HELP!!! Not Enough Back Pressure at EGR??? - YotaTech Forums


Go Back   >


86-95 Trucks & 4Runners 2nd/3rd gen pickups, and 1st/2nd gen 4Runners with IFS

HELP!!! Not Enough Back Pressure at EGR???

Reply
 
LinkBack Thread Tools Search this Thread
Old 09-25-2011, 01:52 PM   #1
Registered User
Thread Starter
 
FieroGTdude's Avatar
 
Join Date: Nov 2009
Location: GA
Posts: 47
HELP!!! Not Enough Back Pressure at EGR???

I have been fighting the EGR for 2 months now tring to get my truck to pass emissions. Basically I think what it boils down to is the EGR is not getting enough back pressure from the exhaust. If you remove the vacuum line from the EGR, I have good vacuum there. But if I "T" in with the Vac. gauge at the EGR I dont get but -2 vac. What I believe is happening is when the EGR opens the back pressure drops and the Modulator doesn't stay closed causing a vacuum leak. Modulator has been tested on another truck and works fine.

Any Ideas on fixing back pressure? I tried a 1 inch restrictor plate and it didn't make a difference. I had to basically totaly block the exhaust to get a -5 vac reading.


Edit: Compression readings are 140-80-145-55, probly got some burned valves.

New Compression Numbers 160-160-165-125

Im thinking maybe I have an internal crack in the head causing low pressure to EGR?

Last edited by FieroGTdude; 09-27-2011 at 04:59 PM. Reason: New Compression Numbers
FieroGTdude is offline   Reply With Quote
Old 09-25-2011, 01:54 PM   #2
Registered User
 
BMcEL's Avatar
 
Join Date: Aug 2010
Location: Oregon, USA
Posts: 2,027
With those compression numbers the last thing I'd be worrying about is the EGR.
BMcEL is offline   Reply With Quote
Old 09-25-2011, 02:32 PM   #3
Registered User
Thread Starter
 
FieroGTdude's Avatar
 
Join Date: Nov 2009
Location: GA
Posts: 47
Quote:
Originally Posted by BMcEL View Post
With those compression numbers the last thing I'd be worrying about is the EGR.
Yeah but it runs fine. I just want to pass emissions.
FieroGTdude is offline   Reply With Quote
Old 09-25-2011, 05:18 PM   #4
Registered User
 
RedResistance's Avatar
 
Join Date: Sep 2011
Posts: 25
You're not gonna pass emissions with those CR's I promise you. When the engine has CR's that low you are not generating enough pressure/heat in the cylinder on the compression stroke to properly atomize (vaporize) the fuel/air mixture. The fuel is going to remain in droplet form due to the lack of pressure and heat and come right out the engine to the catalytic converter. Once this unburnt fuel comes in contact with the catalytic converter it is going to cause the catalytic converter to overheat and eventually fail. You are not going to be getting a good enough Air/Fuel ratio for the catalytic converter to operate correctly even if the unburnt fuel wasn't destroying it. You need to fix your compression issues before you hope to ever pass smog. Sorry to be the bearer of bad news, but like you said, you've been struggling with it for a while, and this is why.
RedResistance is offline   Reply With Quote
Old 09-26-2011, 04:02 AM   #5
Registered User
iTrader: (1)
 
skypilot's Avatar
 
Join Date: Sep 2010
Location: Peekskill, NY
Posts: 958
You got two dead holes dragging you down. You have to fix the valves or rings and probably both. It may seem to run right but its not.
skypilot is offline   Reply With Quote
Old 09-26-2011, 03:30 PM   #6
Registered User
 
peow130's Avatar
 
Join Date: Sep 2008
Location: Spokane, WA
Posts: 3,887
Yeah the low compression is causing low combustion temps which leads to high hydrocarbons..

I'd be looking to rebuild it..
peow130 is offline   Reply With Quote
Old 09-27-2011, 12:36 PM   #7
Registered User
Thread Starter
 
FieroGTdude's Avatar
 
Join Date: Nov 2009
Location: GA
Posts: 47
Quote:
Originally Posted by peow130 View Post
Yeah the low compression is causing low combustion temps which leads to high hydrocarbons..

I'd be looking to rebuild it..

My problem in high combustion temps. Here are the emission numbers.


25/25

HC-119
CO-.58
NOX-3626
CO+ CO2-14.7


50/15

HC-114
CO-.59
NOX-3790
CO+ CO2-14.7

I ran some seafoam through it since I took those compression numbers. Im going to try and check them again tonight.
FieroGTdude is offline   Reply With Quote
Old 09-27-2011, 04:57 PM   #8
Registered User
Thread Starter
 
FieroGTdude's Avatar
 
Join Date: Nov 2009
Location: GA
Posts: 47
New compression numbers are much better. Still a little low on one.

160-160-165-125

Any why Im not getting enough back pressure at EGR? Clog in the head? EGR itself is clean.
FieroGTdude is offline   Reply With Quote
Old 09-28-2011, 12:37 PM   #9
Registered User
 
smogman's Avatar
 
Join Date: Sep 2011
Location: Antelope,ca
Posts: 32
Your egr is probably the problem. It can be 1 of 2 things. pull vacuum on the valve and see if the motor dies or stumbles real bad. If it does not then your passages are plugged. If it does then is a vacuum issue. You way over thinking the process. If you have vacuum at the valve then you tee it in and you have no vacuum, then the valve its self may have a ruptured diaphram. The vacuum side of the bpv is sealed so your vacuum should not drop off.

Http://916smog.com
smogman is offline   Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
87 22r rebuild issue bigjstang 86-95 Trucks & 4Runners 10 06-10-2016 06:15 PM
Wiring help toyotamonster 3.4 Swaps 2 07-08-2015 09:17 AM
Opinions of Viair Compressor models, or other compressors skoti89 Offroad Tech 3 07-08-2015 12:05 AM
New AC Questions (Not the same old ones) HRDC0R19 86-95 Trucks & 4Runners 3 07-05-2015 06:43 PM
back of cab body plugs (1991 sr5) elwood73 86-95 Trucks & 4Runners 0 07-05-2015 07:07 AM


Tags
1985, 7mgte, 88, back, bad, celica, egr, jdm, lines, modulator, mr2, pressure, problem, toyota, vacuum

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -8. The time now is 09:14 AM.


2010 InternetBrands, Inc.