The message to which you are about to reply is shown first. GO TO REPLY FORM



 VIEW    REPLY TO THIS MESSAGE    PRINT   SAVE 

Bad running at idle and cruise 700 1991

My 1991 745 Turbo has a problem that seems to be progressing, but goes away for a while at times.

At idle she will hunt, up and down, and slightly surge. Occassionally it will stall, because the idle drops low enough. But not all of the time, and sometimes it is more pronounced (severe) than others, sometimes not at all.

Sometimes she accelerates slightly weak, maybe with some surging and stumbling.

At cruise, she will sometimes seem to lack power, usually it is just barely noticable. Sometimes, she might suddenly "come to life" and regain her power. Sometimes she actually will hesitate at cruise, like I lifted off the throttle a little bit for a moment. The tach only starts to droop slowly and normally when she does this, no sudden drop like the ignition has cut out.

I know that one of the first solutions to the idle problem and the acceleration problem is to clean the throttle body and check the TPS, but I doubt that those are connected to the third, cruise, problem. I have just changed the fuel pump relay and the radio supression relay. No cure.

I am going to clean the throttle body tomorrow and check/set the closed throttle position and the TPS. Will also replace all hoses (some are original 1991 vintage, according to the printing on them!), and check for vacuum leaks, but somehow I don't think this is the cure for the cruise problem. The fuel pressure regulator does not have a ruptured diaphram. Idle does not really change that much when the hose is pulled off of the FPR.

Anyone have any ideas? While it seems to come and go, it is getting worse, and I can't afford to get stranded (the other two cars in my sig. are inoperative at the moment).
--
Scott Cook - 1991 745T, 1985 RX-7 GSL-SE, 1986 Toyota Tercel (Don't laugh, it is reliable, faithful AND gets 41 mpg!)






USERNAME
Use "claim to be" below if you don't want to log in.
PASSWORD
I don't have an account. Sign me up.
CLAIM TO BE
Use only if you don't want to login (post anonymously).
ENTER CAPTCHA CODE
This is required for posting anonymously.
OPTIONS notify by email
Available only to user accounts.
SUBJECT
MODEL/YEAR
MESSAGE

DICTIONARY
LABEL(S) +
IMAGE URL *
[IMAGE LIBRARY (UPLOAD/SELECT)]

* = Field is optional.

+ = Enter space delimited labels for this post. An example entry: 240 muffler


©Jarrod Stenberg 1997-2022. All material except where indicated.


All participants agree to these terms.

Brickboard.com is not affiliated with nor sponsored by AB Volvo, Volvo Car Corporation, Volvo Cars of North America, Inc. or Ford Motor Company. Brickboard.com is a Volvo owner/enthusiast site, similar to a club, and does not intend to pose as an official Volvo site. The official Volvo site can be found here.