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Discussion Starter · #1 ·
Hey guys what exactly happens when you pull the coolant temp sens wire. I mean I know it puts the computer into limp mode. But what takes place when the computer does this. The reason I ask this is that I had posted about an idle problem and was told to reset base Idle setting and so forth, and I noticed when I pulled the coolant temp sens wire that all the missing and loping went away, and the car idles perfectly. Should this give me any clues as to whats causing this thing to miss and lope on idle. Thanx in advance !!!
 

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The ignition timing gets set to base without the computer moving it. Check out minimopar for more info.
 

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Discussion Starter · #3 ·
Ok, I took the cap, rotor and hep off and checked shutter wheel and everything is a ok there. I had checked the timming before and it looked ok but Im going to check it again tommorrow morning. One other thing that makes me believe its a timming issue is that when I power brake the car it builds up boost and pulls to about 2800 rpm and then just stays there. With either one of my other td's its almost impossible to keep the car/van from moving even with the brake pedal mashed. When the car is started is the computer in closed loop for a few seconds or not. Because thats how long the thing idles perfect and then starts loping. Thanx for all the help, I really do appreciate it !!!!
 

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When the car is cold or on restart the vehicle is in open loop, it takes time and temp to go into closed loop operation and there are different open loop parameters in the controller.
When the vehicle is in failure the controller again is running on a fixed parameter program (idle speed, timing, fuel control) and ignoring the system that is creating the fault, using info from other sensors to compensate for the faulty system.
If you want to isolate your problem you need to get AIS out of the system, the controller is constantly trying to make idle adjustments, remove the brake booster hose for 1 minute and then with the hose still disconnected remove the AIS connector and then reconnect the hose,the vehicle will be at base idle without AIS control, now you can try to isolate a vacuum leak or weak cylinder( engine, ignition, fuel ) with out the controller trying to compensate.
Do not plug the AIS back in until you turn the key off.
 

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Discussion Starter · #5 ·
OK, thanxs NAJ I'll give that a try tommorrow. I didnt get a chance to check timming alignment today as its been raining here and my garage is full with other projects. Im going to go ahead and clean the tb while Im at it. When a person takes the throtle body off the intake to be cleaned, is there a gasket that needs to be replaced or is there some trick that you guys use.
 

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There is a gasket between the T/B and mainifold, your old one may be fine but you will be better off having a new one on hand before removal just in case.
 

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Discussion Starter · #7 ·
Found out what the problem is. Broken head/gasket. The lady I bought the car from had the head and gasket replaced about two years ago. The car has under 100,000 on it. Theres no coolant in the oil or vice versa, but today I noticed the recovery tank gurgling and I pulled the cap and shure as shit it smelled like exhaust and was bubbling like a pist-off steam engine.
 

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Discussion Starter · #8 ·
It just goes to show you that even though a shop has done the head and or head gasket on a td doesnt mean that its gonna last very long. Now its time to take it apart and do it right!!!!!!!
 

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Head gaskets usually fail for a reason. Thats my experience. Either something is wrong with the parts being used or it was just improperly installed.

When a head gasket fails, some people lift the head an inch or so, remove the old gasket, slide a new one in, and bolt it back down. There could be an awful lot wrong down there that a new gasket will fix for a little while.

Like a pissed off steam engine--I like that!
 

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Discussion Starter · #11 ·
Head gaskets usually fail for a reason. Thats my experience. Either something is wrong with the parts being used or it was just improperly installed.

When a head gasket fails, some people lift the head an inch or so, remove the old gasket, slide a new one in, and bolt it back down. There could be an awful lot wrong down there that a new gasket will fix for a little while.

Like a pissed off steam engine--I like that!
Exactly. My guess is that the mechanic did just as you said, even though the lady I bough the car from was charged for head + gasket just a while back, it doesnt look that new to me. Yes, I will do it right by taking the head completely off and inspecting/cleaning etc. Im not trying to be mean to the mechanic. Im sure if you took the time to do it right and got payed by the Mitchell, you would probably lose your ass. The lady I bought the car from was so fustrated with the car because she had put so much money into it. She pretty much gave me the car for free. I fee pretty lucky because the car is immaculate with less than 100,000 miles and has had smec, injectors, w/pump, radiator, belts, hoses, wires, cap, and plugs all replaced. Oh yeah it also had a set of new siped Toyos put on it about 1500 miles ago.
 

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Do not forget to replace thr head bolts.
 
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