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Unread 08-13-2012, 06:15 PM   #31
Old4X
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If it is a throttle body, the parts would match an 88 S10, not the CPI from 94 in GM

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Unread 08-13-2012, 07:03 PM   #32
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Quote:
Originally Posted by Old4X
Your ICM is the "standard" marked part. Howell is using a GM ignition and fuel injection system from a 94 era 4.2 V6. The square box has to do with changing the timing, it handles the spark knock sensor for sure, do not remember the other functions.

On that system the ignition ICM also fires the injectors.

If you ned info on how those parts interact, a maint manual for a s-10 Blazer from 94 would have the schematics.
Phew. Yes two of the wires from the coil go into the left side of that. But the rest just disappear into the loom.

And nonrubi I do have a brass tag on the throttle body.
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Unread 08-15-2012, 05:32 PM   #33
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I pinched the vac line that goes to the vac port near the throttle body to the canister and nothing happened.

And as or the erratic light, I stuck our timing gun on it to fiddle around and see what happened. The light never hit the timing mark at the same place in a row. There were two spots that seemed like it was consistent at. 2 and around 6.
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Unread 08-15-2012, 07:41 PM   #34
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Quote:
Originally Posted by Michaelgoesrawr View Post
Fair enough. I've read that an increased gap with a new could produces a hotter spark which ignites fuel better. JeepHammer has a post that shows how the current bounced around the cap and left marks on the rotor. The upgrade is suppose to stop that from happening so that's mostly why I figured I would do it, to prevent cross fires.

In terms of wires, I take it you buy the connections and boots separately? How long does the roll of wire last on the shelf? I like that because it's all cut to fit. Pretty cool. Do you have a specific brand that you use?
I understand. A stock engine does not have the compression ratio, valve opening, valve duration, rpm or extreme load that would prevent the stock ignition parts from doing their thing. Maybe the picture you saw had tracking inside the cap - all caps develop that over time - so if the cap needed changing, a stock cap would have sufficed.

As long as the plug gets enough energy to produce a decent spark, it is 'enough' to light the fire. Adding more is not really needed, again, for a stock engine. Hi-po motors are something else.

I don't always buy the same brand of wire. I shop Jeg's or Summit and look for something decent I like. I have not had a reason to buy any more for a while; next time I will check Amazon. Sometimes the connectors are bundled, and sometimes they come separate. You should decide if you want straight or angled boots.

You see, there are many possibilities; whatever works for you should be fine.

As I stated in my other post, you shoudl get yourself a decent crimper. You want a good crimp so that the connections don't suddenly fail a few years down the road.

I like to run my wires mint, so I route them carefully and likewise double-check the lengths so that they can be loomed without sags or one getting pulled too tight.

The shelf life of the wire is infinite. Assuming it is stored inside.

There are a lot of funny stories about distributor caps. I once saw a Jag V12 that was running with the hood open at night. It looked like a lightning storm fire show under there. Turns out that the cap had exploded once. Fumes built up inside, possibly exacerbated by the way Jag caps are vented, and the sparks lit it off. But only the sides of the cap disappeared. The top was held in place by the wires - that heat had made nice and stiff, so they did not move - 12 of them and a coil wire. The top of the cap never budged. So the rotor still went round and round and was doing its thing. The car was running perfectly, and it had been that way for a while, with the top of the cap levitating above the rotor.

As you see, the stock systems are very resilient - once they are right, and as long as they are checked from time to time, they can do their thing quite well.
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Unread 08-15-2012, 10:49 PM   #35
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I understand what you're saying and I was just giving you my understanding of the upgrade.

Do you think a tune up would help the erratic timing light from my above description? I'm just trying to get this damn thing done and back on the road.
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Unread 08-16-2012, 06:14 AM   #36
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Erratic timing is usually one of two things. The first is a worn mechanical part - distributor bushings, bevel gears, cam shaft end play, something like that. For example, if the cam is walking back and forth as you accelerate and decelerate the engine, the timing will advance and retard accordingly.

The other is a fault in the items that normally advance the timing. A flaky signal, poor connection, sticky advance weight, something like that.

Can you zero in on the description of the erratic timing? Is it just random, no matter what? How much is it changing - a degree or two, or a whole lot? Does it go one way if you accelerate the motor, and the other way if you decelerate the motor? Does it bounce around no matter what rpm the motor is at?

One item that has puzzled me. In your first post, you said the mechanic said that the timing was erratic, and that it did not pass smog even with the timing retarded all the way.

