My car gets in bad moods, i swear to god.

90% of the time she is fine, boosts and drives lovely. The other 10% of the time she just wont play ball, she bucks, and sometimes plain just doesnt accelerate. I get all of the noises i should get, and no untoward noises - i get a full 10psi of boost, but the car just doesnt go anywhere! I just accelerates really slow...its almost like its bogging, it only happens when i floor it - if i ease her up she is generally ok.

Does anyone have any idea what is causing this? its not boost control because as i say, i get 10psi of boost. Its not a boost leak because it only happens every now and then, and i removed all of my boost pipes today and refitted them (although i did find a small boost leak)

Please someone help me, its really getting on my ****!

Spec is standard bar apexi filters, HKS sqb BOV and magnecor 10mm leads....65k mile engine usually works well however recently blown a coolant seal. (did the o ring fix)

The car did do this before the coolant seal went though...so i guess thats kindof a red herring.

Any help appreciated! thanks

 

what is the status of all regular maintenance? plugs, fuel filter?

 

plugs have just been done, just did an oil and coolant change, leads as i say are magnecor 10mm.

Fuel filter i havent changed, and i dont remember the guy i bought it off say he had changed it. He changed the diff oil, but i dont believe he changed the fuel filter.

Could it be fuel starvation?

 

Just change it if you are not sure, or else..."kabOOom"

 

waaaaaa whats the part number?! hehe

 

doesnt seem to sound like a regular maintenance problem.

if your engine is fine and getting 10lbs, is your clutch slipping?

coolant seal will cause loss of compression though, so even if u got 10lbs into the engine, that doesnt mean its coming out the exhaust. but then u would be overheating real bad too.

bucking + not accelerating means there is a problem. i would like to say a ground wire problem, but its probably worse than that.

 

Get a compression test done.. You might just have low compression in your rotors. Engine may be getting weak...

 

i have basicly the same problem with mine...... my girl has that time of the month as well..... as i have been told it is a mix of things.... i have auto i don't know if you have stick... but i have been told vaccum lines and apex seals, star mazda in LA cali, said i need new engine, i think this is worng becauze i still dust anything that comes my way... but check that and get back to me on it email me at ridge_racer07@msn.com

 

ok i will compression test the car when i get chance...probably tomorow.
I still dont believe that though, as its intermittent. Seems more like fuel/ignition to me. If i change after 5k i often get a soft pop out of the exhaust, and it misfired earlier at WOT in 5th (was testing boost pattern)

Any ideas at all?

 

Apex seal spring(s) could be getting weak allowing compression loss.

 

HDP this could be true, but doesnt really explain the misfire or the fact that its an intermittent problem that sometimes manifests itself and clears again 2 to 3 times per gear!!

and it also doesnt explain the fact that it just happened one day, out of the blue for no reason.

IMHO springs dont just get weak overnight... I Drove the car, it was fine - the next morning it had popped a boost pipe and wasnt driving right. Fixed boost leak, it still dont drive right.

 

That popping isn't misfiring.. It is exhaust gasses igniting in the end of your exhaust. This is normal if not running a cat or one in pour shape.

 

i know saiamne, thats why i mentioned the misfiring and the popping as two different entities.

Car is running a cat...dont know what condition its in though.

 

Ok, just went out and did quite a few boost tests. It either sticks at 10 and goes nowhere, or spikes and surges around, sometimes up to 14 (but the car is still very slow)

could the car possibly be retarding the ignition timing or something because it is detecting a problem?

im guessing its time to remove the UIM and inspect the vac hoses/check valves...

 

just as i suggested in the other forum.... check the hose going to your map sensor, the slightest crack or a lose hose can screw your car's acceleration instantly. a bad pump or filter can also describe your symptoms. i remember when my fuel pumps got clogged, the car could be driven normally, but when i accelerated, the engine would buck and shake before finally moving.

STOP DOING YOUR BOOST CHECKS UNTIL YOU FIND THE PROBLEM, YOU WILL BLOW UP YOUR MOTOR THAT WAY

 

Speaking from experience Mr. No boost gauge? :P
Sorry Martin I had to.

 

martin, i have checked my MAP sensor hoses, the pipes are not kinked and feel in pretty good condition - they are a little loose though (Can be pulled off without much effort)

nevertheless, its all connected ok...im gonna pull my manifold tomorrow night to have a look at it all

 

i didnt have a boost gauge when my car was stock.... lol now i have 3 woot woot!!!!

pfc, a mechanical one, and boost controller.... its a learning experience right dave?

 

zip tie it so you cant easily pull it off... if its easy to pull off now, imagine at 10psi

 

i understand completely what your saying Martin, and yes you are correct - but this still doesnt explain why the car does it so intermittently!

the hose has never popped off, and a loose one (Even at 10psi) wouldnt cause a car to go from slow to fast to slow 3 times in 5 seconds i would say?

Especially since it was working last week and ive changed NOTHING since then. The only thing thats happened is a boost pipe popping off...

 

when was the last time you changed the spark plugs? you sure the magnecor leads are properly attatched? (this past weekend my car was acting funny during a tuning session cuz one of the leading plugs werent connected properly). so double check that.

and just for the hell of it... could help, but probably not... disconnect the positive side of the battery, and step on teh brakes. this will reset your computer, turn your car back on and let it learn your idle for a few mins. (*make sure you know the code for your radio before doing this *)

im sure other people might have other suggestions, but im stumped .

 

Plugs are a couple of months old. but have been fouled recently due to leaky coolant seal. Leads i havent fully checked, will do later on.

I will try resetting the ECU too!!