Chuck Dean

The problem occurs consistently every time I startup the car whether the motor is hot or cold. The histation will last about 5 seconds. I usually just let the car coast until fuel response kicks back on. If I keep my foot on the gas or depress the gas further, a sudden jerk will occur when the the hesitation stops. After that the car drives fine. But if I park it again, start it up a few minutes later, it will do the hesitation thing again.

When a say it's hesitating, I mean that it is stops accelerating. It holds the same RPM regardless of throttle position. It also makes a sputtering noise if you give it gas.

It's very likely that it has something to do with recent work i've done on my car...

I recently installed a wideband o2 controller (PLX m-500). I thought maybe it was an electrical problem so I redid my electrical connections at the ECU. Problem still persists.

I also had to ditch my DSM's (one died on me) and swith back to the stock injectors. The injectors experienced some fuel leaks from the old seals so I replaced some of them. There is still a very minor leak coming from one of them.

Any suggestions on what may be causing the sputtering/hesitation????

Chuck Dean

bump

ATS*Mark

id like to know too i had this problem as well.... mine wasnt 100% though sometimes it did it sometimes it didnt . somebody told me it was because i wasnt letting the check engine light go out after i put the key in. i guess your supposed to turn the key and let the check engine light go out before you start it . dont know if thats the case or not but whatever.

m R g S r

I have never heard about the check engine thing. I always prime the fuel system thou, by putting in the key and turning it w/o starting the car. You can hear the fuel pump, and when that noise is gone, I start the car.

hondapartz

maybe there's a problem on your alternator? try changing to a new one or with a much higher in amperes for your alternator, this is also the cause of hard starting or sometimes cold start as they say. tnx

ATS*Mark

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by m R g S r &raquo;</TD></TR><TR><TD CLASS="quote">I have never heard about the check engine thing. I always prime the fuel system thou, by putting in the key and turning it w/o starting the car. You can hear the fuel pump, and when that noise is gone, I start the car. </TD></TR></TABLE>

thats the same thing as the CEL because the fuel pump primes and that shuts off the same time the CEL goes out .

Chris F

Sorry man, I had the same exact problem, usually when I'm trying to pull out into traffic!

This was on a Twin Cam GM motor though. (97 cavalier Z24). Underdrive pulley, I/H/E. Stock computer.

I had a Fuel Injector duty cycle gauge, it would always read normal numbers for the throttle position.... i.e. the computer wasn't starving it on purpose. Almost like there was air in the fuel pump or it just shut off for a couple of seconds.. It wasn't really time-dependent, it would just be the first time I got on the gas, it would do that 50% of the time.

*shrug*

edit, I also had an A/F gauge, but it didn't do any good because it was still cold.

Come to think of it, maybe you are fouling the plugs for just a bit because the computer is running too rich until the O2 sensors warm up? Cold plugs probably don't help either.

Chuck Dean

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by ccfries &raquo;</TD></TR><TR><TD CLASS="quote">Come to think of it, maybe you are fouling the plugs for just a bit because the computer is running too rich until the O2 sensors warm up? Cold plugs probably don't help either.
</TD></TR></TABLE>

I considered that, but the setup worked fine for about a week. I don't know if it was me messing with the m500 datalogging inputs or if it was the injector leak that developed, but the problem seemed to show up after those two things.

The o2 reading doesn't really change when the car hesitates like this, but perhaps that is because the sensor is completey warmed up yet.

Chuck Dean

I've watched the problem a little closer. On first startup, everything is fine. If you start it after it's warm it will do that hesitation thing about 10 seconds into the start of your drive. It's just a one time thing thing though - it drives fine after that, unless you turn it off and start it again. It seems to not do it if I wait 30 seconds to let the wideband o2 warm up completely. Maybe I just need to stop using the m500's narrowband output and use three o2 sensors (2 for the ecu and 1 for the m500) ?? It's supposed to work the way I have it setup, but that doesn't seem to be the case.

onlinehost

it sounds to me like ethier your injectors are leaking down or maybe you have a slightly blown head gsaket does the engine consume coolant? i had the same problem with my b20vtec but i had 440cc and i would get the same problem as you but mine was fuel pressure maybe you need more fuel i meen you went from 450cc to stock thats a big downgrade just my thoughts on this problem but every car is differnt.

Chuck Dean

No...I fixed the fuel leak. And it doesn't have anything to do with the injector size. The stock injectors drive the car just fine as long as you don't spool the turbo or get into boost. I'm using the stock injectors until the RC 440's come in the mail (been waiting a month....kinda angry).

The problem developed after installing the m500 so it's most likely an electrical problem at the ecu or a problem with o2 sensor / o2 output.

leed

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chuck Dean &raquo;</TD></TR><TR><TD CLASS="quote"> It seems to not do it if I wait 30 seconds to let the wideband o2 warm up completely. Maybe I just need to stop using the m500's narrowband output and use three o2 sensors (2 for the ecu and 1 for the m500) ?? It's supposed to work the way I have it setup, but that doesn't seem to be the case.</TD></TR></TABLE>

You hit it. I can replicate the exact same thing on my Uberdata'd B16 turbo. I am feeding the PLX 0-1v NB to the ECU, and on hot restarts, if I dont let the WB fully heat, it will do just as you described. I am planning on adding another o2 bung to run a factory 02 for the ECU.
I pretty much always wait the 45sec for the WB to heat, and almost never have the hesitation when I do this.

Goodluck