I've done a lot of research prior to posting and before I take her to the mechanic I want to make sure I haven't missed anything basic. Oh, 1974 1.8, stock car.

I drove for 100 miles and then the next morning, all of a sudden, the car runs like crap . The car starts no problem and holds an idle well. When I drive it feels like I'm on 3.5 cylinders. Especially in the higher RPM's and when I'm going uphill. The sound is off too. Letting off the gas will cause small backfires (lean characteristic, right?). All four plugs have no buildup and pure white insulators. Looks like a real lean condition.

Here's what I have done prior to this problem developing.

Replaced all vaccuum lines with the exception being the 4 manifold tubes (they look fine and solid). I can't find any leaks.
All new fuel lines.
New points, cap, rotor, condenser, spark plug wires, plugs. Dwell is 50.2 and timing at 7.5 BTDC at 800 RPM.
Fuel injectors rebuilt by Witchhunter Performance. Clean bill of health.
New fuses on relay board. Cleaned up connectors - no resistance.
Fuel pump runs and I can hear gas gurgling when I listen to the tank.

Also, I closed down the air bypass screw on the AFM and the idle increased a bit but higher RPM's and power still suffer.

Here's a wrinkle that may shed light on this. I have only two relays on my relay board. The two outermost relays; forward and aft. The fuel pump is grounded in the little area with four male connectors (rear passenger side). Should there be any more relays?

Relays aside, am I missing anything?

cylinder head temp sensor? (CHT)

Is that the deal next to the distributor with the green/brown wire?

no, it's the single wire coming thru the engine tin near the #3 (i think) spark plug. i'm not saying your symptoms indicate a bad CHT, i forget what they are, but checking the CHT is pretty easy; measure resistance cold and measure it hot. one reason i suggested the CHT is it was not on your list; it looked like you covered just about everything else.

I'll check that tonight.

did you replace the fuel filter? not noted in your 'done' list. the gurgling sound has me puzzled. did you do the tank to pump delivery and return lines in the process? if so, are you sure you didn't get the lines backwards? how much fuel is in the tank?

k

I had a couple of minutes and looked for a CHT line between 3 & 4 - nothing. That doesn't mean anything except that I'll have to dig around some more.

Fuel lines - all replaced including the fuel filter. It's in correctly. The paper element is facing the line coming from the tank and the arrow points to the fuel pump (you're right to ask as this could easily be the problem, not that I wouldn't know from personal experience in a VW bug outside Baton Rouge, LA). I checked it yesterday and it's clear of sediment. When I did all the lines near the fuel pump I did them one at a time to avoid mixing them up. The car was running great for the first day I drove it so I'm assuming all the lines are in the correct position. This is an "all of a sudden" problem. Runs great one day and the next -

My tank sender is hung up on 3/4 of a tank but I have a little less than 2 gallons in there. I didn't want to put in too much in case I needed to drain it for another problem. The gurgling I mention is the return fuel coming back in.

I noticed the ground connection below the relay panel. I didn't clean that one up yet. Are there other ground connections besides the battery and transmission (not including lights and guages)?

Clean the injector grounds under the plenum.

You should have a 4 pack of resistors on the right side of the engine on the wall under the battery- one for each injector. The wires are notorious for breaking at the solder joint.

Backfire might be an injection system air leak. Check all hoses and the rubber between the manifold and the 4 runners.

Checked for spark AND injection? You can hear the injectors click with a stethescope and check for spark in each wire with a timing light.

Ken

4 pack of resistors - check

Spark AND injection - check

Clean the injector grounds - done

CHT wires - check good

All ground connectors and injector wires - cleaned

Still drives like crap, runs hot and lean, no power. Going to the wrench. This will be the first time I'll see a mechanic in 20 years, 4 VW's, 5 Porsche 911's, and one pretty 912.

(That sound you hear is me spitting on the ground next to the 914)

Checked the timing? too advanced with cause problems

Ok, a night off to cool down has put me in a better frame of mind. I called the local VW mech and he tells me to check the CHT again. The way I was checking was incorrect. Well....I find no change in resistance from the temp probe to the harness wire with either a cold or warm motor.

New one on order, It'll be here tomorrow. I hope that's it.

P.S. timing is spot on at 7.5 BTDC at 800 rpm, hoses disconnected. But I know what you're thinking, and that's a good lead.

I don't care what the idle timing is, what is it at full advance @ 3500 rpms as it should be 28 degrees. Advance problems can come of as lean problems.

Rav,
Does your car have the metal tube running from the oil filler neck to the egr valve to the intake boot?

also true for L-jet? (i gather he has L-jet from replies)

also, i'm not sure about your method of measuring the CHT resistance. if you measure the resistance with the sensor still connected in the harness, could you get a bad reading because you could be measuring the resistance from the harness to the brain to ground. i would think you'd have to measure CHT unconnected to get a real resistance reading. if you measured unconnected, disregard this reply

I'll check the advance at 3500, seems like a smart move. Would you happen to know, in mm, how far 28 degrees is along the fan? The only marks I have is TDC (my own creation) and 7.5 BTDC. I can interpolate based on the 7.5 distance, but just in case....

In fact I'm going to find an advance chart and see where I sit along the full range of RPM's.

No EGR valve on this car. Maybe they came out later in '74? The only tube I have running from the filler neck to the intake boot is a braided rubber one and it's new, no leaks.

Yes the first time I measured resistance it was connected to the harness. This time I disconnected it and achieved, I believe, the correct numbers.

Working late tonight. More tomorrow...

Timing on an L-Jet car is set with advance and retard hoses disconnected and plugged from the distributor, 7.5º BTDC at 850 ± 50rpms.

Use the 28º method if you're running anything other than a stock distributor. Also, the advance hose stays disconnected - the distributors have enough mechanical advance already.

I replaced the CHT sensor - no change. But the heat coming off the motor reminded me of a car with way too much advance. Come to think of it so does the lack of power.

I started over and just for grins I messed with the timing. That helped. I shut off the motor and came upstairs to do more research.

I think my timing is off and I've been adjusting it incorrectly

All this time I thought I had it spot on. I'm going to go over it completely tomorrow. More to follow....

as said the hoses are off and plugged and set the timing at 3500 rpms to 28 degrees. There is a timing mark chart at pelicanparts you can download.

Adjust the timing at 3500 as thats when the mech adv is full in and who cares about the idle as no one drives around at idle....

That'll be my plan. Thanks for the tips. I'm embarrassed to admit...but I didn't plug the hoses when I set the timing the previous round of troubleshooting. I'm my own worst enemy.

Maybe your L-Jet issues would be resolved if you followed the correct tuning proceedure. Whatev.

/krusty moment.