It seems that for the last few months now, my TGP has been hitting fuel cut more and more often as time progresses.
It has not thrown any overboost codes, and now, it seems to want to hit fuel cut at anything much over 7psi. (Autometer boost gauge)
I had the OEM injectors ultrasonically cleaned and flow tested a couple months ago, and the fuel pressure checked out OK at the schrader valve. (40 psi) (Not sure about actual FLOW from the pump though)
The car is equipped with a KAZ Hot Tune chip. The car used to overboost with my old Jeff M chip, but not as often.
All charge piping is secured with T-bolt clamps and new silicone couplers.
All vacuum lines to/from the turbo, actuator and solenoid are 6 months old, with clamps or zipties securing them.
Plugs, wires, 02 sensor, coolant temp sensor, x-over, knock sensor, K&N cone, wastegate actuator and solenoid, fuel filter, 1.6/1 rockers are 1 year old or less.
I've just recently purchased an EP375 fuel pump brand new off of eBay, thinking that my fuel pump may slowly be dying? I have yet to install it.
I also have a brand new AC Delco MAP sensor ordered, thinking it may be related.
I have a brand new AC Delco O2 sensor waiting to be installed, and am considering dropping the $$$ on a new FPR.
What are your opinions? I'd like to hear what you guys think is causing this....
Also! I thought I'd add this in as well. When I'm starting the car when its cold, if it doesn't start on the first crank, I really have let it crank before it'll start.
No sputtering, just cranking. Maybe a lack of fuel? I have no fuel leaks. Maybe there's *just enough* pressure there to get it started right away but if not then it needs to prime more to get enough fuel?
Either it starts turn-key, or it'll crank for 10 seconds. Mostly turn key though.
Hope thats not too confusing. Thanks for the help.
I posted in your thread on W-body, I think its a bad fuel pump.
thanks
I got the same cold start problem, I am leaning towards fuel pump on that, since I just got the new C302 injectors, a new MAP and a new fuel filter installed... so fuel pump seams the only thing left that I can think of...
Interesting. :icon_rolleyes: Maybe you should use the Farmer Bob's tuning to eliminate your fuel cut since the chip won't do it. I haven't had fuel cut in over ten years and I run a whole lot more boost. (real boost) ;) Can't say I haven't hurt a couple of motors. Your choice. Be slow and safe or or fast with the dangers. If you have a stock turbo there are no dangers. You can wire the waste gate closed and get your 15# of shitty air and it won't hurt the motor. You will go slower. :laugh:
Fuel pump. The only real way to test it is to add a coper line to your gauge and attach it to the windshield with duct tape. You will soon know if there is not enough volumn. Do this every time I'am in doubt. There is nothing worse than running out of fuel on a turbo motor. :icon_evil:
Jud
I'd be happy to have consistant 10-11 psi ECM controlled. I don't want to blow the thing up.
You are amazing Jud. :laugh: Why in the world would you run the factory T25 with a factory intercooler at levels above 12 psi at the manifold? Do you enjoy running hot air into an environment prone to detonation already?
Considering the boost is set to 12.3 psi_g and the fuel cut is set to max 14.7 psi_g that leaves a buffer of nearly 2.5 psi_g to NOT hit fuel cut unless you are getting boost spikes from the factory wastegate actuator. Fuel cut is very bad considering it turns off the fuel to the motor. Having too little fuel from a weak pump is even worse though. The motor is trying to produce high boost power on too little fuel...detonation is there for sure with a lack of fuel.
It is possible the pump is running out of pressure flow up top...you can verify the pressure on a gauge with a piece of copper tubing pulled from the moonshine still in the backyard...or pickup a long hosed fuel pressure needle gauge from Harbor Frieght or discount tool supplier for pretty cheap.
Question Matt...does it stutter when it is hitting high load boost...or does it shut down real hard damn near sending your face into the steering wheel?
Thanks for replying Kenny.
I'm going to have to hook up my fuel pressure gauge and take it for a drive. Maybe if I remove the hood louver I can stick it out through there.
When it hits fuel cut, it stutters.
It has never sent my face into the steering wheel. :laugh:
"Fuel cut" is a severe loss in power which happens immediately to the point where you need to pull your teeth out of the steering wheel padding. ;)
If it is stuttering it is most likely that you are blowing out the spark. What are your plugs gapped to? What is the condition of your plugs, wires, and coils (age)? What plugs are you running?
I recommend running ONLY:
GM factory plug wires
R42LTS plugs gapped to .028
GM factory coils
With you saying it is happening more and more often I suspect you have a plug wire that is grounding somewhere on the intake manifold. Once they start to degrade they just get worse as time goes by. I have been recommending to people to use some wire loom on each plug wire were it runs from the front of the motor, across the top, and then they can end it as it emerges from behind the alternator. The edges on the intake manifold will wear through the plug wire pretty fast.
-Kenny
I'm running NGK Iridium Plugs TR5IX spark plugs gapped at 0.040" They are 1.5 yrs old. (8,000mi)
Why do you recommend gapping the plugs so tightly at 0.028" ?? Factory recommends 0.045"
I have a set of Taylor 8mm igniton wires on the car that are 2.5 yrs old. (12,000mi)
The coils are original as far as I know. Jeff (kuntzie - previous owner), and myself have never changed them. (car has 77,000 mi)
What do you think of Magnecore wire sets?
