attention to the motor on the way to work and I think that the clank I'm feeling when I'm at highway speed with a constant gas pedal might be the miss. It's a brief moment where the motor seems to slack off like I've let off on the pedal and the trani has to slow down to match the engine speed.

I did replace the ECM and it has gotten better but still no where close to normal.

Bill

Reply to
Bill

hey bill I recommend you join the DML (dakota mailing list) you can locate them at dakota-truck.net, if its about the dakota they know.

Punch

Reply to
Punch

MotorsForum website is not affiliated with any of the manufacturers or service providers discussed here. All logos and trade names are the property of their respective owners.