New 1988 R30 Classic Custom owner, need help

I'd check O2 sensors (if they Exist) for Lean condition.

And Fuel pressure (you are looking for 12 psi MIN)

You cannot tell if injectors are putting out 12pounds, you can only tell if they're clogged. You Want a super fine conical shaped mist.

I've learned even if it's a nice mist pattern, that still doesn't mean 12 pounds of fuel pressure.

Video kinda sounds like a misfire which is either bad plugs, cracked plug wires, poorly set timing, or you have corroded tower inside the distributor cap (maybe more)

af77 said:

Maybe you can help me with that. I see the firing order, I can read it. I know it means that is the order the plugs fire in.

But how do I translate that to "this wire goes here."

Do I find spot one on the cap, put plug 1 there, then counter clockwise from there put plug 8, then 4, then 3, etc?

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af77 said:

Maybe you can help me with that. I see the firing order, I can read it. I know it means that is the order the plugs fire in.

But how do I translate that to "this wire goes here."

Do I find spot one on the cap, put plug 1 there, then counter clockwise from there put plug 8, then 4, then 3, etc?

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Ok this would be my suggestion on firing order since it's giving you some trouble figuring out whats what. This is not necessarily the best way, but it is the easiest. Here is a picture of the firing order on the engine. https://www.quora.com/What-is-the-firing-order-of-a-Chevrolet-350-smallblock-engine If #1 is in a different location that it shows in the diagram that's ok, just make sure that as you go around the distributor cap going clockwise, that the plug wires are in the right order. 1 8 4 3 6 5 7 2 If you can't get it off of this you probably need to inlist the help of a friend that can show you in person.

Vbb199 said:

I'd check O2 sensors (if they Exist) for Lean condition.

And Fuel pressure (you are looking for 12 psi MIN)

You cannot tell if injectors are putting out 12pounds, you can only tell if they're clogged. You Want a super fine conical shaped mist.

I've learned even if it's a nice mist pattern, that still doesn't mean 12 pounds of fuel pressure.

Video kinda sounds like a misfire which is either bad plugs, cracked plug wires, poorly set timing, or you have corroded tower inside the distributor cap (maybe more)

Click to expand...

If you want to check the spray pattern of the fuel injectors the best way is to hook up a timing light point it at the injectors and pull the trigger so the timing light flashes. It's actually a really cool effect and you will be able to quite clearly see the spray pattern, and also if there is any dripping going on. Personal opinion I don't think this is your problem and if it is the injectors would have to be pretty bad for it to run this bad.

SirRobyn0 said:

If you want to check the spray pattern of the fuel injectors the best way is to hook up a timing light point it at the injectors and pull the trigger so the timing light flashes. It's actually a really cool effect and you will be able to quite clearly see the spray pattern, and also if there is any dripping going on. Personal opinion I don't think this is your problem and if it is the injectors would have to be pretty bad for it to run this bad.

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Yeah I noticed that one time, by accident

Verify Tdc #1 cylinder on compression stroke:

Pull #1 spark plug(closest to driver side headlight)

Bar over the crank with a large socket on the crank snout bolt. This is easier with all the spark plugs loosened, but possible without doing so. Rotate crank clockwise with your finger covering the #1 plug hole until you feel air pushing on your finger. That’s the compression stroke of #1.

Place a long skinny screwdriver in spark plug hole. Continue rotating the crank clockwise slowly as you watch the screwdriver rising out of the hole. You’ll get to where the screwdriver pauses for a brief moment just before it’ll start traveling back down. BEFORE it starts moving back down, observe a couple things.

First, try to locate the TDC notch on your crank pulley as well as a corresponding notch or ribbon on the block or timing cover. There’ll likely be two notches on the crank, it should at this point be fairly close to the one on the left. If not, re-verify the step rotating the crank and watching the screwdriver (which should be two full rotations).

If everything checks out up to this point, pull the distributor cap. The carefully note the direction the rotor is pointing. It’ll be point at or just clockwise of one of the plug terminals. THAT is your #1 plug.

