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Looking for good ’98 – ’99 ECM


vfr800_red
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Hi

I have a 98 5th gen. It no longer runs reliably because of fuel injection problems. Following the step by step diagnostic procedures in the factory service manual I have concluded it has a faulty ECM. Because new ECMs are no longer for sale, I have purchased used ECMs on Ebay. So far I am 0 for 3. All 3 Ebay used ECMs, which are all from different salvage yards, have also had problems, including two that didn’t even power up the fuel pump. It would seem that over time these ECMs go bad, and since Honda no longer carries inventory, it is time to buy another bike. Thoughts please, or does anyone have a known good 98 – 99 ECM they are willing to part with. Thanks in advance.

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How about a lot more details as to the fault you have!

ECM's are generally incredibly reliable, but there are so many external issues that can effect them. You may well Not have an ECM fault.

 

Having 3 ebay ones faulty sounds like you're incredibly unlucky or again, you don't have an ECM fault!

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:1:

 

In years I can't recall anyone reporting a faulty ECM.   These bikes are now 20 y.o., and over that time fuel degradation can cause havoc with spray patterns and flow causing rideability issues that seem like fuel system faults.  Also not to be overlooked are grounds.  Most ECMs operate on a 5v reference voltage, which is not much to overcome a sketchy connection.  Many of the grounds are connected to the aluminum frame - ferrous bolts and terminals can corrode due to the dis-similar metals - often presenting as a white fuzzy material.   The fuel pump may be working intermittently for that reason.  

 

Before jumping to the conclusion that the 4 ECUs are all faulty,  it's probably worth insvesgating issues more likely than failed electronics.   Bench cleaning the injectors costs about  $125 and a tube of Oxgard to treat the grounds is about $5 and some of your time. Maybe start with the grounds (including ones that go through connectors) and see what happens.

 

 

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Hi Grum,

 

When my fuel injection issues started with my original ECM, I had one blink and 19 blinks when the service check connector is jumpered. 1 blink is a map sensor. The diagnostic procedure for the map sensor is on page 5-14 of the service manual. The voltage between pink wire and ground is between 4.75 to 5.25 volts, as is the voltage between pink and green orange wires. The voltage between the light green and yellow wire is 4 volts, which is out of the 4.75 to 5.25 range, but not by much. The map sensor voltage is within the 2.7 to 3.1 range. Per the procedure this means either an open or short circuit in the light green/yellow wire, or loose or poor contact on the ECM connectors. The ECM connectors look fine. Fixing either problem will likely mean replacing the wire harness and replacing the wire harness is a very labor intensive task, right in the middle of prime riding season, and we have long winters here in Chicago. So yes, I did not completely follow the procedure because I was hoping for a quicker fix to get riding again.

 

On the aforementioned 19 blinks, that is the ignition pulse generator. I followed the procedure on page 5-44, and my voltmeter registered much less than 0.7 V. I purchased new one, but my voltmeter still registers much less than 0.7 V. I’ve concluded that this the ignition pulse generator produces a very short spike, to brief for my inexpensive Radio Shack voltmeter to register. I don’t have an oscilloscope, but somewhere I do have better voltmeter.

 

All 3 purchased ECMs came from salvage yards, so who their condition is not guaranteed. The first used ECM produced 1 blink, 9 blink, 14 blink, and 18 blink faults, very different that the faults with the original ECM. I followed the 9 blink procedure (IAT) and all tests passed, therefore the ECM is bad. As mentioned in my post, the other 2 used ECMs don’t power the fuel pump. Thankfully, I have been able to return these for a full refund.

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On 5/30/2021 at 2:51 PM, vfr800_red said:

When my fuel injection issues started with my original ECM, I had one blink and 19 blinks when the service check connector is jumpered. 1 blink is a map sensor.

 

Starting with this one!

Was your bike running at the time AND did your Fi light come ON?

 

With your bike on its Sidestand was it blinking the MAP and Ignition Pulse Gen codes? 

Using the Service Connector link will display stored historical codes that could go back years if they were not previously cleared. The MAP sensor may be because of a previous Starter Valve synch involving disconnecting the MAP vacuum.

