Pirate 4x4 banner

Truck Avenger Problems?

8K views 15 replies 6 participants last post by  herbycj5 
#1 ·
Alright so here is the situation short and to the point. Holley Truck Avenger 770 cfm, 454 bbc, mild off road cam, edelbrock performer intake, holley blue electric fuel pump.

Problem- I mash the throttle from stop it dies, I mash the trottle while moving and let off it dies. oh yea and it idles high but i think the secondary just gets stuck for a minute (holley problem)

Things I have checked- Vacuum leaks, timing.

Questions- I was checking the accelerater pump and looked down the bowls and turned throttle no gas pouring in. Should the electric fuel pump be on during this test?

Any other ideas or tests to find out what is wrong with this thing would be greatly appreciated?:confused:
 
#2 ·
First things first.

Look at the part number on the choke tower. It it ends in a -1, call Holley, tell them whatit is doing, they will tell you to check the part number, (which you will already know) and they will tell you to take it off, send it to them, and they will send you a new and/or improved carb. Free of charge, I might add.

This is typical TA problem.

Now, unless your fuel bowl is completely empty, (or baring some unforeseen problem) the accelerator pump should squirt fuel into the primary venturis.

The high idle problem is not a stuck secondary, I found that its due to the tranny kickdown linkage (if not hooked up) bascially freefloats and gets stuck in a certain position, not allow full closer on the throttle at idle. Happens irregularly.

The TA carbs are getting better, Holley is working on them, I am on my second one for two years now with trouble free performance. And they do work well past the angles advertised.
 
#3 ·
I will look into the tranny kickdown lever. But as for the part number I already new that and checked mine there was no -1 or -2 the part number is 90770 nothing at the end and the Holley guy said the issues were with the 670 not the 770 so i think i am SOL with Holley.

Is there a way to adjust the mixture besides switching jets? I know there are idle mixture screws but I have not found a standard air/fuel mixture like other carbs ( although I am used to small carbs dirtbikes and atvs ).
 
#16 ·
just thought i would share a little info that found out about the TA 670 and 770. I had a 670 on my sand jeep, 435ci ford. the carb upon installation started and ran like a striped ass ape! made absolutely no adjustments. running through the dunes, absolutely no stumble or hesitation. On the long really steep dunes it just couldn't quite flow enough for the cubic inches and horsepower. Bought a 770 and upon start up, fired right up and again while cracking the throttle in the trailer was very responsive. I get to the dunes, jeep fires right up, take it out of the trailer, let it warm up and take it for a test run. jeep runs fine until i put my foot in it and it falls on its face. After hours of trying to make it work, without success, I bolted on the 670 and had a great weekend. I got back home, called Holley. The tech guy, said that the 670 carb was pretty much problem free!! the 770 was actually a different carb and had some problems. He said from what I told him......it very well be the metering plates. They have a small pellet installed in them that is necesary for the off camber ability. Holley knew that some of their metering plates were built with this little pill upside down. Holley cant indentify which plates are wrong.......but they sent me the two metering plates and gaskets to change them out. I swapped the plates and now have the best carb that I have ever owned! It is the closest thing to fuel injection that I have ever experienced!! Maybe this can help you, maybe not. My exp with holley was very good and I didnt even have to send anything to them. Good luck Mickey
 
#4 ·
Im running a very similar setup in my 85 K10, but with a Holley 850. Have the falky idle speed from time to time, but running a 4 speed. The biggest problem I have is when pulling or carrying a load and taking off from a stop aggressively I get thru 2nd fine, but shortly after hitting 3rd I get what is best described as the effect of running out of gas.... rapid fluctuations in power output as if being fuel starved for fractions of a second. VERY hard on the drivetrain! Been fighting this for better than a year now. Fuel pressure never drops so no air i nthe pickup, but cant determine if im unable to pump enough to keep up with power output.
 
