ProfitOfDoom wrote:
Well I put the new map sensor in,and took it out,,It did better,,still a dog on the jam of the throttle,but it built up quicker and got up to plane. Tested it a few times and had the same result each time,,sluggish at first then gradually picking up speed then once I get up to plane rpms jump higher into the normal range and will continue just fine.
I tried to clear the code and im pretty sure it worked but when I came back from my trial run,I plugged up the diy code reader again and it was showing that same code even after the replacement of the map sensor "code 34" Im gonna try to clear it one more time "maybe I did it wrong" do another test ride and see what happens.
A guy down at the marina said maybe my DP props are not aligned up right,I thought I read before it didnt matter which way they go on,Could this be a issue?
Glad to hear you're making progress, and it's currently DIY so not costing you a fortune in mechanics fees.
Although these issues are sometimes very frustrating and not immediately easy to fix, i'm sure we'll win in the end!
As mentioned the prop comment is irrelevant and i'd forget about that.
I'd check you cleared the code, and try again, although as it didn't run perfectly i'd sense there is something else amiss.
The fact at High RPM it ran well and fine is a good thing, we're getting there.
The MAP Sensor, Air Idle Control Valve and Throttle Position Sensor are very closely linked on these engines with Early Fuel injection and work together; it is very possible that there is an issue with something else which is causing the ECU to assume the reading from the MAP Sensor is incorrect.
Out of interest, in Neutral, does it freely rev up and down the range? Are the issues just when in gear and moving under load??
The first thing that springs to mind is the Throttle Position Sensor, this reads how open the throttle is and together with the Manifold Vacuum reading tells the ECU Parameters related to load, performance, and fuel metering.
It's possible the TPS isn't functioning correctly and the ECU is assuming the fault is with the MAP Sensor; i'd test the Throttle Position Sensor, which you can do with a multimeter. It should read under 1 Volt at idle, to about 5 volts or so at WOT. You can test this with the engine not running, by the way, it is much safer. If the Throttle Position Sensor has worn and the voltage reading at idle/low speed is incorrect then this
may be the cause of your issues.
The second thing to check is that the Air Idle Control Valve is moving and isn't stuck closed. With the air filter off the engine, looking into the throttle plate, have an assistant turn the key - not to start the engine but just from 0 to 1, the position before turning the engine over. The fuel pumps should come on but also - the Throttle Position Sensor should buzz and the pintle should move a tiny bit back and forward.
I must say in situations like this, I'm very hesitant to just buy parts without testing things first, as it can be an expensive, frustrating and fruitless way of fixing problems - so although this problem is annoying - please please please persist with checking things before buying new bits - The MAP Sensor may well have been dead but you will end up spending unnecessary money by just changing things without electrically testing them first!
If it helps i have a MEFI Diagnostics manual on pdf from when i had these issues with my boat. It's almost 300 pages long and very comprehensive, but may help as it shows all trouble codes and then has schematics of how to test and diagnose based on the code that flashed up.
If you think it will help then PM me your email and i'll email it to you - like i say it is very comprehensive though!!
But... for now, i'd check the code was clear and go for another run - if it's still not running right and the code reappears - and the MAP Sensor is new, The hose and wiring to it is good and functioning, I'd check the Throttle Position Sensor is working correctly, and the AICV moves.
Cheers
Phil
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