Am 2000 miles in to the Rinse phase. I drove the car to Michigan and back. However the check engine light comes on at various times, mostly at highway speeds of 60-65 MPH. The check engine goes away when the car is restarted. But getting it restarted is a big issue. The car will start up when cold - absolutely no problem. Once, the car is warmed up - it will turn over but will not start. If I let it sit for about 10 minutes or so, the car will start up and go just fine. Any thought's as to why this might be happening, and what I might have to change?
The car is a 1994 Mazda with 141K on the clock. Engine was recently put in and has 80K odd miles on it
Cheers
-- Edited by sunny441 on Tuesday 6th of April 2010 10:06:59 PM
Tough call with an OBDI system. Obviously the condition is not continuous and could be anything. I'd say anything but oil related. The OBDI systems typically didn't monitor oil pressure or stuff like that. Coolant temp (not gauge indication), the (usually single) O2 reading, timing, intake air temp, MAP.
Your system should store the code. It is harder to find OBDI scanners these days. OBDII made this so much simpler.
Have you checked all the usual suspects? Coolant level and whatnot? This could be an EGR issue, but again, with OBDI it's going to be harder to lock down since you kinda have diagnose it the older fashion way.
-- Edited by geeaea on Tuesday 6th of April 2010 11:42:35 PM
Check the hose from the air meter to the throttle body. It is common on those years to have a break in that hose, causing unmetered (and unfiltered) air to get in the engine, making it run lean and hard to start hot at times. Also there is a plastic "appendage" box on many of those along with the hose (located underneath the hose). Those boxes come apart at the seam and may need re-glued to seal off any unmetered air getting in.
Once you are sure you are only getting METERED air in the engine, you can begin to diagnose for other issues that may be causing your hot start problem. Does it idle smoothly when hot or is it chugging and trying to stall due to a lean-burn misfire?
-- Edited by bmwtechguy on Friday 9th of April 2010 03:31:04 PM
Thanks. It idles smoothly when warm. Just getting it started is the big problem. Takes a few tries to get it going. Also the car tries to stall when coming to a stop sometimes. This does not happen very often. Throttle body hoses were tightened and fixed not too long ago.
Sounds like a coolant temp sensor. Can't perceive cold starts if it's reading high by default. I don't know your engine management system, but that would be my SWAG due to the symptoms.
