Dezined

Two questions. One, pumping the pedal during cranking shouldn't do anything besides shutting off the injectors if you floor it. However, my car will rarely start unless I pump the pedal a bit like a carbed motor. Why is this? It may lead to a problem I need to fix.

Also, I don't have a fuel pressure tester, but my car was recently at the mechanic, and he said everything checked out fine. That aside...when I'm out driving, if I come to a complete stop, it's very easy to kill the car when I try and take off again. I have to feather the throttle a little to keep it from stalling. For simplicity sake, if I were to just floor it and pop the clutch, it'd die. That first half a second of giving it gas is when it happens. Why is this?

Dezined

ttt

I really need some advice with this. There isn't enough money floating around to just go to a shop.

fasteddi

iTrader: (2)

Recheck the fuel pressure yourself. And do a leak down test. You can rent one from a local parts store such as Autozone for basically nothing, just a deposit untill you bring it back.

I.E prime the fuel pump and shut the car off, watch the fuel pressure for a bit. Over a 10psi drop in 15 minuets is not good IIRC. You may have a leaky injector or your FPR is leaking by. The only reason I think that you need to look at those things is because your saying you have to floor the peddle to start the car...which means that its flooded, the pump shuts off when you floor it when starting, then finally it gets leaner and starts. I wouldnt be surprised if you have a small puff of black smoke coming out the exhaust when it finally starts as its probly stinking rich.


Just some ideas though, I'm no mechanic at all!

Dezined

I get a poof of just white smoke. Smells like exhaust, not coolant. I have no issues like that. Ill pay attention more next time i start the car, but i dont have to floor it just pump the pedal. But i heard pushing it down 70% or more cuts the feed, so maybe that is what im doing.

What im concerned with most is it almost cutting out when i take off from a dead stop, and having to feather the throttle when i engage the clutch. Ill see about renting a fuel pressure tester monday, and checking the pressure myself.

fasteddi

iTrader: (2)

Yea over 70% TPS will disable the fuel pump. Weird its white smoke.. white smoke=water/coolent. But let me know what the fuel pressure says, im interested to see.

Dezined

Well, I'm at a loss. Hooked up the pressure gauge, and I get nothing. No pressure at all no matter what I do. I'm hearing a whine from rear of car when it's running. I'm assuming it's the fuel pump. Could it be going bad? Can I hook the tester up before the filter to see if the pump is giving pressure?

fasteddi

iTrader: (2)

Yes that whining is your fuel pump. Is it really loud when the car is running, thats not a good sign if its just a stock fuel pump.

Well if your reading basically no fuel pressure at the rail, you can just replace the filter anyways and see if that helps. There very very cheep and easy to put in. Amazes me that your car starts with basically no fuel pressure??

Im not sure but I would think you'd need a adapter to hook the guage up to the line going into the fuel filter.

Could be the fuel pump for sure or other connection issues in the tank itself. If you wana see if the pump is pumping you can take off the fuel filter and hold up a gallon jug to the fuel line going into the fuel filter, have someone turn the ignition on and the pump will pump fuel right off the bat since its purging for a few seconds. Now this is no way to see if its properly pumping enough fuel but if you have 0psi of fuel pressure and your pump is pumping a crap load of fuel out then you know your problem probly stems elsewhere.

Dezined

It's not super loud, but I can hear it over the exhaust, and that's decently loud. I know I'm getting some pressure because when I put the gauge on the shrader valve, gas squirted out. I wonder if the guage is bad. The car runs great except what I mentioned above. Will get at that fuel filter here in a sec. There's adapters in the kit, I think I can get it in line to test the pump

fasteddi

iTrader: (2)

When you depress the shrader valve does the fuel come shooting out like crazy? That guage might have some issues because when my fuel pump went I was pushing 10psi and the car would not start period...it tired but wouldnt starts so seeing that you say there is 0 psi and the car runs, I would look into the gauge and see whats wrong with it.

Dezined

Yeah. My mechanic tested the pressure and couple months ago and he said it was fine. Also said car won't do anything with no pressure and that I may have tester on wrong. Triple checked its connection, and nothing. Gonna take it back to store and see if I can get another. Will update when I get this figured out. This issue is a pain to drive with.

Dezined

Alright. The first gauge was bunk, next one worked. It's only been 10 minutes but holding strong at 41 lbs. What do I check next?

What would make the car stumble if I'm giving it gas from idle?

Also, started car, unplugged MAF until it threw a code, shut car off and tried to start it again. Will start, but won't stay going unless I keep giving it gas. It's supposed to bypass the MAF once the code is thrown right? And enter a different mode? Is this behavior indicating another issue?

fasteddi

iTrader: (2)

Does the check engine light come on all the time? reset the ECM and then see if it has a code being thrown.

Its called fail safe mode when the ECM tries to overcome a problem that your ecm shows. Any time your car throws a check engine light and you try to fix it, always reset the ECM. Just disconnect the ground on the batt.

