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4.9L idle problems by collinwestphal
Started on: 12-07-2003 09:31 PM
Replies: 3
Last post by: Alex4mula on 12-08-2003 01:37 PM
collinwestphal
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Report this Post12-07-2003 09:31 PM Click Here to See the Profile for collinwestphalSend a Private Message to collinwestphalDirect Link to This Post
On my idle speed control motor, the adjuster screw seems loose. As I drive, it slowly turns in and eventually I can't start the car unless I hit the pedal. The motor seems to work fine, do I really need to spend $80 for a new motor? Recommendations? Are used ones normally reliable?

Also, This is my first manual car, and I just swapped in a 4 spd into my 88' 4.9L.
While driving I can get into R,1,3,4. The transmission is used. When I try to get into 2nd, it grinds. Could this be caused by the selector cables? Is there a way to test if 2nd gear is bad? When the car is off, it seems to shift into 2nd just fine.

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PBJ
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Report this Post12-07-2003 10:45 PM Click Here to See the Profile for PBJClick Here to Email PBJSend a Private Message to PBJDirect Link to This Post
I am not sure how the caddy idle motor functions to tell you if it is normal because we run an IAC with a different ecm. I know this is what Rockcrawl recommends you try to set the IDLE.

This is a quote from Rockcrawl for when others are doing a search. They will find his answer.

"Make sure the throttle plates and bores are clean before you start. Also make sure you don't have any vacuum leaks. Jumper ALDL A and B to enter the set timing mode. Verify timing at 10* BTDC and remove jumper. Disable the alternator by grounding the small brown wire, there should be a green connector inline if it's anything like a Cadillac harness. Disconnect the ISC motor where the main harness attaches to the sub harness. Attach two jumper wires to the blue wires of the sub harness. Connect one jumper to ground and the other to bat positive momentarily until the ISC is fully retracted. If it extends, reverse the polarity to make it retract. When it is fully retracted, the throttle lever should be resting on the minimum idle screw. If the throttle lever is touching the ISC plunger at full retraction, use a pliers to turn the plunger in until it's not touching. Use the minimum idle screw (recessed torx) to set the idle to 525 rpm. With the throttle lever resting on the minimum idle screw, set the TPS to .50 volts. Now you can extend the ISC by reversing the polarity of the jumpers. At full ISC extension, the TPS should read between 1.15 and 1.20 volts. Adjust the ISC plunger in or out with a pliers to obtain the correct TPS voltage. Retract the ISC. Reconnect the ISC to the main harness. Turn the key off and wait 20 seconds to allow the ECM to perform a TPS learn. Cycle the ignition on and off once more. It takes two cycles for a sucessful TPS learn. Perform and idle learn. Run engine until coolant temp is greater than 176*. Allow engine to idle in park for ten minutes. With brake applied, allow engine to idle in drive for at least three minutes. The ECM will command a 600 rpm idle. If it's not idling at 600 +/- 50 rpm after doing this procedure there is something wrong."

As for the transmission. It could be a worn sycro within the transmission, I have heard from others if you change the transmission fluid in the standard transmissions to the more expensive GM sycormesh fluid it really helps the shifts.

Pete

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collinwestphal
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Report this Post12-08-2003 12:02 AM Click Here to See the Profile for collinwestphalSend a Private Message to collinwestphalDirect Link to This Post
thank you PBJ, I assume I will need a scanner to get the timing/RPM/TPS data.
Do you have any recommendations. I also would live to be able to scan other vehicles.
GM, Ford, Chrysler. Any other scanner info would be awesome. this is all new to me.
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Alex4mula
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Report this Post12-08-2003 01:37 PM Click Here to See the Profile for Alex4mulaClick Here to Email Alex4mulaSend a Private Message to Alex4mulaDirect Link to This Post
Can the AutoXray used for Fieros be used to scan the Caddy 4.9 swap?? TIA

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