#5 ·
The biggest problem I have is when pulling or carrying a load and taking off from a stop aggressively I get thru 2nd fine, but shortly after hitting 3rd I get what is best described as the effect of running out of gas.... rapid fluctuations in power output as if being fuel starved for fractions of a second.
I had this very problem with mine, only it happend during the warm part of the day. I went through everything and finally realized that my braided steel fuel hose ran close to the motor the whole way from the pump to the carb MIGHT be causing vapor lock issues. So I ran a hose from the pump, over to the battery tray, and from there straight to the carb. Totally getting it away from any heat source.

Never had a problem since. Might check it out.
 
#9 ·
I dont know what the carb is rated for either. But that may be useful information to obtain so I will search for a little bit. I will try turning it down a little but I dont think thats my problem (although I guess I dont even know what the problem is yet) haha. I have heard this is notorious for holley's but if you set the carb up right (tuning/ accelerator pump mod) it can be minimized. It has done this from day one which was one year ago. I bought the bbc from a guy using it on a project and he never fired the motor so he has no expierence with this as well. Maybe I will just rebuild and put the original q jet back on that the seller gave to me.

am i rambling. Maybe a bit.:D
 
#11 ·
I know you said that you checked for vacuum leaks, and I dont mean to sound like an ass, but where all did ye check, and what method did you use?

As long as the fuel pump has been on since the engine last ran, and there are are no fuel leaks from the carb, you should get fuel squirting when you rotate the throttle.. if not then either the accelerator pump is torn or there is a linkage problem.

With no accelerator pump you WILL have a hard time keeping the engine running when you step on the gas. Changing the pump diaphram is very simple... only 4 philips screwes after the carb is pulled.

The high idle is very possible an air leak somewhere.

The problem of mashing the trottle while moving and let off it dies is agian a good candidate for an accelerator pump problem. ie.. engine running ok at 3000 rpm.. stomp on the gas and she goes, but not well (she fuel starved and running really lean) and you quickly let off the gas, closing off the air past the venturies dropping fuel and air. This COULD increase a vacuum leak momentarily making an already too lean stumbling engine run MORE lean.

Just a thought from over the weekend.

GMC --- My fuel lines are routed pretty far from the engine after the pump, but not sure about before it, ill look at that tonight. Thanks
 
#12 ·
my truck avenger ran a little funky at out of box, I had to adjust float levels down some ,adjust the air/fuel screws. now it flat out rocks ! works perfect. I only get some gurgling/flooding when im about to flip over backwards and bouncing. pretty dang good for a carb.

I would start off by making sure the fuel pre is at 4-5 psi, then set the idle,then set the air fuels ,then reset the idle. once thats done I would make sure your getting a good squirt of fuel when you pump the gas. if not replace the acc pump. then set the floats .. mine where to high. I also changed the spring to the other one they sent.

thats a start ....
 
#13 ·
thanks for the replys. Good news accel pump is kicking so that is not a problem. And vacuum leaks I used a propane torch (not lit obviously) and didnt find one I checked intake manifold 360 degrees around, carb, throttle plate, and all vacuum lines I only have three vacuum lines so that wasnt to hard. My floats are properly adjusted (they were set high out of the box on mine as well). No lines are close to any heat source. So I think I am going to start off by setting the idle again (mixture and rpm), change the secondary spring out to a thinner one to have the secondary's turn on a tad earlier (it runs like hell once the secondarys open), and possibly play around with a few other jets.

Thanks for the help guys!:D
 
#14 ·
Ive never used propane to check for leaks.... Ill have to try that. I always use carb cleaner, but Im sure the result is the same. Propane is surely safer though!!

Your 3 vacuum lines... Im guessing brake booster, distributer and vacuum that runs the heat/ac controls? have you tried caping all those nipples (lol - I said Nipples!) to see what it does to idle? Ive seen brake booster diaphrams leak enough to cause issues, as well as vacuum canisters with cracks. Both are frequently overlooked.
 
#15 ·
3 vacuum lines are: 1) brake booster 2) timed vacuum to distributer 3)Vacuum line for transmission to shift out of first (I have never seen this before but after trial and error I found out what the house coming out of the th400 was for):D. Brake Booster is fine. And I have heard the propane method is more dangerous. But I stare danger in its face and piss all over it day in day out.:flipoff2:
 
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top