Mechanical Filter: Follow-up question: '93 del Sol won't start
February 28, 2013 8:45 AM   Subscribe

A few weeks ago I asked this question. Consider this a follow-up question. I have a 1993 Honda del Sol 5-speed Si that has a "mystery" problem of sometimes starting and sometimes not starting. It's always a cold-start problem. I put the key in the ignition, switch it to ON until the check engine light goes on, the fuel pump pressurizes, and the main relay clicks, and then crank it. Sometimes it will fire up right away. Other times the engine will turn over but not ignite. Once it is started, it will start up fine for the rest of the day. It only gives me trouble when the engine has gone completely cold and has been left untouched for upwards of four hours. A new issue has developed since I first posted my question. Even after getting the car started, sometimes just a few minutes later during a sharp acceleration (approaching 4000rpms or more) the engine stalls out. I have to pull the car over and start it up again. It always starts up fine after that and will usually not stall out again. I had this issue looked at by several mechanics, most of whom hadn't the slightest clue what it was or willingness to investigate. The last mechanic I took it to said it was a faulty ignition switch and replaced it . . . but that has done no good whatsoever. Also, just FYI, the spark plugs are relatively new. Any thoughts are appreciated!
posted by fignewton to Technology (10 answers total)
I have no experience with this vehicle. I'd check the forums and see if people have troubles with fuel pressure regulators on this particular car.
posted by tumble at 8:55 AM on February 28, 2013

Spark plug wires. It's amazing how many oddball ignition problems go away with a new set... they're not always changed when the plugs are, depending on the mechanic. Also, distributor cap is a cheap replacement, and an easy fix to mystery ignition problems.

It sounds like ignition issues - so have that checked out, beginning with the distributor. Another issue may be dirty fuel injectors: you can try the fuel-additive cleaners, but if it's causing starting or stalling issues, they may need to be removed and cleaned by hand. Also, fuel injector pump could be going bad.
posted by Slap*Happy at 9:12 AM on February 28, 2013

Best answer: I would say it is almost certainly ignition (not the part you put the key in but the part that makes the spark plugs spark at the right time) and not fuel. Fuel problems tend to be constant and can usually be repeated with the same circumstances.
Ignition problems tend to be intermittent and are usually related to engine and air temperature. However I would change the fuel filter on just general principles (old car with unknown history=always do the basic maintenance stuff first). Then I would change the distributor, rotor and wires next. Altogether the parts are less than 100 and probably need replacing anyway. Don't buy the cheapest stuff at autozone either, I would get DENSO parts from or amazon. I would also use one of the these tools to find out if you are getting spark when the car won't start. If you are it is a fuel problem and you proceed from there. Once you do that i would also change the O2 sensors (one before the catalytic converter, one after) and be amazed at how much smoother the engine accelerates and your improved fuel mileage.

There are a ton of Honda fanboy,err, enthusiast sites out there with lots of people willing to help and offer advice on this as you chase it down. This car is really just a civic with a different body style and was a best selling car for several years in the 90's, you won't have a problem finding parts, advice or junkers to pull parts from for years and years.
posted by bartonlong at 9:44 AM on February 28, 2013 [2 favorites]

Seconding plug wires.
posted by InsertNiftyNameHere at 9:58 AM on February 28, 2013

I'm far from being an expert--or even a competant mechanic--but I had a car with similar symptoms some years ago. It turned to be an issue with one of the fuel filters--in this case the one at the end of the main line coming out of the tank, but before the one going into the carbeurators. I replaced it (it was a simple screen) with a different screen (a pipe screen that I bought--6 for 50 cents at a smoke-shop*), and it worked fine. This car had three filters--one located at the bottom of the tanks, one in the trunk (the fuel line passed through the trunk, then via the undercarriage to the engine compartment), and one under the hood.

This was after a series of trips to three different mechanics, who couldn't figure it out, and were unable to reproduce the symptoms. Turns out that the three filters somehow set up an intermittant vacuum that caused cavitation in the line. I guess vapor lock might be a useful image. After a while the pressure equalized, and fuel drained here and there, so the pump was able to engage properly: I also had to wait for the fuel pump to stop clicking before I fired it up, so I was under the illusion that just because the sensor at the carbs said they were charged all was okay in the rest of the line. Anyhow, changing the middle screen set it all good.

