hesitation

gtir_pimp

New Member
took my car out for a drive yesterday and everythings good. i sit in traffic and sit for even longer in the mcdonalds drive thru. i had been spanking it around so under bonnet temps were hot! when i leave mcd's it seems quite hesitant, like i put my foot down in 3rd and it doesnt seem to want to go like it should. i have a fmic so its not heat soak, but the pipe over the turbo does get very hot and i havent lagged it yet. fuelling is fine as it was on the rollers not long ago and it was checked. what could it be?

also something else is worrying me. 3 times this week i had left myR ticking over,give it a rev every now and then and after about 5mins today it wouldnt rev over 1500rpm! the other days took 10mins for this to happen. you hold the accelerator to the floor and it will rev to 1500rpm then drop to tick over, then back up,and down,and on and and on! what the hells going on here? ecu gone into limp home mode or something? Why? it done this to me once months ago when i had the bleed valve on the wrong way! it has greddy profec b 11 now. If you turn the ignition off and then on again the problem goes away, but then may come back after a while. it hasnt done it to me whilest driving apart from the time i fit the bleed valve backwards!
i have done a compression test and i have 155psi on all 4 cylinders and the ecu fault code check come back all clear 55.
is the ecu fooked? it was in since it was imported from japan, and has a daughterboard on it which i have no idea whats its tuned to. could it be overfuelling?
any ideas people? cheers
 

youngsyp

New Member
Have a check for vacuum leaks. It might be worth getting that I/C hot pipe lagged too.
Also have a check to see if any wiring is damaged, under the bonnet anywhere !

Paul
 

gtir_pimp

New Member
i have lagged the hot pipe today and took it for a drive, didnt really give it too much beans but seemed ok. perhaps the lagging has helped alot. but if i had a vacuum leak wouldnt the boost spike? it holds 1bar and 1.3bar absolutely fine. wiring should be ok as i had an auto electrician do a re-wire on it almost a year ago and i havent touched or played about with anything since. when driving along earlier when the car was up to temperature/hot, almost everytime i changed gear and put my foot down,half putting my foot down it popped and banged very loudly. people walking by took cover as they thought they were being shot!! overfueling? i read somewhere on hear that when it gets hot and running rich you will loose power? is that right?
And when its cold its not loosing power?
 
P

pulsarboby

Guest
yeah just check to see that its making a good tight connection and that the clip is holding tight as they can vibrate about when engines under load, causing bad connection.
 

gtir_pimp

New Member
righty ho, i will check that after work tomorrow. so how does this affect the running of the car, by not letting enough air through or something? i did put a new hks filter on it last friday actually so might of knocked it
cheers bob
 

gtir_pimp

New Member
i just checked the plug as i couldnt wait, and all is fine, its not dirty and it was very tight connection!
 

youngsyp

New Member
gtir_pimp said:
i have lagged the hot pipe today and took it for a drive, didnt really give it too much beans but seemed ok. perhaps the lagging has helped alot. but if i had a vacuum leak wouldnt the boost spike?
Nope, the boost wouldn't spike.
You'd have a lumpy idle and it wouldn't rev smoothly !

Paul
 

antgtir

New Member
Check the earth on the MAF. Also if you have someone near with a known good one swap it to see if yours is knackered.

If its only just started happening after you fiddling fitting the filter then id concentrate my attentions on that area.

Check to ensure nothing is blocking the flow path etc.

Ant.
 

gtir_pimp

New Member
it revs smoothly and the idle isnt lumpy. when you say lumpy do you mean like it has wild cams in it? because when started from cold it ticks over at 1500rpm and after 1 or 2mins its around 1000rpm, but its always done this, sometimes after its hot from some spirited driving it goes up to around 1300rpm, but not changing every 2 seconds.

took the filter off and theres nothing blocking it. i have a mate with a pulsar which i can switch bits. this may sound dumb but where is the earthing on the afm?
cheers
 

antgtir

New Member
You have to strip the earth wire on the plug to the top of the maf (im not 100% sure of its colour but id hazard a guess at black lol, test with a digi volt meter).

I soldered a new earth to the earth wire on the plug and strapped it to the body of the car close to the maf, it worked in improving the earth voltage but as it was not my particular problem it didnt solve my hesitation.

Try swapping the maf over, its simple and easy to do and will save you lots of annoying drives in the future.

With regards to the idle, check the voltage across the TPS, this can speed the idle up.

Ant.
 

gtir_pimp

New Member
this problem is all sorted now. im sure it was the earth on the maf. my mate stripped the earthe wire and earthed another wire to a bolt near the dizzy. not holding back and was rolling roaded at 290bhp and 290ft lb torque at 1.1bar 2 days ago so all is well :-D
cheers people;-)
 
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