problems...

[evan]

i have a super duper weird problem. when i go to accelerate after changing gears the thing just dies. like it slows down FASTER than when i back off. if i take my foot off completely and wait a few seconds i can accelerate again. REALLY shits me. AND the thing makes a funny trumpety type noise when i try and rev it (sometimes). i have no fcuking idea, so if somebody could give me a few pointers that'd be nice!

[Seano]

G'day mate

Why do you think its to do with the LPG system? I'd say your auto is screwed mate. My old 3sp was on the way out for a long time.. slipping reverse rear.. dodgy gear changes. AND every now and then it would go to change into second gear... and seem to not quite engage second.. car slows down massively before finally slipping into second. it also only seemed to happen on a cold start, when first driving away.

sounds identical to your problem, i'd get the gearbox checked out however it sounds like you'll be up for a new gearbox or a rebuild :)

[evan]

yeah my auto is REALLY screwed, i have to shift it manually even!! and the shift pattern isn't in a straight line anymore... it's more like an H... :P

nah thanks for that LOWFD, but i should have mentioned it's a manual!!

i know it's not the gearbox or the computer.

[rustydave]

It could be plugs and leads .As by the sounds of its braking down under load .Maybe even timing .Mines doing something like this and its in the leads and plugs .But its got to wait till these money for the parts

[Seano]

yeah my auto is REALLY screwed, i have to shift it manually even!! and the shift pattern isn't in a straight line anymore... it's more like an H... :P

nah thanks for that LOWFD, but i should have mentioned it's a manual!!

i know it's not the gearbox or the computer.


haha yeah vital bit of info that one :P funny because it sounded identical to my problem until you mentioned the gearbox!

[evan]

hmm it's not breaking down under load, cause i can plant my foot and (sometimes) it'll hammer, it's more when i back off and go to put my foot down again it doesn't do anything. It FEELS like the throttle cable is sticking shut but it isn't, which is why i'm blaming the LPG as i don't know what else it could possibly be...

??? ??? ???

[84LTD]

i had a similar problem a while ago. i suggest you should check your air flow meter especially if its backfiring. also check plugs and leads. hope this helps.

[WYLDXF]

you should take your car to lpg experts and get em to tune the converter up, it would help your starting alot better and could solve your problem if its a lpg prob, our workshop gets alot of cars on gas commodores and a few els n shit on gas usually we have to take em to get tuned up, you carnt even tell if the car is running on gas or petrol:P

[evan]

yeah my AFM is pretty screwed too, in fact it must have broken and fallen off!!

... i should have mentioned it's straight gas, computer doesn't do ANYTHING (but it's still there cause i cbf ripping up the inside) with an impco 200 and a B2. Thanks WyldXf but it starts fine with the primer, and it drives better than it did on petrol (no joke) but i guess i will have to get it looked at...

[Gab250]

Going back to Petrol will solve all your problems if it is LPG related, not good on the wallet but good for the engine.

Gab

[evan]

yeah but then i gotta get the tank back in, rip all the gas out, it's more hassle then getting the gas set up. plus it's cheap!

[Xfish]

are there any pictures of your set-up?

[evan]

are there any pictures of your set-up?

there is now!!!

i've been told it might be because it's running too lean. i've also connected a balance line since that photo but it didn't help. changed the dissy to a mechanical one also...

[evan]

oh and i found today that if i leave my foot semi-down while i change gears to keep the revs up it never happens... ???

[Xfish]

have you diconnected the idle speed control........Because that's controlled by the ecu.......and your running straight gas. could be causing it to F%&K up.

[evan]

have you diconnected the idle speed control........Because that's controlled by the ecu.......and your running straight gas. could be causing it to F%&K up.


nope but i will! thanks for that!!

[PSI_LTD]

nah, that's not your problem.
99% chance your gas feed line is too small. i'm guessing you've got 1/4". i had that on when i was n/a, and it did a similar thing you describe (also helped by recoing the lpg converter). When i went turbo, the problem got worse. now, using big gas lines problem is gone.

[evan]

hmmm... i would have thought the line would be more than plenty? i was told it flows more than enough for 300hp???

the convertor has been reco'd at some point, and that snort kit is still in the pipeline :P

[drew442]

what size line is recommended?

please post here

http://www.xfalcon.com/forums/index.php?topic=122.0

[WAYCON]

What tank are you running?

I had similar symptoms running off an older (read early 90's tank) and sometimes the car would completly stall. Had it in and out with the shop over two months trying this and that until they figured out it was the excess flow valve deciding to cut on and off (or more often than not getting stuck half way in between). If the car stalled you could get out and pop the boot and listen to the little bastard clicking on and off trying to right itself.

Might not be the problem at all - but the symptoms sound similar

[xevan]

Ive just had an almost identical problem less the trumpet noise until the car stopped completely 2 days ago.
1. Rooted coil
2. 1 spark plug lead loose and rooted, when an ohm meter was used it showed no conductivity at all, should be a few thousand ohms.
3. The Hf lead (between the coil and distributor) with a too high ohm reading
3. Slightly broken wire controlling one of the solinoids on the gas line

Fixed these and now it goes like shit outter a shangeye, was quite amazed. My engine is an auto, carby 250.

[evan]

hmm well we tried richening the mixture a bit and it progresses through the dieing bit faster, but it's still there.

i've got to get it on a dyno to check for sure, it hasn't been properly tuned since we put the gas in...

but i'm coming up to the 250k mark so i'll give the ignition system new everything also...

[PSI_LTD]

hmm well we tried richening the mixture a bit and it progresses through the dieing bit faster, but it's still there.

i've got to get it on a dyno to check for sure, it hasn't been properly tuned since we put the gas in...

but i'm coming up to the 250k mark so i'll give the ignition system new everything also...


that is well and truly the lpg line.
get a bigger one. 5/16 will solve your problems, but a 3/8 will protect for future mods.

[XFSpac]

Sounds almost like mine when i am low on radiator fluid. The gas can't heat up or something.

[laredo]

perhaps your throttle is way over centre when it's being tromped.....or you are very low on lpg.

[laredo]

well,ive just returned to see if meethed has posted us any answer to his performance delema with his b2/impco 200 series efi throttle controlled lpg setup.just a thought,but would he have left a rag inside the air intake at one stage and it suddenly said ha..ha..ha.

[evan]

it took me a while to remember this problem, why do you people keep bringing threads from the dead?

i haven't owned the car in question since mid 2007. think i sold it in june. had a few issues after this one which led me to end up fixing a few bits and selling it on.

for those who have been holding their breath for the past 3 years, the problem was a dirty mixer. the diaphragm was gunked up hardcore, as was the centre bit that it slides on.

as you put your foot down, it was getting stuck, preventing the mixer from letting in enough of the good stuff.

the reason it happened mainly when shifting was because of the sudden change in vacuum across the mixer as you take your foot off and put it back on.

give it a hit with carby cleaner and was good to go. even got a chirp shifting into 2nd one time!


thanks to everyone for the suggestions. thanks to XFSpack and laredo for rekindling memories of that piece of shit. good times.

[laredo]

well now shes a fixed problem.its good to know,with all the imputs and suggestions,that we had it all wrong.just goes to show you that theres always a variable cause to a problematic car/truck.cheers for the symptom cause and solution.