If you had a genuine Ignition Pulse Generator fault. The engine will Not start, did you have that situation?

 

The ECM does not act on Stored historical Codes. It will only act on Active Codes.

 

You could end up on a wild goose chase trying to analyze OLD historical stored codes that may not be an active valid fault. Various sensors may have been disconnected and reconnected in the past for whatever reason and then it's fault code will be stored in memory! Stored memory can be handy for analyzing highly intermittent faults.

 

As a Starting point suggestion:

Firstly, make sure your Battery is healthy and fully charged and Battery Terminals are both clean and tight. If you have any doubt about the battery remove it and take it to your nearest Auto parts store and have it Load Tested. Battery terminal voltage is not a good indication of battery capacity - its ability to deliver plenty of cranking amps.

 

With your Original ECM fitted. Clear all the old stored Fault Codes via the Service Manual procedure.

Confirm your fuel pump primes at switch On, then attempt to run your bike and see if any new ACTIVE codes are displayed. Sidestand down!

 

And if your engine runs. Measure your charging voltage directly at the battery. What voltage do you read at idle and 5000rpm?

 

Let's know how you go.

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I can't add much more than Cogswell and Grum.... everything they have said.  It will be important that at minimum the ground spider and the chassis ground on the right side of the frame must be clean and good.  Battery connections must be good.  Otherwise you may be chasing your tail.  Then clear all old codes and start fresh.

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Hi Grum, Cogswell, and RaYzerman,

 

My ground connections were in good shape, as the bike is garage kept and rarely sees rain, but I removed the little bit of black crud with a brass bristle brush and 220 grit sandpaper at all chassis ground connections, including the surfaces between the brake PCV valve and the chassis. Ditto for the battery terminals. There wasn’t any white fuzzy material, I certainly know what that looks like as I have seen it often on car batteries.  I had high confidence in the battery but to be thorough I took it to the auto parts store and it passed the load test.

 

Yes, the bike was running when the FI light came on. Actually, the FI light had been intermittent for a long time, but it was illumination was becoming more frequent when the bike died on me during a ride.

 

I reset the ECM and now there are no codes. The bike runs. The charging voltage is 14.1 V at idle and 14.35 V at 5k rpm. However, the FI light is now always on. To further muddy the waters, the FI light blinks when the turn signals are activated. This tells me there is a short in the wiring harness. Until the FI stays off, I won’t trust it for a ride.

 

I have considered cleaning the injectors, but what is a bench cleaning? Is that a service my local dealership can provide? Should I run the bike on fuel injector cleaner? I had a car which had problematic injectors which were typically solved by pouring a can of Seafoam in the gas tank.

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You've covered a lot of ground (no pun intended), so good job.  Before doing anything with the injectors (it's a bit of a job on a 5th gen), I would get to the bottom of of the FI light blinking when the turn signals are on.  I don't mean to keep harping on grounds, but when electricity cannot find it's way home (back to the battery), it looks for other ways  and can back feed circuits that it's not intended to go through and cause all sorts of bizarre behavior.  I haven't had my 5th gen apart in ages, but on my 6th there are a couple of plugs with ground wires in them - one that can give owners fits.  As you point out, it could be a short but my best guess is that someplace there's a connection (connector) that's causing the FI light blinking with the turn signals.  Grum's electrical diagnostic skills are far superior to mine - hopefully he'll chime in with some suggestions on how to track that down.  Solving that may not cure all your bikes ills, but it's definitely something that needs to be sorted before moving on to anything else.  Hang in there - 5th gens are wonderful bikes - don't give up on it yet! 

 

Cheers

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Good progress, your bike is running, your charging voltage is good, and you appear to now have No Active codes.

 

Can you confirm that when the Fi light is comming on is it at full brightness or dim?

 

The issue with the Fi light comming on with blinkers will almost certainly be either an instrument panel copper track problem OR bad ground for the panel itself, you Must check the state of the orange Ground Block (see the next post). Its known to cause the Fi light to play up!

 

Failing the Ground block inspection.

