bucking and dieing

[boosted79]

Need some help, my new 79 4speed had a problem dieing after a few miles and would need to sit for a while (between 10 min to an hour) and would restart then go for a mile then die again. I found that i was not getting fuel at all or very little, so i dropped the tank, cleaned it out, flushed the sending unit, and line to the engine, then flushed the vent line. After i checked and still had no fuel, with two different NEW fuel pumps. I tried my Holley blue pump and it ran great, till it took a s**t. The carb is rebuilt, no leaks, smells lean from the exhaust, ect. I hooked up the mech pump and it was fine for months, then i was going down the highway a week ago, and it started to buck again, no complete death this time, but close. New ignition module, coil, tune up w/ac plugs, complete 2 1/4 exhaust, w/o leaks. I've had 3 other 'vettes with same engine and trans, and the 86 was a f***ing power house compared to my 79. Cant figure it out need HELP

[hydroli]

Ok, you say the carb is stock, right? If you went with a weber carb, they will take nothing but a regulated 4.5 psi. The stock chevette pump pushes more than that. Have you checked the EGR valve? If the ventury is shreded you could have some symptoms such as you said, bugging when it gets hot and running lean. How can you say you get no fuel to the engine? By checking the plug or reading the fuel presure? If the gas doesn't get to the carb and since the fuel pump draws fuel, you can have a leak in the fuel line and "sip" air instead of gas. I suggest you try with a remote tank with a rubber hose to the pump to check if the problem is before or after the fuel pump. An empty oil bottle will do the job.

Let us know what you find and we'll try to help you in this.

[boosted79]

Ok...... Before I start, thanks for the tip on the fuel pressure Hydr0, I had a fuel pressure reg on it and set at 5 psi just in case so i might have been pushing it, but i also tried a gravity can and it went away but only because the fuel line was no longer under the hood, (VAPOR LOCK) and the plus have been showing a lean out for a long time. The fuel line from the tank to the engine is 3/4 aluminum and it helped but it would still get hot and vapor lock it just took longer. So after changing two thermostats, three different temp senders, and BOTH of my Autometer temp gauges because they were bad i find out this things running hot and boiling the fuel. So I'm in Canton visiting my girlfriends family when this thing stats loosing power, not much but it was noticeable in town on a take off. I started for Wooster to go see my family before driving back to Richwood and it starts bucking again, it never died just got cranky. Since i had checked the entire fuel system over very well (I thought) and the distributor for sticking weights and bad advance, I was lost. So I started my testing all over. It was vapor lock. Now me and my grandmothers latemodel building neighbor came over and we put our heads together and found the mixture screw had vibrated and tightened up, so we adjusted it, set the timing and she purrrrrrred! Now im on my way home and it running balls on until im at a stop and its not idling. I stopped at a Auto Zone and borrowed a compression gauge and checked it out. 60psi max across the bored! It had been a combo of lean carb, faulty temp equipment and a vapor lock condition that got caught to late and warped a head badly. Now it doesn't run hot enough to boil just vapor lock and now she wont idle and takes a lot of pumps of the gas before she will start. Also a little tip i picked up in Wooster, if you need to cool your fuel line and cant run a cool can, but cant (or not aloud due to rules in this guys case) if you take the spring type WOOD clothes pins and snap them on your line the wood acts as a heat sink (as many as you can 1in apart works the best under hood) no more vapor lock at all, what a great tip and almost as effective as a small cool can

[hydroli]

wow, good that you found it. So you are gone change head gasket and everything should work from what I understand? Good work.

[boosted79]

i doubt that just changing the head gasket will fix this one, it was changed before i got the car and it wasnt done right so i redid it when i rebuilt the carb. i must have pulled an entire tube of ultra blue silicon out of the water jackets! WHO PUTS THAT ON A HEAD GASKET! if it was copper maybe, but that much? but i think the head is very warped and the rings might be shot, im getting no bleed over of oil, coolant, or compression anywhere, just running a little hot, and no static compression to speak of. Ill be buying an engine form an 86 with 36000 miles on it to put in it soon while i rebuild this one then ill have a spare, this also gives me time to set the 79 engine engine up for boost like planed. i have a mini cooper supercharger, or a couple turbos (s3 from an audi and a t3/t4) and two different intercoolers to work with want about 115-130hp to the ground and i hear thats not hard to do with the vette and keep it reliable, please let me know if im wrong but i understand it done in Europe and South America all the time. have a carb set up for blow through and a spark controller to keep the detonation away so im going to cross my fingers

[hydroli]

I don't think it is more reliable than another engine. It's an economy car and the main reason it doesn't breaks is because it has only 70hp max out of the factory. If I was you, I would not touch it unless I have some spare money to build a strong bottom end and some more to make it breath properly. You might considere a V6 swap as a cheap alternative. It's not so hard to do if you look at the smaller 60° engines. Good luck anyway you go.