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Starting to get parts for MPFI conversion

5K views 41 replies 3 participants last post by  Brent79 
#1 ·
I’m now getting parts for the mpfi conversion. I have none of the parts yet. I will be doing the conversion with my Uncle who is a mechanic.

I spoke to a guy from a wreckers here in Perth WA, and asked him for a price on the parts. He said it is $210 for the air speed control sensor by its self. I then asked him for the rest and he said roughly $700-$800 I laughed and hanged up.

Is he right about the air speed controller or is he shitting to me?

I really want to do the conversion.

How much should I get all the parts for?

People that have done it, is it really worth the money and time spent?

Please help!

EA'S RULE!!!!
 
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#2 ·
WTF is an air speed controller??? LOL

Be warned dude, make sure u get all the wiring good.. id go with GRK's method and change the whole wiring loom. Dont
go rewiring as the guy who did mine stuffed it all up...

Good luck

Brent
 
#3 ·
ok

I did not know there was a air speed flow controller. I dont even know what it is.

Brent how much did it cost you for the parts?
 
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#6 ·
Re: ok

Ok I really need some help here. I have done the conversion but rather than fk around with mana folds etc i just ripped whole engine out and put in 4ltr multipoint. now before i did this i just had the trans fully worked. so it was working in a1 condition perfect. Now since i have put this new engine in i can not get car into top gear. and it knocks hard from 3 back to second it has no kick back unlessya do it manuallly.
someone told me it could be the fact that i have no gas in the air con. but i dont know. I have new computer in there i have tried diff comps and everything ya can think of.hehe

can someone help please i really need it

Regards
Tim Ker
 
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#7 ·
Re: ok

Nah dude, its coz you dont have a throttle positioning sensor attatched too yer 4spd auto. With the 3.9L multipoint, the throttle body has 2 TPS attached, 1 for the engine management and the other is for the auto controller. With the 4.0L engine, the automatic is controlled by the ECU so a 2nd TPS is not needed. What you need to do is remove yer throttle body and replace it with one from a 3.9L 4spd.
It will have 2 TPS in tandum. You should still have the wiring harness there from yer CFI, thou it may not reach too the TPS. You will need to cut it and lenghten the 3 wires.
Without the TPS, yer auto doesnt know how much gas yer giving the engine and it most certainly wont go into 4th cos when there is no TPS attached, the gearbox thinks you are not accelerating.

Brent
 
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#10 ·
Re: TPS

dude, it does go... those guys obviously dunno shit coz have you ever placed the car in drive with no throttle and felt it eventually go from 1st to 2nd and then 3rd without yer foot on the gas!! It will shift into 1,2 and 3rd but will not slip into 4th or lock-up... when i did my conversion, i had the exact same problem.. Have a look in your engine bay.. you should have a 3pin connector sitting there with colours brown, orange and green (i think they r the colours) this is the connector for your auto TPS. Im assuming they didnt remove this harness when they put in the 4.0L. On the CFI, it sits towards the rear of the engine bay but on MPFI models it needs too reach the front. Cut the connector in the middle and add about 30-40cm of cable.. that should be enuf to reach the throttle body. On your 4.0L you will have 1 TPS.
Problem here is that the shaft on the throttle body wont allow you too simply add another TPS in tandum, so you will need to remove the throttle body (4 screws holding it to the intake manifold) and replace it with a throttle body that has the longer shaft (only came on the 4spd 3.9L MPFI). Im assuming here that the 3.9L and 4.0L have the same sized throttle body and are a direct exchange, can someone verify this?
Once you have it on and connected up you will have correct operation of yer auto again. BTW, the jolt you feel when its changing down is coz the auto is kicking down too early and will revert to normal operation when u get the TPS operational.

Good luck

Brent
 
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#11 ·
TPs

ok cool that makes more sense to me now hehe

just to tell ya what i actually did so ya know what the situation is

IO took the whole engine out old one and the harness out totally

from clean engine bay put complete 4ltr in and also putin new Harness from a 3.9ltr Multi ea and changed computer as well.

There was harness already on the engine which goes to all the ingectors and the throttle body two plugs are there for the tps and then the main harness just goes into that one big plug off engine
and one more big plus from trans to the harness. or engine one of the two

does that make it any different for what i have to do ?
 
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#12 ·
TPS

Also if there is any one in perth that feels like meeting up and helping me with this would be apreciated.
makes it a bit easier lol but anyway i will do my best from the info i am getting Thanks heaps for the help i am getting at the momment much appreciated .. most help i have had ion the last4 months lol
 
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#15 ·
Re: TPS

What do u mean by 2 plugs??? The 4.0L should only have 1 TPS. Forget what the book says and look in yer engine bay...
look for the auto TPS connector, is there one sittin there unconnected??? If so, thats what yer problem is. If not then you have either removed the harness, or your wiring is still wrong. You said u replaced the wiring with a new 3.9L harness? Don't you mean 4.0L? Im not %100 sure on the similarities between the 3.9L and 4.0L wiring harnesses but they may be different... Just check to make sure first that 2 have 2 TPS in tandum on yer throttle body and that each one is connected in to the circuitry... Did you change yer computer over?

Brent
 
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#16 ·
TPS

ok here it is hehe i had a look there is one tps plug on the throttle. no spare plugs are there.

lets get the harnesses right that we are talking about.
There are Two harness right. there is a little one that
sits onthe engine goes to all the ingectors, tps, oil prssure etc. That one is a 4ltr harness it came with the engine rememebr i got the engine as a whole unit

then the big harness in the egine Bay, is a 3.9lt mpfi
harness becuase the 4ltr wouldnt work it was obviusly for an eb and plugs underdash were different.
so im using 3.9ltr harness in the bay its self which goes to everything. Engine plug Auto Trans. alternator, batt, etc

Everything plugs in hey.. nothing is spare..
all the shops around me are bloody useless they just guess none of them actually know anything LOL

anyway.. so what ya think from there
 
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#17 ·
COMputer

Yeah i have chnaged the computer as well.
as far as the tps on the 4ltr throttle there looks like there
is only one if there is two then there is only one plug
it is not a cable but a hard plastic plug which the harness wires into. which is only one plug and had three wires Green black and one more colour cant remember but yeah thats all i saw there
 
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#19 ·
TPS x 2

So i need to not one hey.. So as before if i get a 3.9ltr
throttle body with the two tps and the engine mpfi harness to match then shoudl be all good hey..

so basically the auto is looking for a tps that isnt even there ..
 
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#20 ·
Re: COMputer

Yep! The auto TPS connector should still be there, its prolly sitting under yer intake manifold somewhere. It is identical to the one sitting on yer throttle body! They/you shouldn't have removed it coz it doesnt combine with the engine management wiring. So you need to:
1) get a throttle body with the dual-gang TPS (it has a longer throttle shaft to allow 2 TPS to sit in tandum)
2) Extend the connector so it can reach the throttle body
3) Reset yer ECU

Hope this helps

Brent
 
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#26 ·
thottle body 4ltr

I have on the thottle body one plug looking thing on the side of it with one plug going into it and then on top and alloy cylinder looking thing as well whats that.

it was all making sense until ya said i had to keep my tps..


ihave a wreakers that have a thottle body and harness from a 3.9 for me but he said no tps

what shoudl i do

how is using that with my tps goig to fix it
 
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