So I live in Arizona where it hits up to 100-110 degrees and I have had problems with my del sol not starting ever since summer hit. I'm certain it is a fuel problem and almost 100% certain it is a temperature problem and doubt it's random which I had previously thought. My main reason for thinking this is cuz I have been able to start it up fine at night recently after changing the main relay but still won't work in the hot mornings, so.. I don't know what to replace. Can fuel pumps go bad with high temperatures? Because it is unable to prime during the day or maybe it is just faulty wiring idk I don't know much about these things. When I am able to start it up at night I have to let it sit in aux for a second before I can hear the fuel pump prime and fuel line running, when I hear this, the check engine disappears and it starts up perfect.
I have posted threads explaining the problem but have made progress in knowing what is wrong so I decided to make a new one but those include a lot of important details.

 

Or maybe it's an electrical problem that gets too hot? Kept it in the garage today and it ran fine.

 

-- This is your fourth thread since August 19, concerning your relatively low mileage 1995 Del Sol. As others have opined, and even though the main relay is new, the signs remain that the new main relay may not be working right. This is especially possible in the notoriously hot weather that much of Arizona sees.

-- First, is your new main relay an OEM Honda part? Not that this ensures the integrity of the relay's solder joints in extreme heat.

-- Second, please read the attachment** carefully. Use the attachment to check your main relay's operation. Report back here exactly what you find.

-- Third, your Del Sol is over 25 years old. Many electrical parts are likely way old and may be contributing to problems with diagnosing here. If the main relay checks out okay, then I would next consider a shotgun approach, with said "shotgun" aimed at parts that tend to have problems at high temperatures:

• Replace the spark plug cables with NGK or Denso cables.
• Replace the spark plugs with the ones the owner's manual specifies.
• Replace the distributor cap and rotor with OEM parts.
• Replace the ignitor and CYP coil (both inside the distributor) with OEM ones, or replace the distributor in its entirety.
• Replace the ignition coil with an OEM one.
• Replace the crankshaft position sensor.

Yes, this adds up to tidy sum of money for some folks on a budget. But your Del Sol has 147k miles on it. This is not such high mileage. It's the years that may be problematic for some parts. The above parts wear anyway and many are likely at the end of life.



** A gentleman who goes by "Tegger" wrote the attachment. Tegger assisted countless folks for years with their 1990s Civics. The attachment reflects an enormous amount of thoughtful study of the main relay, based in enormous experience. It was written with the do-it-yourselfer in mind. The attachment has been reviewed by many DIY Honda enthusiasts and found to be valuable.

 

I bought the main relay from my local autozone, I don't believe they sell off brand products. Also I will be sure to check for both main relay clicks right now. Thank you for this list, should I do that in order?

 

Okay I'm not rly sure what I should be listening for I don't hear any clicks; but I did find out if I blast my A/C at my feet it is able to start right up but when A/C is off I'm unable to. So I think that confirms that it has to do with something under the dash close to the main relay. The previous owner had removed the cover for all the wiring under so I can take a peek under and take a picture of it all - is there anything missing? Or what under there could be heating up?

 

-- 99% of Autozone parts are aftermarket. I checked and the only main relay that Autozone sells for your Del Sol is made by Duralast. "Duralast" is a well known aftermarket brand. For electronics, I would go only with Honda OEM or Denso. The Honda OEM main relay part number is 39400-S10-003. Alternatively find a Mitsuba RZ-0132 main relay. A new Honda OEM main relay is just about $10 more on eBay right now compared to what you paid at Autozone for the Duralast brand. Ebay also has many pre-owned Mitsuba RZ-0132 main relays that are probably worth the lower price. Newer Honda OEM and Mitsuba main relays supposedly have an improved design, so the soldering does not fail.

-- You could go to a salvage yard and pick up a few main relays and try them all to see if they make a difference. A number of Honda models use this same main relay. Google the part number and see if you can figure out how to pull up all the Hondas that use this main relay. If you go to a salvage yard hunting for used main relays, the list of all the other models that use this main relay will help you.

-- Do you know how to solder? Tegger has another guide (or link to another guide) for soldering main relay joints. Youtube has at least one guide on re-soldering as well.

-- I think the A/C fan operating could be enough to cool the main relay so that the solder joints do not open up.

-- Can you give me more detail about the A/C system being on and the Del Sol starting right up? Is the A/C system putting out cold air instantly? Have you tried this during daylight hours, after parking in the sun for half an hour or more?

-- When you simply turn the cabin fan on full blast (without the a/c on), directed towards your feet, does the Del Sol start right up?

-- I expect you will have to get your head down close to where the relay is to hear the clicks. Since you are new to what a relay sounds like when it clicks, I think you're either going to have to be quite studious when you try to hear the click, or you will have to turn this over to a shop.

-- For a little while longer, let's hold off on replacing any other parts.

-- I really hope you will make an effort to identify the clicks. It's a good skill to have. When your Del Sol is refusing to start, not hearing all the clicks will tell you (and me) a lot.

 

I'm not sure if it has anything to do with the main relay because I don't even know my old one was bad because it honestly acted very similar. Also I did put my ear right next to the main relay and tried turning the key, maybe the beeping from the aux position is masking it. And for the A/C, blasting cold air at my feet makes the fuel pump prime like I said before and the engine light disappears hence I'm able to start it right up. I will try again to listen for the clicks but I don't believe there is anything wrong with the relays I have.

 

I hear you about the symptoms for the old main relay and the new main relay being the same. And one would think even an aftermarket main relay (like the Duralast main relay you bought at Autozone) would work right out of the box.

