engine bogging after cold start
04-20-2009, 01:04 PM
#1
2nd Gear Member
Thread Starter
Join Date: Jan 2008
Location: NJ
Posts: 401
engine bogging after cold start
I've noticed over the last few weeks, my car has been giving me some trouble after a cold start. Usually it has to sit for over 8 hours or overnight, enough to make the engine and exhaust stone cold. I'm not sure where the problem is coming from, my guess is either the fuel pump, BAP, fuel filter or some other related part. I'm hoping on some feedback from others that have experienced the same hesitation.
Only on a very cold start here are some strange phenomenons i've noticed:
- I can hear a high-pitch tone coming from the BAP. I can hear it from outside my car over 10 feet away.
- During normal to moderate acceleration, the engine will sound like it's bogging down. Then three seconds later, I can hear my BAP get louder and then my normal boost of power will kick in.
- My fuel pressure gauge reads normal, but I have to test that one again.
- My narrow band a/f gauge is pinned to the red during the hesitation (3-4 seconds. After I hear the BAP get louder, the narrow band gauge does it's usual light show.
- Before these issue, my wheels would spin half a rotation under the same acceleration.
- All symptoms go completely away when car reaches full operating temperature.
I used to get a good kick of power the moment I accelerated, even in the winter. I'm planning on changing my fuel filter when it stops raining, but are there any other tests I can try
Only on a very cold start here are some strange phenomenons i've noticed:
- I can hear a high-pitch tone coming from the BAP. I can hear it from outside my car over 10 feet away.
- During normal to moderate acceleration, the engine will sound like it's bogging down. Then three seconds later, I can hear my BAP get louder and then my normal boost of power will kick in.
- My fuel pressure gauge reads normal, but I have to test that one again.
- My narrow band a/f gauge is pinned to the red during the hesitation (3-4 seconds. After I hear the BAP get louder, the narrow band gauge does it's usual light show.
- Before these issue, my wheels would spin half a rotation under the same acceleration.
- All symptoms go completely away when car reaches full operating temperature.
I used to get a good kick of power the moment I accelerated, even in the winter. I'm planning on changing my fuel filter when it stops raining, but are there any other tests I can try
Last edited by Jersey Stang; 04-21-2009 at 01:13 AM.
04-20-2009, 09:53 PM
#8
4th Gear Member
Join Date: Jul 2007
Location: California
Posts: 1,690
ive never dealt with BAP's but im thinking of getting one to run a bigger shot of nitrous soon. have you tried asking this question on some of the other forums?? lots of guys that can help you out if nobody here has answers for you...
04-20-2009, 11:07 PM
#9
2nd Gear Member
Thread Starter
Join Date: Jan 2008
Location: NJ
Posts: 401
I haven't yet...I'll keep it on this forum for a few days first. The problem is I don't know how to diagnose a fuel pump or BAP. After installing the BAP, I could only hear the hum if I put my ear in the trunk. Now, its so loud that something has to be wrong. But I don't know if its the pump not working and the BAP going into overdrive or if the BAP is not running at full capacity. Its strange, the fuel pressure is there, but it's running lean (only on a very cold start). I haven't had any CEL on lean conditions, but I really don't want to wait for that to happen.
04-21-2009, 02:41 AM
#10
2nd Gear Member
Join Date: Nov 2007
Location: Alaska
Posts: 156
hmmm I experience the same symptoms. I have a BAP as well. The only thing that would pull me away from the filter idea is that if there were some blockage then idle would suffer all the way up to wot wouldnt it?