'78 Super Beetle engine chugging

I have recently replaced the fuel injectors, and though there is still about .5mm of o-ring protruding, they seem to be in solidly. The engine now fires, but after about 40 seconds it chugs painfully and dies. The coil is new, the rotor and cap are new. The sparkplugs are new. The mass air flow sensor is new, and I've checked all the vacuum hoses for leaks or looseness.

I sprayed some carburetor cleaner around the fuel injector openings to see if they were sucking in air, but no extra power came, as it would if the Carb cleaner was sucked in. I did not grease the o-rings or the holes for the injectors before I put them in, should I have? The bolt holding the injectors in is fastened all the way down snugly. The fuel pump is new, as is the gas tank and all the gas lines have either been replaced or blown clear.

I was wondering if it was just an idle speed problem as the engine can be kept running if you apply the accelerator. The only other thing I'd guessed was that the fuel injectors are not seating properly and at slow speeds the gasoline isn't atomizing from them right.

On a different subject, I went to pull out the front strut, according to the Muir manual, but both bolts holding the bottom end broke off. I cannot now get these out. I have tried a hammer and punch but it doesn't move. Is there another way I can get the bolts out, or do I have to try and drill them?

Any help would be good. Thanks.

Reply to
Jerry.Snow
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I know that the cylinder head temperature sensor is a forgotten part.

Any vacuum leaks at the air flow box boot? Sometimes that plug might pop out of the throttle body. Are all of the hoses hooked up correctly? Oil cap on nice and tight?

Did you adjust the idle speed and the CO screw in the air flow box? Is the air flow box the one that has that safety valve in the flap that sometimes pops off?

Is the exhaust rich & dark or ???

Just trying to remember how these FI SBs used to be! ;-)

Good luck, dave (One out of many daves)

Reply to
dave AKA vwdoc1

The air flow boot, that large black molded boot from the the MAF, is new and has no holes in it. I would guess that the fuel was rich, due to the chugging, but the exhaust is fairly dirty but not particulaurly dark. I did try to adjust the idle speed, but that had no effect. I did not adjust the idle mixture, even though the service manual says to when you replace the MAF sensor. I figured that if it was just a emission adjustment, I would deal with bad burning until it ran okay. All the hoses appear right, and they are all connected. I've checked the oil cap.

I checked the temperature sensor, and, with the ohm test, speedy jim said it was fine. Even after spraying much carburetor cleaner, I could find no vacuum leaks. The service manual also says that if the idle speed screw doesn't work for adjusting idle up, that it might be EGR. I currently don't have an EGR filter on the car (the old one rusted out) but I did cover the end of the pipe with a plate so there shouldn't be a leak there. Also, there should be no gas recirculation at idle.

Reply to
Jerry.Snow

Here's one you might try. Hop over to Radio Shack and get a potentiometer (volume control). A 5,000 Ohm job would be nice, but a 10,000 will do.

Wire it in place of the head temp sensor. One end terminal to ground. Center terminal to the ECU connector.

Start the engine with the wiper arm pointing at the terminal with no connection on it (maximum resistance). This will produce maximum starting richness. As the engine warms up, start turning the pot "down" (lower resistance). This will make the mixture less rich.

The effect is quite dramatic. Play with it a while to get the feel.

See if it is possible to get the thing running somewhere near normal.

Jim

Reply to
Speedy Jim

Well how is the Air flow box or MAF?

**** Yes adjusting it should be attempted! 8^) ******

Which spark plugs are you running? Also what is the fuel pressure? Is there a vacuum hose going to the regulator?

Reply to
dave AKA vwdoc1

I checked the area around the plate I put over the EGR pipe. When the engine began to die, I sprayed some carburetor cleaner in it and it would rev back up. That seems to have been the vacuum leak. Once I fix that I'll get back with more questions if there are still problems.

Reply to
Jerry.Snow

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