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1999 TL. Cold start OK! After warmup and restart attempt, car has VERY rough idle, and generally stalls when put into gear. Restart requires two or three attempts. Cruise feels normal, but frequently idle still feels a bit rough although tach shows 700. Note: whenever car stalls during these attempts, it wipes out memorized stations from the radio.
After my wife returned home most recently complaining it was running rough all the time, I turned on ignition preparatory to hooking up my scanner. Noticed the radio (this is an aftermarket Axera unit) volume was very low and scratchy -- it had never performed that way before. Fooling around, I hit the "mute" button, and radio went to full normal volume. Apparently the low scratchy mode I heard was the "muted" mode. Inserted connector for scanner and got error message: Scanner encountered an error and could not connect.
Turned off ignition but radio did not turn off!
Started car, drove around the block several times, everything normal. Shut down in garage normal. Don't want to focus too much on radio anomalies --- only mention them as symptoms of the potential electrical source of the idling and restart problems.
Car had new ignition switch installed 2 years ago. Could this be it? Why would it only affect starting after warmup?
Curmudgeon10,
It sounds like something is shorting out when it gets warm. As the temperature seems to be involved and it seems temperature related I would check the main relay (you can find many posts on it here). It is number 10 on the diagram below. The relay has a habit of the solder joints breaking. You can open it and reflow the solder and this works most of the time. If the unit is shorting out or losing power when a solder joint separates you will have strange power issues. Number 10 is the main power relay
The part number is Relay Assembly, Main (Mitsuba)39400-S84-003
I would start there. It is located under the dash on the drivers side. Look for the other threads on this, it will help. If i remember correctly it is about 1 1/2" x 3" and grey in color. It is on a bracket with a 10mm screw holding the bracket.
Gosh, thanks a bunch for that lead. I live in a smallish city with no dealer, and finding someone who can track down problem like this is difficult to say the least. Once I locate the relay, is it possible to note from a visual examination whether that is the problem?
Yes and no. From the outside you can't tell; it will be a black or grey little box. However once you have it out you can get it open (plastic) and look at the relays and circuit board. I don't know your electronic experience but where the relay connects into the circuit board you might see some cracking or separation of the solder joints on those connections. Use a soldering iron and some solder paste to reflow the solder joints. There should be some old threads here that have some closeup pictures and show someone who found and fixed this issue in the past. You can also check online for pictures of broken, cracked, and bad solder joints. Once you reflow (use lots of solder flux or paste), clean the board with isopropanol and q-tip. You do not want to leave flux on the board.
Good Luck. Let us know what happens. The picture below is of the relay. I know there was some inside pictures on some older threads here. You can see the tabs on the outside that slide into a bracket. On the short side, near the connectors, you can see there are recessed tabs that hold the plastic body together, You can press these in with a screwdriver and pull the relay housing apart to look at the circuit board and relays. View from the bottom.
I had this relay changed by my mechanic several weeks ago after I acquired an OEM replacement. I've waited until now to report results as we've not had the higher temperature and humidity until recently that really brought out the worst in the old relay. The car was out the other day in low 80's, made a number of stops, idled for an extended period of time, and had no problems.
It worked!
I took the old relay apart and examined it, but couldn't see any obvious issues with solder or other conditions on the board.
You replaced the Fuel Pump Relay? and still having difficulty starting when warm? have you checked the fuel pressure? how about the fuel filter? has it ever been changed?
I replaced this part: Relay Assembly, Main (Mitsuba) - Honda (39400-S84-003)
At the Acura dealership today, I mentioned the threads on this forum dealing with the fuel pump relay. He told me that it was the same as the Main Relay I had already replaced. True?
You replaced the correct part, it is main relay which powers multiple items including the fuel pump after it goes through two 15A fuses; one in the engine compartment and one under the dash. Since the pump is working I would assume the fuses are not blown. After that it is fuel pump connection in the trunk. This goes into the fuel pump that is in the fuel filter in the tank.
In re-reading your initial post you mentioned an aftermarket radio. Was it a recent install? There have been times where a radio installation was done poorly and the grounds mixed up and tied into the electrical system and not to chassis ground. Have you tried removing all power and connections to the radio and then seeing if the problem remains?
The radio install is now about two years old, and this issue about six months old. I haven't (yet) tried to isolate the radio. If there is a way to do it without deconstructing the dash and console (which is what was required to install it), I can give it a try if the dealership comes up empty. I'm giving the radio a low probability due to the time and care spent in installing it. I got to know all the Crutchfield people by the sound of their voices by the time I was done.
If the radio install was that long ago, without problems before, I wouldn't worry about it now. If it was easy to get to I would check the grounds but most likely something installed that long ago without a problem was installed correctly. The issues you mentioned are probably a symptom not a cause.
Here's what I hope is the final update on this problem. We took the car to the Acura dealer --- not an easy decision to make, as the closest one is 1+30 from home. He had the car for several days, but could not reproduce the startup issues we were having. However, he did diagnose two other problems: one, the driver side radiator fan was inoperable, causing the engine to "run really hot" (I never noticed anything significant on the temp gauge on the dash, but OK), and b) the car was running rich and the recommendation was to check/adjust the valves. I OK'd both repairs, and we've had the car back now for two weeks.
No starting problems have recurred. Today was a pretty good test: mid-90's, and my wife made numerous stops on short errands. Everything OK.
I can't say wheat fixed the problem, but so far, so good.
I can understand a rich condition causing problems starting, usually you can tell its rich by the condition of the spark plugs and the short term fuel reading, if the reading shows a high negative percentage the computer is trying to cut back on the fuel. Maybe when the car was hot the extra rich condition was too much to compensate for making it hard to start. We were looking for electrical issues, I think the way we all frame the questions we predispose ourselves to start down a certain path. Another lesson learned.
Thank you for posting the update, so many people never let on if the car is fixed and what worked. Safe driving!
04-18-2022, 05:47 AM
