03-12-2007, 11:35 AM | #1 |
Registered User
Join Date: Oct 2006
Location: Edmonton, AB, CAN.
Posts: 152
|
Engine bogg
I've done a search on other threads and while informative I don't think the answer to my problem was mentioned.
Here goes; I have had this 71 c10 for 4 months. I have replaced the engine with a rebuilt 350 (1981 I think). The previous owner had HEI ignition installed. I have not replaced the cap and rotor yet, but plan to. plugs and wires are new. Have not checked the condition of the plugs yet. There is less than 1000 km on the engine. when installing the new starter there were three wires. One for the power, one (purple i think) about 16 gauge for ignition and a 20 or so gauge yellow wire, which I believe was for the original ignition system with points. Do I need the yellow wire?? Back to the bogging down. Runs fine when cold, but once running at operating temp. the symptom occurs. I press on the accelerator for a modest acceleration... normal acceleration?? Not flooring it... and it will sometimes bog so bad it stalls. Other times it will bog and then accelerate like nothing happened. Recently I was accelerating and it was switching between bogging then running fine continuously for about 4 blocks?? Things that have been left constant between the original engine and the new engine are the transmission and HEI ignition. The new are the plugs, wires, 1406 edelbrock carb, starter, fuel line with in line fuel filter (which is clear). I had similar symptoms with the other engine prior to engine swap, which led me to believe there was something wrong with the transmission, but I don't think that is my issue, as it makes no weird noises and shifts fine. One last thing. When I first got the truck I parked it over night and tried to start it the next morning... it would not fire. I ended up cleaning the cap and rotor and the thing fired. This was after a couple of days trying to figure out what the problem was?? So I think my cap and rotor definitely need to be replaced. I am curious about the distributor getting the proper voltage. Do you have any suggestions and am I on the right track?? It is properly timed also. Thanks
__________________
May all your ups and downs be in the back of a Chevy!: |
03-12-2007, 01:40 PM | #2 |
GEARHEAD
Join Date: Jan 2007
Location: CENTRAL,PA
Posts: 2,284
|
Re: Engine bogg
For the price, replace the cap and rotor just to eliminate them from the equation. Go from there. RJ22
|
03-12-2007, 03:10 PM | #3 |
Registered User
Join Date: Feb 2002
Location: Vacaville, CA
Posts: 2,745
|
Re: Engine bogg
you can eliminate the yellow wire. Also make sure the other power wire to the HEI is not the original resistance wire or you will not have the full 12V to the HEI.
Some thing to try as far as the boog: by Lars Grimsrud Tech Tip #3 How can you tell if an off-idle stumble is caused by a lean or a rich condition? A carb running rich, as well as a carb running lean, can cause an off-idle stumble or hesitation upon acceleration. To narrow it down, tap the roll pin out of the accelerator pump lever by using a small pin punch or a small finish nail. I actually use a small, broken drill bit that's just the right size. Using a hammer, gently tap the roll pin in towards the choke air horn wall. Don't jam the pin right up against the wall: Leave just a little bit of a gap so you can get a screwdriver blade in between the wall and the pin to pry it back again. With the pin tapped out, remove the accelerator pump lever. I like to do this with the engine running so I won't have any trouble starting the engine without the accelerator pump. Now, rev the engine a little with the throttle. Notice if the engine seems quicker and more responsive, or if the hesitation & stumble is worse. If the engine actually feels more responsive with the accelerator pump disconnected, you have a rich condition. If the hesitation is worse than before, you have a lean condition. If there is no change whatsoever, you have a non-functional accelerator pump. To verify a suspected lean condition after this test, simply hold your cupped hand lightly over the choke air horn area with the engine running at idle, restricting the air flow. If the idle speed and idle quality momentarily increases, you have a verified lean condition. You need to select a jet/rod combination that will give you a little more Cruise Metering Area. Make these changes in less than 10% increments using the Figures provided in this paper. This is for a Q-Jet not an EdleJunk so you will have to find how to disconnect the accelerator pump.
__________________
70 C/10 Light Red 350/TH350, HEI, Duals w/40 series Flows, 91 seat, LED taillights 99 Pontiac S/C GTP, SLP Ram Air hood, GMPP Konis & springs 95 Neon ACR, MP PCM, AFX UDP, 3.0 CAI |
03-12-2007, 03:59 PM | #4 |
Registered User
Join Date: Dec 2004
Location: Arvada Colorado
Posts: 1,321
|
Re: Engine bogg
Just my 2 cents worth....
Every Edelbrock I've ever owned has had a bad to a mild off-idle stumble. I've dorked around with the accelerator pump but that never seems to help. What finally solved it was putting in a heavier metering rod spring. Edelbrock sells the metering spring assortment. Worked for me. Good luck.
__________________
Larry 1949 Willys CJ2A, Kubota Turbo Diesel engine, Warn Overdrive, 11 inch brakes, 12volt, Warn M8000 Winch "Little Green" 1970 Rustoleum Roller Red C20 Custom Camper 454 TH400 "Big Red" 1971 K20 6.2 Turbo Diesel 4x4 4spd Ranger Overdrive "Pumpkin Wagon" 2005 VW Beetle Diesel 44+ MPG "Silver Bullet" |
Bookmarks |
Thread Tools | |
Display Modes | |
|
|