Need advice/not getting gas

[MBC1980]

But you're saying it won't start without a shot of ether?

And that sometimes it needs to cool down an hour (or more) before it will restart?

While it does make sense that having the EGR open at idle will cause stumbling and stalling, it doesn't explain those symptoms.

What codes is it throwing now?

http://forum.garysgaragemahal.com/New-member-with-idle-issues-tp81318p82221.html

Three months ago you told us you replaced the grounds.

You also said (on the 13th) that you had replaced the TFI.

And then on the 20th state that you replaced the distributor, "solving" your problem.

SO.... this makes me think that you have that little screwdriver and changed one at a time.

And this is why I ask about using paste..... when it seems like a heat soak problem.

Correct, I did change the TFI module and then when i replaced the distributor it came with a TFI on it when I bought it and was already screwed onto it so I kept that one on it. I didnt take it off to see if it had the paste on it assuming it was good to go. The only time it wont start is when it has been running for a while and it can be running fine when i cut it off then wont start. This past weekend i tried ether and it did not start unlike other times. Usually it will help.

I will check for codes hopefully today.

[ArdWrknTrk]

Correct, I did change the TFI module and then when i replaced the distributor it came with a TFI on it when I bought it and was already screwed onto it so I kept that one on it. I didnt take it off to see if it had the paste on it assuming it was good to go. The only time it wont start is when it has been running for a while and it can be running fine when i cut it off then wont start. This past weekend i tried ether and it did not start unlike other times. Usually it will help.

I will check for codes hopefully today.

Ah, okay.

Yes, if It came as an assembly there should be thermal paste behind the TFI.

So now, with a replaced distributor (and everything else from your December thread) the truck will not restart when warm.

I would definitely check codes, and consider a shim under the EGR, something like this, depending on what the codes were telling me.

Have you checked for bad caps in your ECM?

Intermittent problems are way more difficult than simply having the truck die.

[MBC1980]

Ah, okay.

Yes, if It came as an assembly there should be thermal paste behind the TFI.

So now, with a replaced distributor (and everything else from your December thread) the truck will not restart when warm.

I would definitely check codes, and consider a shim under the EGR, something like this, depending on what the codes were telling me.

Have you checked for bad caps in your ECM?

Intermittent problems are way more difficult than simply having the truck die.

I have changed out the ecm when it was not starting (with one from the junk yard) and it still didnt start. It sometimes will start after its warm and sometimes not. The long it runs the more likely it wont start especially like when it's been driven and not just idling. What is the shim under the EGR?

[ArdWrknTrk]

I have changed out the ecm when it was not starting (with one from the junk yard) and it still didnt start. It sometimes will start after its warm and sometimes not. The long it runs the more likely it wont start especially like when it's been driven and not just idling. What is the shim under the EGR?

You can buy a cover like I showed, or you can use a feeler gauge, shim stock or even a slip of tin can to block off the EGR where it bolts to the plate.

I didn't ask if you had swapped for a junked one, I asked if you had looked for signs of deteriorated caps.

Capacitors go bad just sitting on the shelf.

35 years is a long time for anything filled with electrolyte.

I'm trying to reason out what is getting heat soaked.

So many parts have already been shotgunned at it, it is hard to keep track.

But if it doesn't want to start, you might do best by asking it why it doesn't want to start.

 

[85lebaront2]

I have changed out the ecm when it was not starting (with one from the junk yard) and it still didnt start. It sometimes will start after its warm and sometimes not. The long it runs the more likely it wont start especially like when it's been driven and not just idling. What is the shim under the EGR?

Let me chime in again. You need to do some basic diagnostics and not just throw parts at it.

First item, you should be able to hear the high pressure fuel pump when the key is turned to run, it will power on for a short time then off again this is to pressurize the fuel rails on the engine. If this is happening hot or cold then that part is working correctly.

Now, when it will not start hot, try several cycles of the key and listen for a slight change in tone of the HP pump, you should hear it change to a slightly deeper tone as the pressure in the system comes up. Once you hear that, try a hot start, if it now starts fairly normally your problem is fuel pressure leakdown.

If that isn't the problem, then it on to the ignition system. Remove the coil wire from the distributor cap and place it near (1/4") a piece of metal on the engine and either have someone watch it or them crank the truck and you watch. You should have a nice blue or yellow/blue spark. If it is orange or no spark, close the gap up to 1/8" and try, if you now get a weak spark, replace the coil.

If both these tests yield satisfactory results, see if the injectors are triggering, they are wired in two groups of 4, the 4 end ones (1458) and the 4 center ones (2367), you should be able to feel the "click" of the solenoid in the injector. If not, then either the ECM is bad, or (more likely) there is a wiring problem. These 1985-86 EFI trucks have some of the crappiest wiring I have seen since the old rubber and cloth wiring in the 50s.

Good luck with it!

[ArdWrknTrk]

Let me chime in again. You need to do some basic diagnostics and not just throw parts at it.

First item, you should be able to hear the high pressure fuel pump when the key is turned to run, it will power on for a short time then off again this is to pressurize the fuel rails on the engine. If this is happening hot or cold then that part is working correctly.

