Tuning and Troubleshooting
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Joined: Dec 2005
Posts: 159
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From: New Bedford, Ma
Car: 1987 IROC
Engine: Destroked 377
Transmission: TH-400
Axle/Gears: 9inch with 3.70's
Tuning and Troubleshooting
Im still having trouble tuning my car. I have posted before and got some good help. Hopefully i can get some more. I cant figure out what to try next. Ive tried to time it a couple of times. The guy who had the engine before me had it timed at 39degrees total timing at 3000rpm. He had a 2 speed powerglide with 4500stall and a 488 gear, the car went 11.6. I put the car together with everything i have below. The car idles good but when i punch it 1st and 2nd seem to go not so good but 3rd it doesnt go good at all. Seems like the engine doesnt have power. Should I have the car timed different? Could I have a vacuum leak? Do I need to lockout my distributor? If anyone can help i would appreciate it a lot. Thanks
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Joined: Sep 2002
Posts: 9,192
Likes: 20
From: Cary, North Carolina
Car: 1992 RS
Engine: Carbed 350
Transmission: 700R4
Axle/Gears: 3.42 posi
I'm certainly no expert, but I can remind you of some basics:
Timing - I don't know all about total timing stuff - My carb motor set at about 11* BTDC - I tried lower timing, but couldn't get the vacuum needed for power brakes, so I bumped mine up to 11*, and reduced carb settings to have decent idle with greater vacuum.
Vacuum leak - while engine running, spray carb cleaner all around intake and carb base, as well as vacuum hoses - see if idle increases. DO NOT USE STARTING FLUID - it's too volatile and flashes easily (ask me how I know LOL)
Fuel pressure? Do you have a guage in-line? If not, get one put in so you can see fuel pressure - should be 5-7psi (I hear Holley's like closer to 7 - check with a Holley expert)
Spark - I recently had a bogging with mine - found a not-so-good plug wire, and also another plug wire that was 1/2 off the plug - just enough to keep a good steady spark from that plug. Maybe try a plug tester - maybe you have a bad wire. Double check firing order too.
These may all sound stupid, but I know I can look at something simple that's wrong all day and not see it - because I've been looking at it all day - "can't see the forest for the trees" kinda thing - so no offense with this - I just know sometimes I overlook the obvious simple things, and it helps to have someone list them for me.
Timing - I don't know all about total timing stuff - My carb motor set at about 11* BTDC - I tried lower timing, but couldn't get the vacuum needed for power brakes, so I bumped mine up to 11*, and reduced carb settings to have decent idle with greater vacuum.
Vacuum leak - while engine running, spray carb cleaner all around intake and carb base, as well as vacuum hoses - see if idle increases. DO NOT USE STARTING FLUID - it's too volatile and flashes easily (ask me how I know LOL)
Fuel pressure? Do you have a guage in-line? If not, get one put in so you can see fuel pressure - should be 5-7psi (I hear Holley's like closer to 7 - check with a Holley expert)
Spark - I recently had a bogging with mine - found a not-so-good plug wire, and also another plug wire that was 1/2 off the plug - just enough to keep a good steady spark from that plug. Maybe try a plug tester - maybe you have a bad wire. Double check firing order too.
These may all sound stupid, but I know I can look at something simple that's wrong all day and not see it - because I've been looking at it all day - "can't see the forest for the trees" kinda thing - so no offense with this - I just know sometimes I overlook the obvious simple things, and it helps to have someone list them for me.
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