Problem with heater/vaccuum??

Thread view:

Enable EMail Alerts

Start New Thread

Thread rating:

Justa Me - 30 Oct 2006 17:42 GMT

Hi All,

I have a 97 XLT with 4.0 SOHC. I have a problem when I move the heater into
the defrost (upper vent) position. At idle, when in this position I hear a
loud click and the engine bogs down to about 400 rpm then recovers. Three
seconds later the cycle repeats. When the heat selecter is in the
floor/defrost position the problem still exists, but it doesn't seem to bog
down so badly.

Any suggestions on what might be causing this? FWIW, I do have the infamous
blend door problem.

Thanks for any input you can offer.

Reply to this Message

Alan Moorman@visi.com - 30 Oct 2006 18:37 GMT

>Hi All,
>
[quoted text clipped - 9 lines]
>
>Thanks for any input you can offer.

The AC is enabled in any positions that include the defrost vents,
and I would guess that's what you're hearing -- the compressor
kicking in and out.

Why the engine is bogging down so much? Don't know.

Perhaps the infamous MAF (Mass Air Flow) sensor in the air intake is
acting up and screwing up the engine management system. That
happens.

Alan Moorman

Reply to this Message

Justa Me - 30 Oct 2006 20:38 GMT

Hi Alan,

Thanks for the reply. Should the compressor be kicking in and out so much
(every three seconds)? It seems somewhat excessive.

>>Hi All,
>>
[quoted text clipped - 25 lines]
>
> Alan Moorman

Reply to this Message

Alan Moorman@visi.com - 31 Oct 2006 03:53 GMT

That's been talked about here, before, but I don't remember the
outcome.

Perhaps Jim Warman could weigh in on this??

Alan Moorman

>Hi Alan,
>
[quoted text clipped - 30 lines]
>>
>> Alan Moorman

Reply to this Message

Ollie - 31 Oct 2006 05:34 GMT

Cycling frequently is usually because low on Freon

As for engine bogging down, slow responding and/or dirty IAC valve ???

> Hi Alan,
>
[quoted text clipped - 31 lines]
>>
>> Alan Moorman

Reply to this Message

Rate this thread: