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| 94 idles fine but start to surge. | |
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| Tweet Topic Started: Oct 20 2013, 05:25 PM (490 Views) | |
| billpinsc | Oct 20 2013, 05:25 PM Post #1 |
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Ive been working on my 94 3/5.with upgraded emmisions. I have cleanned all grounds and Set The TPS.Have new plugs and wires and fuel filter. I have also checked connections and wires for bad spots. The car will start and run But when you come to a stop the idle will surge up and down for a few seconds.Also if you stay stoped too long it will just die when you give it the gas.It will just surge up and down and back fire almost like it dies out.Even If you hold it to the floor. It was worse once i adjusted the TPS. so I put it back where it was. Now it only starts the surging when you stay stopped to long.Sometimes you get a strong gas smell when it statrs to surge. it will always idle good but the surging is when you give it gas.Could this be a bad injector or fuel regulater. No I have not done a compression test yet. I know Most will say do it first. |
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| clarkdw | Oct 20 2013, 06:45 PM Post #2 |
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But surging is not a result of poor compression. Did you set the TPS according to the FSM procedure? Key on engine off, 1.0 volts with a 0.140" spacer in the throttle link? I ended up with mine at a slightly lower volt reading to completely eliminate surging. It is a really sensitive adjustment and took me awhile and several adjustments to get it to where I am very happy with it. Has your throttle stop screw been messed with? That will also contribute to surging. The butterfly needs to be as near completely shut as possible while still preventing it from jamming shut. The last thing that I found that caused or contributed to surging was the ISC itself. The idle switch is in the plunger of the ISC and if it does not tell the ECM that the plunger is against the linkage it can cause idle issues. |
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| billpinsc | Oct 20 2013, 07:39 PM Post #3 |
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Yes I had the TPS set right.(I used t-pins and checked at the senser as you suggested The allen wrench spacer worked great also) It took a few tries but I Finally got it.Im not sure about the idle stop screw. I didnt mess with it but I dont know what the PO did. The ISC makes sense I was getting code 46 The ISC was making a noise when the key was on but the car was not cranked.The plunger was surging in and out on the throttle(tiking sound).I think i will adjust it again and use a little lower voltage. |
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| clarkdw | Oct 20 2013, 10:05 PM Post #4 |
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The ISC cycling in and out with key on engine off might indicate that the idle switch signal is not getting to the ECM. The idle switch is in the plunger of the ISC. The plunger on mine moves out at key on and stays giving cold start high idle. It does not cycle in and out. Try seeing if holding something against the plunger to trip the idle switch changes the cycling. See if the plunger actually moves. It should move in and out and you can feel a very small click as the switch activates when it is not running. |
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But surging is not a result of poor compression. Did you set the TPS according to the FSM procedure? Key on engine off, 1.0 volts with a 0.140" spacer in the throttle link? I ended up with mine at a slightly lower volt reading to completely eliminate surging. It is a really sensitive adjustment and took me awhile and several adjustments to get it to where I am very happy with it.
2:18 PM Jul 11