My car was a 1974 Fiat Spyder, I believe this was the first DOHC system for that model.

* I used the other 5 screens for my pipe. The screen in the fuel line worked fine for as long as I had the car, but I had to replace the pipe's screen from time to time.
posted by mule98J at 10:05 AM on February 28, 2013 [1 favorite]

These things can be real bastards to track down. It is often a case of starting somewhere, and then checking/replacing stuff in a systematic way until the problem goes away. As you have new plugs (they are the correct plugs, right?), I would work my way backwards, replacing plug leads, coils. I would put a fuel bowl (with a glass bowl) or a pressure guage in the fuel line to see that plenty of fuel is getting through. Regardless, after the electrics are done, if the problem continues I would replace both/all fuel filters, and since that will probably mean opening up the fuel tank, I would replace the fuel pump too. I would also blow out the fuel lines, and replace all rubber hoses in the fuel lines, including the in-tank one (don't ask me how I know this).

One thing I would do while the car is running, is play with the wiring to see if there is a loose/broken wire in the harness somewhere - just move it around gently/firmly working your way from the ignition switch all the way to the coil. Do the same for the plug leads, but watch out for electric shocks there, wear some dishwashing gloves to avoid the possibility of a shock from these, they have quite a kick.

If you have rubber hoses to sensors/valves that affect the engine performance, I would check these for leaks, or just replace them to be sure.

That is a lot of work, and money, for an old car - even if you do a lot/all of it yourself. Problem is, you don't know how far along the Eureka moment will be. And once you start this process, you are sort of committed to seeing it through. Is the car worth it to you? That is call only you can make.

Good luck!
posted by GeeEmm at 2:13 PM on February 28, 2013

Has the car got an immobilizer? Mine causes me starting issues sometimes...
posted by prentiz at 3:03 PM on February 28, 2013

Just to add, disabling an immobiliser would be the first thing I would do, or any other anti theft device you may have.

Also, when the fuel pump is out have a very close look at the in-tank wiring and connector plugs. These can give trouble, and your symptoms are not what I would expect, but even so if you can't be absolutely sure that all is kosher, replace it.
posted by GeeEmm at 5:27 PM on February 28, 2013

Best answer: You have a very lucky problem, since you can reproduce it pretty easily every few days and when it's failing, it's really failing. This means the problem will probably be quite obvious once you have to tools and process ready to see it.

What you need to do is stop guessing (and taking it to people who guess) and start troubleshooting. Several people guess here that you need plug wires, but to me that doesn't seem like a good guess - in particular it doesn't match the high-speed stall symptom. It's likely, but not a sure thing, that fixing your failure to start will also fix that. The failure to start is much easier to troubleshoot.

If your car is cranking and not starting, you're missing compression, correctly-metered fuel, or correctly-timed spark.

Since your car runs smoothly some days, you have compression. It is very unlikely to come and go.

So you can prepare yourself for some real troubleshooting steps the next time it doesn't start. Buy/borrow yourself a fuel pressure gauge, a spare spark plug or an old timing light if you can find one, and a broomstick. Look up how to attach the fuel pressure gauge and what the correct pressure should be (there's probably a port where it just screws on.)

Next time it won't start, check for spark by clipping your timing light to a plug wire, or even all of them in sequence, and see if it fires while your friend cranks it. If you have a spark plug instead, pull a wire and stick your spare plug in it, and lay it against the engine block.

Check for fuel pressure by attaching your gauge.

Check for injectors firing by holding one end of your broomstick against an injector and the other end against your ear. Try that ahead of time so you know what a working injector sounds like - they have a loud click that you can't mistake. In fact you can do all of these tests while the car is working, if you want to get to know what normal operation is.

I'm guessing that by now you will have found a gross failure in one of these systems, and now you can go on with that new information and narrow it down further.
posted by fritley at 7:42 AM on March 1, 2013 [2 favorites]

Response by poster: It was a combination of a bad ignition coil and ignition control module. Problem fixed!
posted by fignewton at 8:57 AM on March 15, 2013

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