350 Magnum EFI - 1995

[warrenfine]

I HAVE A '95 MALIBU RESPONSE, HAS THE 350 MAGNUM EFI S/N 349443 RUNS OKAY WHEN COLD FOR ABOUT 5 MIN. AFTER A FEW MIN IT STARTS TO CUT OUT ABOVE 3000 REV IT THEN GETS WORSE, CUTTING OUT AT LOWER RMP. SOMETIMES YOU CAN DRIVE FOR AGES AS LONG AS I KEEP UNDER 3000 REV BUT OTHER TIMES IT CUTS OUT AT LOWER REVS.<br />IF YOU LET IT STAND FOR A WHILE IT RUNS OKAY FOR A BIT THEN STARTS CUTTING OUT - IF I PULL BACK THE THROTTLE IT GOES AT THE LOWER RMP.<br /><br />I HAVE CHECKED ALL BASICS - FUEL LINES NEW PRIMARY FUEL PUMP, TANK VALVE, HIGH PREASURE FUEL PUMP STRAINER. I AM LEANING TOWARDS ONE OF THE SENSORS - I AM COMPLETELY STUMPED - PLS HELP<br /><br />WARREN

 

[newport dave]

Re: 350 Magnum EFI - 1995

I would suggest two things, <br />1) Check for trouble codes<br />2) Check the fuel pressure when the engine cuts out<br /><br />Dave

 

[warrenfine]

Re: 350 Magnum EFI - 1995

i guess that is way i am gonna have to go.<br />the problem is i dont know any dealers here in jhb south africa with the diagnostic equipment to test the box.<br /><br />i will have to look a bit harder see what i can find.<br />i was hoping to find somone that had experienced similar problem.<br />its all symptoms of fuel problem but the lines are all clear and filters good.<br />it is very intermittent ................<br /><br />thnks<br />warren

 

[warrenfine]

Re: 350 Magnum EFI - 1995

WARREN HERE AGAIN<br /><br />I HAD A LOOK AT THE INJECTORS AND THEY CUT OFF COMPLTELY UNTIL THE THROTTLE IS RIGHT BACK AND THEN THEY START GOING AGAIN UNTIL HIGHER REVS APPROX 3000REVS.<br /><br />I AM GUESSING SOMTHING CAUSES INJECTORS TO STOP SPRAYING<br /><br />WARREN

 

[johnbo]

Re: 350 Magnum EFI - 1995

I would look at the ignition system. <br /><br />I've generally found that aburpt misses are generally ignition related. (Although, an EFI system is certainly capable of that too). But, the fact that it seems to get worse and then repair itself for a while, could be a bad coil or ignition module.<br /><br />A bad coil can cause problems very much like this in cars/motorcycles especially in the presence of moisture. I had this happen on an old Yamaha bike, when I got caught in the rain. Turned out to be a cracked coil. Idling for a while would 'fix' it, by getting a chance to dry itself off.<br /><br />I hope that this helps,<br /><br /> johnbo

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS<br />HAVE ALREADY REPLACED COIL AND DISTRIBUTOR MODULE.<br />THIS JOKE IS STARTING TO GET EXPENSIVE. <br />DONT STOP WITH ADVICE I AM AT A DESPERATE STAGE.<br /><br />WARREN

 

[Limited-Time]

Re: 350 Magnum EFI - 1995

warren,<br />Have you got the correct service manual for your engine? If you have to trouble shoot the problem yourself it will be a necessity, and more than pay for its self in the long run.

 

[Reel Poor]

Re: 350 Magnum EFI - 1995

Check the fuel pick up tube. The fuel pick up tube may have a screen in it, possibly a few inches up in it. It would have to be removed from the tank to be checked.

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS LTD TIME<br /><br />I DONT HAVE A MANUAL - I BOUGHT THE BOAT USED AS IS AND UNFORTUNATELY IT DID NOT COME WITH A MANUAL.<br />WE STARTED WITH BASIC COMMON PROBLEMS COMMONLY ASSOCIATED WITH THESE TYPES OF SYMPTOMS.<br />UNFORTUNATLEY I HAVE EXHAUSTED ALL BASIC POSSIBILITIES AND HAVE COME TO THINK THE PROBLEM IS A BIT MORE HI-TECH.<br />IF SOMONE ON THIS FORUM HAS A MANUAL FOR THIS YR AND MODEL ANY ADVICE WOULD BE APPRECIATED.<br /><br />THNKS AGAIN<br />WARREN

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS REEL<br /><br />HAVE STRIPPED AND CLEANED OUT TANK AND CHECKED STRAINER - DEFINATELY NO RESTRICTIONS UPTO THE INJECTORS.<br />HAVE EVEN HAD THE INJECTORS CLEANED AND HAD SPRAY PATTERNS TESTED.<br /><br />ALL OF THAT IS TO SPEC.<br /><br />THNKS KEEP EM COMING<br /><br />WARREN

 

[newport dave]

Re: 350 Magnum EFI - 1995

Sounds like you may be going into "Power Reduction Mode". That is when the computer finds a problem and will not allow the engine to come up to full RPM. It cuts out the injectors just like you reported.<br /><br />It may be as simple as a low drive lube reservoir, or could be a actual issue where the engine is getting hot or has low oil pressure or it may be a sender and/or connection issue on one of the sender circuits.<br /><br />It would still be a good idea to check for trouble codes. You don't need any fancy equipment, just a 12 volt LED light and a paperclip.<br /><br />Here is a link on how to get codes.<br /> http://forums.iboats.com/cgi-bin/ubb/ultimatebb.cgi?ubb=get_topic;f=24;t=010024#000000 <br /><br />From the Merc service manual<br />

