: Lawrence Look



1993 eldorado green1
04-10-04, 09:55 PM
hey man its me jim again with that crazy 1993 eldorado, well after driving this thing some more that problem has came back and sometimes worse, but no codes are present, all are in history, it all started when i tried wot for the first time, now its doing the same idiling real high when im driving, when i stop it doesnt idle down it stays at 3000 but if i kick the throttle real quick it will go down to 1500 then stays at 1200, and the revs are very long, if i tap the throttle even a little bit, she revs way up to like 4000 and stays there for like 3 seconds then slowly comes down, but sometimes it comes down faster, than other, it should be a quick throttle up and down, i never seen this before, its wierd, got anymore advise????:hmm:

joeveto
04-10-04, 10:02 PM
IAC valve?:hmm:

Lawrence
04-10-04, 10:06 PM
That would be my guess Jim, the ISC solenoid. You need to check it while the problem is occuring. If you can close the throttle plate (cam) by hand while running and it slows the idle, it is the ISC motor. Assuming the throttle linkage is not binding.

Lawrence
04-10-04, 10:11 PM
Also pull the 2 vacume lines from the cruise control diaphram and plug them just to make sure its not engaging.

Lawrence
04-10-04, 10:12 PM
Where are you in MI?

1993 eldorado green1
04-10-04, 10:25 PM
ok ill try that, tomorrow, the iac is whats controling the high idle though, do u think that code while the engine is running saying i have a bad crank sensor could be the culprit? and im in garden city, about 30 mins west of detroit.

Lawrence
04-10-04, 10:32 PM
ok ill try that, tomorrow, the iac is whats controling the high idle though,

Not necessarily, sounds like it is very possible though. The ISC motor pushes against the linkage at the bottom. But first eliminate the easier things. Check that throttle linkage and cable at the throttle body and make sure the cruise control unit is not hanging up.



do u think that code while the engine is running saying i have a bad crank sensor could be the culprit?

I don't think that sensor would make the engine race. Is that code back?



and im in garden city, about 30 mins west of detroit.

I'm in Columbus, if you're down this way bring it by.

1993 eldorado green1
04-10-04, 10:42 PM
no current codes, and the throttle assembly moves freely and theres no binding or tightness on any of the cables, lol i dont think in this state its in right now i could drive it anywhere, but i can clearly see the iac making the idle go up and down, but the idle is not really smooth, it seems like the iac has to move alot with only minimal change in idle quality, there is no missing at all, and the only other thing that i notice is the real bad surging when at wot, and it sometimes slams itself into second gear, never used to do that neither, ima gonna go check codes right now and see if it has any, ill write back in a min.

1993 eldorado green1
04-10-04, 10:49 PM
ok with key on and engine off theres no current codes, accept the ac and air bag, with the car running i get the same ones plus p083 witch is crank sensor to ignition failure, i dont know im stumped,

Lawrence
04-10-04, 10:55 PM
With the engine idling (too fast), push real hard on the throttle cam (trying to close the throttle plate). To see if you can slow the idle. Does the idle slow down?

Then disconnect the wire from ISC motor and pull (retract) the ISC plunger back from the throttle linkage. Make sure it's not contacting the throttle linkage. Does this slow the idle?

1993 eldorado green1
04-10-04, 11:08 PM
yes, it slows way down, if i physically move it, if i unplug it the engine revs higher and that plunger wont move in.

Lawrence
04-10-04, 11:14 PM
There you go.

Something is holding the throttle plate open. It should be closed tight when idling, at least until the ISC opens it. Which in your case seems to be opening it too much.

Likely is the ISC motor, so long as your sure it's not a binding throttle cable, throttle cam, cruise control, or broken throttle return spring.

Replace the ISC. Might check for a used one, new I think about $140.00.

After you install the new ISC motor you'll have to do the relearn again.

Lawrence
04-10-04, 11:20 PM
The Cad ISC motor works a little diffeent than say the IAC solenoid on a Honda. The IAC sol allows passage of addtional air "around" the throttle plate to increase speed. The Cad ISC actually opens the throttle plate more to increase speed.

1993 eldorado green1
04-11-04, 03:52 AM
yea ill try one on monday but im not gonna get a new one ill go to the junk yard, 140 is a lot for a non returnable part, thanks, ill let you know what happens.

