90 s10 4.3L just stopped dead

ignition module is a great bet! Have you checked for spark? Pull plug wire lay on maifold and have him crank it,,,, look for spark.

and or pick up coil and or magnets cracked.

Whitelightning

Has the timing Chain ever been replaced ..

Remove the distributor cap and Set Harmonic balancer timing mark and the see if the ignition rotor is pointing to #1 plug wire on the cap.

if the rotor doesnot turn when cranking the engine u have a Broken Chain.

If it is a Manual Transmission and you were driving it and The Chain Broke, 9 times out of 10 it Warped The Valves .

sierra_5300 wrote:

Installed new distributor and associated pickup coil also with ignition control module also. We now hear fuel pump whirring away and smell gas. No fire in the beast yet though! I noticed his rotor and center post in the distributor cap were quite worn and the rotor was heavily laden with carbon. Timing could be way off. Plugs are less than 1 year old. The pickup coil wires and insulation were cracked in several places. Will check for spark. And thanks for any advice and help. I've never been a gm truck owner so his truck is kind of new and different territory for me. His S10 has this RED MSD box(?) under the hood & in the engine compartment (front) and mounted on the driver side fender wall which seems to be some sort of thing for ignition. Haven't a clue as to what it is or does. Don't have any books for his S10 so am wondering what it is? Lastly, do the coils for these S10's ever go bad? Trying to anticipate what may be remaining problems.

He has not replaced the timing chain. We know the rotor is rotating. However, checking the distributor/rotor alignment with #1 plug using the Harmonic balancer timing mark sounds like a real good idea. Now if I only knew where that mark is and what it looks like.

The Mark looks like Someone to a Chisel and made a line From Front to Back on the Balancer .

Also a Compression Check will Show low or no Compression is all cylinders..

Your Starter will turn the Engine over real FAST , Because of NO COMPRESSION

Engine is definitely not cranking anywhere near fast, nor slower than usual. Put in a new coil today as we didn't see any spark at any plug. Also tried to see a spark coming from coil to engine loop used for hoist purposes. No spark there either. No spark, no dang spark anywhere! Can smell gas. Am at a total loss. With a new distributor, coil, fuel pump, it seems like there ought to be a hint of it turning over. Nothing! Only thing we haven't changed is the rotor, distributor cap, spark plug wires, and the ECM.

Found the timing mark just as you describe it. Checked rotor position while at TDC and it leads to plug #1. The firing order on the distributor cap indicates the wires are properly routed to respective plugs. Firing order is 1-6-5-4-3-2. The driver side plugs on the engine are #1,#3,#5 going front to back. The passenger side plugs are #2,#4,#6 running front to back.

He told me the truck just stopped running. Nothing loud happened, it just died, and would not turn over when cranking.

Tried to get to the choke, couldn't budge those star headed screws to see if the flap was going anywhere. Checked vacuum lines to see that they were attached.

Anyone with what might be our next best effort? Help?

CHOKE ??? What Choke.. My 89 s-10 Has no Choke. ( TBI)

pickup coil inside the distributor.. ( Some auto parts supplies can Check It

The module inside the distrubutor can be bad n( Some auto parts supplies can Check It

Many people have destroyed a module by Trying to Check for Spark by holding the Wire and looking for a Spark to GROUND, Since the Earlie

70's I have hooked the wire to a Known Good plug and layed the plug on top of the engine and Check for Spark Via The plug electrode .

By the Way the Computer is located under the DASH to the right of The Glove box .

We got the distributor which came with a new module & pickup coil. This was posted in an earlier msg in this thread. New coil, new fuel pump.

sounds like someone modified the ignition system. factory does not have any red msd boxes, this is an after market add on someone put on. I know that doesnt help much, but it at least lets you know someone has had their fingers in it in the past.

Whitelightning

Yeah, found these little items for sale at AutoZone today and now I see what they are. Supposed to boost the spark and duration. Sounds like a previous owner had reason to boost the spark a bit. Now I'm wondering if the thing went bad and is pulling the truck system down somehow. They are not cheap either, over $200.

Well, with a volt ohm meter, we found there is +12V to each of two leads at the 2-lead connector going to the coil. So the coil is getting juice. The other 4 lead connector to the coil does not show voltage. We were told that there wasn't supposed to be any voltage at this 4-lead connector as the leads are for distribution purposes. The truck owner thinks the battery, nearly brand new, isn't up to full load. He's judging this by looking at a ammeter gauge on the dash. It's an AdvancedAuto battery. Anyway, we're off to test the battery for lack of any other ideas. Thanks Whitelightning.

does this site on the msd red box help you at all?

Thanks. At the moment, after briefly going thru their web site, I cannot see anything that readily looks like it will solve what we're seeing. The hookup picture for GM looks like that might be helpful. Yet, I still have way too many questions of how this thing really interacts with this truck and am not comfortable trying to fix what I don't understand. Unfortunately, I'm also out of time and need to attend to some of own problems in life and not my buddies(?) truck anymore. Tried to solve this for the better part of a week and my usually ample patience is just about gone. But, thanks again though.

Against my better judgment, I went back, today, to try again. Rechecked TDC & where the rotor was pointing to #1. Looks OK. One question still bugging this ignorant idiot, me, is how the

2nd groove in the damper pulley has to be directly positioned in the biggest far right notch on the timing indicator scale and if positioning this damper pulley mark correctly guarantee's that the rotor then definitely lines up with #1 distributor wire position in respect to the distributor cap? I did try this today but am wondering with a new distributor with it's new ignition control module and pickup coil points to TDC every time the crank shaft is rotated 360 degree's? Or does the distributor only rotate 90 degree's per rev of the crankshaft?

The truck owner put on a new cap & rotor today, yet still no spark at the plug. Checked plug wire and R was only 800 ohms. If there is +12V going to each of the two leads going to the new coil, then one would think there should be juice going to the plugs. The AC Delco alternator was checked today and passed just fine. The battery was brought back to a full charge since it had been cranked on a lot trying to start this truck(?). Gas is getting squirted into carb. Fuel pump is whirring.

Can the 4 lead connector and subsequent cable/wire going to the coil be a possible suspect area to check since there is voltage going to the coil and NO spark at the spark plug end that is placed close to the engine to check for spark? Maybe it's compression check time? Oh, please help me! My head is hurting!

My guess is the red msd box is your problem. My suggestion is to remove it from the circuitry and rewire the factory wiring. What is the model number of the msd unit?

My guess is that this should have been one of the first things done.

If all the factory parts have been swapped out, why assume that the aftermarket stuff inserted into the middle is OK?

MSD model number 5200. Thinking of doing that. Think there is a way to test it, if I can remember right. Looked at their web site briefly. The truck owner thinks he heard, 'possibly', arcing under the glove box area at different times, which he claims the sound tended to travel from the passenger side to the driver side. So, either there could be a bad short, the computer died, or the mad box went mad, and died.

Am wondering if a dirty EGR valve could cause no spark problems. Doesn't seem like it to me.

Am not real anxious to take out the dash, at least where it sits now. Maybe if I'm really lucky, somebody will steal my buddies truck tonight, somehow. Thanks for the advice. Am dogged tired..........

We didn't know what it was at first. Couldn't find any info on it initially, so we left it there as if it should be there. Since 'whitelightning' told us online about it we are definitely likely to get it gone, or test it. As in other recent thread message, may try to test it first and look for shorts in the wiring near the firewall and under the dash. Still have to consider the computer. Not my truck so what is done or not done isn't my decision. If it were my truck, I'd run it over a cliff.