Tohatsu MD90A Tldi missing at idle.

Anthony555079

Recruit
Joined
Jul 24, 2016
Messages
4
Hi All.
I am having an issue with my Tohatsu Tldi missing at idle.
During our last outing she wanted to keep stalling at low rpm when coming into the wharf but was performing great at hi revs.
I have done a lot to her as I plan on keeping her for a long time.
I have replaced the following parts with genuine new parts from boats.net.
3 air injectors, 3 fuel injectors, air rail, compressor, temperature sensor, oil pump, fuel filters, 3 ignition coils, 3 champion Rc12ecc spark plugs gapped at 1.0 mm, 105 amp hr marine deep cycle battery.
I have also recently done the head gasket and compressions are all around 150 psi when warm.
I have recently done a fuel pressure test and did notice that the tester gauge was jumping around quite a bit at idle in between 70 and 90 psi, is this normal on a direct injected system?
I have also replaced all of the gaskets on the throttle body, air box, reeds and engine base.
The electronic fuel pump is a Walbro GSC434 but I am having trouble finding information on it, is there a suitable replacement, GSS242 ?
 

pvanv

Admiral
Joined
Apr 20, 2008
Messages
6,500
Did you put the motor in diag mode and see what errors there may be? Did you reset the TPS initial setting? Have you checked the fuel pressure regulator?
 
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