BeelzeBob
04-11-04, 11:39 PM
Just to be sure, here are some things to check...with the engine idling and in park go under the hood and hold the idle high by opening the throttle lever with your hand. Depress the plunger of the idle speed control motor with your finger and it should retract. Keep it retracting by depressing the plunger firmly until it fully retracts and stops. When it is fully retracted, disconnect the wire connector from the idle speed control motor to freeze it in the fully retracted position. Now, return the throttle lever to the "closed bore" idle position. First thing to check is that there is clearance between the ISC motor plunger and the throttle lever. If it is indeed fully retracted and there is no clearance between the plunger and the lever then adjust the plunger so that there is about .030 clearance. There MUST be clearance between the ISC motor plunger and the throttle level when it is fully retracted. The engine should easily idle down to about 450-500 RPM once there is clearance and the throttle can return to the closed bore setting. If not then determine whether something (like the cruise control link) is holding the throttle open. The cruise control link should have enough slack in it to allow the throttle lever to return to the closed bore position and still have a slight bit of slack. If you adjusted it when working on the engine without returning the throttle lever to the closed bore position it may be too tight. At the closed bore position the throttle lever should be resting against the stop screw that is on the other side of the throttle body behind the TPS. If it is not, then something is holding it open. If it is resting on the stop screw and still is idling too fast then likely there is a vacuum leak from the work you did (assuming that you didn't mess with that screw...) I would then check the intake gaskets one more time and the seal around the perimeter of the intake manifold silver top cover....you didn't need to take that off to remove the intake and the seal may have been damaged around the perimeter of the cover or something. If the engine does idle down fine when the ISC plunger is fully retracted and there is clearance between the plunger and the throttle lever at the closed bore throttle setting then the problem is likely with the idle speed control motor...specifically the closed throttle switch in the ISC motor...that "click" you should feel when you depress the plunger.

1993 eldorado green1
04-13-04, 07:02 PM
bbob

thanks for the input, i also wanted to know, if i pull code with the engine running i get a code p083 witch is crank sensor, can that cause the problem? when i snap the throttle even with the isc unplugged, it still takes like 5 to 10 seconds to idle back down to 900rpm, even if its in drive, also it slams itself into drive and shifts second gear hard enough to jerk my head, i know that this isnt right, i got this car from a kid that did nothing to it as far as maintence, im greatful that the head gaskets are still good as it had pure water in the system. and was three quarts low on oil, i love the look of this car and i only paid 400 for this car its a 1993 eldorado etc fully loaded and has 130k for miles, ive already fixed so much stuff on this thing that i dont wanna quit now, another thing is that with the isc unplugged the idle is very sperattic and surges, something that when the isc is plugged in it will make the cars idle go way up to correct this, so it seams smooth but infact its not, also at wot in first gear it surges really bad to the point that i have to let off the throttle, to get it to shift, any ideas? oh and i did reseal the top cover with a thin thin layer of silicone, and it made no difference, the only thing that i didnt try was cutting the green wire on the tps plug, as this wire was broke when i opened the hood and i fixed it and now all the problems:rant2:

BeelzeBob
04-13-04, 10:15 PM
bbob

thanks for the input, i also wanted to know, if i pull code with the engine running i get a code p083 witch is crank sensor, can that cause the problem? when i snap the throttle even with the isc unplugged, it still takes like 5 to 10 seconds to idle back down to 900rpm, even if its in drive, also it slams itself into drive and shifts second gear hard enough to jerk my head, i know that this isnt right, i got this car from a kid that did nothing to it as far as maintence, im greatful that the head gaskets are still good as it had pure water in the system. and was three quarts low on oil, i love the look of this car and i only paid 400 for this car its a 1993 eldorado etc fully loaded and has 130k for miles, ive already fixed so much stuff on this thing that i dont wanna quit now, another thing is that with the isc unplugged the idle is very sperattic and surges, something that when the isc is plugged in it will make the cars idle go way up to correct this, so it seams smooth but infact its not, also at wot in first gear it surges really bad to the point that i have to let off the throttle, to get it to shift, any ideas? oh and i did reseal the top cover with a thin thin layer of silicone, and it made no difference, the only thing that i didnt try was cutting the green wire on the tps plug, as this wire was broke when i opened the hood and i fixed it and now all the problems:rant2:


The code 83 just means that the reference signal from the ignition module (beneath the coil pack) is failed....this could be a crank sensor, the ignition module, the wire between the ignition module and the PCM, etc....not necessarily one of the crank sensors. Yes, this problem could cause the idle problem you are having and the idle instability.

If you retract the idle speed control motor as described above and then disconnect the wire to the ISC motor with it fully retracted to freeze it retracted where does the engine idle at...???

All the wires to the TPS need to be connected....if one was broken or disconnected it will cause a problem...fixing this situation does not involve cutting wires to the TPS... Wasn't it setting a TPS code with the wire broken??

I would really suggest finding or buying a service manual for your car. It details trouble shooting diagrams for each of the trouble codes and each of the components that you are having trouble with. With as many issues as you have to deal with on this rat you could use the help of the service manual.

1993 eldorado green1
04-13-04, 11:05 PM
im not sure about the code, but the check engine light was on, and i didnt cut the wires to fix them actually i replaced the complete end plug and connectors at the tps sensor, i opened up the connectors and stripped the wires accordingly installed them then soldered them as well and then replaced those connectors in the plastic housing, only doing one at a time to ensure that they were back in the correct order, and i didnt know how to check codes until i learned it from this forum when the idle problem started, as far as the isc test ill have to hope for better weather tomorrow, as its very cold and nasty here in my city today, i wonder if some idiot instead of replacing those tps wires just cranked the idle way up on that isc so it wouldn`t stall, sounds possible, especially with some of the things i seen on this car so far, hey do you know if the brake fluid switch has an overide on it? my instrument cluster burned out on me so i went to a junk yard and found one but it was for a 1994 sts and now my abs and traction dont work because of the brake fluid switch code, i checked the float and its up top and the connectors clean, also when i use my 1993 cluster, the traction works and the brake lights go off, any ideas on how to handle this?