RonnieH
Well-known member
A couple of months ago, the car started idling rough ('90 Coupe, 32,000 miles). At start-up, idles fine. Soon as it starts to get up to operating temp, rough idling - the car "lopes" with foot on the brake in "D". Getting up to speed an on the highway, it runs great. I took it to a local shop last week and they spent all day trouble shooting. Did a compression check on a couple of cylinders (the EZ ones to get to). One of the cylinders had 110 psi compression when motor was cool, and then dropped to 90 # as it got warm. Let it cool down and right back up to 110-120#. The guy in the shop thinks there is internal damage to the engine and had me convinced. Last fall, I had a water pump problem and did get warm, but not up into the Hot range, so I thought maybe it had done some damage. I beat myself up for a week thinking I had overheated the engine and ruined a motor w/only 30,000 miles. The car has never been "dogged" and always well maintained. Anyway, after having it checked, my only two options were to live with the problem awhile or put in a crate engine.
After getting over the shock and thinking about it, I tried to come up with other possible causes of the problem. I remember from awhile back that a faulty EGR valve can cause rough idling/loping as the car gets up to operating temperature as it can cause the compression to get out of whack.
Just wondering if someone out there may have had similiar problem with an EGR valve previously or if someone has experienced the same problem as me and cured it by fixing the EGR problem. I may be grasping at straws, but need to eliminate all possible causes before going the crate engine route. Other than the idling, car runs great - averages almost 29 mpg if on the interstate and running the speed limit. No matter what, I can live with the problem for awhile.
I was really wondering if there is a quick way to check by blocking off the EGR or bypassing it. I know it can be checked with a vacuum pump and checking the circuitry, but would like to go a quick check before troubleshooting it further.
Thanks for any help/ideas.
After getting over the shock and thinking about it, I tried to come up with other possible causes of the problem. I remember from awhile back that a faulty EGR valve can cause rough idling/loping as the car gets up to operating temperature as it can cause the compression to get out of whack.
Just wondering if someone out there may have had similiar problem with an EGR valve previously or if someone has experienced the same problem as me and cured it by fixing the EGR problem. I may be grasping at straws, but need to eliminate all possible causes before going the crate engine route. Other than the idling, car runs great - averages almost 29 mpg if on the interstate and running the speed limit. No matter what, I can live with the problem for awhile.
I was really wondering if there is a quick way to check by blocking off the EGR or bypassing it. I know it can be checked with a vacuum pump and checking the circuitry, but would like to go a quick check before troubleshooting it further.
Thanks for any help/ideas.