VR starting issues and sluggish

[luxadore]

I am at my witts end here, I have a VR V6 and auto in my hilux and I have a hard time starting it and find it misses or coughs and splutters at any sudden accelerator movement but I can drive it smoothly up to say 20 odd percent throttle if I progressively open the the throttle as the revs increase but then it coughs and splutters at any more throttle input.
I have done a diagnostic check and it came back with 12, 36 and 56, normal opperation, vacuum leak and engine leaning out under load.
I have checked the MAP sensor voltage and thats well within range for my altitude and when placed under vacuum it reads a bout 1.8V lower just like the manual says it should.
I have checked the resistance of the injectors which all came in at about 14.5 ohms, the coil packs resistances all checked out to be fine, the alternator is putting out 14.2 volts, my fuel pressure regulator is not leaking from the vacuum port on the side of the regulator.
Has anyone got any idea what my problem could be? I don't know what else to check

[delcowizzid]

at idle you should have about 0.5 volts on the MAP volts what sort of reading do you get

[luxadore]

OK just checked it then it's 1.38-1.4V between the A and B terminal on the map sensor

[delcowizzid]

dont worry mate i was meaning the TPS anyway LOL brain fog today.

[luxadore]

haha great! you mean I accidentally stabbed myself in the finger with my multimeter probe for nothing! thats internet persuaded assault

[luxadore]

I am thinking my next step will be to change the fuel pressure regulator and see if that makes a difference, I wish I had the right test gear to check if it's working instead of just standing back and throwing money at the engine till it works right!

[delcowizzid]

did you fit the vr fuel pump in the tank or go external aftermarket pump or something

[luxadore]

I have used a federo lifter pump which primes a surge tank then 200mm after that it enters an inline EFI pump through a 1/2" hose, then exits the pump through an 8mm ID efi hose up to the fuel damper, through the rails, out the regulator, back into another 8mm ID hose back to the surge tank and then the return line from the surge tank back to the main tank.

[JA2Z]

You definately sound like you know what you are doing, but i have a stupid question for you..


have you been able to double check that your have the Spark leads going to the correct cylinders?

i've had a similar issue with the spitting and farting engine, when i changed my leads and accidentally crossed them, it wouldn't idle correctly. issue was simply that i had cyl 2 & 6 the wrong way round.

cylinder config is as below:


trans
-----
6. 5.
4. 3.
2. 1.
X

Front of vehicle
---------


or, your air flow sensor may be not working correctly, stuffing up the air/fuel mix

---------

hope that helps

JA2Z

[luxadore]

thanks for the tip cobber, I definately had that thought the moment I noticed the fault, after a quick check of coil numbers to DFI module orrientation, high tension lead routing and spark gaps I realised it was all correct and not the problem.....unfortunately.
I have a spare DFI module I am going to swap over and see if that makes any difference.
Also the ecotecs had air flow meters not the VR buick style V6's, they have a manifold appsolute pressure sensor, which I checked the opperation voltage ranges at idle and with the engine stopped but ignition on, at sea level, they were both correct according to the ranges specified in the gregorys manual.
I will also check the resistance of the coolant temp sensor and manifold air temperature sensor at ambient temps and compare the values to the gregory's manual.....just clutching at straws now hoping to stumble upon the real problem

[luxadore]

YAY I think I found the problem
I just changed the DFI module and............................................... .................................................. .........That wasn't the problem
so I popped the bonnet started the engine and grabed the throttle and snapped it open while the engine was running it just made a half arsed attempt of a fart noise and coughed up a lung, yep real responsive. So I figure the fuel pressure isn't rising to allow the revs to rise but I can't check the pressure with no equipment, what to do?
I get a pair of pliers and pinch the return line shut at the same time as snapping the throttle open...hey presto she revs, problem is the fuel pressure regulator? I sure hope so.
Off to swap it with a new one fingers crossed

[luxadore]

OK I fitted a mates spare fuel pressure regulator off of a VP and it's worked wonders, no error codes, smooth idle, instant throttle response, quick start ups, smooth acceleration and pretty bloody quick too (for a huge dual cab hilux on 33" tyres, bar work and suspension lift)
thanks heaps for all the tips and ideas along the way, this forum's search function is the bomb so much info and experience out there to help everybody

[delcowizzid]

sweet bet you are a happy lad now

[luxadore]

nearly! trans temp sits on 80-90 degrees celsius on the highway, not bad but want it a tad lower especially with towing and beach driving in mind
I have an inline gauge mounted right as the fluid comes out of the transmission before it gets to my two coolers I have.

check this out pretty interesting info about trans temp

TCI - TECHNICAL INFORMATION: Transmission Life Expectancy

[delcowizzid]

i wouldnt worry to much it normally goes through a radiator at over that temp to cool it so yeah should be fine if you have external coolers and the box doesnt slip much.to cold will be bad too.

[luxadore]

yeah your right coolants at least 82 degrees, the real test will be when I am towing the caravan which weighs 1150kg fully loaded and when I am driving on the beach and dunes have to keep a close eye on the temps, I can fit another trans cooler behind my bullbar if need be, maybe with a pair of 12V fans that can be switched on while towing or beaching