Car breaks up won't run under boost

[Blackonblack89]

Car runs decent untill you give it full throttle then breaks up cuts out won't run at all, boost gauge shows 3lbs never moves even when key is on it shows 3lbs, I found vacuum line that runs to map sensor it was run from map to fuel regulator, no vacuum hooked n anywhere so I teed it into back of intake runs ok, egr hooked up car won't run at all take vacuum line of egr and seems to run better could this be my full throttle problem?

 

[Camfreek]

I had the same problem a few years back, car would run great but under full throttle is would spit and spudder like no tomorrow, found out my cam senor cap was loose

 

[turbonut85]

Start by making sure ALL the vac lines are good and routed correctly. Got a scan tool?? Do you know what your MAF readings are??

 

[Blackonblack89]

I do not have a scan tool, the car seemed to
Have run better when the vacuum line going to pressure regulator was not hooked up to vacuum, when the egr is hooked to vacuum the car idles rough and tries to die, unhooked runs way better. I have currently put a 87 module and ccci hot-wire kit, replaced all plugs and plug wires it is a vacuum night mare I know that the guy I.bought it from had it all screwed up but it ran good that way! Also what's the difference in a code reader and a scan tool? I know code reader does just that but scan tool does it read codes also or what? The prices are about 200 apart but what exactly does a scan tool do before I spend the 300 to buy one?

 

[turbonut85]

All a code scanner will tell you is just that: trouble codes. A scantool like the Scanmaster gives you real-time readings and info while the car is running so you can monitor o2's, knock retard, and gives you the ability to set baseline paramiters on the car. i.e.: TPS sensor voltage, IAC counts etc... It will also let you know if the car is running rich, or lean so you can try to find hidden problems that you can't see or hear. A scantool such as the Scanmaster, is a DEFINATE MUST. Should be the FIRST thing you buy for the car, PERIOD.

 

[Blackonblack89]

Could fuel pressure be an issue in this problem? When you try to stall the car up it black smokes floods out, the fuel pressure regulator reads in the 40-60 range! I would think that's way high, with vacuum line unhooked off regulator it stays in the 30-40 range

 

[turbonut85]

Its possible, but your fp should be set at 43 with the line off. A scanmaster would tell you if it was running rich or lean. Could be the MAF, module, or loose harness grounds...

 

[PARKBOY]

Car runs decent untill you give it full throttle then breaks up cuts out won't run at all, boost gauge shows 3lbs never moves even when key is on it shows 3lbs, I found vacuum line that runs to map sensor it was run from map to fuel regulator, no vacuum hooked n anywhere so I teed it into back of intake runs ok, egr hooked up car won't run at all take vacuum line of egr and seems to run better could this be my full throttle problem?

Did you ever figure out what the problem was?

 

[Blackonblack89]

Yes sir I did the 87 ECM swap ran better but not under boost so I did away with stock air filter assembly and went with open cone filter, runs like a raped ape!!!!! It was not getting enough air!