idle runs low sometimes, stalls engine sometimes
04-15-2005, 03:17 AM
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idle runs low sometimes, stalls engine sometimes
My 97 Prelude been having issues with the idle dropping down and the engine gets rough from it going down so low. Sometimes it drops enough to cause it to stall out which can be dangous if your coasting off the freeway (no power steering and music going and u dont notice right away lol). Also note the problem only happens once the engine is warmed up.
The honda dealer i taken it to cleaned the idle valve, checked just about everything including the battery and alt (all checked out fine). This last time they ended up calling some tech line and told them to run the car with the computer scan tool ( shouldnt they have done this the first time??) they used plugged in and ended up doing a compression test saying cyl #4 is down @ 100psi (others r 125-130psi), suspect a slight bent on exhaust valve and want to do a leak down test to conform. My question is can a 25-30psi drop in a cyl. cause a idle to drop but only once in awhile? They also went on to note that the fuel trim (not sure what that is) was quite rich at .86 (1.00 is normal) but went back to normal on same test drive. Would that be anything? Only reason i ask on this forum is after being to the dealer 3 times it seems they are not sure what the problem is, which i can understand its not a problem that can easly be reproduced to check out. I done some research and the two top suggestions i seem to see for this kind of idle problems are to clean the idle air control vavle or replace the throttle position senser. If anyone has any other suggest or experiance with this same problem please let me know.
The honda dealer i taken it to cleaned the idle valve, checked just about everything including the battery and alt (all checked out fine). This last time they ended up calling some tech line and told them to run the car with the computer scan tool ( shouldnt they have done this the first time??) they used plugged in and ended up doing a compression test saying cyl #4 is down @ 100psi (others r 125-130psi), suspect a slight bent on exhaust valve and want to do a leak down test to conform. My question is can a 25-30psi drop in a cyl. cause a idle to drop but only once in awhile? They also went on to note that the fuel trim (not sure what that is) was quite rich at .86 (1.00 is normal) but went back to normal on same test drive. Would that be anything? Only reason i ask on this forum is after being to the dealer 3 times it seems they are not sure what the problem is, which i can understand its not a problem that can easly be reproduced to check out. I done some research and the two top suggestions i seem to see for this kind of idle problems are to clean the idle air control vavle or replace the throttle position senser. If anyone has any other suggest or experiance with this same problem please let me know.
04-17-2005, 04:21 AM
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Intermittent problems are the hardest to figure out. It's alsmot easier for the thing to totally fail so you know you have the right component.
Anyway..
1) your compression seems off. 97 Prelude you say? Nominal should be 185psi, minimum at 135, and max variation at 28. So all your cyl are below minimum! And you exceed max variation 130-100=30psi. Maybe they should double check their gauge and double check your units. If indeed these # are correct sell your car! or get a new engine. Do you notice loss of power? Has the timing belt snapped on this car?
2) Have you done the ignition recall? I guess this recall adresses random stalls such as this.
3) Not quite savvy about fuel trim #'s but excessive rich can flood engine, a little rich would cause white smoke out the tail pipe.
IACV... might make your idle go irratic/low but i wouln't think a *random* stall. I'd look at items 2 and 1 first.
Anyway..
1) your compression seems off. 97 Prelude you say? Nominal should be 185psi, minimum at 135, and max variation at 28. So all your cyl are below minimum! And you exceed max variation 130-100=30psi. Maybe they should double check their gauge and double check your units. If indeed these # are correct sell your car! or get a new engine. Do you notice loss of power? Has the timing belt snapped on this car?
2) Have you done the ignition recall? I guess this recall adresses random stalls such as this.
3) Not quite savvy about fuel trim #'s but excessive rich can flood engine, a little rich would cause white smoke out the tail pipe.
IACV... might make your idle go irratic/low but i wouln't think a *random* stall. I'd look at items 2 and 1 first.