Electrical Problem-eng surges, tach needle freaks out, shift up light blinks randomly

[DeathByNissan55]

have a 1994 chevy k1500 4x4 ext cab with the original factory 5 speed manual and a TBI 350 from a 1991 chevy caprice(apparently).
What is the usual cause for the problems described below?:

The starter works nicely, but the engine just doesnt want to start easily. It will turn over eventually, but it takes a couple cranks and my foot almost to the floor on the accelerator for it to work. It had a low idle before and sometimes it stalls out before this problem occurred, but now it literally wants to die. When you give it throttle, it feels as if I'm not getting combustion on every stroke as if some strokes werent firing. The aftermarket Tach's needle is going all over the place and the "shift up" light is blinking on and off in a random fashion as if there were an electrical problem(ie bad connection). If I dont try to keep it running, it clunks out.

Someone told me ignition control module, but that doesnt sound right at all cuz how would that affect the tach and shift light. I think its an ECU problem or something along those lines. Or it could be a combo of a bad ground and bad ignition control module.

Edit: Actually the ignition control module might make sense because when i took the air cleaner assembly off and looked at the injectors spray as my dad was trying to keep the truck alive, it wasnt cutting the spray ever...so yea.

Edit: So I replaced the ECM with the correct one and it came with a new PROM that was also the correct one for the truck.....didnt fix the problem totally. However, you can tell that it runs a lil bit better and it doesnt always just die by itself anymore. Also found out when replacing ECM that there was an animal nest in my dash right on top of the blow motor, bunch of the wires were nibbled on. Fixed those and they didnt change anything.

So it leads me to believe its something to do with a sensor. What kind of sensor would cause too much fuel to be added and to make the tach/shift up light freak out? I took off the ignition control module and it turns out its after market, it is an Accel 35370 performance control module. Since it is a performance part, I'm not really sure it would fail. Along with that, this car has an external MSD coil/wires and a stock distributor cap.

What about grounds? What grounds would affect the amount of fuel being injected, the shift up light, and the tach? Right now I know the ground that attaches to the passenger fender and the one that attaches from the negative of the battery to the engine are good. I have to check the one that attaches to the front of the intake manifold. The tether ground that went from the engine to the frame is severed(due to it being chassis lifted), but that wouldnt cause the engine and tach/shift light problems because this has been severed since it was owned and it didnt have this problem initially. Any grounds in that section of power and ground points on the passenger side on the firewall that is "usually" supposed to be covered by some sort of plastic box?

Also, I determined that somewhere in the chassis electrical, the parking light circuit is tied into the brake light circuit. When I have the key off and hit the brake pedal, the dash lights, the parking lights, and brake lights turn on, and the annoying bell goes off in unison with whenever i hit the brake pedal. When I have the key on, the buzzer doesnt go off like that, but the lights still act the same. Also, when i just turn on the parking lights, the brakes will come on too. So where would be the most likely place that would happen? The hitch mount area?

Edit: Replaced the ignition control module, didn't fix it.

Edit: TPS tested bad, threw a new one in, idled a little rough in the beginning. Replaced semi-kinked vacuum hard line, truck cold started rough but drove great and idled great when it warmed up.......Tried driving it the next day, barely got it started, ran like super crap, sounded like misfiring.

After I test compression on the engine, the test will determine if I keep putting more money into getting it running, or just looking for a 350 tbi in better condition/rebuild the one i have(whichever is cheaper) and part out the 350 I have. My best guess right now is that either the IAC valve or EGR is super clogged but not throwing any more money until i test compression.

It would be wonderful to get some thoughts from some people that know their **** on here.

 

[SAATR]

Do you know how the tach is wired in to the tach sense wire on the coil? It could be a bad connection at the coil (if they are both tied into that wire at the coil) or wherever the junction was made for the tach. That could be your tach/shift light issue. I would pull and clean the IAC and do the IAC reset procedure, which you should be able to find an explanation of on this site. Get a vacuum hand pump with gauge and connect it to the EGR and check to see if the diaphragm is ruptured, which would cause issues at speed, but shouldn't affect idle, unless the EGR control solenoid is stuck open. Cleaning the EGR wouldn't hurt, but it would have to be stuck open to cause anything like your issues. I'm leaning towards a sizable vacuum leak somewhere in your system being the source of your running/idle issues, but unless the coil is failing I don't see the problems as being related.

