Jeep Driver Posted July 31, 2014 Posted July 31, 2014 Couple of weeks ago the engine began to idle as though it were in open loop. Last week I replaced the temp sender in the manifold, no change. Monday I had the new AC system/compressor charged, works great, but afterward the idle would drop too low with compressor on. Tuesday I replaced the idle control motor which had never worked since I had the truck. Now it idles too low, and revs too high at start up. Yesterday I replaced the TPS, the last one tested bad, my thinking is that the ECU did not know where the throttle was and was not sending the correct signal to the ICM. Idle is unchanged, still low and rough. I have gone through all my grounds, cables, wires, cap and rotor, sensors (except MAP).......etc. I went through all the vacuum lines and tested......idle is unchanged. Question- The two things I have not changed are the MAP and EGR valve. EGR is stuck, has been since I owned it and I'd like to remove it. Which is most likely to be bad? How do I test MAP? I have searched the web for MAP test and I have not found it. Would EGR suddenly change? Moved? What or how is the idle control motor controlled......what sensors are used to by the ECU to set the ICM? Thoughts? Thanks.
cruiser54 Posted July 31, 2014 Posted July 31, 2014 http://www.cherokeeforum.com/f2/map-sensor-test-procedure-7416/
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 Voltage to MAP is 4.87v Voltage out is 1.79v However....... When I unplug vacuum to MAP while running and working the throttle and then reconnect the vacuum, I get about 10 seconds of normal and smooth idle. Is it possible that the MAP can test good and yet be bad? Also, the EGR is not stuck, I can push it up with my fingers, it stays in the closed position during idle.
cruiser54 Posted August 1, 2014 Posted August 1, 2014 Voltage to MAP is 4.87v Voltage out is 1.79v However....... When I unplug vacuum to MAP while running and working the throttle and then reconnect the vacuum, I get about 10 seconds of normal and smooth idle. Is it possible that the MAP can test good and yet be bad? Also, the EGR is not stuck, I can push it up with my fingers, it stays in the closed position during idle. What happens to the idle when you pull the pintle back on the EGR? What are the MAP output readings at idle and then with throttle?
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 1.79 at idle, I did not test at trottle. Nothing happens to the idle when I raised the EGR valve.......which surprised me......no response at all.
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 At throttle.......approx 2500+ rpm it measures a sustained 1.13v
cruiser54 Posted August 1, 2014 Posted August 1, 2014 I'm guessing you believe your EGR is completely closed but it's actually not. It should puke out and die almost instantly when the EGR is cracked open manually at idle.
cruiser54 Posted August 1, 2014 Posted August 1, 2014 At throttle.......approx 2500+ rpm it measures a sustained 1.13v What about from idle doing a throttle "stab" while observing MAP output.
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 OK, I have not taken a EGR apart, so maybe I do not understand how it works. I assumed that by pushing up on what I consider the vacuum bladder the valve should open.......>? At throttle.......approx 2500+ rpm it measures a sustained 1.13v What about from idle doing a throttle "stab" while observing MAP output. Voltage is erratic and goes as high as 2.42v
cruiser54 Posted August 1, 2014 Posted August 1, 2014 Should go from about 1.1 at idle to as high as 4.7 when you stab the throttle. What does it read when you pull open the EGR? Have you ever checked the Ohms reading on the MAP sensor plug to ground?
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 Now it's reading 1.48v at idle. No change with I push up on the EGR. Stabbing the throttle......I got it to rise to 4.14v for a fraction of a second.
cruiser54 Posted August 1, 2014 Posted August 1, 2014 Either your EGR valve is leaking or you have a vacuum leak bigger than an EGR could leak. I'd remove the EGR and see what's going on there. The hoses kinda under the throttle body are in good shape?
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 Either your EGR valve is leaking or you have a vacuum leak bigger than an EGR could leak. I'd remove the EGR and see what's going on there. The hoses kinda under the throttle body are in good shape? All vacuum lines and hoses are new and I checked the booster......no leaks.
cruiser54 Posted August 1, 2014 Posted August 1, 2014 Pull the EGR. It can leak internally where you can't spray check for leaks.
Jeep Driver Posted August 1, 2014 Author Posted August 1, 2014 Pull the EGR. It can leak internally where you can't spray check for leaks. So, you're thinking that's what it is? I have one more day of work and then I'm going off for the weekend.........I may pull or eliminate when I get back. I'm reading that other's have pulled theirs with no ill effects, you agree with this? And no, I really don't have $85 for a new one.
Jeep Driver Posted August 2, 2014 Author Posted August 2, 2014 Image Not Found Image Not Found Image Not Found Image Not Found Image Not Found Image Not Found No change in rough idle.
Jeep Driver Posted August 2, 2014 Author Posted August 2, 2014 Image Not Found I don't know if you can see much in this pic but the injector seems louder than usual and it soaks the throttle plate at low idle.....seem to be around 300-400rpm What are the chances of the injector going out?
cruiser54 Posted August 2, 2014 Posted August 2, 2014 Image Not Found I don't know if you can see much in this pic but the injector seems louder than usual and it soaks the throttle plate at low idle.....seem to be around 300-400rpm What are the chances of the injector going out? It could be dirty. Search BG 44K on Google.
Jeep Driver Posted August 2, 2014 Author Posted August 2, 2014 I replaced the MAP and poured in some injector cleaner this morning. Idles smoother but still some 'lope' and the sell of unburnt gas at the exhaust. I'm convinced it is the injector.
cruiser54 Posted August 2, 2014 Posted August 2, 2014 I think they're readily available. Same as GM maybe?
outlaw star Posted August 2, 2014 Posted August 2, 2014 I think they're readily available. Same as GM maybe?Yes, same as the early S-10, the early Dodge Dakota 2.5L, Wrangler Yj 2.5L TBI wkn Early Dodge Daytona 2.2L and 2.5L TBI motors.
Jeep Driver Posted August 5, 2014 Author Posted August 5, 2014 There was a seller on Ebay selling a complete throttle body for $250, NOS They are no longer available complete because they sold all the injectors out of them. I was able to find them on the net and I contacted them today. I will need to find a used injector to send to them to be rebuilt and installed in a new TB. They will ship for $200. I used some Rislone injector cleaner and ran about 5 gallons of gas through it today, idle really smoothed out but sill low. I'm pretty certain my problem is with the injector, but If I'm gonna spend the money I'll just replace the whole thing while it's still available.
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