Diesel Place banner
1 - 13 of 13 Posts

·
Registered
Joined
·
77 Posts
Discussion Starter · #1 ·
This is a '90 5.7.

Recently the truck has been misfiring once it warms up. This is a serious misfire issue. Throttling up will make it worse, and if trying to pull away from a light it can stall.

I've had a code 32 for a while and replaced the EGR valve and EGR solenoid. I put new sparks in when I first noticed the problem to no avail. Yesterday put new wires on since I accidentally nicked one when pulling off the EGR. I also put new hoses for the EGR and associated components.

I have no codes associated with the misfire.

Since it only occurs when the engine is warmed up I'm wondering if this is distributer related, or maybe just coil related. It doesn't make sense that it would be fuel related.

Thoughts?

Thanks,
Bill
 

·
Registered
Joined
·
437 Posts
Have your EST module tested. Its inside the distributor, held on with two screws. Most auto parts stores will do this for free. It could also be the pick up coil under the rotor button on the distributor shaft. If the module tests good I would check the pick up coil.
 

·
Registered
Joined
·
4,116 Posts
While you are in the Dist. check for carbon tracing inside the cap, clean the bottom of the module too and regrease it.
 

·
Registered
Joined
·
77 Posts
Discussion Starter · #6 ·
What type of grease? White lithium? or that stuff for spark plugs? Not sure if I'll get the distributor apart today, might wait until Saturday.

Thanks guys. My gut tells me it's inside the distributor.

Bill
 

·
Registered
Joined
·
77 Posts
Discussion Starter · #7 ·
OK so grease comes with the part...

Take a look under the dist cap... NICE! Electrical Parts + Rust = ???

Anyway, How in the @#$%! does this stuff come apart. I figured the "cover" ring looking part (#1 in the picture) would just lift right off, but nooooooo.... Is part #2 holding it on? How do I get part #2 off to get to the pickup coil?

Also since part #2 has more rust then my rocker panels I'm supposing replacing it would be a good idea. What is it?

Oh and any other words of wisdom (like Woodchuck2's!) that a shluck like me could use while in there would be welcome.

Thanks,
Bill
 

Attachments

·
Registered
Joined
·
184 Posts
If this only fails when warm it may test OK when cold. You are probably going to have to throw some parts at it. I believe you are in the right area.
 

·
Registered
Joined
·
437 Posts
Looking at the picture, I would probably replace the Module (black piece with two plugs) and the pick up coil(parts1 and 2). You have to remove the distributor and take it apart to replace the pick up coil. Buy a chiltons manual to walk you through that. Its not that hard, just make sure you mark the location of the rotor button and the base of the distributor before you take the distributor out. DO NOT CRANK THE ENGINE WITH THE DISTRIBUTOR OUT!!! Then when you put it back together just make sure the marks line up.
 

·
Registered
Joined
·
1,798 Posts
Pop the roll pin out of the dist gear and lift the shaft out of the housing, some PB blaster or WD40 shot into the housing will help as the shaft will have burnt oil on it and may be hard to pull out. After that remove the jesus clip (called that because it'll fly away and you'll say "Jesus") and the pickup coil will come off. Wire brush the crud off the shaft and it'll slide right back in. (insert witty sexual reference here)

Pick up coil is most of the firing problems with these engines, also look closely at the shaft for cracks at the points that line up with the PU coil, any there replace either shaft or drop in a new distributor.
 

·
Registered
Joined
·
77 Posts
Discussion Starter · #11 ·
Fortunately or unfortunately I did not have to deal with the Jesus clip. When I took out the distributor, having enough trouble getting the roll clip out and seeing tiny broken teeth dropping out all over the place from the distributor, I investigated to find that a rebuilt distributor costs only $30 more than the pick up coil and EST separately.

Henceforth and to wit, stay tuned to see if I can install the distributor back in place at the proper marking.

It does make me wonder why I had so much rust in there though... So I picked up a new cap even though the old one looked OK.

Much thanks so far,
Bill
 

·
Registered
Joined
·
1,676 Posts
My sister had a '90 Suburban with a 350, it had the same problem. I found that the EGR was turning on full time when it warmed up, so it would open the valve as soon as the throttle was cracked. The computer was at fault, because the solenoid was working. I unplugged the EGR and we ran it 11 years like that.
 

·
Registered
Joined
·
4,116 Posts
Fortunately or unfortunately I did not have to deal with the Jesus clip. When I took out the distributor, having enough trouble getting the roll clip out and seeing tiny broken teeth dropping out all over the place from the distributor, I investigated to find that a rebuilt distributor costs only $30 more than the pick up coil and EST separately.

Henceforth and to wit, stay tuned to see if I can install the distributor back in place at the proper marking.

It does make me wonder why I had so much rust in there though... So I picked up a new cap even though the old one looked OK.

Much thanks so far,
Bill
You may need to replace the seal between the firewall and the hood, if the seal is collapsed or missing then you will have alot of water running inside the engine bay right on the backside of the engine. Check the plugs and wiring for corrosion at the Dist. too. Good find on a rebuilt dist., you will save money and headaches down the road.
 
1 - 13 of 13 Posts
Top