Repost: power loss issue

[nativetexan]

Quick thouth though. If it is suppose to be hei, then why do i have the plugs for the ignition module and the wire for the esc?

[Captkaos]

you got the right thing..  its electronic.  HEI = High Energy Ignition, there is the early model with the big cap and the late model with the seperate coil mounted to the intake on the TBI trucks.

[nativetexan]

  cooool 

[nativetexan]

So I forgot to mention that i put a trashbag over the aircleaner on my truck and it didnt die or change idle speed or anything. Is that a pretty good way to confirm that it has a vacuum leak issue? My friend came over and hooked up his scanner to it. No codes. Nothing out of the ordinary. He still thinks it might be the cc. I will check for vacuum leaks and test to see if the cc failed by removing the o2 sensors to provide a place for the exhaust to exit. Lemme know what yall think.

[Irish_Alley]

well im going to go out on a limb and say vacuum leak, for one back in Dec i think you said you had a code 44 low fuel or vacuum leak. and the whistle is a sign of vacuum leak, and the trash bag test is a sign of vacuum leak. now i think the tbi base plate gaskets are notorious for going bad. Use a hand torch without it being lit and turn it on and follow the mounting surfaces where a gasket should be it should rev up

[nativetexan]

well im going to go out on a limb and say vacuum leak, for one back in Dec i think you said you had a code 44 low fuel or vacuum leak. and the whistle is a sign of vacuum leak, and the trash bag test is a sign of vacuum leak. now i think the tbi base plate gaskets are notorious for going bad. Use a hand torch without it being lit and turn it on and follow the mounting surfaces where a gasket should be it should rev up

What if I used carb cleaner or something like that? Would it rev up? Also, the gasket is new but maybe the TBI is warped. Does that happen? I say that because I had this issue before I put the remanufactured engine in there.

[Irish_Alley]

might be the tb then. idk about the carb cleaner. this is what im thinking. something can be water tight but not air tight due to water molecules being bigger than air molecules. so if you spray a liquid then it might not find the leak if you were to spray air then it should find a finer leak

[1979C20]

Irish, if the leak was so small that water cant get in, I dont think it would make a difference. But, carb cleaner or WD40 would still work because even if the fluid cant get in, the fumes will.

Native, can you recap what your issue is for me? Slow acceleration? Does it bog down with throttlw? Does it back fire through the exhaust or through the carb? Have you checked your initial timing? Have you tried advancing or retarding your timing to see if changes? What do your spark.plugs look like? spray some form of accelerant(WD40, carb cleaner. NOT brake cleaner) on all of your vacuum.lines, all of the vacuum connections, your brake booster, where your intake bolts to the heads, the base of your throttle body, the sides of your throttle body. Spray some directly into the mouth of the tbi and listen to the rpms raise, then youll know what to look/listen for.

[nativetexan]

Ok when there is no serious demand on the engine it runs good. If demand is put on it, the engine bogs out like its going to die until the throttle is backed off. This happens while driving and while idling. I watched the injectors spray gas so i know it is getting fuel. But the gas pressure drops while the demand was put on. I have played with the timing and it seems to do it at any point. I checked it at zero, -10, and +10. I am going to retime once again to zero and check the stuff you guys suggested. Also, when i put a vacuum gauge on it. What am i looking for? Where should i connect it?

[1979C20]

Plug the vacuum gauge into a manifold vacuum port. One that had vacuum at idle. I dont know what to tell you on what to look for. Can you tell me what your spark plug electrodes look like? I installed a new intake on my buddies truck and somehow while doing so, one of the air/fuel mixture screws came almost all the way out. It ran like crap and tried to stall when you let off the throttle and came to a stop.

[muddpuppy01]

When doing the timing you have the vacuum plug off and the idle below 800 rpm. What does the timing go to when you run the engine at 3000 rpm? 

[nativetexan]

Not sure about the RPMs. But I just got done retiming the motor to 0 with the EST unplugged. When I plugged it back in and rechecked the timing, it was way off the scale. Im guessing over 10 degrees ahead of 0. If you are looking at it from the front of the truck, it would be about 10-14 degrees to the left of 0. What is that about??? And when I revd it, it took off even further to the left. Also, when I first started timing it, it started hopping around a bunch. From 0 to the right of 0 about 5 degrees. just back n forth. A few seconds in one spot then a few seconds in another spot. What does that mean? Bad ECM?

[muddpuppy01]

When you hooked up the vacuum line back onto the distributor it called for the vacuum advance to kick in. Reving the motor is calling for the mechanical advance to ramp up. Both normal thing but you need a dail back timing light a tach to determine if the values are correct.

With timing jumping around you may have weak springs or worn out weight.

[nativetexan]

Well i dont have the vacuum line on my distributor. Just the est. Also, the motor is remanufactured so it should be in pretty good shape.

[1979C20]

Do you have headers or manifolds? What do your spark plugs look like? Can you take a pic of them