Starts and dies after about 3 or 4 seconds
 

Ok, first a rundown on the car. Just rebuilt and streetported.
88 TII
All emissions removed and blocked off.
full 3" rb exhaust
true cai
safc
walbro 255
750cc secondaries

i think that's the most important stuff.

ANYWAY....car is put back together from the rebuild...and it runs for several days. It was having a problem with loss of power at 3800 rpm to start with, but made good power up till 3800rpm. Well, the car died after a few days (battery/alternator problem). Fix that, car still runs with the 3800rpm problem. Well shut car off, come to start it the next day and it starts...runs for 3 or 4 seconds then dies....can't keep it running giving it gas...it just dies after a few seconds of starting. Pulled the intakes off and there's no vac leaks. Ran a straight line off the battery...and fuel pump is coming on. The afm seems to be working fine. SO...what else should be checked. Again...car starts up immediately...no problems...but dies after a few seconds. What else should be checked? Is there a way to test the ecu? Will the car start if the ecu isn't working properly? I have an NA ecu laying around. Can that be used to start a 88tII? Just to see if it'll hold an idle? Give me some opinions.

Did you jumper the fuel check connector and try to start? This really sounds like a Vac Leak/AFM problem to me. Also, there have been some that have started a TII on an N/A ECU.

check your fuses, if you were having electrical problems that may be a good place to start

Sounds like you have a pore grounding syste. And a fuel issues normaly chalked up to the AFM. The NA ECU will run the car just fine with your setup, but I would retard the timing around 7deg on the CAS just to keep me happy.

The AFM fuel pump switch is wierd, I have taken mine off to paint it put it back on and the internal wires inside for the pump were all bent out of shape and some other crap. HAILERS has a few posts you can search on of the AFM taken apart and diagramed out. This will help if you feel it is neccisary to take the AFM apart.

can an NA afm be swapped on to run a tII, to see if it will hold idle?

Cant imagine why not..

Rat

with NA afm that was working...same problem.

Vac leak.. Thats my honest .02. Could be wrong, but I doubt it.

tried another cas...same problem.
Can't find a vac leak anywhere.

had same problem wire from my afc to pcm came loose (forgot to resoider after rebuild) would start fine then die

check conections

what happens if you remove the afm all together??? does it have the same problem ??

Probably a large vacuum leak like the brake booster line off the intake. Especially since the engine starts all the time and just won't keep running.

There's an outside chance you knocked the water thermo sensors plug off. That will give you symptoms like you have IF the engine/water is cold. OUtside chance.

^^^^same thing happend to me and it was the brake booster line..put that back on and it runs fine now!

I don't know if the T2 works the same way as a n/a (dynamic chamber wise) But On my N/A I had the same problem. It will shut off after a few seconds. I checked every line, did every check possible for leaks except one thing. I never worked on a turbo so Dont bash me for posting this, but On the dynamic chambers on the left side when it connects to the Intake hose, There are two small bolts holding it tight with the dynamic chambers. One of them was loose. and it caused my motor to shut off. I doubt it is your problem since a turbo motor looks way differnt from pictures but if its the same on that part, see if that has loose bolts.

*""I had this problem.""* Also you have a 3800rpm hessitation ? You just said you got a upgraded Exhaust system ? I was told on this forum by a few people that the s4's use backpressure to open up the 5th/6th ports. Did you eliminate that piping that comes off a s4 cat that runs to the back of the motor ? That could be a factor in your problem with the hessitation maybe ?


P.S I put a brand new exhaust system on my N/A. The whole piping was brand new including a new cat. it was a universal cat. I had the piping that came from the cat to the back of the motor connected, new hoses, I still had my hessitation. I got a little fustrated that yesterday I switched my whole exhaust system from my FC from my other one I have at my Cousins auto shop, This one doesnt have a cat but has the line that comes from the cat welded on the pip. My hessitation went away, so I came to the conclusion that my Cat was clogged. So the point im trying to make is that the universal cat clogged up my system and caused the car to hessitate. I just trying to throw a few ideas in your head to what could hopefully help you out. I understand that you have a Turbo2 and I have a n/a but maybe this information could help you

The 3800 rpm hesitation is caused by the secondary injectors not coming on exactly when they should, not by the aux ports not opening. All the aux ports not opening does is lower the output a little.
First of all, did your car "hesitate" at 3800, or did it just not run at all? Because if it didn't run then theres a problem with the secondaries - either they are messed up or not getting the signal to come on. An as for the 3-4 seconds it runs, does it sound okay like its running smooth then just cut off, or does it sound weird or uneven?

it was likt hitting a wall at 3800...you could ease into the gas and it would go past 3800, but if you got on it...it would just fall on it's face. I "think" that has been fixed...the clip on the secondaries was really loose (found that out looking for this new problem). Can't test to see if that's fixed tho until I get the car running again...ha.

It is not a probablem with the secondarys coming on and not coming on. The car will still rev past 3.8 and pull with the secondarys not even in the car as long as you can keep the flow rate of the P runing. The duty cycle is droped on the P when the secondarys kick in. The hesitation is due to pore ground contacts. But can be chalked up to bad ignition and fule system components, this should be a noticable differance from the comon hesitation.