echdaviem Posted March 3, 2013 Share Posted March 3, 2013 So I've been having some running issues lately, mainly at 0-1/4 throttle. I was looking in the engine bay this afternoon and noticed that when I crack the throttle open the EGR valve opens also. I can feel the solenoid tripping therefore opening the valve. Is the EGR valve supposed to open and close that often? What conditions is it supposed to open and close? What is normal? Link to comment Share on other sites More sharing options...
echdaviem Posted March 3, 2013 Author Share Posted March 3, 2013 Sorry forgot to mention, I have a SWB 4.0 AX15-231 Link to comment Share on other sites More sharing options...
ComancheKid45 Posted March 4, 2013 Share Posted March 4, 2013 Easy way to check the EGR is while the engine is idling activate the plunger and see if it stalls. If it does stall than your EGR is working properly. Just for kicks, pull each of the 6 spark plugs and recheck the gaps. I had a low RPM misfire that was caused by a smashed spark plug ;) Link to comment Share on other sites More sharing options...
cruiser54 Posted March 4, 2013 Share Posted March 4, 2013 TESTING THE EGR VALVE FOR 87-90 4.0 ENGINE Valve Opening Test1) With engine at normal operating temperature and at idle,rapidly open and close throttle. Open throttle sufficiently to obtainat least 1500 RPM. Movement should be noticed in EGR diaphragm.2) If diaphragm does not move, probable causes are: faultyvacuum signal to EGR, defective EGR diaphragm or defectivebackpressure sensor diaphragm (if equipped), or leaks in vacuum linesor connections.Valve Closing Test1) With engine at normal operating temperature and at idle,manually depress EGR valve diaphragm. RPM should immediately drop,indicating that EGR valve is not leaking and had been properly cuttingoff exhaust gas flow at idle.2) If there is no change in RPM and engine is idlingproperly, exhaust gases are not reaching combustion chamber. Check forplugged passage between EGR valve and intake manifold.3) If engine idles poorly and RPM is not greatly affected bymanually moving diaphragm up, EGR valve is not closing off exhaust gasflow. Check for carbon between pintle, leaking EGR valve gasket or badEGR valve.*************** Link to comment Share on other sites More sharing options...
echdaviem Posted March 4, 2013 Author Share Posted March 4, 2013 The EGR valve is opening and closing fine, the problem is that when it does open at 0-1/4 throttle, it bogs down the motor and tries to stall. If I just floor it, the effect is minimal. My question is, is it supposed to be opening that early and that often? Thanks for all the help, appreciate it! Link to comment Share on other sites More sharing options...
cruiser54 Posted March 4, 2013 Share Posted March 4, 2013 It's controlled by the eCU. Disconnect the vacuum source to it temporarily and see if the symptoms go away. Link to comment Share on other sites More sharing options...
echdaviem Posted March 6, 2013 Author Share Posted March 6, 2013 So I Disconnected the vacuum going to it and it runs much better! so now what? just leave the egr unhooked? Link to comment Share on other sites More sharing options...
87manche1 Posted March 6, 2013 Share Posted March 6, 2013 Second time i posted tonight http://www.justanswer.com/jeep/6bdq5-jeep-cherokee-sport-1989-jeep-cherokee-sport-battery-grounded.html has wiring diagram power is sent from fuel pump relay which is controlled by computer. Link to comment Share on other sites More sharing options...
87manche1 Posted March 6, 2013 Share Posted March 6, 2013 Egr should only operate at cruising speeds so what is telling ur computer it needs to open? At idle or 1/4 Link to comment Share on other sites More sharing options...
echdaviem Posted March 6, 2013 Author Share Posted March 6, 2013 If it's only supposed to be open at cruising speeds, What is making it open at low RPM? Link to comment Share on other sites More sharing options...
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