Main Menu
Advertisement
Affiliates
Advertisement
Newest Members
5lbtest, Short fuse 8_5, flymt, ken1, bbrandog
106356 Registered Users
Top Posters
TexDawg 86916
hopalong 78789
Pilothawk 75561
JDavis7873® 67385
John175 ® 65721
FattyMcButterpants 60793
Derek 🐝 58856
Tritonman 57718
LoneStarSon® 53702
SkeeterRonnie 53100
facebook
Forum Stats
106356 Members
61 Forums
811869 Topics
10249991 Posts

Max Online: 36273 @ 01/23/13 02:34 PM
Page 1 of 3 1 2 3 >
Topic Options
#12274413 - 06/01/17 09:28 PM Mercury EFI mystery
barbarian Offline
Pro Angler

Registered: 04/21/10
Posts: 637
1995 Mercury 175 XRI
serial #0G257838

Motor started cutting out at WOT, then it would act like it ran out of gas. Took it in, mechanic said fuel pump was not being given ground connect to turn on, but he couldn't find anything. Thought ECU might be going out or electrical. While he had it, it started working but he admitted it was not from anything he did. Next trip 2 miles from launch, acts like it runs out of gas and won't restart. Fuel pump is not coming on. Take it home and if fuel pump comes on, then motor cranks right up. Decide to send ECU off to diagnose and fix if needed.

So my ECU is headed to Dennis Hoffman, but a friend had me come over today and try his ECU. Nothing, pump would not come on. His did, but mine would not. Zero ground coming from ECU. Logic says it has to be issue from connection, but if we manually get fuel pump to come on, the motor still won't start. Fuel pump will be running, but motor still acts like it is not getting any fuel. Bubble is hard and I can pump gas through line.


Very frustrating. Great compression and spark per mechanic.


Any help?

Top
#12274533 - 06/01/17 10:34 PM Re: Mercury EFI mystery [Re: barbarian]
OPTI Offline
Extreme Angler

Registered: 06/23/04
Posts: 1428
Loc: Benbrook Tex
Fuel pump driver in ECM could be going out or also if battery voltage drops below I believe 9.5 or 10.5 volts it will shut the driver off most of the times I have come across this problem it was the pump driver. And on swapping ECM's if it is not the exact same part # as yours they will not work there 4 different ECM for a 175.....OPTI

Top
#12274677 - 06/02/17 06:41 AM Re: Mercury EFI mystery [Re: barbarian]
barbarian Offline
Pro Angler

Registered: 04/21/10
Posts: 637
I hope you are right about the different ECU's not working. Maybe that still could be the issue. Even though its the most expensive fix, its also the one of the most definitive and that is all I want - fixed and back fishing.


Edited by barbarian (06/02/17 07:50 AM)

Top
#12274718 - 06/02/17 07:20 AM Re: Mercury EFI mystery [Re: barbarian]
gary purdy Offline
TFF Guru

Registered: 05/24/03
Posts: 11205
Loc: Littlefield Tx & Lake A. H. US...
I don`t understand why you didn`t send the ECU in to be tested first 75.00. Other ECU`s will work. You can search yourself with your ECU # and find compatible #. I have replaced the wiring harness on a few of these motors. Have also wired the fuel pump direct to work off of the ignition switch.
_________________________
The world will not be destroyed by those who do evil, but by those who watch them without doing anything. Remember what He has done and remember that He is not done yet!-- GOD IS GOOD

Top
#12274774 - 06/02/17 07:59 AM Re: Mercury EFI mystery [Re: gary purdy]
barbarian Offline
Pro Angler

Registered: 04/21/10
Posts: 637
Originally Posted By: gary purdy
I don`t understand why you didn`t send the ECU in to be tested first 75.00. Other ECU`s will work. You can search yourself with your ECU # and find compatible #. I have replaced the wiring harness on a few of these motors. Have also wired the fuel pump direct to work off of the ignition switch.


