Cylinder #3 suddenly not working.

[Mathew Zelezen]

I started the van to drive home after work last night and it sounded like I was only running on 3 cylinders. Rough idle and poor acceleration. It was after midnight so I limped the 2 miles home and poured a bottle of Heet into the tank thinking/hoping there might be some water in the gas.

This morning I tore into it and discovered that the exhaust pipe from #3 was cold while all the other pipes warmed up.
Maybe its a bad spark plug I thought. Switched the plugs between #3 and #4 with no change.
OK, maybe its a bad spark plug wire I thought. Switched the wires between #3 and #4 with no change.

Then I removed the valve cover to make sure all the valves were opening and closing and everything appeared to be normal.

This is a 3 year old motor with tons of new parts installed in June 18' in preparation for a cross country trip and up until now the only issue I've had was a wheel bearing failure in South Dakota and a failing coil which was replaced in Fort Collins.

I'm guessing the next step would be to swap the injectors?
I'm getting fuel to that side of the rail since #4 is chugging right along..

Anything else I should check that my little brain is missing?
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[crazyvwvanman]

compression test

[Abscate]

Inspect cap,rotor, and plug...you’ve done plug already.

Run compression on plug #3 while out

Fuel injection last.
_________________
.ssS!

[Zeitgeist 13]

Make sure that injector plug is getting a signal, and check the resistance value of the injector itself. Try swapping injector plugs between #3 and #4
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Mathew Zelezen]

Thanks all for the suggestions.

I'm currently on assignment and don't have my compression test kit with me (space in the van was limited so not all my fun tools made the cut) but I'll check the injector plug first for signal and then swap the injectors and report back.
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[Mathew Zelezen]

Found the culprit!

I wasn't getting a reading from the plug for cylinder #3 so I took it apart because I could see a little bit of corrosion.

Luckily I had some of these connectors handy from when I remade the engine wiring harness last year.
Cut back some of the wiring and crimped on a new pair and it fired right up.

I'm going to go thru and check the other three injector plugs and use some dielectric grease to prevent further corrosion.

Thanks for all the help!
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[Zeitgeist 13]

I had that same level of corrosion on the coolant temp plug. It broke off inside the boot.
_________________
Casey--

'89 Bluestar ALH w/12mm Waldo pump, PP764 and GT2052
'01 Weekender --> full camper
y u rune klassik?

[Mathew Zelezen]

Is Vaseline similar to Dielectric grease?

I have a tube lying around from a recent windshield install.
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[T3 Pilot]

Good quick solution...

You should wait to get a tube of silicone / dielectric grease because it will seal up the connectors better. Vaseline will melt in the heat and run out. Careful not to loose track of the rectangular silicone gaskets inside the female end of the plug they are hard to find...
_________________
1988 Vanagon

The most important part in every vehicle is the nut behind the wheel......

[Mathew Zelezen]

Will do.
Thanks for the heads up T3 Pilot!
_________________
87 Syncro Tintop
~Rocky J Motor
~Steedle Trans


Of all sad words of tongue or pen, the saddest are these: It might have been.

[E1]

It's almost always a simple fix.
_________________
‘84 Westy, 2.1L with Digijet, 5.43 R+P, GT Gears
"Adding power makes you faster on the straights.
Subtracting weight makes you faster everywhere."
— Colin Chapman