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Bad gas?

Wunjee

Wunjee

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Location
29 Palms CA
So I got my Blazer home last night. Drove it home from the buddy's house where we replaced the heads. I live in an HOA so they frown upon us doing any work in our driveways..

Anyway, when the truck was parked after the previous owner smogged it, he left the tank full (it's a new tank, too) and the crappy California gas proceeded to go bad. All 28 gallons of it..

So the truck idles great, but when you give it gas it sputters and falls on it's face. It takes quite a bit of cranking to restart and even then it's not happy about it. The exhaust stinks of bad ethanol.

What's the best way to get rid of this much bad gas? I've seen other sources say "just drive it" but it doesn't feel safe considering it's died in the middle of intersections and isn't always easy to start again. And I just replaced the injectors so I don't know if putting bad gas through brand new injectors is the best idea..

Is this even a bad gas issue?
 
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If you’re sure it’s bad gas then the easiest way to drain the tank (assuming you still have the electric pump on your ‘88) is to disconnect the fuel line before the filter on the passenger side frame rail just in front of the tank. There’s a red jumper wire on the firewall that’s used for testing the fuel pump relay. Connect that to +12v to run the pump and drain the fuel into a suitable container. Then you need to look up ‘household hazardous waste’ in your area to see where a drop off site is and how much you can bring at one appointment.

When the fuel tank was replaced do you know if the sender and pump were also replaced? There’s a rubber hose in there that splits due to the ethanol in the gas and needs to be upgraded to a hose that’s ethanol rated.
 
rampage said:
If you’re sure it’s bad gas then the easiest way to drain the tank (assuming you still have the electric pump on your ‘88) is to disconnect the fuel line before the filter on the passenger side frame rail just in front of the tank. There’s a red jumper wire on the firewall that’s used for testing the fuel pump relay. Connect that to +12v to run the pump and drain the fuel into a suitable container. Then you need to look up ‘household hazardous waste’ in your area to see where a drop off site is and how much you can bring at one appointment.

When the fuel tank was replaced do you know if the sender and pump were also replaced? There’s a rubber hose in there that splits due to the ethanol in the gas and needs to be upgraded to a hose that’s ethanol rated.
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Yeah I was told that when the tank was replaced the sending unit and pump were also replaced. I can only go off the previous owner's word but he's been honest with me so far.

Thanks for the advice on pumping the gas out. Do the symptoms sound like bad gas? Is that something bad gas would cause it to do, along with the smoking on start/bad ethanol smell from the exhaust?
 
I don’t know what bad gas symptoms are exactly. Someone else will chime in.
The blue smoke on startup is leaky valve guide seals, nothing to be overly concerned about.
 
I've only had my modern cars have an issue with gas thats sat in the tank over a year. Engine misfire codes.

Have not seen issues with OBD1 GM the same way. If it were less gas I'd probably suggest filling with high octane to bring it up a bit, but you aren't going to get much into the tank.

I don't disagree with letting the pump do the work for you. But I would take the opportunity to test fuel pressure as well. Autozone will "rent" you the tester for free, just make sure it has the right fitting for TBI.

That sounds about like what mine did when the in-tank rubber hose split (from ethanol). Took me a long time to figure that out since I was doing other work to the EFI and thought that was the cause.
 
Bad gas will act like having a lean mixture. poor throttle response, dieing, etc. It will also have less octane, leading to more detonation. It also can stick the valves in the valve guides, leading to bent push rods etc. Pump it out, and use it to start your fire pit, not your engine!
 
So I talked to the guy who set the timing and he said he set the timing to 4*btdc with the automatic advance connected.

It's my understanding that with these TBI systems, you're supposed to set the timing to 0* with the automatic advance disconnected.

Would 4* btdc (at idle) with the auto advance connected be enough to make it run as poorly as it giving it throttle?

I verified it's at 4* btdc. First time I've ever used a timing light. I'm kind of proud of myself.
 
Set it properly and see if it helps. IME when there is too much timing is you get into knock (whether you hear it or not), the knock sensor is used to retard the timing and you feel the performance drop off, but it doesn't run "bad". Just a lack of power. But too much advance and bad gas are probably not a good combo in any case.
 
