JLANE

As persistence over comes Resistance here are the results

Starboard motor

Runs fine, fuel pressure was low at 35 at idle.... I cranked it to 42 psi still runs great. Vacuum is 11 pounds

Port motor still runs the same. Fuel pressure was 42 at 1300 rpm as thats the only place I can get it to run without surging. The full pressure also stayed constant up to 4000 rpm. Vacuum is at the 10 to 11 mark.

I reinstalled the the fittings and vacuum line to the regulator as well as to the gauge thinking maybe that was the leak.... no difference. Although when I pulled the vacuum line from the regulator the surging got worse.

So... now I'm at a loss...

JLANE

I used a Merc scan tool and this is what I got...???

PORT

Engine RPM 850-1400
Coolant Temp 85
Manifold Air Temp 92
TPS Volts .50
Trottle tps 0
Map Volts .72
Manifold Pressure 7
Baro Volts 2.09
Battery Volts 14.1
Spark Advance 3.1 deg
IAC position 41
Base IAC 21
IAC follower 20
Injector on time 2.7
Fuel flow rate 5.5



2nd run for port engine

Engine RPM 1400
Coolant Temp 115
Manifold Air Temp 107
TPS Volts .50
Trottle tps 0
Map Volts .70
Manifold Pressure 6.9
Baro Volts 2.09
Battery Volts 14
Spark Advance 9.8 deg
IAC position 77
Base IAC 77
IAC follower 0
Injector on time 2.8
Fuel flow rate 7



STARBOARD

Engine RPM 830
Idle speed 837
Coolant Temp 81
Manifold Air Temp 70
TPS Volts .52
Trottle tps 0
Map Volts 1.01
Manifold Pressure 8.5
Baro Volts 2.09
Battery Volts 14.2
Spark Advance -.03 (all over the board)
IAC Position 9
Base IAC 9
IAC follower 0
Injector on time 2.4
Fuel flow rate 3.3

I took both throttle bodies off and adjusted the port side to match the starboard side and then swapped them. I swapped one peice at a time and then ran the motors. The starboard motor runs fine and it has all the port sensors, ECU, MAP, IAC, TPS, and trottle body, yet I still have a surge problem. I'm at a loss???

JLANE

Theres only 82 hours on it. Wouldn't the scan tool pick up something if that were the problem?

Panther

[QUOTE=JLANE]I used a Merc scan tool and this is what I got...???

PORT

Engine RPM 850-1400
IAC position 41
Base IAC 21
IAC follower 20


2nd run for port engine

Engine RPM 1400
IAC position 77
Base IAC 77
IAC follower 0



STARBOARD

Engine RPM 830
IAC Position 9
Base IAC 9
IAC follower 0

QUOTE]

I noticed your IAC (idle air control) readings, they're all over. Is the motor making a loud air sucking sound at idle?

Panther

You may have a bad IAC and the motor is compesating by dumping extra fuel?

Someone mentioned that surge is from a lean condition? I always thought it was a rich condition from fuel puddling in the intake....

JLANE

I agree but I swapped throttle bodies and the starboard engine ran fine. The port engine has all the starboard sensors and it still surges.

Panther

Try swapping the ECM from one motor to another. You have the benefit of two motors, so swap away.

The Menace

I always understood that the surge was caused by uneven fuel feed. My idles were adjusted up to approx 11-1200 and surge when first fired up. Aftyer running a minute they calm down to a low surge if any at all.

JLANE

I swapped the ECM as well... no difference. I've run this thing ever evening on the driveway for the past 10 days I really have to wonder what my neighbours must think. lol

Anyway.... I really appreciate everyones input I'm sure will figure it out soon.

Jason

RichardCranium572

Your surge is caused by an over-rich condition. You verified that yourself when you pulled the vacuum line from your fuel pressure regulator and the condition worsened. IF the calibration is correct and this surging was not present before, and since you have swapped all the sensors and ecu.... I'd have your injectors cleaned and flowed, sounds like you got one that is leaking.