I replaced my intake manifold on my '89 and so had the distributor out. I screwed up in marking it properly when taking it out so I had to re-set it.

I have it set as per procedure (marker on TDC and put rotor between 1-8 on the distributor - placed distributor flush with in-take after playing with oil pump position).

After a little dizzy adjusting - I found car starts but after disconnecting the bypass to set the timing, car runs (a little rough) when at about 20 degees BTC. When I rotate the dizzy to around 8 degrees TDC it conks out - no way to get it to spec 6 degrees.

A couple dumb questions...

(1) I set the TDC marker without checking the compression on the No. 1 cyclinder (no helpers today) - If I was on the wrong revolution (2 rotations on the engine for 1 on the dizzy) ... the rotor would be off by 180 degrees - but would the car start? In other words, since the car runs (though rough) does this mean I am at least close to the correct rotor position or could it be off by 180 degrees)?

(2) I've read that it really doesn't matter on the wiring on top of the distributor to the spark wires - since the dizzy doesn't really care - it just fires in the sequence of the rotors rotation. But how is this sychronized with the fuel injectors - doesn't the injector No. 1 need to fire at the time the engine is at TDC for cylinder 1? In other words, the dizzy fires the sequence ( 18436572) - doesn't the fuel injectors have to be synchonized somehow to follow this?


Any other thought would be appreciated,

Thanks,
Paul

 

Ones got nothing to do with the other..

injs are batch fired all together in no particular order...based off #1 perhaps...doesn't matter since when # 1 fires, so does 3,5 &7.

Your dist is one tooth off.Maybe 2. Pull it and turn the rotor 1 tooth counter clockwise and try to time again at the normal 6 degree mark with the base timing wire d/c. When you set a dist, with the balancer on the mark, the rotor should be ON the #1 post, not between, or close or past...ON the #1 post. Thats what you want to fire at that time. The ECM decides when to fire 4 inj at a time based on a reference pulse from the dist. The firing order doesn't matter to the fuel.
Some yrs later the TPI was renamed "Multiport or Sequential FI" when the ECM got enough computing power to handle tracking 8 injectors and fire them when the intake valve opens. The TPI is only able to track 2. Test on conversions show that the multiport ECM and sequential FI only added 10-15hp more than the TPI bank fire system.

Pull the dist and stab it right...it'll be fine.

 

180* off = it will not start

If it starts your close to where you need to be. Since its running rough you have a problem with the wiring sequence ( check it first ) or a vacuum leak or something electrical is not connected properly.

 

plug wire crossed, or the vac line under the dist rr is broken -hard plastic- or came unconnectedl.

if you are reading 20* at idle, trans in drive to pull down to lowest rpm, you have to go a LONG way rotating hnsg CW (retard) to get to 6*. is the engine idling over 1000? if so, the ign module may be advancing timing (not ecm if you have the correct wire unplugged for est.)

the value in getting the dist dropped in "on the correct gear tooth" is for convenience only, so that wiring connectors attach, and also plug wires. you can always rotate out of it, if it is off that much, but then the dist won't be positioned so that the #1 is at the 5 or so on the clock. as it was from factory.

if you positioned it at between 1-8, you should have rotated the rotor CCW towards #2 by the amount the rotor will turn CW when it engages the cam gear. otherwise your #1 wire will be close to #8, the 7 on clock face.
clear as crystal?

 

Keep in mind the rotor has to hit and fire #1 a few degrees BEFORE TDC. By pointing it between 1-8, the OP has mechanically retarded his timing. FWIW, I determined timing is already retarded with the config of the stock 89 cam. Getting it more retarded is going to make it much harder to run at lower rpms. (Remember, retarded timing favors HIGHER rpm performance)

I think he's off a tooth. And, he's not off 180-deg.

 

yep, the fsm apparently says to align between 1-8 -for some reason- but says "install dist, positioning rotor to the TWO previous marks on the distributor." not a direct quote.

he does not have marks, and did not know to turn rotor 30* towards #2 firing pin, since the rotor will rotate CW to #1 when the gears mesh. (If the oil pump drive slot aligns with the dist drive lug, which it probably won't without coaxing.)

there is no assigned tooth on the gear for #1, so he can rotate the dist back CCW to advance it. if he is indeed reading 20*, he SHOULD be reading retarded, if the rotor was pointed towards #8, rather than 2.
sounds like the rpm is too high and he's seeing normal advance from ign module, turns it CW to retard, and it is now ATDC, retarded.

something else is wrong here, maybe confused about wiring order, whatever. I would start over, and it can be dropped in in a matter of seconds to where the housing will align where it should.

