Runs rough - spark plug doctors? Options

[torakki]

On my '74 2.0, I can't get it to run right. It's gone through a restoration and put aside for 2 years. Now, back on it and it's almost done but[b] number 1 and 4 spark plugs are clean/wet and 2 and 3 are black, (after 10 seconds of running). What I've done so far: Rebuilt MPS, gapped points, static timing, set fuel pressure at around 27 lbs. Compession between 90 and 110. Plugs are sparking. All injectors spray (not sure of pattern). I believe plugs were new 2 years ago. They look new. It runs really rough, white smoke out exhaust and some mild popping. I though, maybe injector triggers but all are working from my, spray in the cup, test. Dizzy backwards? Any ideas to what's going on??
Thanks for any suggestions.

[bbrock]

You say you set static timing but not dynamic timing? If not, I would start there. Static timing only gets you close enough to start the engine.

[VaccaRabite]

You need to do all the basics. (In this order)
Check valves. If they are not in spec, set them.
Do your timing (has to be set at 3k rpm)
Do your dwell
Change fluids (oil and gas)
Do compression with a hot engine, open throttle. See if your number come up. 90 is near rebuild.

Then you can worry about spark plugs. Right now you have no baseline. Get the basics done and go from there.

Zach

Ps: if your dizzy was backwards your car would not run and you would shoot fireballs out the intake. Fun times!

[JamesM]

Rebuilt MPS

How did you recalibrate your MPS after it was "rebuilt"?

While its possible you have multuple issues here, I suspect the major problem(s) all have to do with your injection.

First off, looks like you are running really rich so need to check all the things assoicated with that MPS, Head temp sensor resistance, leaking cold start valve etc. Really suspicious of of the MPS given its been apart.

Second, only thing shared between cylinder 1 and 4 is the injector bank, same with 2 and 3. so it looks as if your two injection banks might not be delivering the same fuel (one bank rich and sooting up the plugs and the other bank is SO rich its not allowing firing at all.) though what would cause that im not exactly sure, would have to be electrical though.

Either way you seem to be really rich so I would sort out that issue first and go from there. Might help if you can get access to a known good parts that match your car and try swapping things out.

[JamesM]

I have to ask, does the picture match the position in which they were taken out of the car or do the numbers next to the plugs represent the actual cyl number they were pulled from?

Just want to be clear here as 1 and 3 are opposite each other on the motor (Rearward most plugs) as are 2 and 4(forward plugs).

Makes a difference if you are seeing matching patterns on plugs directly across from each other or diagianal across from each other.

[Tom_T]

On my '74 2.0, I can't get it to run right. It's gone through a restoration and put aside for 2 years. Now, back on it and it's almost done but[b] number 1 and 4 spark plugs are clean/wet and 2 and 3 are black, (after 10 seconds of running). What I've done so far: Rebuilt MPS, gapped points, static timing, set fuel pressure at around 27 lbs. Compession between 90 and 110. Plugs are sparking. All injectors spray (not sure of pattern). I believe plugs were new 2 years ago. They look new. It runs really rough, white smoke out exhaust and some mild popping. I though, maybe injector triggers but all are working from my, spray in the cup, test. Dizzy backwards? Any ideas to what's going on??
Thanks for any suggestions.

There are all sorts of plug condition charts out there if you google for it, & this one is from Champion:

https://www.austincc.edu/wkibbe/plugchart.pdf

The 2 marked 2 & 3 look to be carbon fouled if dry or oil fouled if wet -
& you said 1 & 4 were "wet" - is that H2O moisture or fuel?

White smoke is either moisture (H2O) if it dissipates in the air, or oil if not.

90 - 110 lbs seems low at the 90s one(s) - but correlate those to which plug. It could just be that the engine wasn't warm enough yet to get the rings to seat properly, & therefore also allowing some oil blow-by to cause the white smoke.

Popping sounds like a misfire.

Sitting for 2 years then run for 10 seconds - it's not going to get to operating temperatures, won't have time to burn off whatever collected in there, etc.

First - what's your fuel condition? Is it Unleaded left to sit for 2 years? Did you add stabilizer before storing it? Does it have water separation in the tank & now in the lines & injectors, etc. after running? You may have to drain & clean the tank & refill with fresh fuel, maybe lines too.

Then maybe clean off the plugs, get them back into the original cylinders, then let 'er run a bit longer for several minutes. Then assess by each on plug condition, exhaust & running - but correlate to the proper position & cyl. # & compression readings - as JamesM noted above.

If you get stuck on this & are close to the Bay Area part of NoCal, then there's HPH in Redwood City & a couple of other shops who know our 914s to get it running properly again.

