Misses then runs fine

[notaprob]

hey! I have been reading on here for the past couple of years and figuring out issues with my truck. This is the first time that I have been stumped and I would like to get my problem resolved before school starts.

I have a 1994 4.0 4x4 5 speed ranger. My friend said it was a push rod and not SOHC. Here is what it does. It starts fine, idles fine(most of the time), and when I go to dive it, sometimes it will take off like normal and then start to miss. Whenever it starts acting up the check engine light comes on, engine boggs down and the tach goes crazy. The tach falls to zero and bounces around and sometimes it backfires but then all of a sudden the engine will jerk kind of hard and it will run fine and the tach will read correct and the check engine light will go away. It acts up at any rpm and at any temperature.

The things I have done to it is:
-replaced spark plugs and wires
-ohm-ed out the coil pack (read the same as a new one)
-cleaned MAF
-replaced TPS
-checked vacuum lines(plugged off the ends and put a vacuum tester on it)
-replaced crank shaft sensor
-oil level is full
-timing is -10

Does my engine have a cam shaft sensor?
Could it be the computer or module for the coil pack?
Do you think it is an ignition problem? Maybe fuel problem?

After all of that I still had no luck so I took it to a mechanic that was recommended to diagnose problems. He had it for 2 days and he said my tach had a short and that he fixed it, and then he said it runs bad because it has a blown head gasket. But how can I have a blown head gasket if i don`t have water and oil mixing, not overheating, and all of the cylinders have the same compression and no smoke coming out of the tail pipe? And the tachometer still does what it had been doing (not fixed)....Sorry for the rant! I just had to throw that in there. Your advice/suggestions will be greatly appreciated!!

 

[Explorin94]

Camshaft sensor, no it does not. In front of the battery is the EDIS Module, should be hanging in front of it. If it is not look under it. Once you find it check to make sure that it is plugged in all the way. This is what it looks like.

 

[notaprob]

Yes it was in front of the battery. I took it off and cleaned the connections with electrical cleaner, plugged it back in and bolted it on and it still does the same thing. However, when I had it off, the seem of the module was kind of loose. When I pushed on the seem it was bubbling out the electrical cleaner that I sprayed on it.

 

[PlumCrazy]

There is a cam sensor. It controld fuel timing and the tach.

The cam sensor sounds like the culprit. The sensor is located on the rear of the engine in top, you may have to remove the upper intake to gain access to it. The sensor is on top of the oil pump drive, looks like the lower half of a distributor. Do NOT loosen the bolt holding the drive to the block since it is timed and requires a tool
time it correctly. You can remove the sensor itself by removing the two screws.

The oil pump drive may on its way out aswell, they are known to strip out, I believe a new drive will come with the install tool.
-PlumCrazy

 

[notaprob]

So you are saying that it is on the outside of the motor but underneath the intake? I thought I looked underneath close enough the other day but I couldn't see it. I even looked in the Haynes manual and I couldn't find it in the wiring diagram. I will check again though.

 

[PlumCrazy]

Yes. It is located where the distributor is on the older models.

-PlumCrazy

 

[modelageek]

hey! I have been reading on here for the past couple of years and figuring out issues with my truck. This is the first time that I have been stumped and I would like to get my problem resolved before school starts.

I have a 1994 4.0 4x4 5 speed ranger. My friend said it was a push rod and not SOHC. Here is what it does. It starts fine, idles fine(most of the time), and when I go to dive it, sometimes it will take off like normal and then start to miss. Whenever it starts acting up the check engine light comes on, engine boggs down and the tach goes crazy. The tach falls to zero and bounces around and sometimes it backfires but then all of a sudden the engine will jerk kind of hard and it will run fine and the tach will read correct and the check engine light will go away. It acts up at any rpm and at any temperature.

The things I have done to it is:
-replaced spark plugs and wires
-ohm-ed out the coil pack (read the same as a new one)
-cleaned MAF
-replaced TPS
-checked vacuum lines(plugged off the ends and put a vacuum tester on it)
-replaced crank shaft sensor
-oil level is full
-timing is -10

Does my engine have a cam shaft sensor?
Could it be the computer or module for the coil pack?
Do you think it is an ignition problem? Maybe fuel problem?

