Hesitation, no power, help..
Hesitation, no power, help.. ...me figure this out.
The car is a 402, AFR, FAST 90-90, Walbro 225, green 42's.
It just started doing this a few weeks ago. I give it gas and when I hit 1700 RPM's, it does't power up, it hesitates. and does this until I hit 2300 RPM's where it smooths out. I thought it was only in this range, but today I discovered that it also does it around 5500 RPM's.
Things I have checked or changed, yet still have the problem: new o2's, spark plugs, fuel filters. switched MAF's, cleaned out the SLP 85 mm MAF. New plug wires will be here today.
I checked fuel preasure. it's @ 60, when running, and stays @ 54 with the engine off, and key turned on. Have not checked it under load.
Could the pump be bad, or the regulator? I've almost given up on things that it could be.
The MAP sensor seems to be looser than it should be, as the hole is not as tight as it is on the stock manifold. Could that be it? I put some tape on it to hold it down. It does not seem to be leaking. Any ideas?
The car is a 402, AFR, FAST 90-90, Walbro 225, green 42's.
It just started doing this a few weeks ago. I give it gas and when I hit 1700 RPM's, it does't power up, it hesitates. and does this until I hit 2300 RPM's where it smooths out. I thought it was only in this range, but today I discovered that it also does it around 5500 RPM's.
Things I have checked or changed, yet still have the problem: new o2's, spark plugs, fuel filters. switched MAF's, cleaned out the SLP 85 mm MAF. New plug wires will be here today.
I checked fuel preasure. it's @ 60, when running, and stays @ 54 with the engine off, and key turned on. Have not checked it under load.
Could the pump be bad, or the regulator? I've almost given up on things that it could be.
The MAP sensor seems to be looser than it should be, as the hole is not as tight as it is on the stock manifold. Could that be it? I put some tape on it to hold it down. It does not seem to be leaking. Any ideas?
I forgot, I also switched to a different MAF to check that. No, I dont have any check engine lights on.
I did have a 0103 MAF circuit high frequency code, and another one for low frequency.
I'm thinking that it might be tune related, but makes no sence that it has been running great, and now decides to crap out.
I did have a 0103 MAF circuit high frequency code, and another one for low frequency.
I'm thinking that it might be tune related, but makes no sence that it has been running great, and now decides to crap out.
Me too. I'm checking for exhaust leaks today.. I'll check all the grounds while I'm there.. Anyone have other ideas?
I believe the tuner put a SD tune on it, so perhaps the tune has changed because of the weather...
I believe the tuner put a SD tune on it, so perhaps the tune has changed because of the weather...
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Joined: Jul 2007
Posts: 2
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Hi I just joined on and I was reading the problem you were having and I couldn't believe it. I have a 2002 WS-6 and I've been having a similar problem. My problem has been doing it for awhile now, usually every time a step on the gas the car actually hesitates (slows way down) and then after a couple of seconds it takes off like hell. It almost reminds me when you take a rubber band and pull it all the way back and then let it go. That's how it feels when I experience this problem. Somebody said maybe the sensors so I put a new mass air-flow sensor in, I changed the trans fluid, I've taken it to the dealer and they think I'm crazy. Recently I met a guy who got me in touch with someone from Haddad Motorsport and he said that if anyone can figure this problem out it would be him. I'll let you know the results.
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Of course a good scanning will probly tell alot.The problem sounds like a bad intake air temp sensor or the wire going to it.That or a bad MAP sensor.Really needs to be logged.
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After changing the IAC (air intake temp), I'm going to check the fuel system again. It was @ 60, but that was with the car sitting, and ideling it up. Now I want to try it under load, going down the road. I also want to check injector pulse with a Tech 2 to see if I have a bad injector.
Should I be at 70 psi? I had the understanding that 60 was fine. Perhaps not. It feels like it's just not getting fuel, that's why I checked that first.. Back to the drawing board.
Should I be at 70 psi? I had the understanding that 60 was fine. Perhaps not. It feels like it's just not getting fuel, that's why I checked that first.. Back to the drawing board.
Registered User
Joined: May 2007
Posts: 14
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I'm having the same damn problem with my '98 Z. 
When I accelerate from a red light, for maybe a millisecond, the car hesitates and acts like it wants to die, but then it goes like a race horse after that. It just started doing that. I have a buddy that said it may be my injector(s). If so, do you guys know how hard it is to pull and check the injector?
When I accelerate from a red light, for maybe a millisecond, the car hesitates and acts like it wants to die, but then it goes like a race horse after that. It just started doing that. I have a buddy that said it may be my injector(s). If so, do you guys know how hard it is to pull and check the injector? I've been told that you can check injector pulsewidth, and resistance. But would probably need a tech 2 for that. Injectors have maybe 2500 miles on them, 2 years old. I thought about it. I wish I had some extra 42 lb'ers.
I believe that mine was tuning related. It was tuned in SD, and I dont know how the tune would change, but it did, and after a retune, through the MAF, the issue went away, and I picked up a bunch of power.