<br /><br />Dave

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS DAVE<br /><br />THIS IS EXACTLY THE ADVICE I NEED WILL GET ONTO THE DAM TOMORROW AND GIVE IT A TRY.<br /><br />WILL LET YOU KNOW HOW IT GOES.......<br /><br />WARREN

 

[warrenfine]

Re: 350 Magnum EFI - 1995

HI DAVE<br />I HAVE DONE THE LED TEST AND HAVE COME UP WITH CODES UNFORTUNATELY I DONT HAVE REFERENCE TO SEE WHAT THEY ARE:<br />CAN YOU HELP WITH THESE - THE FLASHES WERE AS FOLLOWS FROM THE BEGINING :-<br /><br />1 + 2<br />1 + 2<br />1 + 2<br />LONG PAUSE<br />2 + 1<br />2 + 1<br />2 + 1<br />LONG PAUSE<br />3 + 3<br />3 + 3<br />3 + 3<br />LONG PAUSE<br />BACK TO START AGAIN<br /><br />THNKS AGAIN FOR THE HELP<br />WARREN

 

[Reel Poor]

Re: 350 Magnum EFI - 1995

Code 1+2=code 12 System is operational<br /><br />Code 2+1=code 21 Throttle Position Sensor voltage high<br /><br />Code 3+3=code 33 Manifold Absolute Pressure Sensor voltage high<br /><br />I dont do a lot of these so some one else my chime in here. It is posible that both sensors are bad but there are a few other things to check first.<br /><br />Charging system over charging could be spiking voltage to ECU. Ck Charging rate<br /><br />Dirty connectors at sensors or ECU<br /><br />Bad/dirty wiring harness groung terminals to block<br /><br />Unplug both sensors then with key on engine off using a DVOM check for voltage should be 5 volt refrence at each sensor if over 5 volts possible ECU failure.

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS REEL<br /><br />I HAD SUSPECTED THOSE SENSORS BUT WILL CHECK THE VOLTAGES.<br />YOU GUYS HAVE ALL BEEN A GREAT HELP.<br />ANY OTHER COMMENTS WELCOME<br /><br />WARREN

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS REEL<br /><br />I HAD SUSPECTED THOSE SENSORS BUT WILL CHECK THE VOLTAGES.<br />YOU GUYS HAVE ALL BEEN A GREAT HELP.<br />ANY OTHER COMMENTS WELCOME<br /><br />WARREN

 

[newport dave]

Re: 350 Magnum EFI - 1995

Reel has some good suggestions. With both the TPS and MAP sensors setting codes, it could be a ground issue at the battery or the ECM. Before messing with the individual sensors, make sure all the connections are good, clear the codes and test the boat to see if either or both codes reset.<br /><br />You can clear codes using the LED/paperclip tool.<br /><br />1) Turn the key to the "ON" position<br />2) Insert paperclip in the DLC (terminals A and B)to put the engine in "Service Mode"<br />3) Move throttle handle all the way forward and then return back to neutral position<br />4) Remove paperclip from DLC (exit Service Mode)<br />5) Turn key to the "OFF" position. Do not turn key off prior to exiting Service Mode.<br />6) Recheck for trouble codes to verify codes have cleared<br /><br />Dave

 

[warrenfine]

Re: 350 Magnum EFI - 1995

THNKS DAVE<br /><br />YOU HAVE BEEN GREAT HLP. <br />I WILL CHECK THE GROUNDS ON THE SENSORS ETC.<br /><br />I HAD AN INJ PROBLEM RECENTLY AND IT CAUSED A BACKFIRE OR 2 AND I THOUGHT THAT THIS MIGHT HAVE DAMAGED THE SENSORS.<br />I HAD TO REPLACE THE IDLE CONTROL VALVE ASWELL AFTER THE INJ.<br /><br />I SUSPECT NOW IT MIGHT HAVE DAMAGED THOSE SENSORS.(BACKFIRE)<br /><br />I HAVE ORDERED NEW SENSORS ASWELL AND WILL LET YOU ALL KNOW HOW IT GOES.<br /><br />THANKS AGAIN<br /><br />WARREN

 

[warrenfine]

Re: 350 Magnum EFI - 1995

HI DAVE & REEL<br /><br />I CHECKED THE GROUNDS AND VOLTAGES AND PLUGS ETC.<br />IT LOOKS GOOD.<br /><br />I THEN RESET THE ECU - THEN CHECKED SERVICE MODE AGAIN AND THE ERROR CODES HAVE GONE.<br /><br />I WILL PUT BOAT ON THE WATER TOMORROW AND CHECK IF THE ERROR CODES RETURN.<br />DO YOU THINK THEY WILL COME BACK ?<br /><br />THNKS AGAIN<br /><br />WARREN

 

[newport dave]

Re: 350 Magnum EFI - 1995

A MAP sensor code (33) can be set by a misfire or rough running engine, so I'm guessing that one might not come back.<br /><br />As far as the TPS code (21), you will just have to run the boat and see if it comes back. <br /><br />If no codes come back but you still have the problem, you should next try to determine if you are in Power Reduction Mode. Locate and disconnect the oil pressure switch, temp switch and drive lube reservoir one at a time to see if it makes any difference.<br /><br />Dave