What did I do or miss?, All better now! Options

[arne]

Background - I got the engine in my '73 2.0 (D-jet) running a while back (after several years slumber). It actually was running pretty decently, other than a spastic AAR. But it had many oil leaks, so I dropped it to get to everything easier.

While it was out, I replaced all the vacuum lines, and a bunch of oil seals and such. AAR was disassembled and refurbished (as best I could). Eliminated the decal valve. No other injection work.

Now that the engine is in the car, it is running way rich, even when warm. So much so that it loads up after a bit and won't rev, and left to idle it will load up and die. AAR now appears to be working fairly well, once warmed there is little or no vacuum at that hose.

Since there really weren't many changes, I'm thinking this must be something fairly simple. Any suggestions?

[ConeDodger]

Cylinder head temp sensor is disconnected?

[arne]

Cylinder head temp sensor is disconnected?

If so, it was an accident. I don't recall that I touched it. But will track it down to check.

[Rand]

It's running but way rich... Check the MPS. Does it hold a vacuum?

[arne]

It's running but way rich... Check the MPS. Does it hold a vacuum?

Will check to see if it holds vacuum. It used to...

I do have a second MPS that came with the car, so that is something I can change out if it seems necessary.

[arne]

MPS in the car now does hold vacuum. The "spare" that came with the car does not, so that's out.

Looking at the CHT sensor now.

[Dave_Darling]

A few things that come to mind that would make the mixture overly rich:

- CHT sensor unplugged or high resistance somehow.
- MPS does not hold vacuum, or hose to the MPS is unplugged or has a large leak.
- Fuel pressure is too high.
- Throttle switch is mis-adjusted, causing extra injection pulses.

Other things can cause it as well. Some of them are very weird... A few that have happened to me:
- Trigger points bounce, causing multiple injections.
- Failure of output stage transistor in the ECU, so the injectors do not get closed. (Warning: Can hydro-lock the motor!)
- Fuel pressure regulator hooked up backwards, leading to 50+ PSI fuel pressure.
- Intake valve seat failure, resulting in lots of blowback into the intake, raising the manifold pressure and richening up the mixture.
- Cold-start valve has failed open, spraying fuel into the intake all the time.

--DD

[arne]

Fuel pressure regulator hooked up backwards, leading to 50+ PSI fuel pressure.

I wonder if I got the fuel and return lines reversed? I thought I had them correct, but maybe...

[arne]

Fuel lines appear to be correct. Nothing is unplugged. Baffling. It ran pretty good before the engine drop, but not after.

[r_towle]

Unplug the car cold start injector electrically and pull both fuel hoses off and put a piece of tubing to connect them together, thus eliminating it from getting fuel.

Make sure all your injector grounds are connected to the multi spade connector.

Check fuel pressure on drivers side, after the regulator (I still vote for this)

[arne]

Well, things just kept getting worse, but I think I'm getting somewhere now.

It turns out that I was fighting at least two separate problems, neither of which cause a rich mixture, but one that made it "seem" rich.

As I kept going through the system checks, the issue kept getting worse, until after a short time it would no longer run or start at all. At that point, I moved into checking the basics. I need fuel and spark. Still thinking this was a single fuel issue, I looked into spark first as I figured I could quickly verify that and dismiss it.

Not so. It didn't take long to determine that the points had almost no gap, which caused very retarded ignition and incomplete burn. This was a cause of what I thought was a rich mixture.

I quickly reset the gap, and it coughed once when cranked and that was all. Looked again and there was again no gap. (IMG:style_emoticons/default/WTF.gif)

Turns out the pivot pin on the point set was loose. Points were bad. Installed new points, condenser, cap and rotor. Now have good, consistent spark in all 4 holes. One down.

Still no fire though. Next step was checking for fuel. Plugs were all dry, so I pulled the fuel line from the passenger fuel rail, put it in a cup and switched on the ignition. Heard the pump run its normal 1.5-2 seconds, but no fuel in cup.

That's where I left it last night. I now need to track back to find why no fuel. Looks like the filter before the pump is full, but I haven't gotten under the car to look closely. Pump and all lines are new, so I'm thinking either the in-tank sock has been clogged, or perhaps I've got a kink in the line coming out of the tank.

Won't have a lot of time to look into this today, but will follow up with what I find when I do get back to it.

[euro911]

... or the fuel lines could be reversed.

[arne]

... or the fuel lines could be reversed.

Thought of that, had my wife pull on them while I watched under the car to verify that the correct hose is hooked to the proper end of the fuel loop. But will confirm that for certain when I get it back in the air tomorrow and get under it.

[PlantMan]

Did you ever disconnect the fuel pump power???
If you did, did you accidently hook it up in reverse? Ask me how I know this......
Having a pressure gauge on the drivers fuel rail is handy.

[arne]

Did you ever disconnect the fuel pump power???
If you did, did you accidently hook it up in reverse? Ask me how I know this......
Having a pressure gauge on the drivers fuel rail is handy.

Would that it were that simple. No, didn't disconnect the pump.

Getting ready to crawl under the car now, to start working backward until I find fuel. Best guesses at this point is either more crud has clogged the tank sock, or I have a kink in the supply hose out of the tank.

[rhodyguy]

Start with the fuel sock visual inpection. Simply drain the tank using an old facet pump, 2 long pieces of fuel line and a battery with long pieces of wire. Put one piece of hose down the fill opening and the other piece going to a LARGE catch can. Next, look down the fill with a flashlight. You should be able to see the screen. Hopefully your tank is fairly empty. When you cut the lines off of the outlet and return be prepared. It will be a gusher.

[euro911]

Did you ever disconnect the fuel pump power???
If you did, did you accidently hook it up in reverse? Ask me how I know this......
Having a pressure gauge on the drivers fuel rail is handy.

I have one in the supply hose between the carbs ... only 3.5 psi but it's nice to know the pressure is there when trouble-shooting a problem.

[arne]

Got it! It runs again!

When dropping the engine, I must have bumped the new steel fuel lines, pushing the supply line forward a bit, which kinked the hose. I went ahead and put a longer hose with a loop in it to prevent this in the future.

Now I appear to be back where I was prior to the engine drop, except without the oil leaks!

[euro911]

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