Good Luck! (IMG:style_emoticons/default/beerchug.gif)
Tom
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[TheCabinetmaker]

Cylinders 1&3 injectors open together.
Cylinders 2&4 injectors open together.

Plugs that are wet with fuel indicates a no fire condition.
Plugs that are oil fouled indicates an oil control problem.

Unplug coil wire. Pull the fuel rails with injectors attached, and place each one in a small glass container. Have someone crank the engine. Each container should have the same amount of fuel. This will verify the trigger points are working properly.

[torakki]

OK, where to start. Lots of good info coming in. Let's start with my mistake. Yes, I wrote the numbers wrong per cylinder. It's 1 and 3 that are clean/wet and 2 and 4 that are dark black. Memory is starting to give me trouble. I'll try and respond to all the suggestions. So, as Cabnitmaker states, 1 and 3 injectors trigger together so maybe that's an issue. Matching patterns straight across. Also, I did crank engine with each injector, in a container, and all seem equal. The MPS, I set it to what it was origianly, per measuring with a caliper and counting the threads. Valve adjustment should be good (as of two years ago, I had engine out and covers off). Has fresh oil and filter and added a few gallons of gas to basicly an empty tank. Fuel going through filter seems like it's darker but consistant. I've tried moving the timing around with no difference. Wet plugs appear to be raw fuel. Two years ago, I would start it and it seem to run good but died after a few seconds. Culprit was the MPS. But, it got put on the back burner, other projects came in. Now, two years later and the engine has been out of the car (Wires and hoses off).

Things I need to do: Check cold start injector, let engine warm up a lot longer, compression test with open throttle and warm engine (last time was cold and closed throttle). Watch the spray pattern for each injector. I'll try timing but not sure with a blubbering engine.

It does seem like it's related to the 1 and 3 injectors. But, I'll try and sort out the basics first. Thanks for all the input and valubale knowledge. Hopefully, an update soon....

[914sgofast2]

Check the trigger points and wiring to them in the distributor. A problem with one pair of injectors not firing is probably related to the trigger points.

[torakki]

Update: Today, I started doing some of the things suggested. I pulled two left injectors out and had my wife crank the engine while I watched them. The spray pattern looked perfect and equal on both injectors. Remember, one was on the wet plug cylinder and the other was on the black carbon cylinder. I also cleaned all the plugs and reinstalled to get the engine warm for another compression test. I decided to put the plugs that were black in the cylinders that had the wet plugs. I ran the engine for a few minutes, (won't idle so it didn't get to warm), then took out the plugs. NOW!!! The plugs that were black, are now wet and the wet plugs are now black. Anyway, went ahead with compression, with throttle open, and the lower numbers came up a little. The higher numbers stayed close to the same.
But, I think I will go buy new plugs and wires and see what happens.
Thanks for the input and I'll update when I get a result.

[torakki]

Another Update:
I put in new plugs and still runs rough but "all" plugs black with carbon now. I then, leaned out the fuel pressure regulator all the way, so the adjusting screw is almost falling out. The car runs much better but plugs still black. I set the timing at between 2500 and 3000, on the red line. I was doing it alone so, holding the timing light with crossed arms, holding the throttle open, setting the light down, move dizzy, picking up light so it's "close". I checked the cold start injector for leaking. Bone dry. Did I forget anything?
I think it will run perfect if I could just get it leaned out more. Maybe, bad fuel pressure regulator? Wrong fuel pump?
Anyway, that's were I'm at. Any thoughts? Thanks for reading....

[JamesM]

Another Update:
I put in new plugs and still runs rough but "all" plugs black with carbon now. I then, leaned out the fuel pressure regulator all the way, so the adjusting screw is almost falling out. The car runs much better but plugs still black. I set the timing at between 2500 and 3000, on the red line. I was doing it alone so, holding the timing light with crossed arms, holding the throttle open, setting the light down, move dizzy, picking up light so it's "close". I checked the cold start injector for leaking. Bone dry. Did I forget anything?
I think it will run perfect if I could just get it leaned out more. Maybe, bad fuel pressure regulator? Wrong fuel pump?
Anyway, that's were I'm at. Any thoughts? Thanks for reading....

Rather than guess, get a gauge and check your fuel pressure. My bet is that you are leaning it out with the fuel pressure to compensate for another issue and as i said before, as the MPS was opened up that is highly susspect.

only two things I can think of that will cause the system to run rich to the point of stalling and that is an issue with the MPS or infinate resistance(broken wire) to the head temp sensor.

A failed fule pressure regulator is usually going to cause you to have low pressure, not high.