That could be a problem. I don't know how much money you want to spend on tools to make old cars run right. Do you know anyone who you could ask to borrow or use his timing light?
http://www.jalopyjournal.com/forum/...quadrajet-id-and-casting-number-chart.474854/ I thought this Powerblock TV program on rebuilding Quadrajets was a good one. http://www.powerblocktv.com/episode/MC2009-18/quadrajet-rebuild#.VztCNp5VIWw
I'm going to throw something in here, Maybe the speedometer is off and what he thinks is a mile is not correct. His mileage can only be figured if he knows the exact mileage he has traveled.
you can get these cheap and they do work ( read the instructions twice before applying one as if done improperly it can be a pain in the ass as it will come off ... ) and measure your balancer before ordering one as they do change in the marking lengths
Joecool, you make a good point. My speedometer is not accurate. When the speedometer says 40mph, I am actually going 48mph.
Well if the speedometer is off aprox 8MPH wouldn't the odometer be off the same aprox amount? But from experience I can tell you if you are using your incorrect speedometer readings to calculate your fuel mileage that too will be incorrect. Try using a GPS for speed and mileage readings to get a more accurate measure. Joe
10 mpg does not sound too unreasonable for a truck with the aerodynamics of a brick. You said the carb # is 17057213 AWP That would be a 1977 Chevy carb. Probably has the side inlet, unless it's been changed. And by the way ... eight digits means it is a 1975 and up unit with APT (adjustable part throttle feature). Earlier ones were 7 digit and were not APT equipped. Also, the 800 cfm units have the venturi "bump" in the primaries. 750 cfm do not. [edit] ... x2 on using GPS to calculate mileage. The 8-mph offset is not a constant. Will be off more the faster you go.
Well something is screwed up with the carb. I had an extremely hard time starting it yesterday, I had to pump the pedal a ton of times before it would start. Once started it ran Ok except it did die once at a stop light. Today before turning the engine over I watched to make sure I was getting a good squirt and I was not. My first thought is the float bowl emptied overnight but I did JB Weld the plugs that are known to leak. At this time I did a fuel pump pressure test and I am getting 8-9 lbs of pressure. It looks like I will need to tear down the carb again but other than looking to see if the plugs are leaking, what should I be looking for?
Check ball in pump ckt, I have had them stick and won't squirt any fuel unless the engine is running, If your bowl is not leaking down..
Be sure there is no pinholes in any of the rubber lines or at a connection a small hole or loose connection will let the fuel siphon back to the tank. Which makes it a pain to start. I replaced all my rubber lines with new hose and had one that was slit with what looked like a razor knife that caused a similar problem. Joe
Just to add some info, the early second gen Camaros usually had a 2.73 rear unless ordered with a better ratio, the smaller cfm Quad looks different outside then the larger (on big blocks or Cadillacs). I love Quads for power and gas mileage, have a few bags of tuning parts from junk yard runs. Also I would check total timing like Squirrel said but I would also bump up the initial timing too.
I disassembled the carb again and the float bowl had fuel in it, so the plugs did not leak. The problem was the plunger fell off the accelerator pump. It appears that there were 4 small plastic tabs holdong it on and one of the tabs was shorter than the rest causing it to fall off. I had the old accelerator pump rod assembly and used that. The truck starts now. Thanks for the suggestions.
Thanks for letting us know the problem and the fix! Seems it's usually a little thing like that to trip us up. Joe Sent from my DL1168A using H.A.M.B. mobile app
with your speedo off, running 48 when showing 40, that is 20% right? add 20% to your milage and you now have 12 mpg not 10. Did I do that right? anyway, how does the motor run? have you checked the plugs? are they black?