But...he could get it in time by turning the housing, as long as cap does not hit firewall or manifold. Just removed the dist from my 91 today, and the timing was 7* when I reinstalled it.
not rocket science, "distributor science."

** the 30* is what one tooth will rotate, since there are 12 on the gear. each plug pin is 45* so you turn the rotor before installing the 30*. towards #2 pin. correct?

 

It really doesn't matter if it's a tooth off if you can get it to time at 6 btdc. Something else is wrong... possibly the timing light is not on #1 or the firing order is not right. It should run better after reconnecting that wire and restarting the car. Never heard it called a bypass before, You are talking about the electrical connection close to the master cylinder?

Between 1 and 8 is correct... 8 is advanced from 1, 2 is retarded from 1

 

here we go again.

myk7, I agree, he is reading wrong plug wire, whatever, or engine is high rpm. But, which direction, CCW or CW, do you turn your housing to advance timing?

I turn mine towards the rotation of the rotor, CCW, counter clockwise.

or have I gone brain dead again?
pic shows the mark where rotor pointed to #1, the next to the right is where it pointed as dist was removed. towards #2, not 8. when rreinstelled, pointed to second mark, rotor aligned at #1.

 

To advance timing, I rotate the housing (ccw) against the rotation of the rotor cap, bringing 8 closer to where 1 was. To advance the timing by moving the rotor cap, I move the rotor cap(cw) towards the number 8 position.

The rotor cap spins clockwise, how would moving the rotor cap ccw advance it?

Your different marks only show how the rotor cap moves as you pull the dist out of the gear on the cam.

 

Ignore my bolded sentence above. I'd fallen and hit my head. I was dilerious. I was drinking. My dog ate my homework. I have alzheimer's. I had a senior moment.

Multiple choice! :o

You can, in fact, insert the dizzy anyway possible so long as it will seat, engage the oil pump, and physically rotate to the point where electronic timing APPEARS correct. If the brown timing wire is unplugged, what you see on the crank SHOULD be correct. Unless the balancer has slipped. And, we certainly have seen that posted more than once. Especially if a cheapo aftermarket balancer was used (like Performance Products).

(To confirm correct orientation of the balancer, I'm thinking the keyway and the timing mark should line up.)

 

we all advance it the same way, of course. I didn't say "move the rotor" because you can't. you can ony move the hsng towards rotor -so it contacts firing pin sooner- or away from.

we should forget talking about #8, 2, whatever, because we time with #1. all cylinders are advanced accordingly, along with #1, OF COURSE..

we are advancing/retarding ALL cylinders, but measuring #1.

the problem with introducing #8 as advance, 2 as retard, is that it gets confusing to someone who has not installed a dist and timed #1.

more than once on this forum and others, advice was to turn hsng CW to advance, when it was just the opposite.

when we rotate hsng CCW, we are moving the #1 firing pin closer to the rotor button. when we align it all to drop in, we align button to #1 dist tower, or mark, then rotate hsng to wherever we want it to be seated in installed position, and THEN turn rotor to the second mark.

if we are starting fresh, we turn rotor CCW -"towards" #2 firing pin- by the approx amount the rotor will turn (CW) when gear engages, which is 30* or less (towers are spaced at 45*). when dist is seated, the rotor should align back at the first mark, or at #1 pin in dist.

of course, the oil shaft has to be engaged, and I assume the OP did that...

 

I understood you, GREG, and he may be off one tooth, which would only put the housing out of the location it was in as-received -#1 tower at approximately the 5 on the clock. as I said, I think, he could rotate it to time it. he evidently has it running....

more going on here than distributor, my opinion. with the major teardown he did, many things are possible.

when I last timed mine -and several times before- the engine rpm would often pull in the advance from the ign module if not in DRIVE, engine at normal temp, as GM specifies. if you react and retard it to 6*, you are probably at 6* or so retarded.


saludos,
joe

 

excellent advice gents ... and I sure learned plenty.

I did have to rotate my rotor before dropping again to get the proper clearances to move the dizzy around.

Intersesting that the injectors all fire on each side simulateously - I guess it just holds on to the fuel until each cylinders compression stroke.

... and the original problem was a massive vacuum leak. Replacing the intake manifold was quite a chore ... I checked everything twice when putiing everything back. Turns out the new EGR valve I replaced had a hole in it that I was supposed to seal (must be an optional usage)- I saw the little bolt that sealed it in the box but didn't no what to do with it - also thought the hole didn't go thru the valve.

I found the vacuum leak by spraying small doses of carb cleaner around the plenum, fuel injectors and of coarse under the plenum by the EGR.

Purrs like a kitten at 6 degrees BTDC.

Thanks all - Cheers.

 

Glad you found the problem!

fixed (Close though....semantics)