I'll just get AC Delco plugs this time around, but I'd really like a nice looking set of quality wires.
That's a good idea with the wire loom, I'll have to do that with the new wire set.
Thanks
Well there is your problem. .040 is HUGE for gap running more than stock boost. The other is they are irridium. Not good for boosted applications. Hell I pull irridiums out of non-boosted LSx series motors at least three times a week and put in plain old TR55 plugs gapped at .050 when the factory calls for .060 or .063 depending on the year. Irridium plugs are not good for a high combustion pressure environment. Long lasting and blah blah blah they claim...but in the end they have a very fine spark arch and it is easily blown out by high combustion pressures.
Get yourself a set of Delco R42LTS plugs gapped to .028 and enjoy your ride! ;) Gapping to .028 will ensure they still fire off at high load / high boost. I have had some guys tell me they are getting away with .033 at sea-level density running my chip...but .028 is a nice gap that will allow for a very large wide arch between the electrodes which will ensure a proper burn rate on each firing.
The wires are getting up there in age for an underhood environment that is very hot. Also they are sitting nearly in the same place being worn out and allowing for a path of least resistance to the intake manifold.
I know some have used other brands of wires. I have also and I always seem to go right back to the factory plug wires. They last longer and help to make sure the maximum amount of energy makes it to the plug. I need to look at my invoice from last week to see what I get them for from the dealer. Maybe they will be a touch cheaper than you can up there...but do not put on anything that is some cheng shin knock off set or the crappy off the shelf auto zone wires. They will not last!
The coils are probably fine. They will work or fail...never really an in between point for them.
Plugs and wires and your car will run like a raped ape my friend!! :icon_twisted:
Good to know!! :icon_biggrin:
I took it for a drive tonight and noticed that when it is stuttering the AF gauge is pegged at rich, so I think you're right that it's not a fueling issue. :icon_idea:
I'll have to go out and buy a set of Delco R42LTS plugs tomorrow and try it out with my old wires for now.
Thanks for the advise. I'll let you know how it goes. :icon_cool:
Well, nobody has R42LTS's in stock so it looks like it's gonna have to wait till Mon or Tues.
Found the plugs today, they had them hid behind the counter for some reason. Gonna try and find some time tonight/tomorrow to put them in.
Put the plugs in last night, gapped at .028" and still hesitates/stumbles above 7psi.....
Gonna try new wires next I guess. Any suggestions?
Try the wires and let me know.
You may still be looking at fuel pressure...but I doubt it.
-Kenny
Will do, just waiting for pay day...LOL
haha Just ordered a nice set of Magnecor KV85 wires, so now we wait......
Quote from: 93luminaz34 on October 01, 2007, 02:16:01 PM
Will do, just waiting for pay day...LOL
Quote from: 93luminaz34 on October 01, 2007, 02:42:47 PM
haha Just ordered a nice set of Magnecor KV85 wires, so now we wait......
Geez Payday came fast! lol.....Good pick up! thats what I have on my motor!
I have the Magnecor 8.5 mm on one of my TIII motors and the 10 mm on the other one. I like them.
Tim
Quote from: bake82 on October 01, 2007, 02:58:21 PM
Quote from: 93luminaz34 on October 01, 2007, 02:16:01 PM
Will do, just waiting for pay day...LOL
Quote from: 93luminaz34 on October 01, 2007, 02:42:47 PM
haha Just ordered a nice set of Magnecor KV85 wires, so now we wait......
Geez Payday came fast! lol.....Good pick up! thats what I have on my motor!
I just put it on my CC to speed up the process a bit.
How much were they and where did you order them from? And what was the part number?
Here's the link http://www.amazon.com/s/ref=nb_ss_/102-5475152-0883348?initialSearch=1&url=me%3DA3TYWMHL1EBP1B&field-keywords=magnecor+6540
I installed a NAPA Gold fuel filter today with no change......
The wires are due to arrive 1 week from today.
Did you ever get this problem sorted out Matt? ;)
Wires showed up on Wednesday, haven't made time to put them on, I should do that today.....
I'll update once they're on.
Any updates?
Well I changed the wires to the new Magnecor's and the chip to the top gun 160 I have to get me through emissions. So far I've had no hesiation or stumbling.
Tonight Im going to switch back to the Hot tune chip with an update.
Well I popped the KAZ hot tune chip back in and HOLY SHIT!!!
It's fast....
The new Magnecor's did the trick.
Do yourself a favor and buy a chip from Kenny.
So you like the chip now that you have spark? :icon_twisted: ;)
How much does it cost to run your car through the emissions station? I will send you the money to run it with the HOT tune chip and a few extra bucks for gas/time. I am very curious if the trims I use are sufficient for Canada standards.
Hell ya, I'm loving the hot tune now.
Its costs $39.90 CDN to run it through the e-test, and $19.95 for retests.
But, you only get 2 retests at that price and I've used them all up.
So if I were to have another one done, it would cost the full $39.90. (thats including taxes)
I'm taking insurance off of the TGP on Nov 1st, so it'll have to be done before then.
We will do it next year sometime.
Glad you like the chip though! ;)