Misfire/Lack of Power/CEL

CubicInch · 02-09-2012, 02:54 PM

If anyone could read these problems over and try to help me figure out what is wrong with my truck, it would be a great help

'96 Explorer, 4.0 OHV. ~235k miles

DTCs
P1405 DPFE Sensor Upstream Hose Off/Plugged *Solved*
P0420 Bank 1 CAT Efficiency Below Limit
P0301 Cyl 1 Misfire
P0305 Cyl 5 Misfire

Symptoms
Lack of Power

Slow Acceleration
CEL blinks while accelerating
Can't go above about 3000 RPM
Becomes slightly better after adding coolant (there is a coolant leak)
Performance has been deteriorating over the past year
This problem happened prior to the misfire
Fuel Additives, higher octane fuel, and I think (but am not sure) higher amounts of fuel make the truck run much nicer

Misfire

Shakes
OBDII Reads Cyl 1&5 Misfire
Started off as intermittent, within the past week has been consistent.

Notes

Problems worsened after running out of fuel.
One time, when I reached about 5.5k rpm, I heard a noise that sounded like a hose rupturing and pressure being released. Ever since, there has been a noise any time the gas is pressed, scaling with RPM. There was no immediate performance problems however. *Solved* (Turns out a EGR hose was unplugged causing this noise and a slight performance hit. I think the hose blew off under pressure?)

Hypothesis

Fuel pump - Replaced filter, resulted in a very slight increase in performance. Truck feels like it isn't getting enough fuel
Injectors - possibly clogged with sediment after running out of fuel?
Deteriorating cat causing restricted exhaust (Goes along with code P0420)
My spark plug wires are shot, could be causing misfire. That's the next thing i will replace

Any input would be greatly appreciated

*Dono* · 02-09-2012, 10:33 PM

do you know where your coolant is going? This could be another symptom of the big picture.

CubicInch · 02-10-2012, 07:22 AM

Ya - its going all over my driveway lol. I don't know exactly where its coming from, however my radiator does seem to be covered in coolant. I've also been told that one of the many sounds coming from the engine could be the water pump, however I have not been able to figure anything out in that regard

*Dono* · 02-10-2012, 08:21 AM

Sounds like you have multiple issues. Is this your daily driver?
You might want to do a compression test, on the offending cylinders, for sure.

You might have blown lower intake gasket. The coolant might be leaking inside the motor, and outside the motor.

When you have a look at the spark plugs on the cylinders that are not firing, can you see a slight crack in the porcelain? When you put a fresh plug in, do the cylinders work ok for a while?

Could be injector issues, but two cylinders? Fuel pump?? Maybe check fuel pressure, but it also seems odd that only two cylinders are affected.

Original heads on the motor?

CubicInch · 02-10-2012, 09:33 PM

Yes original heads as far as I know. Today, i fixed error 1405 and the engine sounds alot better and is running much smoother, however is still misfiring. Also found today that plug wires are shot, gonna replace them and see what happens

*Dono* · 02-10-2012, 11:57 PM

lets hope thats it!

CubicInch · 02-11-2012, 02:39 AM

So today i ran it with $20 Premium, and it feels now like the misfire is the only problem...When I go back to regular it will run like shit again. Any thoughts?

*Dono* · 02-11-2012, 11:20 AM

nope. pretty odd. do you have a compression tester? it sure would be nice to know for sure that you have good compression. i kinda doubt it will be an issue, but it would help rule out valves as an issue.

CubicInch · 02-11-2012, 03:11 PM

No i dont but my old votech does. Also want to check the fuel pressure at the rail, but i need a right angle connector to get to it

02-09-2012, 02:54 PM	#1
CubicInch Wannabe Elite Explorer Red Bank NJ 96 Explorer XL Join Date: Jan 2011 Posts: 9 Vehicle Specs (Original Poster)	Misfire/Lack of Power/CEL If anyone could read these problems over and try to help me figure out what is wrong with my truck, it would be a great help '96 Explorer, 4.0 OHV. ~235k miles DTCs P1405 DPFE Sensor Upstream Hose Off/Plugged Solved P0420 Bank 1 CAT Efficiency Below Limit P0301 Cyl 1 Misfire P0305 Cyl 5 Misfire Symptoms Lack of Power Slow Acceleration CEL blinks while accelerating Can't go above about 3000 RPM Becomes slightly better after adding coolant (there is a coolant leak) Performance has been deteriorating over the past year This problem happened prior to the misfire Fuel Additives, higher octane fuel, and I think (but am not sure) higher amounts of fuel make the truck run much nicer Misfire Shakes OBDII Reads Cyl 1&5 Misfire Started off as intermittent, within the past week has been consistent. Notes Problems worsened after running out of fuel. One time, when I reached about 5.5k rpm, I heard a noise that sounded like a hose rupturing and pressure being released. Ever since, there has been a noise any time the gas is pressed, scaling with RPM. There was no immediate performance problems however. Solved (Turns out a EGR hose was unplugged causing this noise and a slight performance hit. I think the hose blew off under pressure?) Hypothesis Fuel pump - Replaced filter, resulted in a very slight increase in performance. Truck feels like it isn't getting enough fuel Injectors - possibly clogged with sediment after running out of fuel? Deteriorating cat causing restricted exhaust (Goes along with code P0420) My spark plug wires are shot, could be causing misfire. That's the next thing i will replace Any input would be greatly appreciated Last edited by CubicInch; 02-13-2012 at 10:21 AM.

