1997 Ranger 2.3 - Rough Idle/Stalls after Cleaning EGR

[CAJones]

Thanks for everyone who has posted content on how to do stuff, I have used Ranger Station quite a bit already!

I just bought a '97 Ranger 2.3 with a 5 speed manual to use as a shop truck. The engine was rebuilt by the previous owner who was a mechanic, it now has 150k on it since it was rebuilt.

It has thrown three codes total:
When I first got it a month ago it threw 401 (EGR flow insufficient) and 420 (catalyst system efficiency below threshold). I replaced the O2 sensors as they were cheap from Rock Auto and it passed Washington emissions, however they came back on my way home from emissions testing. It just gifted me 301 (cylinder 1 misfire) and now a blinking check engine light, which it did about a mile from my house so it hasn't been driven long with the misfire.

I changed all eight spark plugs, since I don't know when they were last changed) with Autolite A104 (~0.045 gap on each one) and AC Delco 954Q plug wires. I also found a blocked passage from the EGR into the intake, I cleaned that out hoping it would resolve the 401 issue. I also cleaned the IAC as well with carb cleaner. The battery was unplugged overnight to reset everything.

Here are the symptoms I now have:
-Rough/bouncing idle to the point it is undriveable unless I use way to much gas to get it smooth
-If I step on the gas, the engine seems to run just fine
-Strong smell of gas from exhaust
-I can't test the EGR valve or really anything else because it dies immediately.
-Fill the tank up twice so far, average was 20 and 22 MPG.

It won't throw any codes since I can't drive it for it to reset all of the computers. Not sure what to check/change now to get it to at least idle on its own.

 

[adsm08]

Remove the EGR valve and see if you can blow through it. It sounds to me like you have some EGR flow when you shouldn't, which could be caused by a piece of carbon getting stuck in the valve and blocking it open a little.

 

[CAJones]

Remove the EGR valve and see if you can blow through it. It sounds to me like you have some EGR flow when you shouldn't, which could be caused by a piece of carbon getting stuck in the valve and blocking it open a little.

Found the problem, a hose on the bottom of the intake to the EVAP system wasn't connected, hidden by the intake header. Just to be sure, I removed the EGR valve and blew through it, couldn't. Checked to make sure the valve goes up and down and it does. So the EGR is all good.

It starts and idles consistently now, but it's still misfiring, I can feel it when driving. There is a shuttering feeling under acceleration is noticeable. Now to figure out how to diagnose that problem....

 

[telsar]

Buy a cheap scanner that will work with your phone.

Watch Youtube videos of how to troubleshoot your problems.

 

[CAJones]

Buy a cheap scanner that will work with your phone.

Watch Youtube videos of how to troubleshoot your problems.

My scanner didn't work in the Ranger but works on my wife's Toyota so I bought another one off Amazon.

Fuel injector shows 15 ohms of resistance. Fuel pressure is 38 PSI in KOEO and 30 PSI when the engine is running. Seems normal from what I have read so far.

Checking DPFE
Signal - 0.7 volts at idle, increase to 1.2 and then drops back to 0.7 when I hit the gas. When I unplugged the connection, the signal rose to 5 volts. Seems like the DPFE is bad too.
Ref - 0 volts
Power - 5 volts

 

[smo1997]

My scanner didn't work in the Ranger but works on my wife's Toyota so I bought another one off Amazon.

Fuel injector shows 15 ohms of resistance. Fuel pressure is 38 PSI in KOEO and 30 PSI when the engine is running. Seems normal from what I have read so far.

Checking DPFE
Signal - 0.7 volts at idle, increase to 1.2 and then drops back to 0.7 when I hit the gas. When I unplugged the connection, the signal rose to 5 volts. Seems like the DPFE is bad too.
Ref - 0 volts
Power - 5 volts

Hey man. Having some problems with my ranger that sound similar. It’ll come on (roughly) then idling like crap it bounces around then comes down to about ~2-300 and dies. Replaced EGR and IAC valves but now it just runs erratically. Did you ever replace the DPFE? Don’t want to buy a $50 part if I don’t need to