Hey guys, need some help with an odd flooding issue. Have an 87 GN with 93,000 miles. Over the last 8 months I have done alot of upgrades:
Scanmaster and gauges
Turbonetics TE-44
TR-6 ignition
60 pound injectors
Turbo Tweak chip burned for my setup and injectors
Alky control Alky system
New stock ECM
Plenum plate
Walbro 340 hot-wired
Adjustable FPR
The car runs GREAT, smooth and strong right up to 22 pounds of boost which is where I have it dialed in at. The issue is getting it started. When the car is cold it fires right up and goes right into a nice smooth idle. But after the car is fully warmed up, if you turn it off and try to restart a few seconds later, it just floods itself and is almost impossible to get started. Using the "clear flood" feature with the pedal on the mat does help some but even then sometimes it is not possible to get it going. You can smell gas and if the car does fire up it puts out the classic cloud of black fuel smoke and stumles and sputters along until all the excess fuel is burned up - and then it runs good again. When I have this issue, which is almost every time, If you let the car sit for 15-20 minutes it will fire right up with no problem.
One thing I have noticed recently which I think might be related (not sure if it started exactly when the hard starting issue began but it is close) is that when the key is turned half way I get no data on the Scanmaster. This also only happens when the engine is fully warmed up, when cold I have data with key half way. My SM input wire is soldered onto the ECM wire about a foot from where the main ECM plug is, the connection is good. I also tried attaching a scantool to the ALDL port and no data there either when the car is warmed up and key half way. However, once the car is started, data then shows up on the SM!?!
What I'm thinking is that maybe the ECM has some internal issue that only surfaces once it is warm and heat soaked and with no data and ECM input during the start sequence that somehow the car is just allowing massive amounts of fuel through the injectors and flooding it out? Also, could the chip cause this kind of issue? I did put a new chip in with the injectors and this issue did start happening around that time. It is a TT chip burned for my setup.
Oh, I have already replaced the crank sensor and cam sensor chasing my tail on this. I have all green lights on my TR-6 ignition module. My TPS and IAC settings are in the recommended ranges. Fuel pressure in rail remains very solid after shutdown at around 41-42PSI, I am not bleeding pressure. I can hear fuel pump prime and shutoff after about 2 seconds with key turned half way. And -- the car runs great once it is started!
Anyone have this issue before or heard about it? I'm thinking next step is new ECM (even though current one is 6 months old) and different chip (even though it is brand new) to just to see what happens. What else should I be considering? What else is left to replace? Could a coolant sensor or oil pressure sensor cause a problem with the ECM like this?
Thanks, Dan
Scanmaster and gauges
Turbonetics TE-44
TR-6 ignition
60 pound injectors
Turbo Tweak chip burned for my setup and injectors
Alky control Alky system
New stock ECM
Plenum plate
Walbro 340 hot-wired
Adjustable FPR
The car runs GREAT, smooth and strong right up to 22 pounds of boost which is where I have it dialed in at. The issue is getting it started. When the car is cold it fires right up and goes right into a nice smooth idle. But after the car is fully warmed up, if you turn it off and try to restart a few seconds later, it just floods itself and is almost impossible to get started. Using the "clear flood" feature with the pedal on the mat does help some but even then sometimes it is not possible to get it going. You can smell gas and if the car does fire up it puts out the classic cloud of black fuel smoke and stumles and sputters along until all the excess fuel is burned up - and then it runs good again. When I have this issue, which is almost every time, If you let the car sit for 15-20 minutes it will fire right up with no problem.
One thing I have noticed recently which I think might be related (not sure if it started exactly when the hard starting issue began but it is close) is that when the key is turned half way I get no data on the Scanmaster. This also only happens when the engine is fully warmed up, when cold I have data with key half way. My SM input wire is soldered onto the ECM wire about a foot from where the main ECM plug is, the connection is good. I also tried attaching a scantool to the ALDL port and no data there either when the car is warmed up and key half way. However, once the car is started, data then shows up on the SM!?!
What I'm thinking is that maybe the ECM has some internal issue that only surfaces once it is warm and heat soaked and with no data and ECM input during the start sequence that somehow the car is just allowing massive amounts of fuel through the injectors and flooding it out? Also, could the chip cause this kind of issue? I did put a new chip in with the injectors and this issue did start happening around that time. It is a TT chip burned for my setup.
Oh, I have already replaced the crank sensor and cam sensor chasing my tail on this. I have all green lights on my TR-6 ignition module. My TPS and IAC settings are in the recommended ranges. Fuel pressure in rail remains very solid after shutdown at around 41-42PSI, I am not bleeding pressure. I can hear fuel pump prime and shutoff after about 2 seconds with key turned half way. And -- the car runs great once it is started!
Anyone have this issue before or heard about it? I'm thinking next step is new ECM (even though current one is 6 months old) and different chip (even though it is brand new) to just to see what happens. What else should I be considering? What else is left to replace? Could a coolant sensor or oil pressure sensor cause a problem with the ECM like this?
Thanks, Dan
