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2005 honda bf225

S

shawn jacob

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need help have a customer with a bf225 and the problem is that engine surges or actually is recovering idle rpm. I have cleaned the injectors,vst,replaced all filters,thermostats. plugs. cleaned and checked o2 sensor checked v-tec valve no plugging any where does not have problem over 1500 rpm at idle is smooth then rpm's slowly decrease and iac kickes open to recover idle rpm. has 225# comp. all 6 cyl runs out smooth but only at 5200 cust said always 5200 never more 19p prop no (mil)no codes . ran on shop tank will do this after warm up has shut off .plugs all the same more on the lean side but none different from the other. intake port coloring consistant
 
Did you cleaned the throttle body. ? And how was it,too black or normal.? try with another IACV , If not adjust the idle rpm buy adjusting idle air bypass screw. your engine should run without IACV (570 rpm after disconnect the IACV connector)




wajira
 
I don't quite understand the problem. Are you saying that the engine surges, then backs down? If so, at what RPM range?

On my engine, between 4400 and 4600 rpm the engine will surge about 100 rpm, then back down. It repeats this until it gets really warmed up, say from a long run, then straightens out. The Honda tech I deal with said this is pretty normal and explained that the ECU can't seem to make ups it's mind whether it wants to kick in the VTEC, or not. If this is what your customer is experiencing, then there may not be an easy solution except for possibly trading out the ECU.
 
wajira said:
Did you cleaned the throttle body. ? And how was it,too black or normal.? try with another IACV , If not adjust the idle rpm buy adjusting idle air bypass screw. your engine should run without IACV (570 rpm after disconnect the IACV connector)




wajira
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yes we cleaned the throttle body and all the plastic intake was filthy. engine slows and steady with iacv unplugged horn sounds need to get it back together in next hour or so but engine died eventually I think. ill get back to you on that. thank you . to the other guy it runs perfect over 1500 rpm the surge is from the iacv recovering rpm. engine was running fine last week then this happened. I replaced the water pump assy and the drive shaft bushing also impeller ok but plate and cup not , bushing was shot thermostats where stuck open. all new fuel filters, vst cleaned , inj cleaned. o2 cleaned
 
when it is surging advance the throttle a little, rpms are slow and will drop off . don't touch control and rpm will eventually come way up. and run smooth like it is loading up. it doe not have any codes for 02 but will it run the engine rich on the low end then stop over 1500rpm. It does not loadup or fluctuate rpm's above 1500
 
Bit confusing. Its clear your Idle air bypass is ok.I think IACV also seems to be ok but if you can try with another its better. you are mentioned that you checked Injectors? i had same problem,i found leaking injectors.at slow speed one or two injectors fuel dropping so run rich and rpm increase. then more fuel,engine struggle and stop.
That can confirm with fuel pressure.and check fuel regulator also.it might stuck closed.


wajira
 
wajira said:
Bit confusing. Its clear your Idle air bypass is ok.I think IACV also seems to be ok but if you can try with another its better. you are mentioned that you checked Injectors? i had same problem,i found leaking injectors.at slow speed one or two injectors fuel dropping so run rich and rpm increase. then more fuel,engine struggle and stop.
That can confirm with fuel pressure.and check fuel regulator also.it might stuck closed.


wajira
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Thank you I have injectors out and going to send them in and I ordered a new iacv anyways but the engine is loading up and rpm decrease then iacv opens to increase rpm . If you run up to 1500 rpm iit surges up and down then clears and rpm increase to about 2800 and smooth without touching the throttle . don't see the evidence on plugs . I'll definetly let you all know the outcome. I also need a special tool to check the fuel pressure their is no schrader valve. Boy I love yamaha's. But engine runs out fairly smooth at 5200 rpm continually .
 
wee bad news I sent injectors all ohm out good . 3 had fair spray pattern 3 had bad spray pattern and one leaking. they cleaned and all tested good. got new iacv and no damn difference does the same damn thing.
 
Shawn, I've seen the same symptoms you're describing [hunting & surging below 1500 rpm] plenty of times on Honda car engines and it's always caused by a vacuum leak, e.g. vac hose off, hose split, leaking IAC valve, or leaking diaphram, etc.

