Exhaust vs Timing, something else?

Krem · 03-16-2010, 12:17 AM

So car has been degrading in performance for last couple of months. She used to have a nasty noise around 4000rpm and has moved down to ~3200rpm now. Noise sounds like a turbo spooling with a bad bearing, except I don't have a turbo.. After running warm/hot and parking for 15~20 min, she won't want to start back up.. she'll turn over, drop idle VERY low and stall out, then I can smell a funny exhaust smell in the cab. I can get her started if I give it a good amount of gas while turning her over to prevent the low rpm idle. Finally, the headers have been glowing red the past couple of nights after a 12 mile drive home from work where she sits all day.

I'm thinkin it's the exhaust system somewhere as the symptoms first began when I got my car back from a trial and error diagnostic repair where some mechanic pulled the o2 sensor and they did my timing. Not sure which timing they did, but I do know they had to replace my distributor and open the timing case, so another reason I am leaning towards exhaust system more so than timing. Wondered if anyone could confirm, deny or propose a more likely cause.

cre · 03-16-2010, 12:54 AM

I'm leaning more toward the timing belt and a shot tensioner pulley.... Check the mechanical timing as shown in the MKIII FAQ.

Exhaust is easy enough to check... disconnect it right before the cat.

So, no codes?

Krem · 03-17-2010, 03:27 AM

Thanks Cre, guess I get to dig back in the timing case... maybe this time I'll just leave it off, looks much more bad ass with the cam gears visible anyways IMO. Really hope to get this fixed, tired of being out accelerated by a Ford Festiva/Fiesta.. oh, and yea... sorry, but no codes

.. which is why I refused to let someone hook up a diagnostic machine to my car for $90 to pull the codes that aren't there. Yay for 1960's troubleshooting eh?

btwilson86 · 03-17-2010, 04:07 AM

Quote:

Originally Posted by Krem

maybe this time I'll just leave it off

Oh, please don't. Even though these are non-interference engines (thank god), the potential for snapping your timing belt or ruining the teeth on your cam gears is not worth the look (IMO anyway)

I feel like I've been saying this too much lately in a few threads, but check your ignition timing after you check your valve timing. I'm pretty sure fairly advanced ignition timing (maybe it's retarded timing, don't remember for sure) could cause high exhaust gas temps (hence the red headers). Like I said though, check it after you set your valve timing or you'll just have to do it twice

Krem · 03-17-2010, 04:53 AM

thanks for the tips BT.. that is def. why I mentioned that in my post... wasn't sure if it was a good idea or not despite appearance... guess I know better now and have you to thank for that

. So I'll give the timing a look at this weekend. Just hope she'll be ok for travel back and forth this week..

cre · 03-17-2010, 12:42 PM

Retarded timing = high EGT. Advanced timing = more heat transferred into the block and thus lower EGT.

Green7mgte · 03-17-2010, 02:55 PM

off topic but you can get clear cam covers.

Krem · 03-17-2010, 08:06 PM

Quote:

Originally Posted by cre

Retarded timing = high EGT. Advanced timing = more heat transferred into the block and thus lower EGT.

could this be why after driving several miles I smell a lean exhaust smell in my cabin?

cre · 03-18-2010, 12:32 AM

Quote:

Originally Posted by Green7mgte

off topic but you can get clear cam covers.

Cam covers? Ack... not very pretty with all the oil getting thrown around and all...

Quote:

Originally Posted by Krem

could this be why after driving several miles I smell a lean exhaust smell in my cabin?

A smell in the cabin is more likely due to a bad hatch seal or a leak elsewhere in the trunk.

Green7mgte · 03-18-2010, 02:39 AM

oops i ment timing cover. just forget im here..
"slinks into the back"
http://www.horsepowerfreaks.com/perf.../Timing_Covers

03-16-2010, 12:17 AM	#1
Krem 3" Exhaust Join Date: Sep 2009 Location: Las Vegas Posts: 167	Exhaust vs Timing, something else? So car has been degrading in performance for last couple of months. She used to have a nasty noise around 4000rpm and has moved down to ~3200rpm now. Noise sounds like a turbo spooling with a bad bearing, except I don't have a turbo.. After running warm/hot and parking for 15~20 min, she won't want to start back up.. she'll turn over, drop idle VERY low and stall out, then I can smell a funny exhaust smell in the cab. I can get her started if I give it a good amount of gas while turning her over to prevent the low rpm idle. Finally, the headers have been glowing red the past couple of nights after a 12 mile drive home from work where she sits all day. I'm thinkin it's the exhaust system somewhere as the symptoms first began when I got my car back from a trial and error diagnostic repair where some mechanic pulled the o2 sensor and they did my timing. Not sure which timing they did, but I do know they had to replace my distributor and open the timing case, so another reason I am leaning towards exhaust system more so than timing. Wondered if anyone could confirm, deny or propose a more likely cause.

03-16-2010, 12:54 AM	#2
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	I'm leaning more toward the timing belt and a shot tensioner pulley.... Check the mechanical timing as shown in the MKIII FAQ. Exhaust is easy enough to check... disconnect it right before the cat. So, no codes? __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-17-2010, 12:42 PM	#6
cre Toyota Racing Development Join Date: Apr 2007 Posts: 5,038	Retarded timing = high EGT. Advanced timing = more heat transferred into the block and thus lower EGT. __________________ If something breaks or you need to contact a member of the administration please post HERE. Unless it's a private or administration matter please post it on the forum. It benefits no one else if car related questions aren't posted for future users and takes away from the time I'm able to spend helping on the rest of the forum. If you're so inclined I'm always more than happy to accept tips via PayPal. Tip Jar --->

03-17-2010, 02:55 PM	#7
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	off topic but you can get clear cam covers. __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

03-18-2010, 02:39 AM	#10
Green7mgte Supra Forum Moderator Join Date: Nov 2009 Location: Green-Ohio Posts: 1,297	oops i ment timing cover. just forget im here.. "slinks into the back" http://www.horsepowerfreaks.com/perf.../Timing_Covers __________________ 92 Ma71 7mGTE Auto. SafcII Supra FAQ Supra MKIII FAQ Classified Section guidelines :

03-17-2010, 03:27 AM	#3
Krem 3" Exhaust Join Date: Sep 2009 Location: Las Vegas Posts: 167	Thanks Cre, guess I get to dig back in the timing case... maybe this time I'll just leave it off, looks much more bad ass with the cam gears visible anyways IMO. Really hope to get this fixed, tired of being out accelerated by a Ford Festiva/Fiesta.. oh, and yea... sorry, but no codes .. which is why I refused to let someone hook up a diagnostic machine to my car for $90 to pull the codes that aren't there. Yay for 1960's troubleshooting eh?

03-17-2010, 04:53 AM	#5
Krem 3" Exhaust Join Date: Sep 2009 Location: Las Vegas Posts: 167	thanks for the tips BT.. that is def. why I mentioned that in my post... wasn't sure if it was a good idea or not despite appearance... guess I know better now and have you to thank for that . So I'll give the timing a look at this weekend. Just hope she'll be ok for travel back and forth this week..

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