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Master Auto Tech.
Master Auto Tech., master tech.
Category: Transmissions
Satisfied Customers: 600
Experience:  A.S.E. Master technician. Over 20 years working on import & domestic. Owner/operator of an auto shop
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I have a 97 Accord and it has a hesitation problem. Runs

Customer Question

I have a 97 Accord and it has a hesitation problem. Runs fine when you start it up but starts to stumble once warmed up. I recently replaced the Autolite plugs with NGK and the problem went away for about 30 days. So far I have checked all the ignition components, fuel pressure,
JA: How many miles are on the vehicle? And when was it last serviced?
Customer: In January I had the head rebuilt, replaced the timing belt, plugs, cap and rotor. Have had regular oil changes since then. Late last year I replaced the O2 sensor and cleaned out the EGR stuff. About 170K on the miles.
JA: What year is your Accord?
Customer: 1997
JA: Are you hoping to fix this yourself? What have you tried so far?
Customer: Yes, so far I have checked the ignition components and they are all in spec, checked the compression and fuel pressure and they are in spec, checked for vacuum leaks and there are none.
JA: Anything else you think the mechanic should know?
Customer: As stated earlier I replaced the plugs and the problem went away for about 30 days.
Submitted: 1 year ago.
Category: Transmissions
Expert:  Master Auto Tech. replied 1 year ago.
I'm sorry you are having problems with your vehicle. I will try to help.I'm a full time mechanic and have been a mechanic for over 20 yrs and I work part-time here on JustAnswer to help you and others repair their own vehicles, and I get credited by your ratings.. So before leaving the site make sure and leave me a rating. You can still reply to me as many times as neeed, even after the rating.. I will need for you to be my hands and eyes since I'm not there.So from the sounds of it once it goes into closed loop the engine starts to stumble.Try unplugging the o2 sensor when it's stumbling. If it's better then the o2 is bad. I know you said it is fairly new but I've seen it happen beforeThe other possibility is the coil starts to short out once it's warm. If you remove the coil from the distributer and look for any arcing where it's coming through a crack that opens up as it warms up.Let me know what you findThanks
Customer: replied 1 year ago.
Thanks for the quick reply!I unplugged the O2 sensor while the car was warmed up and stumbling but there was no change. My coil is external and I visually inspected it but did not see any cracks nor was there any arcing. I retested the coil and found .8 ohms between terminals A and C and 19K ohms between the primary (terminal A) and secondary post (where the wire between the coil and the distributor comes out). Any suggestions?
Expert:  Master Auto Tech. replied 1 year ago.
Let me look a few things up later at work. I'll get back to you on that
Expert:  Master Auto Tech. replied 1 year ago.
I need a bit more information, do you have a scanner with data? I need to know is the problem coming as it hits closed loop or just after it's been running a bit? Watch the data stream on the scanner and see if it starts to act up when it switches to closed loop.Also see what the base reading is on the tps (throttle position sensor), and the CTS (coolant temp sensor) and finally watch the o2 sensor and see what it is reading.Let me know what you find.Thanks
Customer: replied 1 year ago.
Unfortunately I do not have a scanner. My Haynes tells me how to check the TPS, CTS, and O2 but not the closed loop. Should I test them?
Expert:  Master Auto Tech. replied 1 year ago.
please do. The closed loop isn't a huge deal. Just would help to figure it out if that's when it starts acting up.
Customer: replied 12 months ago.
the O2 was around .8V with the engine warm, the TPS had 0V from Y/B wire and G/B wire until key turned on then 5V. R/Bk wire and G/B wire read .5V with throttle closed and 4.3V when fully open. The MAP sensor read 5V all of the time when engine running or key on but not running and nothing when key off. ECT has 5V to it but no ohms on the sensor. The Guage works inside the car.
Expert:  Master Auto Tech. replied 12 months ago.
the ect was infinite on ohms? Or 0 ohms? Was that warm or cold? If I remember right, your car uses 2 sensors, 1 for the ecm and one for the gauge. If the one for the ecm isn't working correct it will cause problems. But I'll check on that tomorrow. Also the map sensor should have 3 wires a ground a 5 v + and then the signal or reference wire back to the computer. The reference wire should vary a little in volts between engine off key on and key on engine running. And vary between rpms as well. It tells the computer what load the engine has. If it's not varying the signal back then it's bad and will cause the stumble as well.Let me know what you find.Thanks
Customer: replied 12 months ago.
Right on both accounts. The ECT was further under the distributor and while hot it read about 750 ohms and the MAP single wire was within spec.
Expert:  Master Auto Tech. replied 12 months ago.
right it has 2 CTS? One for the computer and one for the dash? And map didn't just read 5v all the time? It varied?
Expert:  Master Auto Tech. replied 12 months ago.
to figure out what CTS is for the gauge, when warm remove the connector and it should drop to 0 on the gauge. Then the other is for the computer.
Customer: replied 12 months ago.
Correct, I checked the right ETC this time and it was within specification.
Expert:  Master Auto Tech. replied 12 months ago.
Do you know how to test the power output of the coil? Basically see how long of a gap it will jump. Can you check that for me?
Customer: replied 11 months ago.
Hey Sonny, I am finally back in town and tried your last suggestion. I pulled the coil wire and the car remained running until the wire was about 2-3 inches away from the coil before it dies. it seems pretty strong to me but you are the expert, what do you think?Thanks,
Expert:  Master Auto Tech. replied 11 months ago.
the coil sounds like it's fine. Let me ask, is there any oil inside the distributer?
Expert:  Master Auto Tech. replied 11 months ago.
here are two things that can be effected by heat as well, 1) crank sensor
2) ignition control module. Which actually go bad on older Hondas a lot.
Take a close look at them and let me know.
Expert:  Master Auto Tech. replied 11 months ago.
I was just rereading the posts as well, would you mind testing the fuel pressure when it's warm?