last summer my car lost compression

[butlar]

Ok here is the deal. I only drive my talon TSI in the summer, and end of last summer my car lost compression. So a few weeks ago, I took her all apart to discover that my tming belt had stripped and i had bent some valves, no biggy. So i installed new headgasket with arp headstuds new timing belt, tensioner and all that stuff. May I add i also added DKS 272 cams as well and 750 CC injectors along with a eprom ecu burned for my injectors. if you read my profile you will see my up to date list of mods, i havnt posted much here because i search and usually find my answer. So i hooked everything back up this evening and the car ran pretty crappy, like it was missing or had a major vacuum leak. So first thing i did was double check timing, and it was dead on, second thing i noticed was when i pulled my old ecu which i no longer have stupid me for getting rid of it before i checked this new one but ohh well, the pink wire from my safc came out, so i dicovered that and thought for sure that was my problem, hooked it all back up, no CEL (but i think i got my CEL changed to shift light with my new chip, but i guess it will still show CEL's) but still ran crappy, better but crappy. So i proceeded to do a boost leak test since vacuum was so bad and boost leak tester held pressure until it blew off end of turbo. Now i thought i could hear hissing coming from drivers side back of engine somwhere around the intake manifold.

Secondly, i am running a MAFT which i have set up just before my throttle body so i know leaks before maft arnt going to affect system near that much, i am truly stuck and i feel like just blaming it on the chip or faulty ecu, but no leaky caps and was purchased from a reputable source. Also i tryed using propane around intake manifold, but that changed nothing, and injectore are brand new FIC 750cc so i find it kind of hard to blame them, but it is a dsm and I know its ###### just some stupid thing. I was wondering if someone knows what i should do next. I also replaced my plugs and wires, I was thinking of pulling injector electrical connectors one by one to see if that made a difference.

So to claify only mods that have been done sice timing belt stripped are.. NEw headgasket, 750cc FIC injectors, and dks 272 cams. CAr sputters and kind of idle surges like a vacuum leak and is rough, better when revved but rough backfires and misses for the most part and vacuum never goes past -10 and i know -20 is where it should be but it violently shutters between -3 and -10 very unstable vacum. Thank you any help would be appreciated, i know ther are so many things it could be but i wouldnt post on here unless i really needed to because i know how many bs newbie posts there are. thanks again

 

[TwoLiterLaser]

Twice in your thread you state what mods since the timing belt jumped, but not once did you state that you put in new valves. You did put in new valves right?

Are you using any after-market monitoring tools? Such as a wide-band O2? A set of big injectors, a chipped ECU and a MAFT with no way to monitor what is going on is not a good idea.

If you are having a leak at the intake manifold, which is after the GM MAF, then that is part of your problem.

 

[butlar]

I can monitor with datalogger. and i think i have a leak, but i couldnt confirm it with the boost leak tester, there are lots of people that run set ups like mine with ..safc, maft, and eprom chip. and of course i replaced valves that were bent.

 

[butlar]

UPDATE:
i hooked boost leak tester directly up to intake manifold , and it help 20 psi easy, so what i was hearing was ###### timing belt going around or something, but it wasnt a boost leak. Since i am runnign a GM MAF, i was wondering if that could be the problem, ive read a few posts and some people have had trouble with these. I would try to hook up my stock 1g mas, but my chip in my eprom is burned for GM MAF, i gues i could get another maf and try it, and thoughts?

 

[ROOKIE1]

Your statement reads as if car was running when tested . That is the only way you would hear the tbelt and mistake it for air . Don't laugh it has happened . Did you replace intake gasket when you did head gasket ? Lower injector seals ? Throttle body gasket or seals ? Is brake booster hose in good shape ? You will lose some vacuum when you use an aftermarket cam in alot of cases .

 

[butlar]

No. NO. What i meant was when running i thought i could hear a hiss noise, but when i shut car off and hooked my boost leak tester up to the intake manifold there were no leaks, ANYWHERE. So tomorrow I am going to try a different MAF. I checked all things you listed, they all checked out fine, keep the informative replies coming, thanks again.

 

[ROOKIE1]

750's . What fuel pump ? Fuel pressure regulator ? Could be a bad maf . I had similar problem with mine . I went with a 2g maf , dejon intake ..... Check my classifieds . How are plugs and wires . Gapped properly ?

 

[ROOKIE1]

I lost between 5-10lbs of vacuum when I switch to bc272 . I have been told some vac loss is normal .

 

[butlar]

UPDATE #2
Found vacuum leaks on all lines on throttle body, only little ones but found something at least.car revving fine now, but if i hold at sat 3500 rpm its is revving and every second or 2 it misfires like a popping noise misfire, Also it starts horribly, but when i give it some gas it revs to around 1200 stays there and runs a lot better but with a misfire pop pop pop. Secondly when fan cuts in its gets really rough again and dies sometimes.I haven't gapped my plugs yet, but i will tomorrow, it seems an awful lot like timing off by one tooth, but i checked and double checked and it isn't that. Well all of my marks are dead on for my timing so i don't see how it could be timing, but i have had timing off by one tooth and it is acting just like this, I havn't had a timing light on her yet , but i will. I hope gapping plugs helps, if not i wont know where to go from there.

 

[butlar]

fuel pump is walbro 255 and adjustable fuel pressure regulator.

 

[butlar]

update #3
changed my MAF today, no luck, next thing to check is fuel filter after that
it looks like it is either my ecu/chip, or injectors, any help would be appreciated. t has a miss if i rev to say 3000 and hold, it revs fine, then there is a constant miss miss miss a clear misfire noise.