Engine hesitation in the rain?
Thread Starter
Instructor
Joined: Jan 2018
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From: Greensboro NC
Engine hesitation in the rain?
He guys,
I have a 2007 base Z51 that has some engine hesitation when it's raining. It only does it at high throttle but may do it at low (1500) or high RPM. When it happens, the engine does not try to shut off or anything, but it feels like it cuts power to 50%. It does it regardless of driving mode as well. Any idea what could be causing this to happen?
All the mechanical components are stock apart from Airaid CAI and mufflers. As far as I can tell, all the hose clamps are tight. I tightened the air filter a bit farther when the issue first came up a year ago. Granted, this has only happened 3 times.
EDIT:
I ran the car (everything perfectly dry) and it did it at 5500 RPMs in second gear, WOT. It felt as if I let off the gas halfway when I didn't. It lasted for maybe 1/4 of a second and then came back full power. I did a WOT pull 5-6 more times without anything happening.
None of the diagnostics are showing any codes or codes pending.
I have a 2007 base Z51 that has some engine hesitation when it's raining. It only does it at high throttle but may do it at low (1500) or high RPM. When it happens, the engine does not try to shut off or anything, but it feels like it cuts power to 50%. It does it regardless of driving mode as well. Any idea what could be causing this to happen?
All the mechanical components are stock apart from Airaid CAI and mufflers. As far as I can tell, all the hose clamps are tight. I tightened the air filter a bit farther when the issue first came up a year ago. Granted, this has only happened 3 times.
EDIT:
I ran the car (everything perfectly dry) and it did it at 5500 RPMs in second gear, WOT. It felt as if I let off the gas halfway when I didn't. It lasted for maybe 1/4 of a second and then came back full power. I did a WOT pull 5-6 more times without anything happening.
None of the diagnostics are showing any codes or codes pending.
Last edited by Stevengineer; Feb 23, 2020 at 09:27 PM.
Thread Starter
Instructor
Joined: Jan 2018
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From: Greensboro NC
Racer
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From: Pittsburgh PA
Thread Starter
Instructor
Joined: Jan 2018
Posts: 148
Likes: 10
From: Greensboro NC
And the 1500RPM was when I had to hit the gas without taking time to downshift because of another driver. Thinking back on it, I think it was 4th gear, not 6th.
Thread Starter
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From: Greensboro NC
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St. Jude Donor '11-'12-'13, '15, '16-'17-'18-'19
My full size Ford Transit does that but it's a known problem with them with no known fix 
.
As it turns out, when it rains, water gets into the air box , then travels to the mass air flow . Make sure you do not have a similar situation.
Mine has the same symptoms when water gets in but once it dries, the van is just fine.
.As it turns out, when it rains, water gets into the air box , then travels to the mass air flow . Make sure you do not have a similar situation.
Mine has the same symptoms when water gets in but once it dries, the van is just fine.
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Thread Starter
Instructor
Joined: Jan 2018
Posts: 148
Likes: 10
From: Greensboro NC
My full size Ford Transit does that but it's a known problem with them with no known fix .
As it turns out, when it rains, water gets into the air box , then travels to the mass air flow . Make sure you do not have a similar situation.
Mine has the same symptoms when water gets in but once it dries, the van is just fine.
.As it turns out, when it rains, water gets into the air box , then travels to the mass air flow . Make sure you do not have a similar situation.
Mine has the same symptoms when water gets in but once it dries, the van is just fine.
Thread Starter
Instructor
Joined: Jan 2018
Posts: 148
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From: Greensboro NC
Update:
I I ran the car today (everything perfectly dry) and it did it at 5500 RPMs in second gear, WOT. It felt as if I let off the gas halfway when I didn't. It lasted for maybe 1/4 of a second and then came back full power. I did a WOT pull 5-6 more times without anything happening.
None of the diagnostics are showing any codes or codes pending.
I I ran the car today (everything perfectly dry) and it did it at 5500 RPMs in second gear, WOT. It felt as if I let off the gas halfway when I didn't. It lasted for maybe 1/4 of a second and then came back full power. I did a WOT pull 5-6 more times without anything happening.
None of the diagnostics are showing any codes or codes pending.
Last edited by Stevengineer; Jan 15, 2020 at 10:40 PM.