 

With your meter to measure lowest ohms and one lead on the battery Negative terminal. Check the three instrument panel grounds at the Blue and Gray connectors of the Instrument Panel.

On the Gray connector make sure the Green wire and the Green/black wire have zero ohms to ground (ie back to battery Negative terminal).

On the Blue connector do the same for its Green/black wire.

 

If the Grounds are ok you're going to have to get the back off the panel and inspect the copper tracks. These can suffer badly from corrosion causing breaks and crud buildup possibly causing tracking, this causes very strange effects with indicator lights just like you're having. Locate your Fi light and check the copper tracks for continuity back to the main panel connectors, clean any blackened areas, open circuit tracks can be repaired by simply soldering a wire each side of the break to make the circuit. See attached panel examples.

 

As for your bike originally dying on you. Have a very close inspection of Main Fuse B 30amp next to your starter relay this fuse and its wiring can suffer badly from high resistance connections in the fuse holder and its inline connector. Also check the state of Main Fuse A 30amp on the Starter Relay make sure the fuse is not overheated or stressed/discolored. Remove and check the Red plug of the Starter Relay check for any stress or burning of the Red wire and it's spade connector.

 

Check these things out and get back to us.

 

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EF79D2E6-8E27-4F00-87F3-C99F83E6BE32.thumb.jpeg.09d26801311b53185228c34b60382593.jpeg.jpg

 

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The Grounds we are referring to are the wiring harness Ground junctions which are not mentioned in the Service Manual or shown on the circuit diagram!!!!

On the 5gen you have an orange block buried under black tape in the harness above your chain guard. As you can see, multiple devices and sensors have their ground come into the junction which is divided into two sections and each section then has only one wire that goes to a frame ground, as shown this can suffer badly, you may have one device with an issue or if the one of the  main grounding wires has issues you will have multiple devices with problems.

 

Bottom pic shows an excellent repair of the grounds all soldered together, with the addition of a large new ground wire that goes back to the battery negative terminal.

 

 

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The orange junction block seem to be the culprit. See pictures. As a quick fix I cut the connector and mashed all the wires together with a big wire nut, and the FI light has gone away, and the bike is running well.

 

To answer Grum’s other questions. The FI light was full brightness. The bike died instantly when the FI light was on. I’ve checked the main fuses and they are ok.

 

I did not check the instrument panel, but that no longer seems necessary.

 

Some questions about soldering all these wires together.  What gage do you recommend for the wire going back to the battery? I’m ok at soldering. Of course, wires should be tinned before they are soldered together, but it would seem impossible to keep all these tinned wires together, even with a cable tie, so is it ok if I skip the tinning?

 

I knew that solving this electrical gremlin was going to be challenging. Thank you all for your help. After too long, I’m ready to ride again. I need to hang out here more often and I’ll make a donation.

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Glad you have found the culprit. You can cancel the request for yet another ECM.

Don't worry, you wouldn't be the first to get caught up chasing faults stored in the ECM memory which are not current faults. The good thing is you've learned a lot going through this exercise.

 

Yep, no need to go further into the Instrument Panel, you've found the cause of the Fi light issue.

 

As to soldering all the wires together(which I've never had to do). You could do it a number of ways. Maybe solder groups of threes then wrap a copper wire around them all and solder them all together.

Whatever way you do it ALL wires need to be properly joined together as a bunch.

There will be two of the wires that go to Frame Ground and as you've checked the frame Grounds as all being good then you may Not need to add the extra ground wire.

Once done just neatly tape up the bundle and tape it back to the main harness.

 

Good luck and as Cogswell states the 5gen is a fantastic bike.:wheel:

 

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That's great!  We always love photos of member's outings , my personal favorite featuring 5th gens!   Shiny side up!

 

Cheers 

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Here is my 5th gen. Because of your help it is running well, two short but nice rides this weekend. Sargent seat, Givi top case, Heli bars, Zero Gravity windscreen, Race Tech front suspension and Penske rear shock. The rest is stock. 83k + miles on odo. It’s been a great bike, mine since 2003.

 

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