HO , you should replace that acell pump with a good one as it will keep coming apart ( sounds like a cheap kit ) you can get just the pump assy from quadrajets .com for $15 . you have to measure the old unit to buy a new one . and also go salvage yarding and buy up any q jets you can find , every now and then you can go on craigslist and find someone selling them for $25 ( this is how I buy my cores ) also do not forget to check the filter at the base of the carb ( behind the big nut ( which is easier to break loose with the carb mounted on the vehicle as its tight and use a proper wrench, not a nut rounder wrench ( adjustable ) ) ) as they plug up and most people do not know they are there . ( I remove them and install a small steel can filter or one of these http://www.ebay.com/itm/like/261871035134?lpid=82&chn=ps&ul_noapp=true ) between the pump and carb )
I am really enjoying this thread, I sure hope it continues and the Qjet is fixed, I run an 85 chevy truck engine with a Qjet carb, all factory and I sure appreciate how well the carb works after all these years.
Stimpy, I bought the kit from NAPA, for two reasons, one, is they did not need an application for the carb kit they just used the carb number, and two, I thought their kit would be better than Oriellys or Auto zone. As mentioned, I ended up using the old pump rod as the little flanges/tabs that hold the plunger on, were intact. Something else I did ,and I hope this was the right thing, the old rod was 1/8th inch longer than the new rod, which was specific for this carb. So before reinstalling the old longer rod with the new plunger I sawed off the extra 1/8". I have not pulled the spark plugs but I will this weekend. I also have not driven the truck since the accelerator pump incident, only started it.
well cutting off the rod shortens your pump shot or delivery , not a biggy as your not pulling a heavy load , and most people do not use the whole squirt ( unless your racing and matting it ) but if there is a bog or it backfires when you give it gas at a medium speed then I would find a new rod . I know what you mean on the napa, Echlin has cheapened up because of the box store competition ,and half the time the Napa RDC warehouse in Naperville is out of stock and has to order it , I now only buy blue standard ( standard ignition ) , I found the catalog online and order it thru rock auto or use quadrajet.com . I also use Kem kits when I can find them online
Buy a timing tape that are they are cheap find TDC put the tape on the balancer and check it that way. Depending on the distributer it may need ot be modified to 34 degrees total advance without a lot of initial lead to start with.
Stick a piece of masking tape on the damper starting at tdc line. With the damper at 0 mark a line at 12 degrees rotate damper to put the 12 degree mark to the zero and mark 24 degrees at the 12 notch repeat once more now you are up to 36 degrees. Put the small hashes in between the 12-24-36 lines reverse the tape on the other side of the line and use whiteout or a paint pen to mark 34. This mark will be at 0 on your pointer. or you can buy the timing tape
bonzo-1, that is a pretty cool trick. Once I have 34 degrees marked on the balancer, time the engine at 3000 rpm with vacuum advance disconnected and have the 34 degree mark line up with zero on the timing tab?
I ordered the timing tape, should arrive next week. My questions are, what if my timing at 3000 rpm is not at 34 degrees but is correct at idle, do I change it so 3000 rpm is correct and idle is incorrect? Secondly, where does the 34 degrees at 300 rpm come from, I do not find it on any tune up charts?
The thing about modified engines, is that you kind of have to understand what they need, and also understand how the original design worked. Stock engines have a spec for initial timing, you can find it in any tune up chart. But the advance curve is a little harder to find, you can often find it in the factory shop manual, it will tell you how many degrees advance at what rpm, but usually in distributor degrees (half as much as the crankshaft degrees number). Do the math, you'll figure out what the total timing of the stock engine is supposed to be. But the problem is that we usually install some different distributor in the engine, plus we swap the cam, and we don't have to worry about emissions issues, etc. So we end up with ignition timing that is not what it was when the factory made the engine. The usual approach is to set it so it has around 34 degrees of total timing (initial plus mechanical advance), then see what the timing is at idle. If it idles ok, and drives ok, and doesn't get too hot at idle, etc, then just note where the idle timing is, and set it back to there when you do any work on the car or just want to do a timing check. But if it needs more advance at idle, you can modify the advance curve by using different weights and springs, and stops, to get it to behave like you want. It's a tricky business, but it's one that hot rodders have been doing for decades. Having a buddy with a distributor machine helps
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