Now, when it will not start hot, try several cycles of the key and listen for a slight change in tone of the HP pump, you should hear it change to a slightly deeper tone as the pressure in the system comes up. Once you hear that, try a hot start, if it now starts fairly normally your problem is fuel pressure leakdown.

If that isn't the problem, then it on to the ignition system. Remove the coil wire from the distributor cap and place it near (1/4") a piece of metal on the engine and either have someone watch it or them crank the truck and you watch. You should have a nice blue or yellow/blue spark. If it is orange or no spark, close the gap up to 1/8" and try, if you now get a weak spark, replace the coil.

If both these tests yield satisfactory results, see if the injectors are triggering, they are wired in two groups of 4, the 4 end ones (1458) and the 4 center ones (2367), you should be able to feel the "click" of the solenoid in the injector. If not, then either the ECM is bad, or (more likely) there is a wiring problem. These 1985-86 EFI trucks have some of the crappiest wiring I have seen since the old rubber and cloth wiring in the 50s.

Good luck with it!

Bill,

Micah's first post stated (in part)

"So far here's some things that have been done recently.

Intake and valve cover gaskets

Idle air control valve

Thermostat

PCV valve

Throttle position sensor

MAP sensor

Fuel pressure regulator

Swapped out a computer from junk yard

Harmonic balancer

New belts and hoses

Spark plugs and wires

02 sensor

Fuel relay

Oil sending unit

Water pump

Fuel filter is relatively new

Solenoid

Starter

Motor was rebuilt 20 years ago and has low miles on it since rebuilt.

No vacuum leaks

Fuel pressure is good"

I'm not sure what "fuel pressure is good" really means..

But stated new FPR and relay.

This is why I suggested real time monitoring.

Heat soak doesn't come to mind causing a pump problem, but as you said you can have all the fuel in the world, if the injectors don't open you'll have no joy.

He states new grounds and a new distributor/TFI.

So again new parts, but not the problem.

But if the ECM is getting a signal from the PIP the pump relay should continue on the clock.

And the injectors -should- fire.

A noid light is cheap.

You can also pull the spout and see if the noid light starts working with the computer out of the picture.

[MBC1980]

You can buy a cover like I showed, or you can use a feeler gauge, shim stock or even a slip of tin can to block off the EGR where it bolts to the plate.

I didn't ask if you had swapped for a junked one, I asked if you had looked for signs of deteriorated caps.

Capacitors go bad just sitting on the shelf.

35 years is a long time for anything filled with electrolyte.

I'm trying to reason out what is getting heat soaked.

So many parts have already been shotgunned at it, it is hard to keep track.

But if it doesn't want to start, you might do best by asking it why it doesn't want to start.

I'm not exactly sure where to be looking for deteriorated caps. I've learned alot through this process but still have a ways to go and I'm not sure what I'm looking for on the caps.

Also, do I remove the EGR, place a plate between it and put it back and start it to see if it does it still? I can always just get an Egr and replace it if I have to and return if it's not the issue. Actually we may have a spare that was a trial and error in the past trying to fix an issue. Thanks for your expertise in this.

[MBC1980]

I'm not exactly sure where to be looking for deteriorated caps. I've learned alot through this process but still have a ways to go and I'm not sure what I'm looking for on the caps.

Also, do I remove the EGR, place a plate between it and put it back and start it to see if it does it still? I can always just get an Egr and replace it if I have to and return if it's not the issue. Actually we may have a spare that was a trial and error in the past trying to fix an issue. Thanks for your expertise in this.

Coincidentally or not it has gotten better when I switched tanks back and forth. Could it be the fuel tank switch valve?

[grumpin]

Coincidentally or not it has gotten better when I switched tanks back and forth. Could it be the fuel tank switch valve?

Could be the pump in the one tank that doesn’t work good.

Edit: on the tank that it doesn’t run right, with the engine running take the gas cap off that tank and try and listen to the pump. It should be continuous and smooth.

Before my pump went bad in my rear tank I could hear it not operating as it should.

[ArdWrknTrk]

Could be the pump in the one tank that doesn’t work good.

Edit: on the tank that it doesn’t run right, with the engine running take the gas cap off that tank and try and listen to the pump. It should be continuous and smooth.

Before my pump went bad in my rear tank I could hear it not operating as it should.

That might well be the problem, Dane.

But like Bill said, do some diagnostics.

Since the truck is doing its own diagnostics -constantly- the first thing I'd do is pull codes.

Even if the pumps are good and the valve is bad, what matters is pressure in the rail.

That's why there's a Schrader valve.

If you have a fuel pressure gauge stuck in front of your face you can see if the fuel pressure is low or non-existent, while you're driving or when it won't restart.

If the injectors aren't cycling it doesn't matter if there's fuel.

Again, a flashing light makes it pretty obvious if the computer is grounding the injector or not.

It's been three months now, hundreds of dollars in parts even before then, and the truck still won't start when heat soaked. (It seems)