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Hey everyone,
I, for the past week have had a heck of a time trying to get my car fixed.
Flash back to a week ago. Drove to work just fine. After work, got into the car, cranked it just fine but no start. The fuel pump didn’t kick on so I figured it was either the main relay or the fuel pump and took an uber home.
Since relays are such a huge problem with these cars, I hastily replaced it with no luck. After this, I took my multimeter and realized that the fuel pump was not getting power. In a fit of denial, I replaced the fuel pump for good measure. After I replaced the fuel pump, it took about 5 seconds for it to start to turn on after I turned the key, but hey, IT WORKED!
So I drove it home and made a few more trips without difficulty. Well, today, after work I got in and the fuel pump would not turn on until the second crank attempt. Once I got it running, I immediately took it home and parked it.
I have the 1994 del sol Honda shop manual so, after much reluctance to fuss with the electrical system, I broke it out and started down the trouble shooting algorithm (yes, I know I should have done this all along :))
The relay passed its tests.
The fuel pump will turn on if I short it to 12v.
All of the diagnostics from the relay connector passed.
And now I’m stuck at the ECU portion. It’s asking me to test some pins (specifically, a7, a23, a25, and b1) but I do not have access to a test harness and cannot afford one.
I have a feeling that the problem is some sort of short to ground since it has proven to be (somewhat) intermittent but I don’t think I can completely rule out a bad ECU. Do any of you guys know how I can go about testing this thing without buying a test harness?
Any tips would be much appreciated!
Sam
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Are there any codes stored in your ECU ?
The fuel pump isn´t switched on by the ECU, until a few criterias are met. Like there has to be a signal from the crank sensor. Ignition also has to be detected, since unignited fuel guzzling through your engine would be bad for the catalytic converter. One of those criterias is probably not met or is working randomly, i.e a bad connection to a sensor, the ECU or otherwise.
You can measure the fuelpump all day long and switch all the parts you can afford, but all to no avail if the criterias aren´t met.
Hey!
Thank you so much for the response and sorry that it has taken me so long to get back here. Life happens.
To answer your question, there are no codes stored in the ECU. I followed the procedure of shorting the black and brown wires that are on an unpopulated plug next to the ECU. I then turned the key and waited for the code. The CEL just stayed illuminated like normal.
Any other thoughts?
Some other things that I should note:
– The ground’s that I had easy access to in the engine bay are fine (specifically the one on the thermostat housing)
– Fuses are all fine (both under the dash and under the hood)
– The CEL does not switch off after a few seconds when the key is turned to the on position. I look over this earlier but I think it’s maybe supposed to be turning off?Seems like things are pointing towards the ECU unless you guys have any other ideas.
Thanks!
The fuel pump is powered up by what is know as the PGMFI relay(programed Fuel Injection). The fuel pump relay is soldered to a board on the PGMFI relay. It is a common issue to have solder joint crack and not make contact. you can usually just reflow them and fix the relay. I would start there. I attached a pic of how to find the relay.
Thanks for the reply but the relay passes tests recommended by the 94 del Sol Honda shop manual. Also replaced it to make double sure as stated in the first post.
Thanks
Ha ha you did say that sorry. Ok so what I would do is a voltage drop test on both the power and the ground circuits of the fuel pump. If both those test good then your problem is in the pump or at the connector itself. Maybe spread pins in the connector. Did you replace the whole fuel pump module or just the pump itself. May be a wiring issue inside the tank if you just did the pump.
Thanks again for the response but the fuel pump and the connector are not the issue.
The fuel pump was replaced.
The fuel pump can be shorted to 12v from the main relay connector. When it is directly connected to 12v it turns on just fine. If there was a problem with the connector, then giving it 12v from a connector that is ‘upstream’ would not work. Since giving it 12v from a connector upstream from the connector at the pump turns it on, the pump and the connector are fine.
Thanks,
SamIf you short the pump and make it run, will your car then start effortlessly ?
Sorry for the delay, I´ve been rather busy lately.
Hey everyone,
Ended up replacing the ECU and now it runs like a dream!
Here are some takeaways from this repair job
– Make sure that your ground are good (specifically the ground on the thermostat housing)
– Make sure your main relay is good. If you have a multimeter, a 12v power supply, and some alligator clips, you can verify that both relays are working without taking it apart. The procedure is in the Honda Del Sol shop manual.
– You should short the fuel pump directly to 12v to verify that it is indeed working.
– If you have a solid CEL that does not turn off when the key is in the on position, this indicates that there is a problem with either power going to your ECU or the ECU itself.
– It is super fun to have the ‘top trim’ level of a rarer honda such as the del sol when you first buy it… When it comes to repairing it, it is not so fun because things that are specific to your engine such as the ECU are very expensive 🙂Thanks for the help everyone.
Solid cell is known as code 0. Usually what happens is the capacitors blow out. If you open the ecu most likely it will smell of rotten fish or there will be a burn mark around 1 or more caps
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Where were you a couple of weeks ago 😉
And, by the way, before I replaced it, I bought new capacitors and replaced them. Still wouldn’t start! Now the old ECU is in the project pile for further messing with 🙂
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