Racer
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From: Pittsburgh PA
where do you live? Do they flip gas to a winter blend that's causing you to knock? I know if i run pump gas in summer it's OK and i can even do a WOT to 4k RPM or something (supercharged) but in winter I cannot WOT anything on pump because it'll knock. Reproducible over an over though... however, i'm seeing my AFR go lean, if you don't have a wideband, you likely wouldn't notice until you go hard enough and knock enough for the car to pull timing? Sorry, just throwing out ideas.
Last edited by sonnysucks; Jan 16, 2020 at 01:30 PM.
Thread Starter
Instructor
Joined: Jan 2018
Posts: 148
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From: Greensboro NC
where do you live? Do they flip gas to a winter blend that's causing you to knock? I know if i run pump gas in summer it's OK and i can even do a WOT to 4k RPM or something (supercharged) but in winter I cannot WOT anything on pump because it'll knock. Reproducible over an over though... however, i'm seeing my AFR go lean, if you don't have a wideband, you likely wouldn't notice until you go hard enough and knock enough for the car to pull timing? Sorry, just throwing out ideas.
I don't have a way to watch my AFR while driving. I am a bit surprised I would have this problem with factory parts and electronics. But it did start back up or at least get worse after I filled up last time. Also around the time the weather got warm.
Last edited by Stevengineer; Jan 16, 2020 at 02:01 PM.
Racer
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From: Pittsburgh PA
Do you get gas at the same place always? I worked full serve as a kid and we definitely had water in the tanks come spring annually. You could try some dry gas in the tank as well. I think it's really a stretch, but it seems like a very odd problem.
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From: Cape Coral, Florida
If it happens only when it rains I'd kinda lean towards secondary ignition...even if it does it under dry conditions the wires may be breaking down under load...you can try mixing some baking soda with water and when it gets dark out spray the wires and coil packs with the water and see if you see a lightning show under the hood when giving it some gas !!...I would expect to see a flashing check engine light with a P0300 stored but maybe not !!
Thread Starter
Instructor
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From: Greensboro NC
Diag - I may give that a try sometime.
It's a place that I've filled up at many times before, but not always.
Thread Starter
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From: Greensboro NC
I regret to inform you guys that this is a continuing issue.
It definitely seems to be related to the rain or soon after washing the car. It seems to happen at any RPM and under almost any acceleration but not while maintaining speed.
With all the rain the past week and having to drive it from NC-AL-NC in the rain, it became a big issue getting on the highways. Water is getting to something it shouldn't, but I can't find anything that seems really wet. The only thing I can find, is some water can splash up near the air filter. Could the engine be sucking in water through the air filter? I have a airaid cold air intake on the car.
It definitely seems to be related to the rain or soon after washing the car. It seems to happen at any RPM and under almost any acceleration but not while maintaining speed.
With all the rain the past week and having to drive it from NC-AL-NC in the rain, it became a big issue getting on the highways. Water is getting to something it shouldn't, but I can't find anything that seems really wet. The only thing I can find, is some water can splash up near the air filter. Could the engine be sucking in water through the air filter? I have a airaid cold air intake on the car.
Safety Car
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From: Erlanger, Kentucky
I would bet it is a coil pack, plug wire, or spark plug. My bet is a coil pack.
I had a similar issue when I had my car dyno tuned a few months back. Engine ran great until hitting about 5500 rpm, then it would lose power and you could hear the exhaust note breaking up. HP tuners showed a miss-fire in one of the cylinders. Moved the coil pack of that cylinder to a different one and the miss-fire also moved. Replaced coil pack and no problems since.
So either the extra moisture in the air going into the cylinders putting more ignition stress or the increased moisture in the air is affecting the coil.
I had a similar issue when I had my car dyno tuned a few months back. Engine ran great until hitting about 5500 rpm, then it would lose power and you could hear the exhaust note breaking up. HP tuners showed a miss-fire in one of the cylinders. Moved the coil pack of that cylinder to a different one and the miss-fire also moved. Replaced coil pack and no problems since.
So either the extra moisture in the air going into the cylinders putting more ignition stress or the increased moisture in the air is affecting the coil.
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From: Central MO
Easy way to eliminate the CAI is to remove it and put the stock intake back on if you still have it.
If the filter is oiled cotton gauze I would at the very least pull the MAF and clean it with MAF cleaner to make sure oil contamination isn't at least part of the problem.
If the filter is oiled cotton gauze I would at the very least pull the MAF and clean it with MAF cleaner to make sure oil contamination isn't at least part of the problem.
Last edited by BadAV; Feb 24, 2020 at 07:28 AM.