Originally, my mechanic wasn't sure what the problem was and it seemed to start working. But it didn't. Debated what to do next then a couple people suggested sending it to Dennis Hoffman in TN which I did. While waiting on that process, a friend told me he had an extra to come over and see if it would work. We tried that last night and it did not work. My fuel pump still would not come on when starting. We would wire fuel pump direct and while it was running, try and start motor but even though fuel pump was running it would not start and acted like it was not getting gas. Which is where I sit now. So fuel pump is not coming on via differnt ECU's, but even when we get it running by wiring direct, there still seems to be no fuel getting to motor. I don't mind bringing it to a mechanic, but I can't let him spend unlimited hours searching. He's got 6 hours now without any luck. Dennis said he should have an answer on my ECU by Monday.


Edited by barbarian (06/02/17 07:59 AM)

Top
#12275110 - 06/02/17 10:31 AM Re: Mercury EFI mystery [Re: barbarian]
gary purdy Offline
TFF Guru

Registered: 05/24/03
Posts: 11205
Loc: Littlefield Tx & Lake A. H. US...
You might want to clean the fuel pressure regulator. Surely the mechanic checked that hidden fuel filter in the U shaped hose coming out of the bottom of the VST to the fuel pump
_________________________
The world will not be destroyed by those who do evil, but by those who watch them without doing anything. Remember what He has done and remember that He is not done yet!-- GOD IS GOOD

Top
#12275208 - 06/02/17 11:11 AM Re: Mercury EFI mystery [Re: barbarian]
barbarian Offline
Pro Angler

Registered: 04/21/10
Posts: 637
Nothing is surely anymore. This morning I did go pop the cowling and I've got fuel coming out of fuel pump when I manually hook fuel pump direct with a pressure of 35-40. That's where my lack of knowing much ends. It seems fuel is coming out of fuel pump, but motor acts like it is not getting it. I mean it will not even attempt to fire. Just turns and turn without a hint of anything.


Edited by barbarian (06/02/17 11:13 AM)

Top
#12275214 - 06/02/17 11:13 AM Re: Mercury EFI mystery [Re: barbarian]
TLW Online   content
Extreme Angler

Registered: 11/16/06
Posts: 2236
Loc: ft worth
gonna disagree with OPTI here.. we have ran every ecu imaginable (150 ta 225's, even analogs) on all different horse power 2.5's jus for testin' purposes.. you would be surprised on tha difference with perimeters in 'em.. some 150's ran better ona 200 than tha 200 and so on....

yours sounds like it may be tha ground in tha "ecu harness"... only common part that would effect drivers, includin' injectors, when swapin' ecu's......... but who knows for sure settin' here ona keyboard..

dennis will probably figure it out for ya though..............

Top
#12275350 - 06/02/17 12:45 PM Re: Mercury EFI mystery [Re: TLW]
barbarian Offline
Pro Angler

Registered: 04/21/10
Posts: 637
Originally Posted By: TLW
gonna disagree with OPTI here.. we have ran every ecu imaginable (150 ta 225's, even analogs) on all different horse power 2.5's jus for testin' purposes.. you would be surprised on tha difference with perimeters in 'em.. some 150's ran better ona 200 than tha 200 and so on....

yours sounds like it may be tha ground in tha "ecu harness"... only common part that would effect drivers, includin' injectors, when swapin' ecu's......... but who knows for sure settin' here ona keyboard..

dennis will probably figure it out for ya though..............


I hope. But heres where I get stumped. If Dennis says my ECU is bad and fixes it. I still seem to have a problem since the other ECU didn't work last night. That's the part that is such a mystery. Let's say Dennis says my ECU is good or says it is bad - either way he sends me back a good ECU. And the motor still acts like it isn't getting to fuel to fire??

Then what could causing the problem?

And if theres a mechanic within 2.5 hours of Houston who thinks they can help, let me know and I'll bring it to you asap. Not looking necessarily for free help. Just want to get back running again.