02-09-2012, 10:33 PM	#2
Dono Supercharged OHV Winnipeg, Manitoba 00 Explorer XLT 4.0 OHV Join Date: Feb 2009 Posts: 2,025 Vehicle Specs	do you know where your coolant is going? This could be another symptom of the big picture. __________________ Rebuilt 4.0 OHV with about 6000 kilometers. M90 Supercharged. Tuned by James Henson. 422 cam, dual rate springs, si valves, polished combustion chambers, Rebuilt lifters and 30 thou shaved heads. Headers, and custom exhaust. Water/meth injection. Aftermarket projector headlights w HID's. Electric fan. DELTA RV CAM FOR SALE. low miles on it.

02-10-2012, 08:21 AM	#4
Dono Supercharged OHV Winnipeg, Manitoba 00 Explorer XLT 4.0 OHV Join Date: Feb 2009 Posts: 2,025 Vehicle Specs	Sounds like you have multiple issues. Is this your daily driver? You might want to do a compression test, on the offending cylinders, for sure. You might have blown lower intake gasket. The coolant might be leaking inside the motor, and outside the motor. When you have a look at the spark plugs on the cylinders that are not firing, can you see a slight crack in the porcelain? When you put a fresh plug in, do the cylinders work ok for a while? Could be injector issues, but two cylinders? Fuel pump?? Maybe check fuel pressure, but it also seems odd that only two cylinders are affected. Original heads on the motor? __________________ Rebuilt 4.0 OHV with about 6000 kilometers. M90 Supercharged. Tuned by James Henson. 422 cam, dual rate springs, si valves, polished combustion chambers, Rebuilt lifters and 30 thou shaved heads. Headers, and custom exhaust. Water/meth injection. Aftermarket projector headlights w HID's. Electric fan. DELTA RV CAM FOR SALE. low miles on it.

02-10-2012, 11:57 PM	#6
Dono Supercharged OHV Winnipeg, Manitoba 00 Explorer XLT 4.0 OHV Join Date: Feb 2009 Posts: 2,025 Vehicle Specs	lets hope thats it! __________________ Rebuilt 4.0 OHV with about 6000 kilometers. M90 Supercharged. Tuned by James Henson. 422 cam, dual rate springs, si valves, polished combustion chambers, Rebuilt lifters and 30 thou shaved heads. Headers, and custom exhaust. Water/meth injection. Aftermarket projector headlights w HID's. Electric fan. DELTA RV CAM FOR SALE. low miles on it.

02-11-2012, 11:20 AM	#8
Dono Supercharged OHV Winnipeg, Manitoba 00 Explorer XLT 4.0 OHV Join Date: Feb 2009 Posts: 2,025 Vehicle Specs	nope. pretty odd. do you have a compression tester? it sure would be nice to know for sure that you have good compression. i kinda doubt it will be an issue, but it would help rule out valves as an issue. __________________ Rebuilt 4.0 OHV with about 6000 kilometers. M90 Supercharged. Tuned by James Henson. 422 cam, dual rate springs, si valves, polished combustion chambers, Rebuilt lifters and 30 thou shaved heads. Headers, and custom exhaust. Water/meth injection. Aftermarket projector headlights w HID's. Electric fan. DELTA RV CAM FOR SALE. low miles on it.

02-10-2012, 07:22 AM	#3
CubicInch Wannabe Elite Explorer Red Bank NJ 96 Explorer XL Join Date: Jan 2011 Posts: 9 Vehicle Specs (Original Poster)	Ya - its going all over my driveway lol. I don't know exactly where its coming from, however my radiator does seem to be covered in coolant. I've also been told that one of the many sounds coming from the engine could be the water pump, however I have not been able to figure anything out in that regard

02-10-2012, 09:33 PM	#5
CubicInch Wannabe Elite Explorer Red Bank NJ 96 Explorer XL Join Date: Jan 2011 Posts: 9 Vehicle Specs (Original Poster)	Yes original heads as far as I know. Today, i fixed error 1405 and the engine sounds alot better and is running much smoother, however is still misfiring. Also found today that plug wires are shot, gonna replace them and see what happens

02-11-2012, 02:39 AM	#7
CubicInch Wannabe Elite Explorer Red Bank NJ 96 Explorer XL Join Date: Jan 2011 Posts: 9 Vehicle Specs (Original Poster)	So today i ran it with $20 Premium, and it feels now like the misfire is the only problem...When I go back to regular it will run like shit again. Any thoughts?

02-11-2012, 03:11 PM	#9
CubicInch Wannabe Elite Explorer Red Bank NJ 96 Explorer XL Join Date: Jan 2011 Posts: 9 Vehicle Specs (Original Poster)	No i dont but my old votech does. Also want to check the fuel pressure at the rail, but i need a right angle connector to get to it