Very Strange 93 4.0 issue No Cam Synchronize......

[FEandGoingBroke]

Folks, 83 Ranger 4.0 as title says, NO cam sensor...

Runability issues are driving and the engine skips a beat on acceleration, less noticeable at higher rpms, but definitely still there.

Had water leak so I ordered a new cam sensor, because the new crank sensor changed nothing, the new coolant temp sensors changed nothing, cleaning the MAF sensor changed nothing, new coil pack changed nothing, new fuel filter, new TPS sensor changed nothing, Belden wires are only 12 months and 500 miles old, no issues with spark jump, plugs are only 500 miles old also.

This is definitely an Electrical issue, there's no popping or backfiring, just Missing on acceleration from NOT getting spark occasionally, and not quite evenly enough of misses to point to a single component other than the cam synchronizer synching with crank sensor... Which brings me to this point...

There is NO cam sensor in this block... Check the photo.... just a bolt holding a cover over the hole...

Pleas lend all brilliant thoughts, and the occasional toomfoolery replies as well.

Thanks! FE (Gary)

 

[RonD]

That's the Oil pump drive under there, not just a cap

4.0l OHV only got a Cam sensor/Synchronizer in 1995, but Calif sold Rangers required it, along with EGR valve, in 1993/4

O2 sensors need to be changed every 100k miles or 12 years, period, these are the only sensors that wear out, they use a chemical reaction to detect Oxygen and simply run out of the chemical in that time/mile frame

1990-1994 4.0l uses an EDIS-6 spark system
It consists of 3 parts, plus its wiring
Crank sensor
EDIS-6 module
Coil pack

Its a self contained spark system so popular with hot rodders for use on 4.0l other V6 engines
It can do RPM spark advance on its own, so autonomous for startup and idling
But does need input from the engine computer for Load Advance, i.e. Vacuum Advance on older distributor spark systems
Engine computer calculates Engine Load spark advance based on RPMs, MAF data and throttle position(TPS)
It sends that info to EDIS-6 module on the SPOUT wire
There is a SPOUT connector on that wire that can be removed, if it was pulled out or is loose then that would cause a hesitation in acceleration
In 1993 the EDIS-6 module is most likely on driver's side of Rad Support, on engine side OR on Grill side down low
The SPOUT connector will be on the EDIS-6 wiring harness but always on the engine side of rad support so close to the EDIS-6 module not close to computer end

Hesitation in acceleration can be a few other things
Obviously fuel pressure, should be 35psi and no lower than 25psi when REVing engine, dirty fuel filter can cause hesitation

TPS is a 5volt sensor, it gives the Computer a "heads up" when driver wants to accelerate, MAF sensor is way to slow for that
So the TPS serves the same purpose as the Accelerator Pump did in a Carburetor, instant throttle response
It has 3 wires
top wire is 5v
bottom wire is ground
center wire is voltage sent back to computer
spec is 0.69v to 0.99v throttle closed, under 1volt
4.5v to 4.8v throttle wide open(WOT)
So easy to test, key on/engine off
Should have a steady increase in voltage as you manually open the throttle slowly, no jumping/dropping of voltage

Spark plugs need a wide gap on the 4.0l, 0.054"

 

[FEandGoingBroke]

Well, there’s a new fuel filter new crank sensor new throttle position sensor and a new coil pack still did exactly the same thing so I am going to research the EDIS try to locate it on this rig check the wiring and also check my spout connector although them things are normally really hard to pull out so they rarely wiggle out on their own lol

 

[RonD]

"New" is the problem

"New" use to mean tested and working, back in the 1960's
New now means "YOU TEST IT and we will replace it if it doesn't work"

Sensors rarely fail(except O2s)
My 1994 4.0l has all the original sensors(except O2s), 450k+ miles

People like to replace sensors because its simpler than testing, and they "feel like" they are doing something positive, even pro-mechanics do that, lol, but you are not, just adds another layer of possible problems

So "new" just means you have a lot more things to deal with, if possible put back on all the old stuff that's been replaced, except fuel filter
spark plugs and fuel filter are OK to replace on speculation