Edited by barbarian (06/02/17 12:47 PM)

Top
#12275384 - 06/02/17 01:10 PM Re: Mercury EFI mystery [Re: barbarian]
TLW Online   content
Extreme Angler

Registered: 11/16/06
Posts: 2236
Loc: ft worth
if tha fuel pump will run if ya put 12v's straight from battery, not from tha ecu. after testin', fixin', and/or replacin' tha ecu and know for a fact its good ta go thats when ya gotta look else where and harness is a main item... its tha only common denominator left really............

Top
#12275543 - 06/02/17 02:30 PM Re: Mercury EFI mystery [Re: TLW]
barbarian Offline
Pro Angler

Registered: 04/21/10
Posts: 637
Originally Posted By: TLW
if tha fuel pump will run if ya put 12v's straight from battery, not from tha ecu. after testin', fixin', and/or replacin' tha ecu and know for a fact its good ta go thats when ya gotta look else where and harness is a main item... its tha only common denominator left really............


You talking ECU harness?


Edited by barbarian (06/02/17 02:30 PM)

Top
#12275943 - 06/02/17 06:21 PM Re: Mercury EFI mystery [Re: barbarian]
TLW Online   content
Extreme Angler

Registered: 11/16/06
Posts: 2236
Loc: ft worth
yes.. i'm sure dennis will check from cannon plug and into tha ecu while hes doin' his thing but tha motor side of tha cannon plug needs ta be checked also... that plug consists of several small pins that can get loose and/or disoriented ta tha extent of partial/intermittent/no contact............ don't have a diagram here right now but pretty sure all tha drivers in tha ecu operate from a ground comin' thru that harness..jmo.


Edited by TLW (06/02/17 06:21 PM)

Top
#12276675 - 06/03/17 10:53 AM Re: Mercury EFI mystery [Re: barbarian]
BassCrankin Offline
Outdoorsman

Registered: 10/26/15
Posts: 59
Loc: Northeast Texas
I really don't know if this is even on the right track with your problem as I'm not anywhere near knowledgeable in mechanicism, but I have a 1996 200hp Mercury XRi and mine was doing pretty much the same thing last year. I would get WOT and then it would die, wouldn't crank, and acted like it was out of gas. Sometimes it would start with a hard start, other times it wouldn't crank for a few days. I changed my plugs, threw some sea foam in it, ended up having to change my starter in the midst of all this, and bingo, I haven't had a problem with it in a year. It cranks right up every time no problem and runs like a champ. The motor has always been well taken care of and serviced yearly, but I was at a point where I couldn't afford a mechanic and I did a few simple things myself. Like I said, I'm no mechanic, this may not even end up being anything similar to your problem, but I figured since I saw this post, I'd chime in with what I did. Hope this helps. May have been the wrong thing for me to do or I've jinxed myself and will have trouble tomorrow. Good luck!
_________________________
Bass Crankin'

Top
#12276679 - 06/03/17 10:56 AM Re: Mercury EFI mystery [Re: barbarian]
T-racer Online   content
Pro Angler

Registered: 08/24/16
Posts: 558
Loc: Melissa/Grand Prairie, Tx
The pins in the harness can get bent, had that happen on my opti computer.
_________________________
Bullet 20DC

Top
#12276773 - 06/03/17 12:15 PM Re: Mercury EFI mystery [Re: barbarian]
boatwhisperer Offline
Extreme Angler

Registered: 09/25/10
Posts: 1493
Loc: hurst, tx
what year model is the engine if it is an early model 200 EFI you may check the fuel hose for a plugged up screen the early ones had a screen in the you hoes going from the VST to the electric fuel pump
_________________________
boatwhisperer

Top
Page 1 of 3 1 2 3 >



© 1998-2017 OUTDOOR SITES NETWORK all rights reserved USA and Worldwide