FlatBlack Posted February 26, 2009 Share Posted February 26, 2009 Abstract: My timing is off, due to a great many possible things, the car will rev fine while idleing but once under load it stumbles and will not run properly. My vacuum advance is hooked up. The Full Story: I did do a quick search, didn't find much in the way of helping with my problem though. I figured this would be new thread worthy. Last weekend I put a new headgasket and ARPs on my 1980 L28 F54/P79 motor. I thought I might had dropped the chain, so I pulled the front cover off. While down there I put my new 83 L28ET oil pump in there. I set the timing chain up according to the FSM, with the crank timing mark at 3 o'clock on the right side, and the cam gear timing mark at 3 o'clock directly above it, and counted 42 links as it said. Put everything back together, and the car wouldn't start, backfiring through the intake, etc. I figured we had set the timing on the exhaust stroke, so I took the oil pump back off, rotated the gear 180*, and put it back together. The car would start and idle when I turned the dizzy all the way clockwise. I got back under there and moved the oil pump shaft over again, but it still was not perfect. I had to unbolt the 'slot' for the dizzy [the one that you tighten when you are done setting the timing] and rotate it clockwise, but the car ran fine and would rev all the way up. I then decided to move every spark plug wire around one spot so that the dizzy would be back over the timing slot and I could bolt it up. The motor sounded great, it revved up to 4,000 RPM no problem. and I put the car on the ground. As soon as I let the clutch out to move it forward, the car bogged down and almost died. I got out and played with the position of the dizzy but nothing changed that much. It would rev up fine again, but under about 15-20% throttle it would bog down as if it were under a load. Also, my headlights will not turn on. I am not sure if this is related, though. Running lights and everything else work great. My questions: - Could I have set the timing chain wrong? - Could it be related to setting the timing up on the exhaust stroke? - Could the turbo oil pump be different than the N/A pump in terms of the dizzy shaft? - Could the dizzy/cap/rotor/ignition wiring/coil/etc. be bad? - Is this something I can fix without having to tear the motor down again? I will do whatever is neccessary, I have all weekend, but this 'project' has already tripled in time and I am getting worn out. ANY suggestions that you have would be great, thanks for reading the long novel up there. Quote Link to comment Share on other sites More sharing options...
ben280zx Posted February 26, 2009 Share Posted February 26, 2009 Sound similar to my situation, but can it rev pass 4k rpm? Mine can't, I have't drop it on the ground yet, and I've found that my downpipe is leaking, which lead me to I don't have pressure. Therefore, I can't rev over 4k. Do you have a timing gun to check timing? Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted February 26, 2009 Author Share Posted February 26, 2009 I'm picking up a timing gun today, I've been adjusting the dizzy by hand to 'dial it in.' It will rev as high as I want it to while idleing, as soon as I gets under load it starts sputtering. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted February 26, 2009 Share Posted February 26, 2009 Wow this sounds all to familiar, A timing light will help a ton, also, instead of taking out the shaft an repositioning it every time unbolt the dizzy so you can move it however much you want and see if you can find a sweet spot. Ah, and Im having problems with my lights to! maybe my bad luck did transfer over, Im going to go see if my car will run any better now, haha. good luck. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted February 26, 2009 Author Share Posted February 26, 2009 I did unbolt the timing bolt so it can rotate as much as it needs to, but it's already within that range. Did you ever figure what happened to your headlights?? That's really random that would happen to us both. Quote Link to comment Share on other sites More sharing options...
MJLamberson Posted February 26, 2009 Share Posted February 26, 2009 Nope, only it was the dash and tail lights for me, not the headlights, it kind of has me stumped cause I only touched the engine harness, which should have no affect. Did you chck your TPS? remember how I told you mine would bog and stuff under load but rev fine, that was the problem, just a thought. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted February 26, 2009 Author Share Posted February 26, 2009 Nope, only it was the dash and tail lights for me, not the headlights, it kind of has me stumped cause I only touched the engine harness, which should have no affect. Did you chck your TPS? remember how I told you mine would bog and stuff under load but rev fine, that was the problem, just a thought. Are you serious? Man I'm going to flip out if that's it. Trumpet and I had a good laugh at your expense after hearing that. I will definately clean and check the wires tonight. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted February 27, 2009 Author Share Posted February 27, 2009 I didn't go out to the shop last night, but I will be there when I get out of class today. Does anyone else have some suggestions? Quote Link to comment Share on other sites More sharing options...
ben280zx Posted March 1, 2009 Share Posted March 1, 2009 For the dimming lights, check the fuel on the passenger side. The 10A fuse might be ready to go. I've change mine and it didn't happen again. Just my 2cent. Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted March 1, 2009 Author Share Posted March 1, 2009 cool - I will check it out. The car ran today - without the TPS. Still kind of confused, it runs but has a lot less power. I got a timing light today, but it was snowing here and I called it a day early. Quote Link to comment Share on other sites More sharing options...
islanddozer Posted March 1, 2009 Share Posted March 1, 2009 I am quoting MY FSM set tdc timing mark on crank gear and shinny link line up other shinny link on chain to be at #1 mark on cam gear "I set the timing chain up according to the FSM, with the crank timing mark at 3 o'clock on the right side, and the cam gear timing mark at 3 o'clock directly above it, and counted 42 links as it said." how can you set timing without being dead-on tdc ? 3 o'clock is close but you need to be dead on. Just put the balancer and cover back on set, then remove and install chain Could the turbo oil pump be different than the N/A pump in terms of the dizzy shaft? No same internal size Just impeller is longer Could the dizzy/cap/rotor/ignition wiring/coil/etc. be bad? no - Is this something I can fix without having to tear the motor down again? yes Hope this helps Quote Link to comment Share on other sites More sharing options...
87grandnational Posted March 24, 2009 Share Posted March 24, 2009 hey flatblack. Any updates? Quote Link to comment Share on other sites More sharing options...
FlatBlack Posted March 24, 2009 Author Share Posted March 24, 2009 Yes, sorry - I actually updated my "member's page" thread, and mentioned that I got the issue sorted. It was an incredibly dumb mistake and I don't quite know how I missed it. I have about 3 or 4 AFMs, so I usually adjust the spring rate [most people strongly advise against doing this] to get a good AFR as best I can on the stock EFI. This wasn't a problem in Baton Rouge, but up here in Northwest Arkansas the weather is really up and down in the Spring/Winter months. I stripped out the adjustment screw on one of my AFMs while trying to get it to run [and it wasn't running at that point] so I threw on another AFM. The only way the car would run was if I had the spring rate on the new AFM set all the way 'lean.' I pulled the dizzy and the dizzy had a gawdaweful amount of shaft play [both vertically and horizontally] so I swapped it out. After that, I checked my 'AFR' again [but manual adjusting the AFM position at half throttle] and the mix was waay lean. It was a dumb mistake, I should have checked that immediately after swapping dizzys, but I didn't and wasted a week. My dizzy rotor is set exactly 180* opposite of what it should be, I have no idea what I did, but it runs stronger than it ever has, so I suppose it is fine for now. I went on a spirited 2 hour cruise on Sunday and after I got home - nothing had leaked I'm very happy with my new head gasket. Quote Link to comment Share on other sites More sharing options...
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