Whats up with my redtop?

[ka24dave]

I got a 91 240 coupe with a redtop sr. mostly stock, only mods are a greddy profec b spec II EBC, fmic, downpipe, megan exh, hks ssqbov, (of course a walboro 255), and upgraded clutch. I have blown a few turbos before and replaced them no prob, but the last one i blew it looked like something was in the intake side blades and it chewed the blades down and caused shards of metal to get into my fmic (luckily it didnt get upstream the other side - it looked like it didnt get past the pass-side elbow hose of the fmic.) I may be wrong though becuase now the car (since the day i got a bad exhaust leak and the turbo blew) always bucks, pops, and backfires alot. if you granny the living hell out of it keeping out of boost it mostly drives ok, but then at times AND whenever you go into boost it feels like it has a miss and it sounds like a subaru from under the hood and my friend says the exhaust sounds like a turbo harley davidson.

the car often at cruising when heated to normal temp in any gear will sputter and miss not with every engine revolution (at least it doesnt feel like it) but every 50 foot or so it misses sometimes backfiring. my back bumper is covered in blackness so i know im running rich, but i also know there has to be more to it,

Ive already fixed the following problems on the car/or checked these things:

1. Oil pan dent fixed, pressure is nominal (abt 64psi cruising @3k rpms 5thgear.)

2. Exhaust leak from the turbo to mani-Replaced the gasket. HOWEVER i have a stud that stripped the threads in the block in the center underside on the manifold. and im almost positive its leaking (i need use of a smoker!) ...could this be my only issue?

3.I pulled my plugs and they are correctly gapped, the plugs not looking too rich or too lean. but 1 of them was a bit black, not bad enough to cause concern though.

also im not sure but i might have boost leaks as well...tried testing before using a can of computer duster, then i tried starter fluid....nothing happened.

I do not have a gasket on the elbow on the intake side that goes from turbo to the intercooler piping. but i never have had one there before either and it ran good...good enough to pull a 13.1 pass on 14 psi.

any help would be appreciated or any ideas

[ka24dave]

bump.............

[ka24dave]

bump.... surely there has to be someone out there with some useful info....

[ka24dave]

[homeslicej2]

vacuum leaks other than IC piping? Spark issues? How did you blow the turbo?

[ka24dave]

i dont believe i have any vaccum leaks, although i have had probs in the past with the crappy stock clamps (mainly on the brake booster hose) where it would fall loose and the hose would pop off under hard launches and sliding etc... but i checked my hoses and they look ok.

i really dont see any reason for spark issue but should i test the coil packs? and i really dont know how so any info guiding me the right way would be appreciated

and the turbo blew (im assuming) the same time my manifold to turbo gasket decided to fry a corner off itself, which happened at about a 13.5psi race against my friends honda cbr bike...

it was strange i didnt really notice the turbo going out nor did it make any odd noise like they usually do before they croak. the next day it just wouldnt boost past 4psi and i took it apart and thats when the blades looked like they got chewed up. since then it has always had a sort of miss feel to it.....

but hell, for my first win over a bike it was worth it.

[rustest86]

i had a leaky exhaust gasket on my KA-T and it did the same thing. you need to fix any and all exhaust leaks before the turbo for sure. do a compression test, and check for holes or anything in the piping or couplers, the blades fly off the turbo at a VERY high rate of speed and would only make a slit that would make an unnoticed vacuum/boost leak

[exode]

Its a boost leak. It could also be fouled plugs, or bad coils, look at the spark plugs and don't assume it is a coil pack because thats very unlikely.

Seeing how it just started I would put money that it's a boost leak. Do you smoke pot? Pull one of your vacuum lines off, and try getting a good hit into it. Then stick either a very low pressure air compressor (7-13psi) and push air into the line, look for smoke. Yes, it will have to be a joint. It would make your life a whole lot easier if you could find a shop with a smoke tester... thats the easier way I've found to find leaks.

No leaks? Don't be so sure, check behind the throttle body. Rev it up and feel around the injectors, check everywhere air goes. Most smoke tests don't get behind the throttle body. If your plugs are good I wouldn't say you blew your turbo, its a vacuum or boost leak, or you ef'd up your BOV. Which could still be considered a boost leak...

The pot thing was a joke, but it does work. And you do get the idea...be creative.

[ka24dave]

Its a boost leak. It could also be fouled plugs, or bad coils, look at the spark plugs and don't assume it is a coil pack because thats very unlikely.

Seeing how it just started I would put money that it's a boost leak. Do you smoke pot? Pull one of your vacuum lines off, and try getting a good hit into it. Then stick either a very low pressure air compressor (7-13psi) and push air into the line, look for smoke. Yes, it will have to be a joint. It would make your life a whole lot easier if you could find a shop with a smoke tester... thats the easier way I've found to find leaks.

No leaks? Don't be so sure, check behind the throttle body. Rev it up and feel around the injectors, check everywhere air goes. Most smoke tests don't get behind the throttle body. If your plugs are good I wouldn't say you blew your turbo, its a vacuum or boost leak, or you ef'd up your BOV. Which could still be considered a boost leak...

The pot thing was a joke, but it does work. And you do get the idea...be creative.

Well I do have a stud that decided to strip the threads in the block on the middle of the exh manifold... what can I do about it? one of my idiot friends suggested jb weld, and i called him a jackass. i do believe after driving tonight i hear a boost leak as well... time to hook the smoker up

by tomorrow evening i should have the intake side checked, im not doing the exhaust side though because im almost positive theres a bad leak now it sounds like it burned through most of the gasket.

[exode]

Did you strip the manifold stud or did you ruin the tap the stud was in? If you ruined the tap I would just get a larger self-tapping bolt and try that, it would make you life easier in such that you wouldn't have to take the manifold off. You could tap and do a bolt, same effect. If you wanted to do another stud you'd have to retap probably to npt and then put the stud in.

[sr28]

check the spark plug wires and the injectors.. check the fuel pressure regulator.. check the iacv.. i had a similiar problem.. and after correcting all of these it was fixed..

[ka24dave]

it just ruined the tap that the stud was in. I do not have any means to fit it either I guess i will have to wait for now til i can get it fixed....hopefully this is my problem! because the car runs and sounds like a 3 cyl turbo harley concoction and its very annoying

oh yea, and if this will help...

on my EBC it reads like -60 or so cruising @ 55mph..... when it has the miss

it is about -70 or so at the same speed when it doesnt miss.

[ka24dave]

also wanted to ask anyone who has a walboro255 fuel pump if they have had noise coming from them at random times and even peridoically during shutoffs. it will sort of, chime a semi high pitched tone for seconds then it stops. it was a new pump when i bought it 5 months ago and i have lately been running it below a 1/4 tank frequently.... is it possible i burned it up already?

[exode]

I've yet to hear of someone burning one of those up, but it is possible.