Right where do i start finally finished fitting my new project in to my sierra 4x4, managed to get hold of a couple of kits for a sierra dohc and rebuilt the engine to mate i up to it. Had a pig off a time to fit it as i was short of time due to this being my everyday car. After finding a load of faults got it running and it goes brilliantly EXCEPT that it dont seem right on boost. If you give it full throttle it goes but feels like its holding back, if you then let off the throttle to about 1/2 - 3/4 it takes off.

This car is not your off the shelf turbo as to control the timng and extra injector TT have used an extra ecu, loom with additional map sensor so it makes it a harder to trace faults.

I am a novice to turbo's as i have always had n/a cars so please any help as to what my hesitation could be would be appreciated.

 

one question, how much boost is it running and what plugs are you using and what are they gapped to. Does it missfire at all in high boost ?

 

Its running on bcp6es which is what the TT plate recommends left the gap as factory because the plate did not say what do you recommend, cant say for sure about the boost as i have not got a gauge in yet but if it is as it should be its only 6.5 psi. It certainly doesnt eem to be missing just really hesitant as i said almost like it is missing and when you give less throttle it cures itself.

 

Check your TPS output, and try tweaking up a bit, but CO must be checked on boost as well.
tabetha

 

Will check it, had that in mind but had no had time to try it out but how do you mean tweaking it as it just bolts on no room for adjustment. How do i get the co level on boost. I guess its a rolling road job. Whilst on the subject would people recommend any in south brum area, was thinking of reyland as they are not far from me?

 

Reyland are ok, it is hard to say what to do on this as it is a uncommon conversion, so is only guesswork, is there any way you could file slots on the TPS fixing to allow some movement ?
tabetha

 

Maybe they are small spacers to stop you over tightening it, could file one side out. Which way do you think i should twist it?

 

Watch the direction of rotation then move slightly the other way so it has some more reading to start with.
tabetha

 

i used to run this conversion, infact i ended up having ne running 14psi of boost,
2 things

Firstly you ned to make sure the DCU is working, it only uses a pressure switch, you should have a pipe t pieced into the unit to show it vacum and boost,

You need to make sure that this is working when it sees anything over 2.5psi it will trigger the injector until your under 2.5psi again.

2, There is a wire you need to earth so the ecu's map changs to run a lower RON rateing (the earth adjusts it to 92 Ron instead of 95), you must also run super unleaded to avoid det

dont forget your running a 10.5:1 compression engine, you should be on a T25 also, if its genuine TT Kit

 

Hi there it is running the original T25 turbo from TT as i wanted to keep it all relatively standard. With regards to the wires your on about Mine does not have the pressure switch on this kit, the other kit i have got does but i was missing the frequency limiter for that so bought another car which had a later conversion and the loom was nothing like previous one. It is alot like a 2.9 TT loom and relies entirely on map sensor.

When you say wire to ground for ron rating i assume you mean the service lead for the ford ecu (little white plug by the coil). I looked on the car i bought and there was no earth lead on this but i am aware of this and tried to short it to earth and did not seem to make any difference.

Had a look at plugs last night and gaps are all ok tested the tps and all seemed to be ok was getting an output from both map sensors ford and TT (vauxhall) one. Took it for a quick run and it still seems the same hard to explain but could be detonation. It does not seem to want to go when on low revs and you give it full throttle let off a little bit and it picks up, the further up the rev range you get does not seem to be as bad hard to explain even harder for you to understand.

One last thing read some info of yours some where and tried it on super unleaded did not seem to make any difference. Really want to sort this because the car other wise is great any suggestions greatly recieved.

 

It must have a pressure switch, its built into the DCU, it must have a vac feed going to it, if not will not trigger the injector.

They lead does need to be earthed, even if you think it makes no differencem, it will when its running right

They do run better on Super because of the octane rating and can reduce det

Are you local, where you based

 

I am birmingham so not really may try to get to a couple of shows this year to so let me know where you will be and i can aim for it.

There is definatley no switch i know the one you mean as i have it in the spare manifold i have which runs the old type TT loom but to be sure i got all the bits off the donor car i strppied the whole loom out as i did not want to be short of bits like i was with the first kit i had the only sort of pressure sensor is the map one. There are 2 earth leads which both came off the battery -v and thats where they went back. there were 5 points on the loom map sensor 5th injector earth coil connection and splice the spout signal from the ecu no extra wiring or switches/sensors off the car

 

sorry to bring this thread back up,

Jase, ive done this DOHC conversion.. and my MF2 injector unit, is opening my 5th (cossie yellow) injector fully, from 4000rpm... and im only on 6psi..

do i have scope to up the boost at all.. if yes, what to? cheers

 

sorry to bring this thread up again but in having the same problem as the OP. how do i earth the white plug beside the coil?

 

where are you all getting these kits from?

I want one lol