After all of that I still had no luck so I took it to a mechanic that was recommended to diagnose problems. He had it for 2 days and he said my tach had a short and that he fixed it, and then he said it runs bad because it has a blown head gasket. But how can I have a blown head gasket if i don`t have water and oil mixing, not overheating, and all of the cylinders have the same compression and no smoke coming out of the tail pipe? And the tachometer still does what it had been doing (not fixed)....Sorry for the rant! I just had to throw that in there. Your advice/suggestions will be greatly appreciated!!

Maybe I am missing something, but did you say the CEL comes on and off and then you proceeded to never check for codes?

 

[modelageek]

There is a cam sensor. It controld fuel timing and the tach.

The cam sensor sounds like the culprit. The sensor is located on the rear of the engine in top, you may have to remove the upper intake to gain access to it. The sensor is on top of the oil pump drive, looks like the lower half of a distributor. Do NOT loosen the bolt holding the drive to the block since it is timed and requires a tool
time it correctly. You can remove the sensor itself by removing the two screws.

The oil pump drive may on its way out aswell, they are known to strip out, I believe a new drive will come with the install tool.
-PlumCrazy

I don't own a 4.0 and I have never worked on a 4.0, however from my reading over the years I thought the camshaft positioning senor in the 4.0 came out in 1995 as they were switching over to the obd-II. You should have an obd-II port in your 1995?

 

[notaprob]

I took it to Oriellys and their free, cheap computer could not get the codes. It was meant to read obd2 but it had obd1 hook ups and I tried but it failed. That's why I took it to a mechanic to diagnose it for me and he dint tell me all of the codes but one of them was an ignition problem. In all reality, checking for codes on an obd1 is almost pointless. It may help narrow it down a little but saying that there is an ignition problem is still too braud.

 

[modelageek]

Also I did not see your location or your tranny type in your sig. I did notice that you have a 5 speed. In California in 1994 they started to switch over and add Cam sensors in some models. I know a 1994 Cal 2.3 has a camshaft positioning sensor but the other 49 states do not. I am not sure if the 1994 4.0 cal engine switched to a Camshaft sensor. I think some earlier 5 speeds had a cam sensor....................but as I said in my first post............WHAT ABOUT CHECKING FOR CODES.!!!!!!!!!

 

[modelageek]

I took it to Oriellys and their free, cheap computer could not get the codes. It was meant to read obd2 but it had obd1 hook ups and I tried but it failed. That's why I took it to a mechanic to diagnose it for me and he dint tell me all of the codes but one of them was an ignition problem. In all reality, checking for codes on an obd1 is almost pointless. It may help narrow it down a little but saying that there is an ignition problem is still too braud.

checking for codes on an obd-I is pointless........where did you learn that..... a Ford Dealership ...........since it is pointless I guess you are not going to bother...but I think the reader is only $20 and the manual method is FREE........but if it is pointless...

 

[modelageek]

I took it to Oriellys and their free, cheap computer could not get the codes. It was meant to read obd2 but it had obd1 hook ups and I tried but it failed. That's why I took it to a mechanic to diagnose it for me and he dint tell me all of the codes but one of them was an ignition problem. In all reality, checking for codes on an obd1 is almost pointless. It may help narrow it down a little but saying that there is an ignition problem is still too braud.

did the brain surgeon mechanic do a Block check on your engine?

 

[PlumCrazy]

Yes, my 95 is OBD2.

I thought all DIS 4.0's had a cam sensor. I could be wrong.

-PlumCrazy

 

[modelageek]

Yes, my 95 is OBD2.

I thought all DIS 4.0's had a cam sensor. I could be wrong.

-PlumCrazy

Like i said I am not positive either. I thought the cam sensor was added when they did the obd-II upgrade.....for what it's worth I checked rockauto and they do not show a cam sensor for the 1994 4.0 but do show one for the 1995 4.0..............

 

[notaprob]

I done some more research and I confirm that my 1994 4.0 does not have a cam shaft sensor or E.G.R. valve.