Bob
 
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I had this same problem on my bf200 last week,ended up having loose hose on intake AND a bad IAC and bad 02 sensor..
 
seem to be bad time, no choice now you have to try with IAC and check all vacuum hose.Did you check IAB (intake air bypass) butterfly ?,sometime this get stuck.maybe you already checked and clean,make sure it is working smooth.and vacuum hoses connect and no loose (vacuum tank also )




wajira
 
wajira said:
seem to be bad time, no choice now you have to try with IAC and check all vacuum hose.Did you check IAB (intake air bypass) butterfly ?,sometime this get stuck.maybe you already checked and clean,make sure it is working smooth.and vacuum hoses connect and no loose (vacuum tank also )wajira
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I have triple checcked all vacume hoses, cleaned butterfly,vac tank. Replaced iac , cleaned injectors,replaced all filters, plugs,no codes, checked o2 clean, problem on port side I believe no o2 on that side, no o2 codes, to me engine feels like a cylinder is loading up and rpms slowly decrease,then computer makes engine increase rpm by opening the iac , you can put in gear and increase rpm slowly on hose, under 2,000 and will fall down a couple times then take off if you go straight to3-4000 will not bogg as bad , in river not noticeable above 2,000 rpm or so runs out smooth. When you bring to idle in gear it lunges as it surges or loads up or whatever if I knew it would be fixed , but I'm pretty sure I don't have a vacume leak, and their are no whistles or sucking from anywhere but the throat.and iac , no engine noises, and good compression, no smoke , when I got the boat in there was a little black soot on the port exaust exit. None on the strb. I was hoping the leaky injector would solve that prob. I have not replaced the o2 sensor because of no codes and is clean. I don't think the prob is on that side anyways . He has trolled in the ocean for tuna with this motor for a year and a half that I got outta him.he had to have the damn thing for a tuna trip so it's gone but I'll be getting it back , I'm open to any suggestions, I really want to make this thing run right . Maybe by then it will blow up and we can put a Yamaha or a Suzuki on it.
 
I've been following this thread with great interest.

I don't think a bad HO2 sensor would cause surging like you described.

When you pulled the fault codes by shunting the service connector, did you get any codes at all? When you get the motor back, I would pull codes again.

I know you said you triple checked all vacuum hoses, but I would consider hooking up a vacuum gauge at several locations. Several of those vacuum hose locations are pretty obscure and a small split or hole can be hard to find. On page 5-3 of the Helm shop manual there is a diagram of the entire vacuum system. Looking at that, two things immediately come to mind - is the fuel pressure regulator operating properly, and does the vacuum tank have good connections, and holds a good vacuum - i.e. no pin holes. If you don't have the manual, send me an e-mail at [email protected], and I will try to make a copy and send it to you.

Speaking of the fuel pressure regulator, if you have or can find a fuel pressure gauge, you can hook that up by removing the fuel check service bolt, and check the fuel pressure while the engine is running. It should be between 41 and 48 psi at idle, according to the manual. Be sure to tie off, or plug the vacuum hose first. If that checks out, then it seems that would indicate there is likely a problem between the HP fuel pump and the injectors. If pressure is low, or shows variation, then back up through the fuel system. Pay special attention to the fuel line cut-off solenoid to make sure it is working properly.
 
Any possibilities to use Dr.H (Honda diagnostic tool ) ?,that might help to find the problem,everything tested,
all working fine but machine performing not ok.
like this problem normally we do take full time Dr.H report or if old model note down reading(against RPM- MAP,TPS,ECT,Injector time etc.) then same reading we have to compare with good working engine data. this system is helps a lot.




wajira
 
wajira said:
Any possibilities to use Dr.H (Honda diagnostic tool ) ?,that might help to find the problem,everything tested,
all working fine but machine performing not ok.
like this problem normally we do take full time Dr.H report or if old model note down reading(against RPM- MAP,TPS,ECT,Injector time etc.) then same reading we have to compare with good working engine data. this system is helps a lot.




wajira
Click to expand...
Huh???
 
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