Distributor acts like REV LIMITER

[Bear in the woods]

Also has new injectors. slightly bigger than factory. But doesn’t flood.

 

[Bear in the woods]

1990 with 2.9 and manual trans 4wd

 

[rusty ol ranger]

1990 with 2.9 and manual trans 4wd

90 only has one pump.

Have you pulled codes and checked fuel pressure?

 

[Bear in the woods]

No pressure tester. Need to do the codes I guess. definitely will show o2 sensor. But that won’t make It undrivable. Just miss and bad fuel mileage. Think this first started after a plastic vacuum line broke a couple times. Went to little black canister on firewall between the AC fan and engine

 

[Bear in the woods]

Checked my catalytic converter while it was acting up. Wasn’t hotter than normal. Either of them. And seemed to be blowing plenty of pressure out of the exhaust

 

[rusty ol ranger]

No pressure tester. Need to do the codes I guess. definitely will show o2 sensor. But that won’t make It undrivable. Just miss and bad fuel mileage. Think this first started after a plastic vacuum line broke a couple times. Went to little black canister on firewall between the AC fan and engine

Thats the MAP sensor line.

Its pretty important.

The MAP tells the ECM the amount of vaccuum in the intake so it can meter fuel correctly.

If its leaking or collapseing that could be the issue

 

[Bear in the woods]

The line going to the canister under the MAP

 

[rusty ol ranger]

My truck dont have that.

I think its just a vacuum resivor

 

[Bear in the woods]

When it was acting up this last time. I disconnected the MAP and it started doing a little better. Believe I need to do the rest of the freeze plugs as soon as possible. Starting to leak a little on one of em. Put another module on the new distributor. No more acting like a rev limiter. Cleaned the tank. Again. New pump sock. New inline filter. Cleaned IAC . Started cleaning the throttle body.. cleaned ground connections.. checked most all plug connections. Checked throttle position sensor, need to do again. Battery wasn’t fully charged. And my old ohms meter was acting up. Was reading 4.3 constant, was falling smoothly as accelerated. Rigged up a redneck “ cold air “ blower on my module/distributor area.
Old 90 is getting a little better each time. But really just bandaids till the 99 is up and running again.
Only transportation till the rangers are fixed for several months now has been the old 1991 Harley Davidson Softail Custom But it’s getting cold now. So these babies need to get back going soon.

 

[gw33gp]

I am not trying to redirect this thread, but the title reminded me that my 1970 2800CS BMW has a rev limiter in the distributor. I think it is in the rotor. There is a contact in it that is held closed by a spring. When the rpm gets to a specified rpm, the centripetal force overcomes the spring which opens the contact and shuts down or weakens the spark. That is not very good for emissions because unburned fuel goes out the exhaust.

One time I was taking a high-speed driving school at Riverside Raceway. A friend gave me some race fuel that he was not going to use. That resulted in my car getting the name of the flame car. I was over revving when shifting down into third while entering a high-speed corner. This would load up the exhaust with unburned fuel and when the spark came back on it would shoot a ten-foot flame out the tail pipe. If I was using pump gas it probably would have exploded in the exhaust pipe. The high-octane race fuel was slow enough burning that is just did a fast burn without exploding.

 

[Cees Klumper]

Maybe a long shot, but could it be a vacuum leak somewhere that gets worse as the engine heats up? I had that recently, due to poor seal at the intake manifold.

 

[Bear in the woods]

I’m thinking the rubber grommets in the valve cover. They are wore out. Not sure if vacuum would make one run so bad after heating up that it would barely move in low range. lol. But 30 minutes later. Drive like new. This thing has had me confused for a while.