Rough Idle, Missing, Pulling my hair out.

[DasBaldDog]

Yep, tested the fuel pressure. Was good.

Found a tiny bit of gas in the vacuum line from the FPR and replaced the FPR to prevent a problem. No change in the performance.

 

[MrShorty]

And, if memory serves, you aren't getting any A/F mixture codes from the computer, correct? Do you have any other indications (condition of spark plugs, for example) that would tell you if it is running rich or lean?

Another thought: the sulfur smell comes from unburnt fuel. In addition to being from a rich mixture, that could also come from a misfire. Have you tried a cylinder balance test to see that all cylinders are contributing?

 

[DasBaldDog]

And, if memory serves, you aren't getting any A/F mixture codes from the computer, correct? Do you have any other indications (condition of spark plugs, for example) that would tell you if it is running rich or lean?

Another thought: the sulfur smell comes from unburnt fuel. In addition to being from a rich mixture, that could also come from a misfire. Have you tried a cylinder balance test to see that all cylinders are contributing?

Spark plugs are inconclusive. They look grayish.

No codes at all from computer.



When you say balance test, if you mean the GOOSE test during the KOER, then yes and I get no codes.

 

[hawkfire1]

Hello.
The 1994 ranger V6 4.0 was offered factory direct with cali emmlssions (egr and cmp) and with no egr or cmp.

The 94 no egr injectors are batch fire and have the 3 wire harness instead of the 7 wire sequential fire harness that the 93/94 with egr come with.

You cannot do a cylinder balance test using the pcm for batch fire.

If you replaced only one or two injectors vs replacing the whole bank, you might have flow issues or injectors stuck open.

I had a similar issue to yours but what cured mine is a teardown and rering due to coked up rings on cylinder 3.

Compression was good with all cylinders at about 158-159 except for cylinder 3. Cylinder 3 was 140 which the book says is within spec.

Dropped some oil in number 3 and pressure went up to 161 so teardown and rering it went and no problems since.

I went through it all as well.

Replaced vacuum lines, coil pack, plugs and wires, air and oil filter with oil, all ground wires, all 6 relays, fuel pressure regulator, fuel pump and filter, 6 injectors and the wire harness, thermostat ,TPS, AIT, IAC, ECT and CPS with harness, PVC valve were also installed.

But the rering, and gasket replacement solved my poor idle and miss.

Your milage may vary.

 

[DasBaldDog]

A teardown and rering are beyond my financial abilities to hire someone and will take too much time for me to complete by the time winter will hit us.... Especially since my car is in the shop for a collision.

So I am going to try and clean/check the flow on the injectors again. If they seem okay and no improvement comes from it, I'm selling the truck. I've spent over a year and several hundred dollars fixing it, and I'm done. At this point I will sell it and buy something else before I spend $1000+ getting someone to rering it or spend 20+ hours doing it myself.

And to make things worse, now the damned radio just hisses, no signal.

 

[DasBaldDog]

Okay,


Does anyone know what the small capacitor-looking thing that is located on the Ignition Coil Bracket below the coil itself is?

It's connected to the main wiring harness via a small gray box connector.

 

[Roadrunner777]

I have seen that same size/shape capacitor in other automotive applications, and they have always been for radio interference suppression.

Edit: I can now confirm this, shown in one of my diagrams as a Radio Noise Capacitor. For what it is worth, there is a wire from the ignition switch to the coil pack, the only apparent purpose of this wire is to supply the (+) leg to the actual coil primaries. (The coil pack switches the negative leg, which oddly enough is exactly how things worked in the old point/condensor distributors.) The capacitor is on the (+) lead I mentioned, probably to absorb any ac/rf being kicked back out from the coils.

 

[DasBaldDog]

Okay.

A side project to give me something else to focus on so I don't set fire to the truck in frustration.

Any idea why the radio suddenly gets nothing but static? Could I have unplugged the antenna or something? Anything I can check?

 

[Roadrunner777]

My first step would be to pull the radio and check the antenna lead.

 

[osteologation]

Does the harness have plugs for egr?

I guess I am having a hard time following ya, but a 93 engine will not work with a 94 harness. That is what I understand you have.

I know this is old but I put a 91 motor in a 94 using the 94 engine harness. Left the egr and cmp unplugged. Runs fine so far. Obvious cel but i am in a non inspection state.