If the computer was controlling the timing while it was adjusted he retarded the crap out of the timing. Disconnect the computer timing wire and set the timing to 0-4 as you like.

the connector pictured below

s-l640-90233664.jpg
 
Definitely fix the timing issue next. If you set it with the computer in the loop, it's going to keep advancing to get timing where it wants, so you have to get to the limit of how much the computer can adjust to get way back to 4*. I'll just go ahead and call this move "full retard" :D. It's also possible when getting a distributor wrong to reach the limits of where the rotor is lined up with contact in the cap and then the spark falls off quickly trying to jump a larger gap. It's also possible the guy just forgot how he did it, but if you saw 4* with the timing connector installed, that is not nearly enough advance. Curious to know what the timing reads with the connector unplugged.

full retard.PNG
 
We got the bad gas out (thanks for the tips on pumping it out), replaced the fuel filter and cleaned the injectors real good. We brought it up to operating temp, killed it, unplugged the electronic advance, started it, timed it to 0*, killed it, reconnected the advance and fired it back up.

It's still running the same - like ass. Lots of "popping" from the exhaust. Engine sputters and stumbles as it transitions into RPM. Lots of black smoke from the exhaust. Put it in gear and give it gas, dies almost immediately. Then starting again is very difficult. With the advance plugged in we were seeing between 45* and 38* advance...

I've got a new set of injectors on the way, but I don't know what else to look for here. Could it be a bad distributor? It's a brand new distributor but I've read that the remans are really hit or miss. My drawing a blank here isn't a surprise but my buddy, who's been doing this for a long, long time, is drawing blanks too. And it's getting frustrating.
 
Do a temp check on your catalytic converter with an IR gun. IIRC the outlet is suppose to be cooler than the inlet by a certain amount of degrees. Do a Google search to get the specifics or someone else will chime in.
 
was cap changed ? if not check for cracks. check rotor for burn through, dubble and triple check spark plug wire firing order.
 
Wes Harden said:
was cap changed ? if not check for cracks. check rotor for burn through, dubble and triple check spark plug wire firing order.
Click to expand...

Distributor and cap are brand new. But from what I've read that doesn't mean much and these 'new' remans have a pretty high attrition rate.

That may be something we change.

I also got a new ICM. They're cheap so I figured it was worth throwing at it.
 
I've never heard of any of the distributor components being bad and allowing it to run. Basically an on/off deal if an intermittent problem.

Advance should be nowhere near as high as you are seeing at idle. Maybe 20* or so...can't recall what TBI idle timing is set at. Something else is going on if its that high however. I'd figure that out first, as it's absolutely incorrect.
 
I agree that you should check the timing "for real" by pulling #1 plug, wait till you feel compression, then use a drinking straw or some object to find exact TDC. Then you can verify if your timing marks are mismatched and if the distributor is installed correctly (if mismatched, you can paint a white line to keep the troubleshooting moving). It's weird how far out they can be (like 180 degrees) and still have the engine kind of run. We've probably all assumed you've triple-checked the plug wire routing, but I haven't seen it mentioned here. There are some swaps that let it kind of run, but does poorly under load. Another weird one you can look for as you're going through stuff is a broken, mis-located or incorrect length carbon button in the distributor.
 
Reading this again, there are some fundamentals that haven't been discussed. Replaced the heads? How were they set up and did you touch the timing chain? How much fuel pressure is it making?
 
Another question I have. How were valves adusted. 0 lash plus 1 turn?
When I hear the popping out the exhaust, my mine goes to valves leaking. Yours might be adjusted to tight. My preference is 0 lash and then a half turn.
We're the heads new, used, or remanufactured? If so who did the work.
Avoid El Monte head service. Little far for you, but in the past they had provided ready to go heads for parts stores.
 
Thanks for the replies!

Yeah my buddy who installed the heads did 0 + 1/2 turn for the valves.
The heads were new remans from Bishop.
Timing chain wasn't touched
Plug wires have been quadruple-checked, replaced and quadruple-checked again. It seems like it's firing on all 8, using the 'water squirt bottle' test. Plugs are new, wires are new, distributor's new, cap is new.

We're going to install the new injectors, CTS and check to see if the balancer slipped tonight.

Question: The first time we set the timing we set it with the advance connected. We remedied that and disconnected the advance when we reset the timing. Someone in a YouTube comment on similar issues said that before you reset the timing you have to clear the ECU by disconnecting the negative terminal on the battery because it stores the timing info. Is this true?
 
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