I think I broke it ... - Tilted Forum Project Discussion Community

MSD · 01-05-2004, 05:30 PM

1993 Lincoln Town Car Executive Series with Limo Package (not stretched)
289(4.6) OHV Engine

Engine was diling roughly an dbackfiring until it warmed up. Diagnostic test showed that teh EGR valve was sticking and that cylinders 3, 5, and 8 weren't putting out as much power as they should have been. I replaced the plugs and smacked the EGR valve wiht a wrench until it un-stuck. It ran fine for a while. It got bad again. I replaced the plug wires as advised by a mechanic. It got really bad. It backfires and misses no mater how warm the engine is, the wires are connected properly in the right order and making contact.

I'm stumped

Peryn · 01-05-2004, 06:04 PM

Could be that rather than unstickin the EGR...you got luck and got a very short term fix. It probably stuck again...but this time in the full ON position. My advice, since you know you were having EGR problems, would be to disconect the thing. Try it with no exhaust going back into the cylinder and see what happens. If it gets better, take apart your EGR and clean it well, or buy a new one. If it gets worse...something else is wrong.

Gimli · 01-05-2004, 07:43 PM

Yeah, if the diagnostics said the EGR was malfunctioning, I don't think the shop manual would've called for some smackin'.

Online prices seem to be about $50 - $60 for a new one. No smackin' required!!!

BTW, the 4.6 is a SOHC, not OHV, AFAIK.

Moonduck · 01-05-2004, 11:18 PM

Last time I had a backfire problem with multiple cylinders losing power, I traced it back to bad spark plug wires allowing crossfire.

Smacking the EGR valve with a wrench would be contraindicated though. Try a hammer. Always use the right tool for the job =)

Ashton · 01-06-2004, 12:55 AM

It sounds like a timing problem to me, did you set the timing with a timing light? Did you check the distributor cap? It could be arcing inside...... missing is usually caused by a vacumm leak, bad plug, bad plug wire, cracked distributor cap..... but backfiring usually means your out of time.

MSD · 01-06-2004, 08:51 AM

Quote:

Originally posted by Ashton
It sounds like a timing problem to me, did you set the timing with a timing light? Did you check the distributor cap?

According to the Haynes book, the timing can only be adjusted by the engine computer, not manually. It has an electronic districutor (actually, two of them,) so no cap and no rotor. I'll start by checking for vacuum leaks since that seems to be the most likely problem and the easiest to fix.

01-05-2004, 05:30 PM	#1 (permalink)
MSD The sky calls to us ... Super Moderator Location: CT	I think I broke it ... 1993 Lincoln Town Car Executive Series with Limo Package (not stretched) 289(4.6) OHV Engine Engine was diling roughly an dbackfiring until it warmed up. Diagnostic test showed that teh EGR valve was sticking and that cylinders 3, 5, and 8 weren't putting out as much power as they should have been. I replaced the plugs and smacked the EGR valve wiht a wrench until it un-stuck. It ran fine for a while. It got bad again. I replaced the plug wires as advised by a mechanic. It got really bad. It backfires and misses no mater how warm the engine is, the wires are connected properly in the right order and making contact. I'm stumped

01-05-2004, 06:04 PM	#2 (permalink)
Peryn Junkie Location: San Diego, CA.	Could be that rather than unstickin the EGR...you got luck and got a very short term fix. It probably stuck again...but this time in the full ON position. My advice, since you know you were having EGR problems, would be to disconect the thing. Try it with no exhaust going back into the cylinder and see what happens. If it gets better, take apart your EGR and clean it well, or buy a new one. If it gets worse...something else is wrong. __________________ Dont cry kid, It's not your fault you suck.

01-05-2004, 07:43 PM	#3 (permalink)
Gimli Loser	Yeah, if the diagnostics said the EGR was malfunctioning, I don't think the shop manual would've called for some smackin'. Online prices seem to be about $50 - $60 for a new one. No smackin' required!!! BTW, the 4.6 is a SOHC, not OHV, AFAIK.

01-05-2004, 11:18 PM	#4 (permalink)
Moonduck Junkie Location: SE USA	Last time I had a backfire problem with multiple cylinders losing power, I traced it back to bad spark plug wires allowing crossfire. Smacking the EGR valve with a wrench would be contraindicated though. Try a hammer. Always use the right tool for the job =)

01-06-2004, 12:55 AM	#5 (permalink)
Ashton PORNHOUND Location: California	It sounds like a timing problem to me, did you set the timing with a timing light? Did you check the distributor cap? It could be arcing inside...... missing is usually caused by a vacumm leak, bad plug, bad plug wire, cracked distributor cap..... but backfiring usually means your out of time.