brookman

Other than timing is there something else I need to look at to solve this hesitation I am having when I accelerate from idle? When you get on it the car really moves out.

Sean79 5spd

Check pump and cold/warm control pressures. Ensure there are no vacuum leaks. A 79 should have all vacuum hoses replaced.
These are just the first things to check, there are many other things that could cause hesitation.

SharkSkin

Had the same problem with mine, and I'm not sure exactly what the problem was. Could have been related to the vac hoses, which were all replaced, or the injection system, which was completely disassembled and cleaned. In any case, after those changes(plus timing belt, water pump, and cam tower recondition which are unrelated IMO) it ran perfectly and passed smog with flying colors.

I'd say start by replacing all of the vac hoses, except any that have been done recently. Also, if you just bought this car, check the routing of all hoses.

Randy V

Fuel distributor.

You can try taking it apart and cleaning it - the small plunger may be fouled with build-up, and/or the small catch screens may be gunked up, resulting in that initial hesitation. In my case, I had to install a new rebuilt one from 928 International.

SharkSkin

Randy, I seem to recall hearing somewhere that if the fuel distributor is disassembled beyond a certain point, many/most places including Bosch won't even take it as a core. Have you heard anything to confirm/refute this?

Randy V

Not sure about that. The piston and cylinder assembly is machine-matched with extremely tight tolerances, meaning that the pistons are not interchangeable.

Ben Allison

brookman,

I would suspect your vacuum advance is malfunctioning (potentially from a vacuum leak or from a malfunction of the vacuum advance unit. Pull the line and check the line for vacuum. It runs on ported vacuum so there will be no vacuum at idle, but some vacuum when you first hit the gas, and no vacuum at WOT. Make sure you are checking the advance line and not the retard line (which runs off of manifold vacuum). If you see vacuum at part-throttle off-idle, then suspect the advance unit (I think there are diagnostic steps in the WSM). If you see no vacuum at part-throttle, suspect a vacuum leak.

Kevin Michael

check your af mix. very small increments c-clockwise for leaner, clockwise for richer mixtures. if your vacuum checks out o.k. , you would be surprised at what a slight adj. here can do. adj. screw at front of fuel dist. doubt it is the fuel dist. these rarely go bad. ask jim bailey how many he sells! be careful these are very sensitive adjustments, kevin

brookman

Thank you for all of the responses. This car belongs to a friend of mine. It sat for 6 years because it kept dying on him. Come to find out it was the aftermarket alarm that was hooked between the fuse panel and the ignition coil. (it took me about 2 months to get to this point) . I had to start with the fuel system. The under tank pump was seized.(replaced both) Fuel injectors were clogged. (replaced- including cold start) I pulled the fuel dist and cleaned up the stuck piston. It still has the original vacuum lines . (they are hard) So I will replace all of them. The idle is a little high. That is why I was suspecting the timing. 1000 rpm when warmed up.

Thanks again - I will update this soon.

Mark

EZ check (BTDT). If your tubes are in less then good condition, they can allow lots of hot air into the intake. Make sure they don't have gaping holes in them.