Can you control your idle with your heater switch?? I can... Help??

[strutterfly]

just recently bought a 87 daytona shelby z for 125$ from an auction in my area. it was a steal engine runs great, turbo still gives solid 13-14 psi boost, body is solid....neways got rid of a few engine codes (23, 24 and 35) checked the plugs and found my tps and ias sensors were infact no good so i replaced them and rewired the fan so i have a manual switch(as to what ive read on these forums) all was well until i turned my heater on the other mornign and noticed my idle jumps from 8-900 to 1500-1700 and goes back down when i turn the switch off... does anyone have any suggestions as to where I should look first lol....

[turbovanman²]

Make sure all the engine grounds are intact. Theres one at the right side motor mount, back of the cylinder head to firewall, one on top of the trans just rear of the timing window and of course, the thick neg cable. If all good, then check the charging system.

[strutterfly]

I checked all the grounds the one from head to firewall was corroded and broken so I replaced it. The otheres looked intact so I removed the bolts cleaned the connectors and refastened them I still have the same problem. I tested the alternator its putting out 14.5v i can turn on pretty much all the interior options and it doesnt seem to cause a drain untill I turn the fan on then the lights dim a little and my idle jumps could it be that my fan is no good and is drawning too much power?

[turbovanman²]

You can't test an alt using volts, you need to test it for amperage. An alt can put out 14 volts but only 10 amps. If you don't have an amp tester, take it to a shop and they can test it in 5mins.

[strutterfly]

had to run to my work quick and grab my amp meter from my tool box... alternator is putting out apprx 87 amps

[turbovanman²]

had to run to my work quick and grab my amp meter from my tool box... alternator is putting out apprx 87 amps

Hmmmmmm, then thats not your issue. Maybe watch the volts and amps while you turn it on? it could be just a computer glitch due to the added load.

[Turbo_Rampage]

Does the car have factory A/C? If so i'm pretty sure when you turn the heater on (defrost for example) it will kick on the air conditioning, because it's supposed to get rid of the condinsation faster... and the A/C turning on could be causing the high idle from the extra load? I have never owned a TD with factory A/C so i don't know if it does this for sure, but i know Neons and Intrepids do this, and probebly every other Dodge with A/C.

I think their is a writeup on the allpar website on how to disable the A/C kicking on with the heater.

Hope this helps

[turbovanman²]

Does the car have factory A/C? If so i'm pretty sure when you turn the heater on (defrost for example) it will kick on the air conditioning, because it's supposed to get rid of the condinsation faster... and the A/C turning on could be causing the high idle from the extra load? I have never owned a TD with factory A/C so i don't know if it does this for sure, but i know Neons and Intrepids do this, and probebly every other Dodge with A/C.

I think their is a writeup on the allpar website on how to disable the A/C kicking on with the heater.

Hope this helps

Hmmmmm, that could be it but my idle only goes up a few 100 rpm, not 1500-1700 rpm. Also, if I disable my a/c, the idle won't kick up.

[strutterfly]

yea the car does have factory A/C and the pump is shot so i have the belt off

[LynX853]

umm simon, i know you have a shop and everything, but it IS possible for an alternator to produce the right amprage under idle then when a load is put on it cant keep up and is no longer under specs...

test your alternator at a parts store with a tester and make sure all the diodes inside it are good..
if you cant do that turn on your headlights, heater on high interrior lights, defrost, EVERYTHING and see how many amps your alternator is pumping out. if your car stalls its most likly your issue

we had a bug for our lab final at school where the batterylight was on and the charging system was opperating normaly at idle, but as soon as a load was put on the circuit things went down hill.

i hooked up the charging system tester, hit the "cheak diodes" button, and BAM that was it!

..and dont take any offence simon, you know i love you

[rbryant]

Check to make sure that you don't have a vac leak in the heater control tubes...

The easiest way to do that is to unplug the line from the brake booster and plug it. Then move the heater control and see if it still changes things.

That isolates the vac problem from the electrical...

-Rich

[turbovanman²]

umm simon, i know you have a shop and everything, but it IS possible for an alternator to produce the right amprage under idle then when a load is put on it cant keep up and is no longer under specs...

test your alternator at a parts store with a tester and make sure all the diodes inside it are good..
if you cant do that turn on your headlights, heater on high interrior lights, defrost, EVERYTHING and see how many amps your alternator is pumping out. if your car stalls its most likly your issue

we had a bug for our lab final at school where the batterylight was on and the charging system was opperating normaly at idle, but as soon as a load was put on the circuit things went down hill.

i hooked up the charging system tester, hit the "cheak diodes" button, and BAM that was it!

..and dont take any offence simon, you know i love you

No offence and good suggestion on the diodes. I have a tester here that makes it work hard so I know if there good or bad. BUT if you full field an alt, and you get say 80 amps, then it will produce 80 amps under load as long as the diodes are good.