We've already discussed erratic timing; let's focus on the other statement. Did you mean that, even with the timing retarded all the way, the mechanic could not set the timing to spec? Or, did you mean that the timing was at spec, the vehicle did not pass, the mechanic tried to retard the spark to get it to pass, and there was not enough adjustment for him to retard it as much as he wanted?

If the latter, was it because he could not twist the dizzy enough, for example because the vacuum advance was hitting the block? If that is the case, you can probably select a different cap post as #1 so that you can get enough swing.
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Unread 08-16-2012, 12:19 PM   #37
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Quote:
Originally Posted by plym49
Erratic timing is usually one of two things. The first is a worn mechanical part - distributor bushings, bevel gears, cam shaft end play, something like that. For example, if the cam is walking back and forth as you accelerate and decelerate the engine, the timing will advance and retard accordingly.

The other is a fault in the items that normally advance the timing. A flaky signal, poor connection, sticky advance weight, something like that.

Can you zero in on the description of the erratic timing? Is it just random, no matter what? How much is it changing - a degree or two, or a whole lot? Does it go one way if you accelerate the motor, and the other way if you decelerate the motor? Does it bounce around no matter what rpm the motor is at?

One item that has puzzled me. In your first post, you said the mechanic said that the timing was erratic, and that it did not pass smog even with the timing retarded all the way.

We've already discussed erratic timing; let's focus on the other statement. Did you mean that, even with the timing retarded all the way, the mechanic could not set the timing to spec? Or, did you mean that the timing was at spec, the vehicle did not pass, the mechanic tried to retard the spark to get it to pass, and there was not enough adjustment for him to retard it as much as he wanted?

If the latter, was it because he could not twist the dizzy enough, for example because the vacuum advance was hitting the block? If that is the case, you can probably select a different cap post as #1 so that you can get enough swing.
I should say ahead of time that this is the second time I have used a timing gun and I only have the basic knowledge needed to understand this so I apologize if I am doing anything wrong or not explaining myself clearly. I'm doing my best lol.

At idle and the gun set to zero advance it bounces from 8-10/12 degrees a few rotations and then jump to 16 degrees every few times. And when the gun is set to 8 degree advance it bounces from 0-4 a few rotations ad then jumps to 8 degrees. I don't know the advance curve but at higher rpms the timing mark advances up the curve and only deviates from the degree mark by tiny increments. I'm talking half a raised timing mark back and fourth., so it's fairly steady in my mind. And then goes back to bouncing when it hits idle.

I cant comment on the timing because he didn't say anything about not being able to set it. Just that he couldn't retard it anymore because the vacuum advance was hitting the block. Wouldn't moving the number one plug to the number five cap stop and changing all of the plugs one stop change where tdc is and mess up the timing?

I rolled the Jeep at 35mph that the engine was in prior to my current Jeep. Could that much bounce cause problems?
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Unread 08-16-2012, 09:54 PM   #38
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Quote:
Originally Posted by Michaelgoesrawr View Post
I should say ahead of time that this is the second time I have used a timing gun and I only have the basic knowledge needed to understand this so I apologize if I am doing anything wrong or not explaining myself clearly. I'm doing my best lol.

At idle and the gun set to zero advance it bounces from 8-10/12 degrees a few rotations and then jump to 16 degrees every few times. And when the gun is set to 8 degree advance it bounces from 0-4 a few rotations ad then jumps to 8 degrees. I don't know the advance curve but at higher rpms the timing mark advances up the curve and only deviates from the degree mark by tiny increments. I'm talking half a raised timing mark back and fourth., so it's fairly steady in my mind. And then goes back to bouncing when it hits idle.

I cant comment on the timing because he didn't say anything about not being able to set it. Just that he couldn't retard it anymore because the vacuum advance was hitting the block. Wouldn't moving the number one plug to the number five cap stop and changing all of the plugs one stop change where tdc is and mess up the timing?

I rolled the Jeep at 35mph that the engine was in prior to my current Jeep. Could that much bounce cause problems?
I have seen the type of timing variation you describe before, and IIRC did not affect emissions testing or drivability. One thing I am curious about, however, is whether the rpm is varying when the timing bounces. Regardless, I am not sure I would worry about this too much.

You can't mess up TDC. Each piston hits TDC once every crankshaft revolution. Ignition timing is which spark plug lights up relative to where each piston is in terms of the four stroke cycle and the firing order.

It is completely arbitrary as to which post in the cap you select as #1. The only thing that can matter is if, as on yours, the post selected prevents the rotation of the distributor to set the timing where you want it because the vacuum advance hits the block.

