Skip down to paragraph break #5 for the Hondata specific issue

Hey guys, hate to start my first thread with an issue solve but I'm in a bind and desperate for a solution. I recently started working again on my car, 99 Civic Si turbo, and am having starting issue. I haven't gotten the car started since working on it but can explain what's going on and the events that lead up to this moment.

The car was a no start previously to what I'm about to explain, I started working on it after the car had sat for over 5 years.

I was having a starter issue and was trying to troubleshoot it so at one point put a ground wire directly from the ground on the battery to the body of the starter. This worked fine if I would hold the wire for short periods but I held it for 5+ seconds to see if it would be a permanent solution and got a huge spark and the battery either died or some fuse/relay burnt because the car lost power. I checked all fuses under the hood and in the cabin and they were all fine. Since then I've had a problem with a weak battery on a battery that didn't have issues holding power. I also had an issue of pulsating dash lights which I found out was due to a weak battery. After jumping the battery and trying to start the car, I get nothing but cranking and cranking with no actual start. And more recently, a huge problem with cranking power(which I could imagine is just a battery issue).

Aside from the battery, I thought the no start issue was the injectors being locked up or the resistors I was using but I bought some high impedance Injectors, Injector Dynamics, and that didn't solve the problem.(Not mad about this, actually wanted ID injectors). So with the new injectors I still get an all crank, no start problem. I do get fuel to the system because the spark plugs are wet when checking them and there is fuel on top of the piston in each cylinder.

The fuel pump was working so it wasn't that except I started having another issue. When I have "plug C" on the jumper harness plugged in, the fuel pump doesn't turn on. When I have it unplugged the fuel pump does turn on. This is backwards as you need all 3 plugs to be plugged in for the car to start but for some reason this is my most recent problem which is affecting the fuel pump. There's no way to troubleshoot the car till I get this fixed because plug C has all the vital sensors needed to actually start the car. Another issue with this plug, "Plug C" on any ecu pinout diagram, is that when I have it plugged in the Hondata on my ecu doesn't give a green light. There is no light coming from the USB port. When it's unplugged and I turn the car on, 2 clicks no start, there is a flashing red then the light turns green. To the best of my understanding the light should be green when the ecu is given power. What could be causing this problem?

Another thing to note is that I do get spark. I had my brother test every spark plug by holding them to the valve cover and each spark plug gave a spark. So the car gets fuel and spark, but I have no way of testing if I get proper air or if the air related sensors are working.

This is all I have right now and I hope some of you guys have insight into my problem. Feel free to ask any questions and I will try to answer to the best of my ability. Thanks!


Also, if this is a bad place to put this type of thread please guide me as to where would be the best place to put it. I was gonna post it in the Forced Induction and Engine Management sections as it seemed relevant, but I didn't wanna be a double/triple poster and get in trouble with any mods(or just simply not be annoying by posting the same thing everywhere). Thanks again

 

Found out, thanks to muellersfan, that when I unplug the MAP sensor the fuel pump primes.

No change when unplugging the TPS sensor.

Also, the Hondata light now comes on with the MAP sensor unplugged!

 

Just plugged in my new MAP sensor and the fuel pump now primes with the ECU plugs plugged in. Had no idea that the MAP sensor could affect the fuel pump and the Hondata light.

Should this fix my starting issue? (I can't try right now as my IM/TB are off for boring purposes)

 

Somehow I feel this was coincidence...

 

Are you referring to the no start issue or the connection between MAP sensor and fuel pump?

This is what muellersfan wrote in my other thread;




edit: Anyways, I'll know later today as I'm probably gonna have the IM/TB back on later today. So I"ll come back with an update.

 

Ok THAT makes sense from an electrical perspective - thanks for posting the response from muellersfan.

Even though I repair these ECUs for a living, the no-start issue is usually related to the power circuitry in the ECU - specifically the power supervisor IC. In this case, I learned it can be caused by your specific issue and I love to learn!

I guess that either muellersfan was talking from previous experience or you had previously stated that the map sensor voltaje was not in spec. Either way great news that the issue has been resolved!

 

Nope it was all him, I had no idea the MAP sensor could cause the fuel pump not to work.

Same here, came back to honda-tech to learn! That's exactly why I quoted what he wrote, to pass on the knowledge.


Yea I'm glad too, I was thinking I fried my Hondata/ECU due to the Precision high impedance injectors I had on previously. Thank God it didn't. It did force me to buy some ID injectors, which I did want anyways but couldn't take the leap and buy lol I hope this also fixed my no start issue, I'll know later today.

 

>> When I have "plug C" on the jumper harness plugged in, the fuel pump doesn't turn on. When I have it unplugged the fuel pump does turn on.
>> plug C has all the vital sensors needed to actually start the car.
>> when I have it plugged in the Hondata on my ecu doesn't give a green light. When it's unplugged and I turn the car on, 2 clicks no start, there is a flashing red then the light turns green.

These lines allowed muellersfan to diagnose your issue. Maybe if I would have read the entire post, I wouldn't have jumped to my conclusion. Connector 'C' and the fact it carries sensor data allowed him to concentrate in this area. Excellent troubleshooting muellersfan!

 

No worries, I wasn't upset or anything. But yea he must have experience with that issue, all credit to him for the help.

 

Bad news, I got everything put back together and the changing of the MAP sensor didn't fix the no start issue. What else could it be?

I have fuel and spark and am gonna check compression later today.

 

With my Cp pistons(9:1 compression ratio) the compression numbers are, left to right, 177.5 172.5 165 165

There not the best but it should in no way be causing the no start issue. I believe I'd see much lower numbers if that was the case.

Anyone have any input?

 

Can the issue just be the tune I have on it right now? It's an old tune from the previous owner but the specs are very similar, if not exact.

 

Hi to anyone who sees this. So I've gone through all the test needed for the car to start (fuel, spark, compression; all good) and even some bigger problems (new map sensor causing fuel pump not to work/ecu to not receive power, injector 3 and 4 switched; changed and fixed) and the car still doesn't start. I have come to the conclusion that this may be a problem with the current tune on the ecu, unless someone has anymore input on why my car won't start. (I'll put the link to my other thread below where I keep any readers updated in the comments)

So, I'm running Hondata and the tune that's on the ecu ran the car before it sat. It ran fine except for a bad idle and misfire while cruising. I've concluded that it was due injector 3 and 4 being switched. Aside from that it drove fine, even at WOT.(Actually, especially at WOT) After sitting for 5 years or so and going through a lot of troubleshooting/tests, the car still won't start. That's why I think it may be a tune problem. What's my best option? Find a basemap tune and see if it runs? None of the tunes on SManager suffice as I have 1000cc injectors and other aftermarket parts.

If you want to help me troubleshoot the no start, feel free to post in this thread or the one below. Another member has been helping and am very grateful as he helped me a lot already! (Thank you muellersfan)

https://honda-tech.com/forums/tech-m...start-3350614/

 

If you think the ECU is the cause for my no start, I'm all ears. I've tried troubleshooting everything except for the tune that's on my Hondata right now.

What is the power supervisor IC? Is it a check system in the ecu that gets triggered thus stopping the ecu from allowing the car to start?

 

Yes, it's a problem I repair daily with these 25-28 year old ECUs

 

The last problem turned out to be wrong placement of the spark plug wires on the distributor. I had the sequence correct just not the starting point.


Feel free to check out the other thread that's active where we're talking about the Hondata tune/troubleshooting.