1999 Firehawk Cutting out
12-29-2008, 11:09 AM
#1
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1999 Firehawk Cutting out Alright, I tried a search, and came up empty.
I have a 1999 Firehawk M6 LS1 stock motor, all stock car(LS7 wires, new plugs, new fuel filter(10k miles ago) LM1 cat back. There is nothing else done to the car. It has 117k miles on it, and ever since I bought it a year and a half ago, the car would feel like it didn't have as much power sometimes. When I had it tuned(it was pinging sometimes) they told me it had a hypertech tune(spark advance, no fuel adjustment) and that's why it was pinging. He tuned it, told me it was a little lean before he started, and that it should be fine now. The car made 303rwhp and 328rwt on a 100 degree day with 103k miles on it. I figured the slow feeling was just in my head.
The other week, I was driving the car on a 10 degree day, and it started cutting out around 2000 RPM. I got to a stop sign, and it wouldn't restart. I waited a few minutes, coasted back into a driveway, and tried it again. It started, but would only pull out going down hill. Luckily downhill was toward home, so I limped it about 10 miles home, all the way with it cutting out if I would go for the throttle. Got it in my driveway, went out and unplugged the MAF, and got in the car. The car ran better(not perfect) but there was no SES light even with the MAF unplugged. Went out and plugged the MAF in, and it still ran the same as when it was unplugged(still no SES light). I thought maybe I got some gas with water in it, and because it was so cold I was having fuel delivery issues.
I let the car sit for a week, and took it out in warmer weather the other day. It ran fine, and I filled up with gas again. After running correctly for several trips, it started f*cking up again. Acting similar to before, without stalling(thankfully). It feels like it is leaning out up top(no power) but it is intermittent. It will get bad enough to completely cut out sometimes around 2500RPM. This was also on an unseasonably warm 60 degree day, so I don't think water freezing in the fuel line is the problem. I'm leaning toward a MAF, or TPS, but wanted to hear if anyone else had these symptoms before.
Please feel free to ask for any information I haven't provided.
Thank you ahead of time,
Gary
I have a 1999 Firehawk M6 LS1 stock motor, all stock car(LS7 wires, new plugs, new fuel filter(10k miles ago) LM1 cat back. There is nothing else done to the car. It has 117k miles on it, and ever since I bought it a year and a half ago, the car would feel like it didn't have as much power sometimes. When I had it tuned(it was pinging sometimes) they told me it had a hypertech tune(spark advance, no fuel adjustment) and that's why it was pinging. He tuned it, told me it was a little lean before he started, and that it should be fine now. The car made 303rwhp and 328rwt on a 100 degree day with 103k miles on it. I figured the slow feeling was just in my head.
The other week, I was driving the car on a 10 degree day, and it started cutting out around 2000 RPM. I got to a stop sign, and it wouldn't restart. I waited a few minutes, coasted back into a driveway, and tried it again. It started, but would only pull out going down hill. Luckily downhill was toward home, so I limped it about 10 miles home, all the way with it cutting out if I would go for the throttle. Got it in my driveway, went out and unplugged the MAF, and got in the car. The car ran better(not perfect) but there was no SES light even with the MAF unplugged. Went out and plugged the MAF in, and it still ran the same as when it was unplugged(still no SES light). I thought maybe I got some gas with water in it, and because it was so cold I was having fuel delivery issues.
I let the car sit for a week, and took it out in warmer weather the other day. It ran fine, and I filled up with gas again. After running correctly for several trips, it started f*cking up again. Acting similar to before, without stalling(thankfully). It feels like it is leaning out up top(no power) but it is intermittent. It will get bad enough to completely cut out sometimes around 2500RPM. This was also on an unseasonably warm 60 degree day, so I don't think water freezing in the fuel line is the problem. I'm leaning toward a MAF, or TPS, but wanted to hear if anyone else had these symptoms before.
Please feel free to ask for any information I haven't provided.
Thank you ahead of time,
Gary
12-29-2008, 11:14 AM
#2
Well I would says you need to check fuel preasure. I weak fuel pump would let it run ok at idle but die when you try and drive it. First thing I would do is check fuel preasure. Let us know what you have and we can go from there. Should be around 58psi
12-29-2008, 11:26 AM
#3
Check fuel pressure. How old are your O2 sensors. My car did the same thing recently and my wideband showed lean. I have a Racetronix fuel pump kit that has maybe 2k miles so I didn't even consider the fuel pump. I hooked my laptop up and logged some driving to see what was going on... it was the O2 sensors causing havok. I have Bosch 13111 that have about 15k miles, but I use leaded race fuel occasionally. Gotta pay to play.
12-30-2008, 11:09 AM
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Hey while i'm under the hood checking the fuel pressure, I'd like to test the TPS to make sure it is reading correctly. What is it supposed to read @ idle, and what should it read @ full throttle(no bump stop mod).
