Running really rich i thnk?? help

[Jbagel2]

i have done a bunch to the car tring to get it ready for safty and emissions, well i went in to have emissions done, and it fail really bad. 13.8 on CO i guess they give me to 5.0 he told me that is a sign that is is running really really rich, i was wondering what could be causing that, could it just be my fuel pressure regulator. or could it be something different?? any ideas??

74 2.0 still fuel injected

[Dave at Pelican Parts]

It could be your fuel pressure regulator. Spec pressure is 29 PSI in the high-pressure loop on top of the engine (that's everything "downstream" of the pump and "upstream" of the FPR)--check to verify. You can adjust the pressure on the stock regulator.

It could also be extra resistance in your head temp circuit (dirt, corrosion, etc.), or an unplugged intake air temp sensor, or bouncing FI trigger points, or a blown-out MPS, or....

High HC readings can also be caused by an ignition system that is not quite up to snuff.

--DD

[Jbagel2]

i just did a full tune up, plugs, wires, cap, rotor, coil, valve adjustment, it has the petronix ignition so i didn't change the points, there is no air intake temp sensor that i am aware of, this is a 74 (before the emissions control). my HC was very low at idle well below standard, but at 2500rpm it was double tolerance. does that change anything?? it was my first time doing my own vavle adjustment, it was the first time i have done it since i have had the car, about 5 monthes. all of the adjustment screws when the engine was cold were tightend all the way up to the valves, so backed them out to .006 on intake, and .008 on exhaust.

[Dave at Pelican Parts]

Your car does have an intake air temp sensor--or rather, a manifold air temp sensor. It sticks straight up out of the manifold.

I'm sure there's a big clue in your HCs being very low at idle and very high at 2500 RPM. Not sure off the top of my head what it could be, though. Hmm--how's the centrifugal (and vacuum, if any) advance working?

If all of the screws were all the way in during your first valve adjust, I would stop and double-check the adjustment procedure. Make sure you had the engine rotated around to the correct place to check the valves! Double- and triple-check it. I would also consider pulling a lifter out to see if the engine has been "upgraded" to hydraulic lifters; those use zero lash (and actually the lugs are screwed in about a half-turn more!).

Has the manifold pressure sensor been messed with? Is the epoxy plug still on the one end? If not, it has probably been "monkeyed with", and may need someone with the right skills and tools to straighten it out.

--DD

[Jbagel2]

i'm positive of the adjustment prosedure, i just don't know what has been done to this car previously, i was wondering if it might have a different cam in it. i'm bringing it into a european olny auto shop. the do alot of porsches, and i guess we shall see what they say. how can i pull out a lifter and check??

[Dave at Pelican Parts]

To get the lifter out, you have to pull out the pushrod tube. (Do you have any leakers? Those would be good ones to pull, so you can replace the seals at the same time!) To do that, you have to remove the rocker arms and rocker shaft for that cylinder, plus pull out the pushrod tube retaining spring. Not the easiest thing in the world, but quite doable without removing the engine.

Easiest way to tell if the lifter is hydraulic or not is to visually compare it to a solid lifter. It will be taller, among other things. The pushrod will also be slightly shorter.

A good VW shop will be able to tell which kind of lifter it is by looking--they will have dealt with hydro lifters in the late model Vanaog engines, as well as solids in 914s and all the other VW applications. They may be able to tell by pushing in on the pushrod, but that's pretty "iffy"...

...Oh, and I would still double- and triple-check the valve adjustment. I've gotten confused enough times about exactly which valves I was checking that any time I find a valve is more than a tiny bit out of spec I immediately stop and verify where the engine is on the cam.

--DD

[larrym]

classic cause of this is incorrect resistance for head temp sensor or broken or badly frayed wire to it; you can geta a dial adjustable resistance gadget at radio shack and put it inline between sensor and connecting wire;

then just start experimenting with resistance until the thing leans out; once you've figured out the correct resistance you can get a fixed resistor & put it inline;

also - do you have an CPU with adjustment dial? If not - get one