Help with rich condition

inou2

New Member
May 26, 2004
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Ex-Chevy guy has switched to Mustang needs help. After fooling with small block chevys all my life, I've got an '89 gt with the following mods: mac short tube headers/flowmasters no cats, tremec tko, 373 gear, drag springs/shocks/struts, adj upper/lower control arms, really mild cam, 75mm pro-m bullet, 75mm throttle body, full tune up. I'm getting ready to do some bracket racing, but I've got to solve some problem first. I'm getting some codes: egr (not in use), and lean condition. The car runs great, but when the engine is cold, it idles fine, but once the engine warms, it runs extremely rich, and idles like a pro stock. I've checked for the usual suspects like ignition and vacuum leaks with no success. I've replaced about every sensor on the car. I'm losing my mind, and want to go racing! Please help, I love this car, but I'm getting very frustrated!
 
oh yeah, which is it: you said it runs rich when warm, yet you are getting a lean code. or is this a test? :)
good luck.
 
Still more problems

Pulled off the egr and it was in bad shape and would hold no vacuum. Put on new Ford one and using a vac diagram I found posted here hooked it back up. I seemed to help allittle. Yeah, it idles smooth when first started (cold), but as it warms up, all of the sudden, it starts sounding like it's got a big cam (it has a very mild cam with smooth idle). Codes show egr problems and lean condition. Even though I hooked the egr back up, I can't see any movement at 3000 rpm and higher. I cleared the codes and went for a ride, CEL came right back on. I'll check the codes again tomorrow. May donate to army for grenade practice. Also, it runs so rich it will burn your eyes.
 
Pulled Codes

The adventure continues. A new egr seemed to help. The old one was not hooked up. It appears that the egr vac regulator may be shot, it has voltage to it, but not letting vac get to the egr at any rpm. KO engine off codes are: 11,12,33,41,91,22. With the engine on: 91,33,41. Surely the egr is not causing the lean codes. Apparently the computer is sensing lean and adding fuel. O2 sensors have about 200 miles on them. The car has shorty headers, off road h-pipe w/flowmasters with dumps. Could the exhaust set up cause a problem? This is getting frustrating. I've been from one end to the other on this thing. Thanks for any input! By the way, it has a 180 thermostat.
 
Check the fuel pressure regulator, as I had a similar issue a while back... Changed a bunch of sensors, car ran great cold, rich when warm and the CEL would come on only after engine was warm...

I just replaced mine w/o testing pressure, but it solved the problem as my mileage went way up and the CEL stopped coming on...
 
inou2 said:
The adventure continues. A new egr seemed to help. The old one was not hooked up. It appears that the egr vac regulator may be shot, it has voltage to it, but not letting vac get to the egr at any rpm. . .
im confused again (easily done). you put a new EGR (valve) on, but the EVR solenoid is not working, right? so the valve is not being used..?? the EVR is the solenoid that has elec and vac lines connected to it, and it sends the signal to the valve to open. it would be like putting new injectors on a car with no fuel pump. im betting im just misreading or missing something.

unless you burn a chip, you need the egr hooked up. the spent gasses cool the chambers and the puter dials in a ton of timing (knowing that the mixture is being diluted with EGR gasses). no chip and no EGR, and the extra temps and added timing can cause detonation. but you did not mention that, so again, i must have missed something.
 
That'r right, Hissin50. The old one was not hooked up when i bought the car, just bolted in place. I had gotten some advice to hook it back up. Got a digram and went to work. I first put some vac on it and the diaphram was shot, would not hold any vac. Replaced it, and installed the vac lines. Reved past 3000 several times with no observed egr action. I think what marginally helped was there was so much gunk the egr piston may have been slightly open, and the new one is closed tight. However, still getting the same codes and poor idle after warm up. Checked for voltage at the evr and it was present. Had to order one from dealership and will arrive in afew days. Regardless if the egr takes care of my problems, I'd like to run one anyway for several reasons. I'm also going to install a fpr and gauge to monitor that. Next i'm going to run through the valves. On carb'ed engines, i had some similar problems with incorrect lash settings. I appreciate everyone's help. As I learn more about efi I hope to pass along some of my experiances and the forums are a life saver!
 
thanks for the info - we are on the same page (clears up the questions i had).

are you running a solid lifter set up? if not, the lash is hydraulically set - no need to tinker with it.

good luck, Bud.
 
Thanks, Hissin. I picked a new egr vag regulator at the ford store, and of course they gave me the wrong one. I'll take it back and try again. I hope there is no valve lash issue, with the pedestal mount setup. Thanks a million for your help!
 
OK, I now have a new egr, egr vac regulator, new vac lines, and there is NO egr movement at any rpm. Ran codes: KOEO 67,12,94,91,29,41. KOER: 91,41,31. Plenty vac source. I think at least some of my problems are egr related, but why no action at the egr? Engine temp @180, is this warm enough for the computer to start signaling egr? This is crazy!
 
BOY HOWDY!!! After no success with the egr vac reg, I decided to re-check all the vac lines, wiring, connectors, etc. I did find an orange wire not connected to anything. After looking at some diagrams, and looking on hte web, I found an article on o2 sensors. One tip was "allways check your ORANGE hego ground reference wire". I found a good ground source, made the connection, cleared the codes and went for a ride. It idled just as it should, with a crisp,slight lope regarless of temp, no cel, and ran like a bat out hades. Re checked the codes, and only had a few:no air injection sys (it's gone), and a manual trans sensor. Talk about getting over a hurdle! I'd like to thank all who provided guidance and advice. What an awesome forum!
 
PnyPwr...the 16ga orange wire came out of the harness at the rear center behind the intake, below the"salt and pepper" harness extension is located. I missed it because it was under all that stuff. Apparently, when the previous owner had the some head work done he poorly made a connection somewhere that came loose. On mine, it was an exposed wire, out of the harness. I figure at one time, it may have had sone type of insulating material on it. I just routed it away from anything it could come into contact with.