Misfire, where do i go from here. (Page 14/18)
82-T/A [At Work] MAR 03, 10:13 AM

quote
Originally posted by zkhennings:

I would still hook up a fuel pressure gauge and record it with a gopro while you drive, if nothing else to eliminate fueling prior to the injector being a cause. I have had the submersible fuel hose fail that couples the pump to the sender, you could have wiring/connector issues preventing enough current getting to the pump with higher fuel demands, etc.




I would echo this. I mentioned the same thing a few pages earlier... I've personally had that issue where the connecting hose would restrict flow under hard driving (I used normal fuel line, not the kind that's intended ot be submersed in fuel). But removing the tank is a bit time consuming. At this point, I would clean or replace the injector, and check all the grounds. If it still is giving you problems... then that's my guess.
Dukesterpro MAR 03, 11:01 AM
I will get my big honkin scope out and give the tps a try
Dukesterpro MAR 03, 11:02 AM
I will reverify fuel pump pressure aswell
Dukesterpro MAR 07, 09:16 AM
I am going to go ahead and say that this will likely never be resolved. I did find the TPS was wrong and the cause of the high idle. Never found out what the misfire was.

I was driving home Friday night and noticed dropping oil pressure. With the idiot light coming on at idle. The top end was beginning to tick on and off. I hightailed it home and parked it for the night.


I rolled the motor over on the starter the other morning and heard a sound like a jar of yogurt getting pored on concrete. Shut the motor off and found 2-3 quarts of oil all over the driveway that was not there when I started cranking. It looked like it was coming from around the oil filter. I'm not sure what the heck I'm supposed to make of this. A new filter and fresh oil made no difference. It just pours out from what appears to be under the filter where the motor mount bolts to the block. I currently have the intake off trying to find where the oil is coming from.

Maybe a clogged oil galley? The engine was sludgy when I redid the lifter. Maybe the Lucas breaking additive released the sludge.


Just be know that there likely wont be an answer to what the misfire was if this engine died. But the high idle was verified to be the fault of the TPS and not a ground.
zkhennings MAR 07, 01:28 PM
The motor is probably fine, did your oil pressure sensor back out? Could have lost an oil galley plug. Hopefully nothing in your block is cracked (would be very unusual).

But something in the pressurized oiling system has failed. Distributor seal? Don't think a leaking dizzy seal would drop oil pressure that much though. Hopefully an easy fix.

Was your misfire not solved by the TPS? I have found a bad TPS results in backfires as the fueling goes all wonky from the TPS input not matching the cells in the tables.
82-T/A [At Work] MAR 07, 08:16 PM

quote
Originally posted by Dukesterpro:

I am going to go ahead and say that this will likely never be resolved. I did find the TPS was wrong and the cause of the high idle. Never found out what the misfire was.

I was driving home Friday night and noticed dropping oil pressure. With the idiot light coming on at idle. The top end was beginning to tick on and off. I hightailed it home and parked it for the night.


I rolled the motor over on the starter the other morning and heard a sound like a jar of yogurt getting pored on concrete. Shut the motor off and found 2-3 quarts of oil all over the driveway that was not there when I started cranking. It looked like it was coming from around the oil filter. I'm not sure what the heck I'm supposed to make of this. A new filter and fresh oil made no difference. It just pours out from what appears to be under the filter where the motor mount bolts to the block. I currently have the intake off trying to find where the oil is coming from.

Maybe a clogged oil galley? The engine was sludgy when I redid the lifter. Maybe the Lucas breaking additive released the sludge.


Just be know that there likely wont be an answer to what the misfire was if this engine died. But the high idle was verified to be the fault of the TPS and not a ground.




Ah man, that sucks. If I was nearby, I'd come over and help. Just know, an engine for this car is really cheap. And at this point... you've basically built a new car already since you've replaced everything! (bad attempt at humor, sorry).
Dukesterpro MAR 08, 01:03 PM
Sending unit is bone dry.

Its coming from around the oil filter. and it is ALOT of oil. Is there a reference for oil gallery plug locations?
Patrick MAR 08, 03:35 PM

quote
Originally posted by Dukesterpro:

Its coming from around the oil filter. and it is ALOT of oil.



Basic question (checking the simplest things first)... what oil filter are you using?

I forget how it's designed, but... does the oil filter screw and tighten up directly against the block, or does it screw onto an assembly of sorts that is bolted onto the block? If it's the latter, any chance the assembly has somehow gotten loose and/or is leaking?

[This message has been edited by Patrick (edited 03-08-2023).]

Dukesterpro MAR 09, 10:30 AM
I am using an AC Delco PF52e.

Screwed directly against the block
82-T/A [At Work] MAR 09, 12:22 PM

quote
Originally posted by Dukesterpro:

I am using an AC Delco PF52e.

Screwed directly against the block




Does it look like anything is cracked or broken? Just curious...