Dezined

I get no CEL and no codes. I have a good habit of resetting it too anytime I force a code. I'm sure this is related, so I'll throw it out there. When I cold start the car, it will idle very rough around 5-600 rpms until about 4 or 5 minutes later, then something kicks in and idle will smooth out and pull up to 1500 like it should till it reaches op temp. This always happens on cold starts. Related maybe? Timing is correctly set at 10* and advances when revved like it should. New cap, rotor, coil, pickup, plugs (Delco coppers), wires, Cts, tps. No vacuum leaks, new egr. Car runs awesome, but heavy exhaust smell.

Need ideas.... I'm running out lol.

Dezined

Also, I have never been able to get my TPS to put out the correct voltage. I've gone through 5 of em. They just won't line up right. I can usually get it to about. 54 volts with it cranked all the way up, but never 5V at WOT. The mechanic said it didn't matter as long as I had voltages from idle to WOT, but I'm wondering now with this stall issue

fasteddi

iTrader: (2)

Just a thought here but....O2 sensor? Even though I would think it would throw a code, it will cause a rich condition if its going bad. Or another thought.. IAC Idle air control valve? Of course you dont wana just change parts till ya fix it but these are just some more ideas?

The tps vts could be a problem but to be honest im no help there as I've never messed with that part of the car..sorry.

Dezined

I have taken out and cleaned the iac and throttle body many times. No play in tb plates either. O2 sensor is new, but I was looking for a way to test it in case I got a bad one.

fasteddi

iTrader: (2)

Man, you really have me stumped. You've covered alot of your bases. Could you take out your injectors and just ohm them out to make sure they check out ok? Its pretty easy to do, you dont have to take them off the rail, just ohm them out on the rail to make it easier. Could also be clogged or something? Just guessing here.

Dezined

About a month ago I had the upper intake off, and went ahead and checked then. They all came back good.

fasteddi

iTrader: (2)

Is this a ittermitten problem or is it basically happening all the time?

Dezined

All the time. What are the typical steps to improve throttle response? I'm wondering if maybe a P. O. put a mild cam in, and I'm having this issue because I'm setting default timing when I should be adjusting it differently because of the cam.

fasteddi

iTrader: (2)

The other owner put a cam in it??? How long has this issue been hapening with your car? I hope its not that a lobe got wiped out in time because the owner didnt break in the cam right.

Does adjusting the base timing help at all? Advancing it to 13,14,15*?? Play with that and see if it helps at all. If its skunk rich at idle it could very well be, but you have MAF which should adjust to the fueling.

Dezined

I'm not sure if it has one or not. I took it in to a shop to get an idle problem fixed, and the mechanic said he thought there might be one installed but didn't know for sure.

I haven't played with the timing at all besides setting it to spec. Since I've had the car its had issues. I did some work on the ignition, and all of a sudden it ran way better. That's when I noticed the throttle issue.

fasteddi

iTrader: (2)

I guess go see if it like to run better with more timing? Just a idea. May have a cam in it. Make sure to disconnect the ESC wire when setting timing, just in case you dont know, and reset the ecm after your done.

Dezined

All right, I'll try that tomorrow, see what happens. I'll report in with any change. If anyone else has any ideas, eddi is scraping the barrel I think, and I was long ago too (thanks eddi)

fasteddi

iTrader: (2)

NP man.
Have you ever tested the MAF sensor? I think autozone or places like that will hook it up and test it for free....

Dezined

No I haven't. Didn't even know they could do that. I did a simple test my mechanic told me to do, but it didn't really tell me anything. I'll do that tomorrow when I take the tester back.

neilb

Do you have any means to watch your data? It does sound like a MAF, TPS , IAC issue. Your MAF should read (if I remember right) 4-7 grams per sec at idle at op temp. and should read approx 150 grams per sec at WOT. Your TPS doesn't really matter as long as it doesn't exceed 4.8v at WOT. I try to set them around .45v closed and close to 4.5v at WOT. The ECM "relearns" the TPS after every restart, so there is no real absolute numbers to set it at. Also the IAC at op temp at idle should be in the range of 20 to 30 counts. The real pain is that to adjust this, you have to adjust the throttle blade stop screw. This also will change the MAF reading and TPS values, so for every small change, you have to check the other values to make sure they are still in spec. And remember after every change, turn off the car and restart to "relearn the TPS position. I hope this helps and I am really interested in seeing what it turns out to be. My personal opinion is the MAF is packing it in, because it is (next to the O2) the MOST important sensor for fuel/air control and closed to open throttle transition control.

Dezined

I'm gonna rent a scan tools this weekend (400 bucks, holy ****), and I'm wondering what process I should use. Car cold? Hot? Stationary? Driving? Uphill? Downhill? Do I need to log the data? I've never used a scanner before, so am unfamiliar with the steps that I should take, because this is a one shot deal until I get that much cash to throw down again. Any pointers you guys can throw my way will help me get this done efficiently.