Still getting this bugger to idle proper
#1
06-20-2011, 08:11 PM
Still getting this bugger to idle proper
I'm still trying to get this 420SEL to idle right and elimanate hard starting. For months been working on and eliminating possible parts.
A couple of things that can cause high idle is idle control valve, OVP, the Idle control relay, the idle control computer that is in the passenger footwell, vaccuum leaks, cold start valve for hard starting, distibutor cap rotor spark plugs, injection things. Geesh, even I sometimes wonder what the more simpler Cadillac world is like sometimes. Even the e23 was easier to get to idle properly.
So far, I eliminated the injectors as each of them tested spay pattern propery. New spark plugs, wires, and distributor cap and rotor. The old spark plugs was not even near worn but I hate platinum in this car and they had to go and went on and replaced the dist. and rotor while I was at it.
Tested the ICV in another car, it worked perfect. The cold start valve doesnt spray meaning something is telling it not to spray aka the car is in hot start mode which is fine for hot starts as it starts right up. But the forst start of the day is a pain in the ***. Might be totally separate from the high idle. Not the car runs like a scalded dog as it should and smooth as it could be but stop at a red light either the idle is rough when in gear. Then when in park or neutral, the high sky rockets.
No ABS light on or any other lights that point to OVP directly and it's new. Two different idle control relay in the passenger footwell didnt make difference. The Idle conrol unit when unplugged made slight difference, probably getting very low power or is half past dead and migth be the problem. Ready to order but cant or dont know if I found one. It looks like the one that is under the hood. New fuel pump, filter etc. Basically new fuel system. The air intake and idle control hoses are still good condition and spraying around them with various liquids did no change.
So my hypothesis is that the passenger footwell Idle control box, (Not the relay) the actual jetronic box, is about or is dead. I ran without it for a day unplugged no difference. Still started up when hot and hard start when cold and rough idle in gear and high idle at park and neutral.
Anyone have an idea where to pick one up and or what the part number?
I think this might be my last hurrah and I might have to call it a night and move on to something more simple or more common motoring. I dont have the time like I used to to fix cars and still dont have the facility and my German mechanic, probably the only one worth his salt in entire El paso has retired. I'd hate to leave the Mercedes world but lack of resources in El paso is finally wearing me thin.
I think I'ma go ahead try to fix this idle problem, get the AC converted to R134 and turn the w126 into a parking lot/garage queen. (even more than it is now only 3,000 on it in two point 5 years.) On last try, and aint no way I'm the only one that ever had this problem so speak up. Even if it's just a theory. I might have missed something.
A couple of things that can cause high idle is idle control valve, OVP, the Idle control relay, the idle control computer that is in the passenger footwell, vaccuum leaks, cold start valve for hard starting, distibutor cap rotor spark plugs, injection things. Geesh, even I sometimes wonder what the more simpler Cadillac world is like sometimes. Even the e23 was easier to get to idle properly.
So far, I eliminated the injectors as each of them tested spay pattern propery. New spark plugs, wires, and distributor cap and rotor. The old spark plugs was not even near worn but I hate platinum in this car and they had to go and went on and replaced the dist. and rotor while I was at it.
Tested the ICV in another car, it worked perfect. The cold start valve doesnt spray meaning something is telling it not to spray aka the car is in hot start mode which is fine for hot starts as it starts right up. But the forst start of the day is a pain in the ***. Might be totally separate from the high idle. Not the car runs like a scalded dog as it should and smooth as it could be but stop at a red light either the idle is rough when in gear. Then when in park or neutral, the high sky rockets.
No ABS light on or any other lights that point to OVP directly and it's new. Two different idle control relay in the passenger footwell didnt make difference. The Idle conrol unit when unplugged made slight difference, probably getting very low power or is half past dead and migth be the problem. Ready to order but cant or dont know if I found one. It looks like the one that is under the hood. New fuel pump, filter etc. Basically new fuel system. The air intake and idle control hoses are still good condition and spraying around them with various liquids did no change.
So my hypothesis is that the passenger footwell Idle control box, (Not the relay) the actual jetronic box, is about or is dead. I ran without it for a day unplugged no difference. Still started up when hot and hard start when cold and rough idle in gear and high idle at park and neutral.
Anyone have an idea where to pick one up and or what the part number?
I think this might be my last hurrah and I might have to call it a night and move on to something more simple or more common motoring. I dont have the time like I used to to fix cars and still dont have the facility and my German mechanic, probably the only one worth his salt in entire El paso has retired. I'd hate to leave the Mercedes world but lack of resources in El paso is finally wearing me thin.
I think I'ma go ahead try to fix this idle problem, get the AC converted to R134 and turn the w126 into a parking lot/garage queen. (even more than it is now only 3,000 on it in two point 5 years.) On last try, and aint no way I'm the only one that ever had this problem so speak up. Even if it's just a theory. I might have missed something.