Because its a 1993 it would be a good idea to pull out the computer and inspect its circuit board and to replace the 3 barrel capacitors on the board, under $2 fix
The capacitors leak after 20+ years and will cause odd running issues
Also unplugging the 60 pin connector on computer and plugging it back in cleans the pins/slots
All the sensors run on 5volts, well less, as 5v is max, so any slight corrosion changes the "return" voltage a lot

Once computer is off the table a the source of any running issues you can test sensors
First warm up the engine, 5min is fine
Let it idle
Unplug 2 wire connector on IAC Valve
RPMs should drop to 500 or so, or engine may even stall, either is GOOD, it means no vacuum leak
If idle doesn't drop you have a leak which can also cause the hesitation

 

[FEandGoingBroke]

Yes, new means testing, it’s not my truck and buddy said replace anything that could be the issue until it goes away . He’s got plenty of money and I’m short on time.

 

[FEandGoingBroke]

Gentleman there is NO hesitation, this is definitely a NO FIRE issue but random on acceleration, happens all the time, less noticeable at higher rpms at smooth cruise but still there but it’s not synchronus so it don’t happen at the same point every time. So after replacing the timing cover gasket putting in new water pump and both upper gaskets I’m going to dig deeper into the edis firing system.

 

[RonD]

And replace O2s

 

[alwaysFlOoReD]

Double check your spark plug porcelain for cracks.

 

[Eddo Rogue]

Everything @RonD said +1.

Also be glad you don't have one. That is a rare blessing. Mine keeps going bad and squeaking, despite hunting NOS OEM quality parts and following R&R procedure insanely and anally to a T. I'm sick of swapping a discontinued part. Thanks advanced modern civilization. Idiots.

Don't get me started on Cam synchro. it is the bane of my existence, other than the toyota prius.

 

[FEandGoingBroke]

OK new properly gapped double platinum plugs replaced all my intake gaskets that were leaking replace timing cover gasket etc. Ran the codes after driving it there are no codes I just get three ones.

On Acceleration in second on up it misfires and even produces a tiny pop now and then through the intake. Any suggestions?
It does have a new fuel filter the IAC motor is working correctly the TPS is working correctly the MAF is clean and it idles great, I am just coming up empty on this. Especially with no check engine light.

 

[RonD]

I would check the coil pack firing order
3 4
2 6
1 5
front

The 5 6 4 side is often wrong and you may not feel it at idle, just under load
Then check it AGAIN, lol
Also inspect coil pack for cracks

And a good test is to wait until dark and run engine while you look around coil and spark plug wires for ARCing, REV engine a few times while doing this

What you have is a misfire of course
Could be defective new spark plug, it happens
Dirty injector, try Seafoam in the gas tank, 1993 is Batch Fire injection, not sequential, so single injector issue wouldn't cause same cylinder to misfire all the time

When a cylinder misfires, the unburned air/fuel mix is dumped into exhaust and is partially ignited by last cylinder to fire's HOT exhaust, and exhaust valve is still open so some of that explosion goes into cylinder and out the intake valve when it opens, so "pop" out of the intake

Can also indicate LEAN air/fuel mix that ignites as it enters the cylinder, lean burn is very very hot, so if a cylinder has a lean mix, it gets hot inside so can ignite the air/fuel mix on entry, and "pop" out the intake
So possible dirty injectors, for either

But the basic thing is................... you need to find the cause of the misfire
Spark
Fuel
Compression
Missing 1 or more = misfire

 

[Shran]

other than the toyota prius.

Hater My wife's Prius has been a great car other than burning an obscene amount of oil between changes (guess "green" cars do that.)

 

[Eddo Rogue]

Hater My wife's Prius has been a great car other than burning an obscene amount of oil between changes (guess "green" cars do that.)

Lol maybe there's just so many of em....

Every time the fast lane is blocked by a slow driver....Prius.
Every time you are trying to back out of a parking space and get blocked in then honked at....prius
every time 3 parking spaces are reduced to one....prius.
every time the light turns green and nobody moves until its yellow....prius.

I can keep going....