Well I've been struggling to find the problem with my poor teener for the past couple of days (again). It all started a few days ago as I was leaving the girlfriends house. It idles completely fine (lil high when cold) and runs consistently but as I drive off she has no power to speak of and begins a series of small backfires with an occasional large one.
Well I diagnosed it this morning, timing is dead on, all plugs are gapped perfectly as well as the clean points, and all injectors are squirting fuel.

Has anyone had an experience close to If not exactly like this???

FI or Carbed?

My bad, 1.7 d-jet

Does it run fine when cold and then start to stumble after a few minutes warming up?

If so, check your CHTS or your AAR!

If not give us a few more details.

Try looking for a tight valve.

With that explanation check:

the Condensor or does your Dist. shaft wobble at all?

Stu

Aar is just fine however I'm curious about the CHTS The fuel pump out of the blue refused to work this morning despite the relay being fine and I had to jump it off the coil to test the injectors. If the CHTS failed would that cut out the fuel pump?

I had a similar issue for the last month or so, and posted basically the same question over on the bird board 911 site since I'm running a 6.

The usual answers that came back were plugs, timing, bad wires, distributor cap, etc....


For the last couple of month's, I'd take my car for a ride, and all would be fine for the first 20 minutes or so, than it'd just start losing power, as if it'd lost a cylinder or two. Feathering the gas would minimize the issue, and if I slowed down, it would idle just fine. The car never left me stranded.

I checked all he usual suspected items, to no solution.
Last Saturday, I drove the rocket about 70 miles to a VW event, and back home, but this time there was issues. I waited anxiously for 140 miles to feel the engine begin to misfire but it never did.


What if anything was different about Saturday the 14th, than any other previous day??

The temperature... It was at least 10 degrees cooler than the previous 3 weeks of driving days.

I'm not in any way suggesting what your problem is, but I'm almost convinced in my case that due to the 95-100 degree days We've had here in SC, that my car was vapor locking due to the build up of heat in the engine compartment after a 20-30 minute continuous drive. I put my infared Temperature gun in the engine compartment, and it was not unusual to see 150-160 degree temps on one of those days.

I will soon be working on doing some insulating of the fuel lines to help minimize the possibility of vapor locking on these extremely hot days..

JM2CW,

Ron

Tight as in adjusted too tight?

I see no mention of checking dwell or fuel pressure.

No on the fuel pump inop cause of the cht

vacuum leaks?
check hoses?

check the oil cap? it needs to be tight and the gasket under it needs to seal.

The CHTS leans out the fuel when the car warms up! The car will sputter & die at low idle because a bad CHTS is telling the motor that it is still cold and floods out!

Hey Stig, I have a dwell meter if you need to check yours. Timing is nothing w/o correct dwell.

the lack of power and backfiring sound like ignition to me.
I like the dwell train of thought....


also I would check the advance plates on the distributor
maybe they test "correct" at full advance but are not springing back at idle (any chance you turned the idle screw down lately due to a fast idle)

anyways I'm only throwing out a guess which is easy to do from a computer... but I'd check the timing advance and dwell.

brant

Just saw this, I have a variable resistor(too) you can plug in if you suspect the temp sender

I may take u up on that kent, look for a pm from me over the weekend possibly!

I would have to say this tells me there is an issue with the fuel pump or the circuit that controls it being intermittent. The pump should run a second or two when you first turn the key on. After the engine starts the pump should continue to run.

To see if the problem is with the CHT after the warm up and while you are in the failure......disconnect the chts from it's plug connect a test lead to the plug (NOT THE CHT) and connect the other end to the battery negative or a known good ground...this will tell the brain the engine is warmed up even it the CHTS won't.

Well I was finally able to work on der kraut rod yesterday. I threw new points in it just for fun( gapped at .016). Replaced a burnt spark plug, cap and rotor I had laying around, and checked the valves which were perfect(thanks for the tip Ron!). I also checked every component of the FI which were operating in range.

Upon doin all that b.s. I took her out for a ride at night time and it felt EXACTLY the same! I did however notice my generator light it seemed to be half way on... Got her back in the garage and the nut had rattled off on the top alternator bolt!!!

Do I feel dumb? Yup!

Just wanted to update u guys and say thank you for all your input!