 

[DeathByNissan55]

Do you know how the tach is wired in to the tach sense wire on the coil? It could be a bad connection at the coil (if they are both tied into that wire at the coil) or wherever the junction was made for the tach. That could be your tach/shift light issue. I'm leaning towards a sizable vacuum leak somewhere in your system being the source of your running/idle issues, but unless the coil is failing I don't see the problems as being related.

The only reason I think they're related is because they literally occurred at the same time. The wiring on this truck is a nightmare, it was done by someone that didnt wire it for permanent use. What I thought it might be was a shared ground between the sensor that is used on the trans or engine to monitor engine speed for the tach and some other sensor that controls the engine.

 

[SAATR]

Well, if it's that bad then I would consider taking the tach out of the circuit to simplify things and see if it clears up. That one wire should be the only wire common to both the tach and shift light, though I fail to see how any issues found in or with that wire would cause the engine to run poorly. As the tach sense wire connects to the coil, and a faulty coil can cause some of the symptoms you describe, perhaps you should get a known good coil and give it a test run to see if anything changes. Coil and module aside, I think the only other item in the ignition system is the pickup coil in the distributor, which is what tells the module when to fire the coil and is the signal which eventually becomes the signal for your tach and shift light... could be a possibility also. It would be great if you had a buddy with a running TBI motor that would let you swap some components around for testing, though I know not everybody has that luxury.

 

[DeathByNissan55]

I'm trying to find the info but it doesn't say anywhere. If I have msd wires, an accel 35370 performance control module, an msd ignition coil, and what seems to be a stock distributor, cap, rotor, andpickup coil, but want to buy either msd or accel cap and rotor anyways,would I need afancy pickup coil magnet or could I buy a stock pickupcoil magnet? Cuz that pickup coil sounds exactly what the problem is cuz my cap is actually missing a chunk and is open to whatever dust is kicked up in the engine bay.

 

[DeathByNissan55]

So took the distributor apart and found out the pickup coil was toast, there were shards of copper EVERYWHERE in the distributor. and the cap was actually broken. So I just replaced the distributor, got an accel cap and rotor, and reused the accel performance ignition control module. But, my dumbass forgot to take a picture of where the distributor and wires were going and since this motor is a plethora of parts from different cars, i have no idea what model I'm supposed to follow so I just basically put the spark plugs in the firing order that is pressed into the intake manifold and then i just move them all one by one in one direction until i get it to work. I found one position that wanted to start but wouldnt, but by that time I think the engine might have been flooded haha So i'm going to let it sit for a while and then we'll try again.

If anybody has the numbering for wires on the distributor for non hei i would appreciate if you posted it, mine has the coil mounted next to it and there is no vacuum advance and has the opening for the little control module. I've found references online, but they always reference the one that has the coil sitting in the actual distributor cap(which i think is whats known as HEI) so that doesnt apply to me.

The distributor that matched the one that I had was from a 1990 Caprice that had the high power 350 or the code that was with the engine was HP so i assumed high power

 

[DeathByNissan55]

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This is what my cap looks like

 

[heavychevy98]

start with number one on your cap and followq the firing order on your intake. Should be 1-8-4-3-6-5-7-2 starting with one going clock-wise. #1 should be marked on your cap if your having trouble with that as well.
here are cylinder #'s
front
1 2
3 4
5 6
7 8
dist.

 

[DeathByNissan55]

start with number one on your cap and followq the firing order on your intake. Should be 1-8-4-3-6-5-7-2 starting with one going clock-wise. #1 should be marked on your cap if your having trouble with that as well.
here are cylinder #'s
front
1 2
3 4
5 6
7 8
dist.

The problem with that is there is no number on my cap, I know how the cylinders are numbered already too. If you have a picture of the same style cap that I have with a number on it, could you show me which post its referring to?

 

[heavychevy98]

Get number one cylinder up on compression stroke. Put it on Top Dead Center. Pull your cap. Mark on the base of your distributor where the rotor is pointing. Replace cap and see which spot on the cap lines up with your mark. This is number 1. Be sure it is for sure on the compression stroke or it will be 180* out.