When looking at the engine from in front of the grill, cylinders are counted starting at the driver side headlight (1), then crossing over to passenger side headlight (2), then crossing back to the driver side to the next one back (3) and so on and so forth ending with #8 being closest to the heater core at passenger side firewall.

Back to the distributor cap. Ensure that number 1 wire is located on the correct tower of the cap then CLOCKWISE 8-4-3-6-5-7-2.

From there you’ll at least know your order is correct. Then you’ll want to check timing. I believe those TBIs like around 8 degrees of base timing, but I’m not well versed on what has to be disconnected from the dizzy to check. There are many youtubes for that though.

Not to pile on, but hopefully help.
Sounds like it has a serious misfire.
1. Verify your #1 cylinder position on the rotor first, like described above, or you can bar the engine over to TDC and check the mark on the crankshaft and see if it's pointing at #1 or #6. (#6 is opposite #1) It's all relative. It "should look like the diagram posted, BUT could have had the distributor inserted at any position and then the spark plug wire positions matched to it. IE don't freak if #1 wire ends up being somewhere else on the distributor cap as long as the #1 cyl is verified at tdc compression stroke when the rotor is pointed at that plug wire.
Once verified then it's 18436572.
2. Verify wire positions. If plugs and wires are new, cap n rotor contacts arent arced or burnt appearing, could have 2 cylinders in the wrong order. It sounds like at least 2cyl misfire. 1 fouled plug you can get up to speed and it's just a bit rough (in an otherwise healthy good running engine). 2 cyl misfire and it's real rough. 3 is barely driveable, IIRC about where you're at.
3. If cap n rotor are old, replace. even if they look decent.
4. If all of the above is verified and it checks out, could easily just be way out of timing. Actually you can check this as #1. Mark the distributor position and even if you don't have a timin light, loosen dist hold down and adjust the distributor both directions slowly, 10-20 deg in each direction and see if the running improves. Backfires are a symtom of timing issues. So check that first.
5. All that done, hope it runs. If not, verify timing with timing light. With advance wire unplugged, wherever it is, you should be reading 0deg BTDC, I'm almost certain or 8deg BTDC if plugged in.

It really sounds spark/timing/distributor related.

Then proceed to fuel/O2/EGR issues, IMO. But it is easy to verify fuel pressure and injector operation.
Anyone correct me if I'm wrong. Been a long time since I've diagnosed any old TBI or carbed Chevy motors.

Okay this is all a lot to digest. I was going down the path of sensors and fuel pressure.

But I have a timing light gun now. Learning how to use one after watching YouTube videos.... well it's rough. I'm just out of my element here.

The big question I have is where in the world are you all heading misfires? I hear occasional backfires, but i don't hear cylinders missing at all. I'm sure you all are right I just don't hear it. My experience with timing issues and misfiring is that they are very obvious. This just seems like a fuel/air mixture issue (hence the code for lean condition).

I only listened to a few sec at idle and trying to accelerate. Sounded like a serious miss unless I didn’t hear it right.

Edit. You may not hear it missing because it sounds like a couple 3 cylinders are actually nonexistent!
Verify spark and timing and firing order etc, but after listening to it again, if all that stuff is right, check compression, lifters and cam.
Could have a dead hole or 3, collapsed lifter(s) or a flat cam.

af77 said:

Okay this is all a lot to digest. I was going down the path of sensors and fuel pressure.

But I have a timing light gun now. Learning how to use one after watching YouTube videos.... well it's rough. I'm just out of my element here.

The big question I have is where in the world are you all heading misfires? I hear occasional backfires, but i don't hear cylinders missing at all. I'm sure you all are right I just don't hear it. My experience with timing issues and misfiring is that they are very obvious. This just seems like a fuel/air mixture issue (hence the code for lean condition).

