vr 5l bad on fuel, miss fire

[E-T-H-A-N]

hey guys, i bought this vr a little while ago, got it cheap. it had a bad miss fire when i got it, i got it checked out and the mechanic said it was dizzy cap, rotor, plugs and leads, i did this, it got better but never went away. i changed the map sensor last week, didnt do anything. ive also notice for a 5.0 its pretty pathetic in power. when its warm it gets alot worse, when i first start it up at work i put my foot down and it almost stalls. about a week after i got it, the fuel pump shat itself and thats been done since. i was thinking maybe o2 sensor? and it does around 300ks to a tank. wich isnt good because it takes me 3 tanks to see the week out.


any idea's ?

[mrv8]

I would check the base timing, also injector service as well? I do heaps of K's in mine, and a tank is more than enough a week for me, I do like 600k a week, with fuel still left in the tank.

[Scrubmonk]

Any error codes? Is your timing spot on? Have you done a compression test?

[petergl67]

Get a mechanic to do a break down test or a leak test I think it's called

[E-T-H-A-N]

its been to the mechanics 3 times, no error codes. i havent done a compression test yet. not sure on the timing ? i got told it has a cam, but if it does theres something wrong it doesnt have enough power for a cammed 5.0

[dirt drifter]

mine had a similar problem not long ago. missing real bad and chewing fuel but not lacking that much power, after replacing bloody everything it turned out to be a broken valvespring. if nothing else works maybe lift the rocker covers and check for a dud spring/ worn off cam lobe

[E-T-H-A-N]

oh yay that sounds pretty fun, can this cause me to drop a valve ? because that killed a mates engine :/

[dirt drifter]

yeah can do if the collets come out, if its ur problem to begin with that is. have u compression tested it yet?

if u do lift the rocker covers to check that everything is ok under there i highly recommend getting some rubber gaskets, not the cheapo cork ones.. i got them first up and they blew out straight away!

[E-T-H-A-N]

nah i dont have a compression tester, ill ask the mechanics at work on monday, where should it be sitting around ?

[dirt drifter]

as long as all cylinders are within 10% of each other they should be right. could be reading anywhere from 120-160 psi depending on how fresh the motor is

[E-T-H-A-N]

hey guys, a fella at work sugested to change my coolant temp sensor in the inlet manifold, a bit of dicking around and a can later, hey what do you know, no miss fire. buuuuuutt, for some reason in park/ N it sits at around 1500 rpm and in drive 1000, now the thing is this thing is suposed to have a cam in it, my theory is that because the sensor was stuffed it was'nt idle'ng right, i think that the old owner may have thought it was the tune and got the idle set higher, and now that the computer is getting the right reading the idle is now too high, does this sound right to you guys ? im going to phone a few places in the mornning and try get some one to have a look at my tune. doesnt help me not knowing the cam specs though. its not huge though.

i did try to loosen the throttle cable and reset the computer but they didnt work, i thought it was worth a try though.

[Scrubmonk]

Nothing will beat a custom tune specific for your cam.
To adjust your idle, there is an adjustment screw for the throttle butterfly that sets how far your throttle is closing at idle. Try screwing it out maybe 2 turns to start with and see if it makes any difference to your idle. (Make sure there is enough slack in the throttle cable to allow it to close further.)
It is also a possibility that your IAC (Idle Air Control) valve on the throttle is stuck open as well.

[E-T-H-A-N]

yeah i played around with that little screw and the throttle cable, it didnt make a diffrence. so my next thing is IAC, bursons are the only place that carry that kinda thing in stock, so getting one in the mornning hoping thats the problem.

[E-T-H-A-N]

ahhhhhhhhhhhhhhhhhhhhhhhhhh so i changed the IAC, the idle dropped and its miss firing again, #### this car lol.

[E-T-H-A-N]

anyone have any other ideas ? lol

[E-T-H-A-N]

i figured out, after i did everything, i put e10 in it, has anyone else had a problem with it ? ive spoken to a few people and they recon e10 is just crud and yeah...