Update! Engine Running....Bad Idle.... RESOLVED!!
05-10-2007, 04:02 PM
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Three Wheelin'
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Update! Engine Running....Bad Idle.... RESOLVED!!
New fuel filter and checked fuel pressure and it appears within spec. No change to starting situation.(See https://rennlist.com/forums/showthre...42#post4153542 )
Checked connections again and found the Temp II and TPS connector not connected or seated properly! The engine now starts and runs.
However, it will not hold an idle. Wavers slightly and then gradually the swings become worse and worse until it stalls, or if you close the throttle from a higher rpm it will stall. I suspect the ISV. I cleaned it of carbon build up before putting it back in, but when I jumper it at the engine terminal I don't hear any change in the engine's rpm.
How do I know if it is (is not) getting a signal from the LH and is not actually functioning? The WSM does not show anything (that I can find) for checking the '85 ISV on the '84/'85 LH trouble shooting list. The WSM references the '84 "auxilliary air regulator" and the "87 "idle speed actuator", but they look different from my '85 (though I expect they perform the same function). There must be pin outs or something?
Glenn
Checked connections again and found the Temp II and TPS connector not connected or seated properly! The engine now starts and runs.
However, it will not hold an idle. Wavers slightly and then gradually the swings become worse and worse until it stalls, or if you close the throttle from a higher rpm it will stall. I suspect the ISV. I cleaned it of carbon build up before putting it back in, but when I jumper it at the engine terminal I don't hear any change in the engine's rpm.
How do I know if it is (is not) getting a signal from the LH and is not actually functioning? The WSM does not show anything (that I can find) for checking the '85 ISV on the '84/'85 LH trouble shooting list. The WSM references the '84 "auxilliary air regulator" and the "87 "idle speed actuator", but they look different from my '85 (though I expect they perform the same function). There must be pin outs or something?
Glenn
Last edited by sharkmeister85; 05-13-2007 at 04:10 AM.
05-10-2007, 04:40 PM
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You can test the ISV without removing it once the Mass-Air Sensor is out of the way.
To test directly at the ISV: middle pin is 12v. Other two pins are ground. Connect 12v to the middle pin and then ground at one outside pin should cause the ISV to turn one way. Ground on the other pin moves it the other way.
If you have the WSM CDs there's an EZF troubleshooting guide that covers this IIRC.
To test directly at the ISV: middle pin is 12v. Other two pins are ground. Connect 12v to the middle pin and then ground at one outside pin should cause the ISV to turn one way. Ground on the other pin moves it the other way.
If you have the WSM CDs there's an EZF troubleshooting guide that covers this IIRC.
Last edited by worf928; 05-10-2007 at 06:58 PM.
05-10-2007, 04:53 PM
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Thanks, Dave! That will show that the ISV works and I will try that first. I have to consider that with all the "intake reseal +" that I did that I may have broken/shorted out one of those crispy wires in the harness to the ISV. Can I measure LH output at the connector to the ISV or is there pins in the big LH connector that I can do the same thing and apply power to the ISV from there?
Glenn
Glenn
05-10-2007, 05:10 PM
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you should be able to test the pins of the connector too. Middle is ground and then see if you can get any signal on either side pins.
05-10-2007, 07:04 PM
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First, note, that I editted my post above. Middle is 12v. The outer pins are ground!
Reminder to self - always check the wiring diagrams first!
Yes. I believe so.
Do you have the WSM CD's? Look for the EZF troubleshooting guide. It diagrams the connector pin-outs for the ECUs.
Pins 10 and 23 on the LH connector are the 'ground' connections to the ISV. Power to the ISV comes from the fuel pump relay by way of the W13 pin on the bottom of the fuse panel.
I would be inclined to check continuity and resistance from the LH connector to the ISV if your direct test of the ISV indicates that it works.
Reminder to self - always check the wiring diagrams first!
Originally Posted by sharkmeister85
... or is there pins in the big LH connector that I can do the same thing and apply power to the ISV from there?
Do you have the WSM CD's? Look for the EZF troubleshooting guide. It diagrams the connector pin-outs for the ECUs.
Pins 10 and 23 on the LH connector are the 'ground' connections to the ISV. Power to the ISV comes from the fuel pump relay by way of the W13 pin on the bottom of the fuse panel.
I would be inclined to check continuity and resistance from the LH connector to the ISV if your direct test of the ISV indicates that it works.
05-11-2007, 12:51 AM
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Gelnn,
If you need any parts for testing just let me know. I can send whatever I still have for you to test, this way you don't have to buy parts that are still good. Just send them back when you are finished with them. We are both in Canada so shipping will be easy, cheap and quick.
If you need any parts for testing just let me know. I can send whatever I still have for you to test, this way you don't have to buy parts that are still good. Just send them back when you are finished with them. We are both in Canada so shipping will be easy, cheap and quick.
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05-13-2007, 04:10 AM
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Thanks for the offer, Imre. I think I've sorted the problem out. After testing the ISV and connections, I was pretty certain it was not the problem. Since I had the MAF out, I decided to hook my vacuum gauge to the 6-way splitter to check if I was maybe dealing with a vacuum leak. Vacuum was reading 20-22 in/hg, so no significant vacuum issues, but still an erratic idle.
I was back to wondering if my fuel pressure/pump might still be the culprit. But after discussing it with another local R-Lister (Lizard931), it seems he had the same kind of fuel pressure readings I had and he had no issues. This left me thinking that I might have some bad fuel or MAF problem. I had an old MAF on the shelf, so I swapped it in, not knowing if I might just be going from bad to worse. Son of a gun if the problem didn't go away! Nice steady idle now.
Glenn
I was back to wondering if my fuel pressure/pump might still be the culprit. But after discussing it with another local R-Lister (Lizard931), it seems he had the same kind of fuel pressure readings I had and he had no issues. This left me thinking that I might have some bad fuel or MAF problem. I had an old MAF on the shelf, so I swapped it in, not knowing if I might just be going from bad to worse. Son of a gun if the problem didn't go away! Nice steady idle now.
Glenn