Yet parts of Arizona are unusual in how hot they get. You say that specifically blasting cold air at your feet allows the Del Sol to start just fine. To me the latter justifies a thorough check of the main relay (even the new one from Autozone). The soldering joints on 1990s main relays have been a known problem (in hot weather) for over two decades now. To me, if at all possible, eliminating the main relay by doing further checks would be best.

Can you steer cold air from another source (that is not from the Del Sol) into the footwell and try to start the Del Sol? I would want to confirm that this is all about temperature.

Another check a DIY-er can do is to take the case off the old relay and examine the solder joints. For photos of bad solder joints, see the attachment and also all of

https://techauto.tripod.com/mainrelay.htm

​​​​​​MarkLamond.co.uk - PGM-Fi - Main Relay

This youtube video, starting at about 5:29 for great photos of bad solder joints in the main relay:

Another approach is to grab a few main relays from a salvage yard and try them.

I would not want to add any other parts until I had gathered the above information.

Lastly, if you google

"main relay" site:honda-tech.com

then you will get an idea of how common main relay failure is. You will also see threads discussing how symptoms that seemed to point to a bad main relay often were resolved by doing something else.

 

Sounds like the ICM inside the distributor has gone bad from heat soak, when these go bad from the engines heat or temps they will prevent you from starting until they cool down or the temps drop.

Try testing and replacing that unit and see if the issue goes away. Very easy to test and replace!

I have also seen the Ignition coil inside the distributor go bad and give similar issues. These usually go bad before the ICM. Both can be tested and replaced easy.

 

Do u think the A/C is able to cool that down? Because I think the main culprit is under the driver dash

 

I had the same problem with my VX, I took out the main relay and opened it up and the circuit board had on solder spot that had separated the wire from the board, so when hot, the material expands and wouldn't make contact, but when cold, the material shrinks so it made contact. I just got a lil solder, and soldered that spot back together, and now it starts cold or hot. Its a common problem in 92-95 Honda civics. Main relay.

 

I think my fuel pump is just going out and the main relay is fine because there is now a really faint whining noise coming from the pump and the car is not priming at all anymore even now that temperatures have cooled downed a lot like it was 68 today and wouldn't start. For the past 3 weeks I've been driving it fine but I think it's finally giving out. I'd like to confirm that the faint whining noise is indeed a noise of giving out? If so I'll replace it as soon as possible.

Edit: It might be 2 problems though, both the melting main relay and bad fuel pump, I'll have to see. It is getting a lot cooler though so I'll be able to drive it.

 

Replaced fuel pump because it was whining a bit before my car fully stopped starting/priming. Main relay is clicking... New fuel pump... New battery... still won't start, what should I do now? It's not a temperature problem anymore as it is cooled down here so I don't understand why it won't prime. Please help! I found this forum https://honda-tech.com/forums/honda-...prime-3253681/ with EXACTLY the same problem as me but the thread was never completed as the guy didn't post that he fixed and forgot how he fixed it years later.

 

I think you have been given pretty good advice, although some can be ignored. You do not have a crankshaft position sensor. I would disregard the spark plugs, plug wires, and fuel pump, because their operations is not as affected by the ambient temperature. It's possible they could be the issue, but I would focus on the other items.

The main relay is the most obvious culprit. But if it's new and you hear it click, I am inclined to believe that it's probably okay.

As wunfstgsr said, test the ICM and Coil inside the distributor. I would start there. I think the instructions are in the FSM. There is probably only one factory making these very specific parts and supplying them to Honda, Autozone and everyone else. Or entire distributors can be had for not too much money, and would eliminate a lot of possible causes.

Very frustrating, but good luck.

 

I believe it to be a possible ECU problem not priming my fuel pump. How can I test this before I go buy myself a new one?

 

Reading through your symptoms, it sounds more like an ecu problem than a main relay. This is pretty typical with old fuel injected cars (not just Honda).

Take out your ecu and pull the lid off. Have a good look at all of the big capacitors that live near the plug end of the board. There’s likely a few that are leaky. You need to replace them all before the hoard gets burned up from them failing.

 

looks like c15 and c19 are bad. Can I get new caps? or should I just buy a new ECU
edit:c24 & c21 are a little leaky as well.

 

I bought a set of replacement caps for my 94 Del Sol SI ECU on EBAY. 10-15 dollars.

Have a good solder tip.

 

Every single one of these old ecus should have their caps replaced, they are all well past their service lives. You can get kits from reputable sites like https://www.xenocron.com/ or from eBay, YMMV there.

You've got some damage on that board but it might be save-able. C19 and C15 look pretty bad so it's hard to say from a couple of pics. If you look at that and you're not somewhat skilled and already in possession of a nice soldering setup you're definitely better off sending it out to a pro or getting yourself a refurbished ecu from somewhere (who may do a core swap anyway).

Start a new thread in the engine management forum and get some feedback from folks who repair these things more often or try to get @7rrivera7 's attention.

 

I just decided to buy an OEM ECU for about $150, although expensive I just want to end all my problems already as it has gone on for too long. There are a lot more leaking than what you can see in those photos as well and I have no soldering equipment nor experience. Thanks for all the help guys and if I had more time searching honda-tech forums I could have found my ECU problem quicker. I will update this forum in 4 days if my problems are fixed or not.

 

Issue is the ECU. The replacement should solve the issue.

 

ECU hasn’t arrived yet but I tried starting my car last night and it took awhile but my fuel pump primed and I decided to start it up like usual. It gave me some bad start up surges/idle surge and I woke up to a big leak that I don’t know what is. I can’t smell anything right now so I can’t determine it rn but here’s a pic.
-I will refrain from trying to start my car until my ECU arrives

 

When it rains it pours.

 

ECU came in today and my car now starts and runs perfectly! FINALLY :D real question is... turbo or swap