Hi there, I have an 86 IROC originally 305 Auto. Now its a 350 with a T-5 behind it. Comp Cams XE268H, bored out .40, all rebuilt, including the tranny, stock iron heads ported and polished. MSD Cap, MSD Coil inside the cap, MSD 8.5mm wires, MSD 6AL,Removed Screen from MAF, K&N Filters, ESC Module replaced with a 350 module. knock sensor replaced for 350, got a chip from harris performance, i gave him all data about car, and he made one up for me. The chip is programmed for a #24 injector, but currently I have a 19# in there. I will be replacing it with LT1 24# injectors today.I took off the AIR lines, and the pump. I do not have my AC hooked up, but I do have the compressor still on there.
My problem is that when I try to set the timing I hook up the timing light to #1 which is on drivers side, and disconnect the brown wire by the Vent box in the corner, and I put a white mark on the balancer, and I try to time it, but I cant even see the line at all, the only way I could see the line is if I turn the distributor clock wise a LOT, then the line appears, but then the engine is dieing, and it backfires if I try to give it gas, I got it running pretty good right now by ear, but when I'm in any gear, lets use second for now, and its around 1300 rpms, and I take my foot off the gas the car starts to jerk back and forth, its really annoying. Any ideas on what I need to change.

Any help would be really appriciated

Thomas

 

try putting the timing mark on zero ,take the dist.cap off ,rotor should be on #1or#6.if not & the engine is running fine id look at the harmonic balancer.sometimes the elastometer will let the outer ring move giving you a false reading on the timing,ifso replace the balancer and retime it. hope this helps,jimmy

 

I never take that brown connector loose, because you don't need too. I never have, and I advanced my timing to 36*, and found that to be the best, and with the bosch injectors, from '87 the '88's and newer are rochester, the bosch's liked 47.5 psi of pressure. And if you use bosch +4 plug's TPIS proved there worth 6.5 hp on the dyno, and 6.8 lb ft of torque. The best way to see what your motor likes for timing, depening on it's condition, cam, and injectors, is at the track. I tried mine a lot at the track, and found out 36* on my sears craftsman timing light was the best.

But just take this as an opinion, but it worked great for me, that's why my iroc ran a 14.86 at 86 mph with two gears, and it was a 350 TPI with the rear end, car craft said '87's didn't have, the borg warner. I had it though, and it was never changed. That run at Route 66, I can always scan my time slip. That was at 156K miles, and the trans wasn't taken care of well enough, the best I ran before suspension mods was a 13.81 at 99 mph. The last burnout I did, was 150ft from each tire with lakewood suspension.

I'll actually have my firebird out soon, check out my site, and see how much I spent on an order, about $1000 www.cardomain.com/ride/471099

 

Thanks for the replys. 'm ganna try these things and let you guys know.

 

Some balancers have a small mark at 180deg from a larger one, which is the correct one. Both are #1TDC, but one is TDC exhaust stroke, one is TDC compression stroke.

Disconnect your brown ESC connector like you've been doing, it's the only way to obtain a true base timing reading. I'd agree on the track testing to determine what an engine likes, but you must absolutely disconnect the brown lead to know what you're setting base to, and it shouldn't be far from stock unless you've also edited the timing curve in the prom. Not to mention it's darn near impossible to set a repeatable timing value without disconnecting it. Actually, in a worse case scenario you can advance the timing so far this way that the knock sensor is unable to prevent knock and actually damage your engine.

 

That's funny, I just talked to TPIS yesterday, his name was Chris, he agreed with my way of adjusting the timing, you can't even find the brown wire in some cars, in some cars, its not a brown wire, and some don't even have a connector.

The knock sensor, according to the eprom and memcal chip, will only work if you really over time the engine, more than 36* of timing. But if you have premium, there won't be a problem, I've tried 37, 38, 39 and noticed when driving, you lose some of the power, that's when you go back. True base timing, means very little, because you can turn the distributor, like all gen 1 motors, so the computer is always what is putting in the base timing, that's why it really makes little difference.

All balancers have one mark, to slid it on, the keyway one. But what if you know about engines, then you will be able to easily find the compression stroke, when the piston is coming, up, with your finger over the spark plug's hole, without a plug in, you will notice the compression stroke, when theres pressure, and look when the piston is all the way up, or when the damper is at 0 at the timing pointer.

This is basic knowledge of mechanical engines, and of a 4 stroke, on any 4 cycle engine, they work the same way for ignition timing. When you have your finger over the number 1 cylinder, and the timing marks on the damper, are coming to the pointer, that is the compression stroke. This is the same for all engines. The base timing, means nothing; the computer always has some control over the timing, just when the connector, isn't connnected, it won't advance the timing. But based on idle, the computer will always have control over it. The tps voltage, the MAF/MAP also has some minimum relavence on a stock prom/computer, without further timing.

I have had two f-bodies, and have learned alot of things about them, tuning them, timing them, TPS voltage, bypassing certain sensors, and what not also. I have done a lot of reading, talked to John Lingenfelter before he died, spoke to TOM NELSON, the king of turbo motors, and have had a offer to work at a machine shop, and worked on over 50 f-bodies, mostly new and some old.

I have also recently finished the tuning of a dominator on the street, the 1050, 3-circuit model. I have timed the original points motor, and that's when timing is more critical, because if you advance it too far, you burn the points. Now we have MSD everything, and with a pick up, magnetic sensor, it's a lot easier, but there is more to do, with how much timing you want to run, if you want it locked out, or based on two springs if you want to have it advanced at different times, or more so. Some old timers, even recommend running 40 degrees of timing, but it's different on different engines.

I just thought I'd mention this, because I do have quite a bit of experience on timing, even with 2stroke boat engines.

I just don't want someone steering you in the wrong direction with things, more esperience, is the key at this time, go to my site and read stuff, about my iroc on page 8, and learn some things about tuning, I did, I've learned so much, and asked guys with 6 second cars questions about things. I know a lot of people at Route 66 in joliet illinois.