When the distributor vacuum advance hit the block when the timing was being set, any mechanic worth his or her salt woould just have selected another post as #1. It takes all of 2 minutes. That he or she did not, to me, and without hearing the other side of the story, tells me your mechanic was ignorant or dishonest (wanted to sell you a new distributor).

Here is the absolute easiest way to plug spark plug wires into the cap. With the motor off, line up the line on the crankshaft damper to the mark on the timing cover. Then pull the dist cap. See which post the rotor is pointing to. Select that as #1. In the direction of rotor rotation, plug in the rest of the firing order: 1 5 3 6 2 4. Start the motor. If it starts, you are done. If it does not, then swap the wires one half of the firing order. IOW plug #1 where # 6 was, # 5 where # 2 was, and so on. Now your motor will start right up.

The reason for this is that it is a 4 stroke motor. The crank turns twice for the cam - or the rotor - to turn once. So, whenever the timing marks are lined up, you have a 50:50 chance that the motor is on the top of compression stroke (when the plug should fire) or the exhaust stroke.

Some folks say to remove #1 plug and stick your finger in the hole to feel the compression to find out if you are on the compression stroke. Some say pull the valve covers to see if both valves are closed. Methods like this are fine; they just are extra work. You cannot hurt the motor by trying to start it with the wires 180 degrees out - you are just firing on the exhaust stroke. Nothing will happen.

If your dizzy is installed way off (physical relationship of the vac advance to the block), you need to pull it out and reinstall it such that the vacuum advance is in a better spot. Usually you only have to move it a tooth. Then, follow the procedure above to rewire the cap.
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Unread 08-16-2012, 11:04 PM   #39
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That's good to know. Now would retarding the timing or re wiring the cap so the vac advance has more play towards the block get rid of the high hydrocarbons that is preventing it from passing smog? I'm new to this whole timing distributor thing. If the dampener slipped would that hurt anything?

And for the record the mechanic did not offer to install a distributor and I doubt he expected me to ask them to do it because he knows I switched motors myself.
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Unread 08-17-2012, 10:03 PM   #40
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Originally Posted by Michaelgoesrawr View Post
That's good to know. Now would retarding the timing or re wiring the cap so the vac advance has more play towards the block get rid of the high hydrocarbons that is preventing it from passing smog? I'm new to this whole timing distributor thing. If the dampener slipped would that hurt anything?

And for the record the mechanic did not offer to install a distributor and I doubt he expected me to ask them to do it because he knows I switched motors myself.
10-4.

I woulddefinitely get that distributor situated correctly because without the correct timing, nothing is going to get better. Passing emissions can be like a house of cards. The straighter each individual card is, the better your chances it will not come crashing down.

If the dampener slipped, then at some point it could fail, which would be bad. You also would not have a good reference for TDC, and that is not good, either.

By slipped, you mean the rubber-to-steel connection within the damper, yes?
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Unread 08-17-2012, 10:13 PM   #41
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Yes, meaning the alignment mark isn't correct. I guess I could find tdc to verify. It's a pain to get to the number one cyl because of the ac pump. This engine passed smog before too.

Edit: the timing on the smog cert said it was at 7btdc. How much more does it need to go in order for it to pass?
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Unread 08-17-2012, 10:29 PM   #42
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Yes, meaning the alignment mark isn't correct. I guess I could find tdc to verify. It's a pain to get to the number one cyl because of the ac pump. This engine passed smog before too.

Edit: the timing on the smog cert said it was at 7btdc. How much more does it need to go in order for it to pass?
If the marks are off you cannot set the timing accurately because you don't know where the crank is. You won't even know if the distributor really has to be moved, because the frame of reference is bad.

In general, you set the timing where the smog sticker on the fender says to set it. If anything, you can advance it some, or a lot, but never retarded to get better readings. I say in general, because there are interrelationships between the various items measured. As the HC go up, the oxides of nitrogen go down, and vice versa. It is a balancing act.
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Unread 08-17-2012, 10:41 PM   #43
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Makes sense. So after all of this what is the course of action you would take? I have a new distributor just in case, so that is know. I'm fine with working with the dist just not sure on the actual timing part.
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Unread 08-17-2012, 11:08 PM   #44
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Makes sense. So after all of this what is the course of action you would take? I have a new distributor just in case, so that is know. I'm fine with working with the dist just not sure on the actual timing part.
All bets are off if that damper is slim shadied. If it is, you need to fix that first.
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Unread 08-17-2012, 11:12 PM   #45
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Okay. I'll check that out tomorrow.
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