02 FLSTCI still sputtters at low speeds after top end rebuild

[sincityharley]

I just finished with a full top end rebuild. I only did the rebuild because I thought there was an intake leak causing the sputtering. This was only after I pulled the tank and replaced all the hoses inside the tank and tested the fuel pump. I replaced the plugs and plug wires. I replaced the TPS. At this point I have replaced just about everything. After the rebuild the bike ran perfectly for 3 days. The first day that i decided to open it up just a little bit, it starts sputtering again just like before the rebuild. If I open the throttle enough the sputtering mostly stops. Its definitely more prevalent at lower speeds but still happens every once in a while at higher speeds. At this point I am thinking the problem could be the ECM, fuel injectors or the two larger square fuses under the seat. Can the ECM lose its tune? Is there a way to test the fuel injectors? I'm planning on buying the fuses tomorrow. I cant believe the bike is still having issues. I could use some advice. Anyone have any suggestions?

 

[Hoople]

I could use some advice. Anyone have any suggestions?

Your still fighting the same "sputtering" issues from December of last year? You never got back with the results of clearing out the DTC's and if the clearing procedure I gave you worked. Did you ever resolve the code 24 of no combustion. Is your current error log free of any DTC's. And is your fuel pump pressure steady at the same psi as before.

It's hard to know where you stand with the current issue at hand based on non-closure from your last thread but I doubt it is an ECM problem. Not saying it can't be 100% but the issue sounds just too specific for me to believe it is the ECM. Same goes for corrupted software (can ECM loose it's tune question).. Possible but very very remote.

I would be closely looking at the MAP sensor. You can't depend on DTC's to tell you a sensor is bad. DTC's and firmware only catch the near open or dead shorted sensors. I would also clean & test the crank sensor using an AC volt meter just to get an idea how strong the signal was.

 

[Jack Klarich]

Grab the injector wires and give them a tug see if that makes a change in how it runs:s

 

[BUBBIE]

I just finished with a full top end rebuild. I only did the rebuild because I thought there was an intake leak causing the sputtering. This was only after I pulled the tank and replaced all the hoses inside the tank and tested the fuel pump. I replaced the plugs and plug wires. I replaced the TPS. At this point I have replaced just about everything. After the rebuild the bike ran perfectly for 3 days. The first day that i decided to open it up just a little bit, it starts sputtering again just like before the rebuild. If I open the throttle enough the sputtering mostly stops. Its definitely more prevalent at lower speeds but still happens every once in a while at higher speeds. At this point I am thinking the problem could be the ECM, fuel injectors or the two larger square fuses under the seat. Can the ECM lose its tune? Is there a way to test the fuel injectors? I'm planning on buying the fuses tomorrow. I cant believe the bike is still having issues. I could use some advice. Anyone have any suggestions?

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My opinion..Unless you have a ton of Money, You are sure buying a lot of parts it doesn't need..

What did you do in the heads???

Were the valve springs addressed????

What BUILD is in the motor..88 to 95?

cams??

head work done?

signed....BUBBIE

 

[sincityharley]

Yes this is the same issue from December, actually longer. So I read up on the DTC codes. They are all historical issues according to the check engine light and the manual. My codes are 11 and 24

Code 11 indicates
71 P0122 Historic 11 TP sensor open/low
72 P0123 Historic 11 TP sensor high
105 B0563 Historic 11 Battery voltage high

Code 24 indicates
79 P1351 Historic 24 Front ignition coil open/low
81 P1352 Historic 24 Front ignition coil high/shorted
83 P1357 Historic 24 Front cylinder combustion intermittent
98 P1353 Historic 24 Front cylinder no combustion

Ive already replaced the TPS. Today I went and bought a new ignition coil, thinking that was the answer. It wasn't. I just tested the fuel pressure with a tester that I made. It came back with idle PSI of 30 and open throttle of barely 40PSI. I know that's low. I am aware that I'm spending money needlessly but I refuse to take the bike into the stealership. It may not be the best way to learn but its a way. Nothing upgraded in the rebuild. I was just frustrated at one point and decided to rebuild since I couldn't find the issue. I can tell you at this point, Ive learned its not the engine. Still stock 88 aside from new gaskets and breather units and whatever else came in the rebuild kit. Going to buy a new starter relay and system tomorrow unless I come up with something brilliant.

I would be closely looking at the MAP sensor. You can't depend on DTC's to tell you a sensor is bad. DTC's and firmware only catch the near open or dead shorted sensors. I would also clean & test the crank sensor using an AC volt meter just to get an idea how strong the signal was.

I will try these suggestions tomorrow. Also to clear the codes according to the manual I have to cycle through the Start and Run process 50 times. I will also do that tomorrow and see what codes show up after that.

 

[Hoople]

Yes this is the same issue from December, actually longer. I just tested the fuel pressure with a tester that I made. It came back with idle PSI of 30 and open throttle of barely 40PSI. I know that's low.

You know that's low.
Please don't misunderstand me because I am trying to help you. Back in October of 2010, Chopper suggested the following. (copy & paste)

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"When the ign. is turned on the pressure jump high then goes back down between 55 & 62 psi if I rember right. The pressure valve allows the excess pressure to blead off in the tank and should keep it a min of 55psi. The factory guage has a bleed off valve to get the air out before testing, you could put a Y with a shut off valve between the guage & the induction manafold and bleed a little gas along with traped air into a bottle then shut the bleed off valve. With the engine is running the fuel pressure should stay steady somewhere between 55 & 62psi at any rpm, I mean rock steady probably at 58psi. Does the pressure stay steady when your riding the bike and it sputters? Good chance you could has a pin hole in one of the lines in side the fuel tank or a restricted fuel filter, try draining most of the gas out of the tank and try to see inside while turning on the ign. You might see a stream of fuel being squritted from one of the lines. Bad fuel pressue can make the bike act like it has a electrical problem."
********

I am pretty sure 58-62 psi is the factory spec. That would have been the 1st thing I fixed. You need to get that pressure up to spec. Save some money & forget what I said about the map sensor until you get you fuel pressure to spec.

 

[sincityharley]

Please don't misunderstand me because I am trying to help you.

I sincerely appreciate all your help

I am pretty sure 58-62 psi is the factory spec. That would have been the 1st thing I fixed. You need to get that pressure up to spec. Save some money & forget what I said about the map sensor until you get you fuel pressure to spec.

Ive already replaced all the lines in the tank. What else could cause a drop in fuel pressure?

 

[glider]

Ive already replaced all the lines in the tank. What else could cause a drop in fuel pressure?

A bad pump or a fuel filter that needs replacement would cause low pressure.

 

[Hoople]

I sincerely appreciate all your help

Don't forget that these are running pressures. There was some confusion back in October of 2010 with "bleed down pressure" vs "running pressure". At that time you said your running pressure was 55 psi & that is why I suggested a possible issue with the map sensor. But if you are currently at a running pressure of 30-40 psi, I would agree with what Chopper suggested way back then. Gotta get those numbers back up.

I have to hand it to you though. Not giving up on a problem for 6 months does show you are determined & resilient. I probably would have set the bike on fire by now.

 

[sincityharley]

I probably would have set the bike on fire by now.

You have no idea how many times I thought about it ! :newsmile07:

On a side note I just got back from a short ride with no sputtering. Fuel pressure is showing in the 55PSI range. I replaced both the starter relay and system relay. Looks like $11.95 part was all it needed. It only cost me a $1000 to find that out but I like I said I learned a great deal in the process.

I owe you a beer if you ever make it out to Vegas. Thanks for your direction