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Several of us are essentially saying the same thing. Verify firing order, timing and check over ignition components. You have already done a number of things regarding fuel, several of us including myself think we hear a miss so that's the direction we are pointing you. Plus checking things, called diagnostic, when done yourself cost you only time and you eliminate stuff. You have already spent some money on unnecessary parts called parts throwing, and I doubt you want to spend anymore than you have to.

Yes it has a lean code, could there be something to that yes, but the computer system in these trucks is rather limited and can't detect things like a misfire. It only uses 1 O2 sensor for entire engine, so a bad O2 sensor, could set the code, a lean condition or some other problem could set the code. The thing is you have checked fuel pressure, installed a new pump, installed a new fuel filter new MAP sensor and checked for vacuum leaks maybe more. Other than to test the fuel injectors, and to look at the wiring to the coolant temp sensor you have checked the fuel system over pretty much. Time to look elsewhere for the problem.

I know your out of your element, but none of this is really incredibly hard. Digest it for a bit, make a list of what need to do, take your service manual out to your truck and do what you can. If / when you get stuck post back. Let us know how it goes.

I think I found the misfires/bad cylinders.

Using a heat gun, one exhaust header is 100 degrees cooler than the others.

Second, and I don't know if this is an issue, I found an exhaust header with a hole in it right where it joins to the engine where you can see the spark and hear it.

Two short videos showing what I just described. Am I on to something?

Cold hole = no fire. Either due to spark or other causes mentioned above.
Again, didn't watch all of video, but if the wire you took off was the same cyl (that didn't make a different sound) then it's confirming that.
Have ya actually removed the spark plugs yet? Ones that are not firing for whatever reason will be wet/fouled.

I'm not certain how you could ever see spark plug spark through a hole in a header. Is that what you really mean to say? When the plug fires, the piston will be blocking the exhaust port.

Grit dog said:

Cold hole = no fire. Either due to spark or other causes mentioned above.
Again, didn't watch all of video, but if the wire you took off was the same cyl (that didn't make a different sound) then it's confirming that.
Have ya actually removed the spark plugs yet? Ones that are not firing for whatever reason will be wet/fouled.

I'm not certain how you could ever see spark plug spark through a hole in a header. Is that what you really mean to say? When the plug fires, the piston will be blocking the exhaust port.

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Where the exhaust attaches I can see the flame because there is a giant hole in the exhaust.

I'm going to check the plugs but I just put all new ones on 10-15 days ago.

Grit dog said:

Cold hole = no fire. Either due to spark or other causes mentioned above.
Again, didn't watch all of video, but if the wire you took off was the same cyl (that didn't make a different sound) then it's confirming that.
Have ya actually removed the spark plugs yet? Ones that are not firing for whatever reason will be wet/fouled.

I'm not certain how you could ever see spark plug spark through a hole in a header. Is that what you really mean to say? When the plug fires, the piston will be blocking the exhaust port.

Click to expand...

Where the exhaust attaches I can see the flame because there is a giant hole in the exhaust.

I'm going to check the plugs but I just put all new ones on 10-15 days ago.

Just pull the plugs and wires of the suspect cylinders. No need to make more work since you just replaced them.

If you have a multimeter check the suspect wires or swap the old ones back on to see if anything changes.

As far as the hole in the headers... You need new headers or manifolds. Might be able to get a temporary fix with some of that exhaust tape. Temporary though, that stuff isn't really for headers and if there is one hole there are sure to be more coming shortly.

gotyourgoat said:

Just pull the plugs and wires of the suspect cylinders. No need to make more work since you just replaced them.

If you have a multimeter check the suspect wires or swap the old ones back on to see if anything changes.

As far as the hole in the headers... You need new headers or manifolds. Might be able to get a temporary fix with some of that exhaust tape. Temporary though, that stuff isn't really for headers and if there is one hole there are sure to be more coming shortly.

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I bought a tester that plugs in line between the plug and the cable.
It definitely is firing through that wire; it also shocked me.

I replaced the spark plug anyway. Made no difference.

I also stuck a block of JB weld over the crack in the exhaust header.