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Pulling Motor, New one in! New flex pics on last pg.

munepit

munepit

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Hey guys, need your help. I have a 87 burb,350tbi,700r4,np208. I was driving down the freeway at 65. About thirty miles into the trip I heard a funny noise out the tail pipe. I pulled over and it sputtered and dies. I check the cap, rotor. All seems fine. Everything looks good. Doesn't idle . Pull the plugs and one is burnt. What is the problem? I pulled a code 42. Then later it pulled a code 12. I am lost. Please help. Thanks a lot!
 
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Sounds like your running a little lean, burning a plug? yep lean! Piston will be next...
 
How do I fix it? It will bearly start. I have to give it a lot of gas to keep it running. I can smell a lot of fuel. I don't know if the plug id burnt, but it is black like carbon or something. Very rough idle.
 
Sounds like it's dumping fuel in there. Possible MAP sensor problem or a broken vacuum line to the MAP sensor.

Could also be an injector stuck open. Possible but unlikely.

Fuel pressure regulator problem causing too much pressure.

Could also be a bad ignition module not firing properly.
 
I checked the injectors. I changed both, They are working good. MAP sensor vacuum line is good. I will change the map sensor and the ignition module. How do they go bad when there is no moving parts? The ignition module is in the dist. right? Thanks.
 
Check coolant temp sensor also. If it fails it can tell the computer to fuel the motor like it's -20 degrees out. I've had this happen.
 
Crap, nothing changed. I changed the MAP sensor, ignition module, coolant temp. Sensor. The vacuum line to the MAP sensor is good. There was a blue wire on the injector that was not fully hooked up to the injector. So I changed both of those plastic clips that go onto the injector, but not the injector itself. My brother said there is plenty of fuel being dhot down into the T.B. but he is not a machanic. When I try to fire it, I can smell fuel. The cap and rotor are fine also. It seems like there is a plug wire on wrong but that's not the case. I'm. Stuck. What now? Thanks for your help!!!!!
 
i HAVE THE SAME TRUCK AND NOT TOO LONG AGO I had the same problem spent $$$ replacing everything you just talked about and just could never get it to idle so I finally took it to a shop and it was an idle control module and some other electrically controled module, in conjunction with a burnt plug wire.
 
I'd check the wiring running down the passanger side of manifold. wiggle them around a little bit and see if it improved or will start. If you get it running wiggle them around and see if you get it to happen again. Broken wires from distributor to your EST module (think that's what it's called) are the bad ones. Hope this helps.
 
Now it is showing only code 12. I can't see any burnt wires. All wires look good. I am going to take off all the plastic covers on the bundles of wires and check that. Could it be the timing chain? It seems like more than just a wire. The motor shakes pretty bad when I try to fire it up. What the hell could it be. Is there a diagram for the dist. Wires. Maybe somehow they switched by themselves while I was driving. Thanks for your help guys! I'm supposed to go wheeling on sat. Hope I can get it running.
 
I just changed the plug that looked bad and the plug wire. Still no go. Damm. WTF? I need to figure this out without buying every part possible. Need to go wheelin this weekend. Plus I have our last birthing class tonite. Thank god. That's some boring class. Any ideas guys whould help. Thanks!!
 
Well I have no compression in one cylinder. ****, I'm ****ed. I did a compression check. They were all at 110psi. Except the one with the burnt or fouled plug. It was at 15psi. What now? Do I have to replace the whole motor? Guess no wheelin for a year or do. I'm having a baby in 8 weeks. What now guys? Thanks.
 
I'm no machanic. Could I just take the heads off and take them to an engine builder. Or take the whole truck in? I have nerver taken heads off. Looks like I could do it.
 
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Never Satisfied said:
Pull the valve cover first and check out the components on that cylinder.
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Ok. Got the valve cover off. Everything looks normal. Execpt, the cylinder with the problem. The rocker arm is loose. Not the bolt, it tight. I can move the rocker are quite a bit. A lot more than any other ones. There is another one that seems a little loose, it on another cylinder though. On the one I'm concerned with, I can move the valve spring. I can compress it a little bit. Like 1/2" its loose. Now what? Thanks.
 
pushrods ok?
maybe a broken lifter.
 
76zimmer said:
pushrods ok?
maybe a broken lifter.
Click to expand...




Pushrods look good. I can see a broken valve spring. I took some pics. I will post in the morning. Can I replace one valve spring? Or, do I need to take the whole top end apart and take both heads to a machine shop. Sure would be nice to just replace one vavle spring.
 
Yes, you can replace the bad one, but it might be a good idea to check the rest for adequate seat and open pressures. That can be done by removing the rocker arm on each spring, and using a handheld spring tester.
Do you rev this engine alot? RPM kills valvesprings.
 
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