confusing running issues ...SOLVED
Turbo Mini Forums

im hoping im going to be able to get some advice as ive reached the end of my ideas.
ive recently got my turbo refurbed on my basically standard metro turbo engine, its was running perfectly before the turbo came off..everythings now back together and besides initial starting problems due to a bad earth everything went back together as it was previously.
to start with the car was really reluctant to start first thing and would only do so if i didnt touch the throttle at all, to which it would just about tick over...if i really lightly dabbed the throttle the revs started to build up but if i suddenly applied any throttle it was back fire from the carb and jolt badly, and when driven on the road it was literally firing all over the place under any load at all... ive seemed to have got it going abit better now after identifying a dodgy HT lead but its still painfully under powered, doesnt like pulling away at all and feels flat and strangled

..ive checked the plugs to see how they look and theyare white in colour which made me think it was running lean...but i seems to be doing really low miles to the gallon.
checked each cyclinder is sparking and they are
re did the earth to be sure
had the carb off and the float was still in place ok with a decent amount of full in there.
ive sprayed wd40 on the inlet and it doesnt seem to be leaking.

i did notice there was very little if any oil in the dash pot, so put some in now but not sure if this could have initially damaged the plugs etc.
the exhaust is blowing badly from the very bottom of the down pipe ( its awaitng finishing after modding) but this would only effect over all performance ?

ill try my best to answer any questions that might help people give me some advice.. please beforei take a hammer to it

Edited by Bman on 18th Feb, 2010.

Have you set the fuel pressure at tickover? it should br 3psi. If you don't have a pressure gauge there is a way to set it without.

What else have you had to bits? have you taken the plenum off the carb? It's common for people to put the wrong gasket on blocking the signal/pressure feed to the float bowl.

I'd also say that the symptons you have could be caused by a dodgy ignition module on the dizzy. Somtimes they are wired up using the ballast feed which is only 9V. They don't work very well at this voltage and eventually fail.

So a few things to check.

Fastest 998 mini in the world? 13.05 1/4 mile 106mph

thanks for the reply...i set my fuel pressure to 4psi ..possibley some bad research on my part, and it seemed to run fine previosuly but obviously it could be that it wasnt running correctly before..so will drop it back down to 3psi.
i did have the plenuim off previously but this time round i removed the whole carb.
ill definitley check out the dizzy tho as so far any problems ive found and that have made it run abit better seem to be electrical. ill have to admit that my distributor knowledge is lacking tho :/ where abouts o nthe dizzy is the igniton module ? and is there any simple way of testing if its gone AWOL ... thanks for the help so far

its ok ive got off my ass and found so helpful posts on here regarding the modules so that bits ok.. ill post my updates as i work through them, any more suggestions would be greatly appreciated as its so far its throwing its toys out its pram

TBH I'd also check the very basic engine condition first, ie do a compression test (or better still a leakdown if you have access to the equipment).

Some of the symptoms you describe could be burnt/leaking valves or low compression for other reasons (ie, the bad starting, misfiring, lack of power).

Schrödinger's cat - so which one am I ???

is it worth me rullng out compression and valves due to the car being in great working order before hving the turbo off etc ?? its been sat for about 2mths without starting so im going to check some of the basic stuff like youve suggested and go from there...ive just noticed since turning the fuel pressure doen the car is revving higher now so it seems ot have atleast dropped the fuelling down to a sensible level..its now carrying on running breifly after ive turned the engine off so would this just be the mixture being abit off now ?

If you have a compression tester it is definitely worth doing the test, at least then you can rule it in/out.

Running on more likely is ignition timing too advanced.

thanks for all the info boys, its giving me plenty to check..its progressivley gettign beter and better...i guess once istopped treating it as one big problem and started working through each little bit ive found various issues.

bad earth.
dodgey HT lead
too high fuel pressure
and reset the idle
think ive now tracked down that despite checking it the inlet manifold is leaking pretty badly so thats coming off for a new gasket..aaaand i found a boost leak while i was at it, and re did a load of bad connections

fingers crossed boys we are heading in the write direction..sloooowly

another update after yet another day working on the mini..sorted the inlet gasket and replaced the ht leads and spark plugs which has instantly improved the whole car..starts better runs smooth pulls much cleaner etc im now down to one last running issue.
so here goes...now when i start to press on and try to accelerate harder it starts to pick up, boost starts to come on and it feels like a fuel cut defender or rev limiter kicks in, i thin kthe best way yo describe it is.

i literally starts popping power completley flattens out and it stop pulling.

would this be to a Lack of fuel supply ?

search for t pipe trick .

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

can you run the car with the fuel pressure gauge in line?

if so check to see if the fuel pressure tracks boost pressure (less 3 psi obviously)

do what tom fenton suggests, compression test it,

sounds simular to my problomn witch turned out to be a burn'nt/chpped valve!!!!

SKYLINES ARE LIKE CLITS, EVERY FLANGE SEEMS TO HAVE ONE: see this sticker on my silvia

the Search-section on this forum is blummin superb & simple to use, unlike some other forums, without the search-section & the help of this bunch of chaps on here i'll never be able to !!!Start the day with a 998cc turbo!!! :) i'm getting closer though!

Tom Fenton says: I have it all, make me an offer

your adice has been invaluable so far boys, and wanted to give a quick update... replaced the dash pot oil with something abit thicker and thats definitley helped and it feels less sluggish , and def pulls cleaner
replaced the vacuum pipe from the top of the carb to the inlet, and propelry blocked off the other vacuum, will do the t pipe trick aswell to rule out it being a vacuum propblem.
im now goin to take tom fenton's suggestion of it possibley being timing being to advanced but am abit down on knowledge with adjusting this. is this done by turning the dizzy slightly to advance or retard the ignition ?? if so which way retards it and which way advances it.

the engine is literally almost running as sweet as it was before , just that last little tweak needed hopefully

well boys im feeling like abit of a plank... after all the running issues and me constantly thinking it was going to be something big and ignoring my first hunch (timing) . i booked it in with the local mini specialists to get the timing checked and a test done on the coil etc...he rang me to say the timing was MILES out..i have no idea how that happend as it was pretty spot on previosuly and i havent so much as touched it since working on the car this time round
the queue starts here ----> to call me a nobb haha

anyway after tweakign the fuel pressure down abit more its pretty much runnign as before, ive got a slight boost leak to sort but im pretty certain i knwo where thats coming from...im almost certain the idle mixture is waaay to rich coz its literally bogs down like a bitch below 2000 revs, which was fun finding out this morning pulling away from a round about this morning with a bus coming..literally didnt move, i shit myself til it kicked in and i shot off down the road haha

nobb

Nob

Lol, glad you got it sorted :), its always good to trust your gut in my experience, second guessing yourself usually ends in greif.

3rd nob.

Glad you got it sorted bud!

its been a long stressful lesson hahah

best thing to come of it is that i found loads of other tiny problems that have all added up to a more sorted package.

i did notice aswell yesterday that when i was adjusting the fuel pressure, that the fuel pressure needle was spiking up and down between 3.5 and 4..didnt do it before but my new found " go with your instinct" philosphy checkedthe new fuse box that ive got running from the same ingnition power supply the fuel pump runs from, and what d you know as soon as i unpluged the fuse box stopped the fuel pressure going mad..not sure why its suddenly started doing it as im using the same power supply as i did before ..but hey ill save the hassle and run the power from somewhere else.

Thanks to everyone who gave me some advice throughout this post, proved invaluable