Stalling after Start 91 GSX

[dvbrien]

Well after several days of reading about, Boost leaks, ISC, MAF, TPS, I believe I have unique situation... About a week ago I pulled off my intake manifold to swap out a bad gasket which was leaking around the egr valve which has been blocked off. After reinstalling the new gasket I started the car and was extremely happy to hear that the loud popping behind #4 had finally been silenced... the car ran decent and I honestly didn't run it for long because I still had to reinstall the drive shaft and some other things so I could drive it for the first time in 8 months.

After I got everything installed I started the car and it had seemed like I was running out of gas. Idling erratically and the stalling... After I got gas and was Really ready to go, I still had the same problem.

So here is what I've done...

First when I start the car right now my vac is at 19 and after about 8-10 sec. it drops to 5 or so, boggs a lot shakes around and then dies. My initial though was the FPR was bein overrun by the rewired 255 but, the injectors have never seen much more than idle. I'm not sure why but at some point when screwing around with it I unplugged the MAF and the idle seems to steady a little but sound as if its only firing on 3 sometimes. With it plugged in, If I try to rev. the motor it will hesitate for half a sec then respond. If I hold it throttle to a certain point it hesitates, then revs up to some given point, bogs back down and nearly or does die (all while holding the throttle in the same position). I have checked the ISC 29.1 all around and have also checked the TPS, Seems smooth throughout entire movement. I am getting a tank and other stuff to do a boost leak test today. Though I am pretty damn certain I have little to none.

It seems no matter what I come up with to test the car (when cold) will start up as if it is normal for about 8-10 secs. choke and die.
Any Clues here?
Sorry I haven't come to yall after the boost test, money it tight and a compressor and tank isn't an easy expense.
Thank you in advance for any help you can contribute.
Daniel

here is the list of my junk... 8.5 : 1 Ross pistons bored 20 over, eagle rods,
Hks stage 264 /272 camed, Ported /Polished head, Turbonetics Manifold, 20g. Hybrid 10cm, 3" Turbo Back, Arp Studed, Rewired 255 walbro, RC 550cc, Eprom 5 speed Ecu 5 spd. Conversion, Blitz POS /TT , 2G MAF, AEM Adj. Cam Gears, Godspeed FMIC.


I did forget, My ECU appears to be fine however I bought a TCU from another member and had it plugged in when I noticed the dreaded smell coming from it a day or 2 later. Can the TCU cause the ECU to go bad , something like the ISC could?

 

[jpbrazill]

When was the last time you replaced the fuel filter? This sounds like a boost leak, but you will not know until you perform the test. Thinking that you dont have a leak, and knowing you don't have a leak are two seperate things all together.

You should not have any issues putting the 255 in with a stock regulator. I had one in for almost a year with no problems back in the day.

Chances are, the reason it ran a little smoother when you unplugged the MAF is because if you have a boost leak, the MAF is not compesating for air, which in turn could help the AFR becuase the computer is not richening the fuel for lost and unaccounted air. Again, until a leak test is performed, it's like serching for that needle in the hay stack.

J.P.

 

[dvbrien]

Got a tank, made a tester... Found a bad weld on my Bov flange so far, Gets to 5 psi according to my boost gauge b4 it leaks. Gettig it re-welded tomorrow, so I can continue to test, will keep ya posted.
Thx

 

[Apeximprt2nr]

I would retest it for leaks.

Pull your plugs and see how they look.
They're gapped to spec right?
0.028-.031
Make sure you're getting sufficient fuel too and there aren't any leaks.
Was the fuel filter changed recently?

 

[dvbrien]

Leaks... fixed all that was making sound. I only have a little 10 gallon tank soo. I run out of pressure pretty fast. I found the majority of my leak was comming from the BOV itself... I changed the fuel filter a couple of weeks ago on a whim. Plugs look good gapped correctly. Getting gas for sure... Real frusterated with this damn thing. All I did was change the intake manifold gasket suddenly WTF! Is there any way to test the Maf/Mas ?I am not throwing any CEL check engine lights~ it would be great if I could drive...

 

[dvbrien]

Turned out to be th O-ring on the fuel pump letting gas escape back downward into the tank... Wasn't creating enough pressure to even get through the FPR... Yea~ Driving again!