#2
05-06-2012, 01:00 AM
Re: idle
I am having the same problem with my 1988 420 SEL but so far can't find a solution so if you do please let me know what it was and I will do the same.
I'm still trying to get this 420SEL to idle right and elimanate hard starting. For months been working on and eliminating possible parts.
A couple of things that can cause high idle is idle control valve, OVP, the Idle control relay, the idle control computer that is in the passenger footwell, vaccuum leaks, cold start valve for hard starting, distibutor cap rotor spark plugs, injection things. Geesh, even I sometimes wonder what the more simpler Cadillac world is like sometimes. Even the e23 was easier to get to idle properly.
So far, I eliminated the injectors as each of them tested spay pattern propery. New spark plugs, wires, and distributor cap and rotor. The old spark plugs was not even near worn but I hate platinum in this car and they had to go and went on and replaced the dist. and rotor while I was at it.
Tested the ICV in another car, it worked perfect. The cold start valve doesnt spray meaning something is telling it not to spray aka the car is in hot start mode which is fine for hot starts as it starts right up. But the forst start of the day is a pain in the ***. Might be totally separate from the high idle. Not the car runs like a scalded dog as it should and smooth as it could be but stop at a red light either the idle is rough when in gear. Then when in park or neutral, the high sky rockets.
No ABS light on or any other lights that point to OVP directly and it's new. Two different idle control relay in the passenger footwell didnt make difference. The Idle conrol unit when unplugged made slight difference, probably getting very low power or is half past dead and migth be the problem. Ready to order but cant or dont know if I found one. It looks like the one that is under the hood. New fuel pump, filter etc. Basically new fuel system. The air intake and idle control hoses are still good condition and spraying around them with various liquids did no change.
So my hypothesis is that the passenger footwell Idle control box, (Not the relay) the actual jetronic box, is about or is dead. I ran without it for a day unplugged no difference. Still started up when hot and hard start when cold and rough idle in gear and high idle at park and neutral.
Anyone have an idea where to pick one up and or what the part number?
I think this might be my last hurrah and I might have to call it a night and move on to something more simple or more common motoring. I dont have the time like I used to to fix cars and still dont have the facility and my German mechanic, probably the only one worth his salt in entire El paso has retired. I'd hate to leave the Mercedes world but lack of resources in El paso is finally wearing me thin.
I think I'ma go ahead try to fix this idle problem, get the AC converted to R134 and turn the w126 into a parking lot/garage queen. (even more than it is now only 3,000 on it in two point 5 years.) On last try, and aint no way I'm the only one that ever had this problem so speak up. Even if it's just a theory. I might have missed something.
A couple of things that can cause high idle is idle control valve, OVP, the Idle control relay, the idle control computer that is in the passenger footwell, vaccuum leaks, cold start valve for hard starting, distibutor cap rotor spark plugs, injection things. Geesh, even I sometimes wonder what the more simpler Cadillac world is like sometimes. Even the e23 was easier to get to idle properly.
So far, I eliminated the injectors as each of them tested spay pattern propery. New spark plugs, wires, and distributor cap and rotor. The old spark plugs was not even near worn but I hate platinum in this car and they had to go and went on and replaced the dist. and rotor while I was at it.
Tested the ICV in another car, it worked perfect. The cold start valve doesnt spray meaning something is telling it not to spray aka the car is in hot start mode which is fine for hot starts as it starts right up. But the forst start of the day is a pain in the ***. Might be totally separate from the high idle. Not the car runs like a scalded dog as it should and smooth as it could be but stop at a red light either the idle is rough when in gear. Then when in park or neutral, the high sky rockets.
No ABS light on or any other lights that point to OVP directly and it's new. Two different idle control relay in the passenger footwell didnt make difference. The Idle conrol unit when unplugged made slight difference, probably getting very low power or is half past dead and migth be the problem. Ready to order but cant or dont know if I found one. It looks like the one that is under the hood. New fuel pump, filter etc. Basically new fuel system. The air intake and idle control hoses are still good condition and spraying around them with various liquids did no change.
So my hypothesis is that the passenger footwell Idle control box, (Not the relay) the actual jetronic box, is about or is dead. I ran without it for a day unplugged no difference. Still started up when hot and hard start when cold and rough idle in gear and high idle at park and neutral.
Anyone have an idea where to pick one up and or what the part number?
I think this might be my last hurrah and I might have to call it a night and move on to something more simple or more common motoring. I dont have the time like I used to to fix cars and still dont have the facility and my German mechanic, probably the only one worth his salt in entire El paso has retired. I'd hate to leave the Mercedes world but lack of resources in El paso is finally wearing me thin.
I think I'ma go ahead try to fix this idle problem, get the AC converted to R134 and turn the w126 into a parking lot/garage queen. (even more than it is now only 3,000 on it in two point 5 years.) On last try, and aint no way I'm the only one that ever had this problem so speak up. Even if it's just a theory. I might have missed something.
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