Possible MAP issue?
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,205
Likes: 0
From: Dallas City IL
Possible MAP issue?
Guys,
Coming home from a car show last week, the car started to stumble and run rough. A week earlier, I had melted a plug wire on my B&B short tube headers, and thought I had fried another. I replaced all wires, as I was having a hard time finding the one. Well, that wasn't it, next I replaced the sparks that only had 2k miles on them, which were very black, meaning rich. But instead of just one of them, they all were. After replacing them, this issue still exists. My wideband is now showing a rich condition, (11:0 to 1 at idle) and the car smells as such. It stumbles and doesn't want to idle. This is a SD tune, the MAF is out of the loop. It is running a COS3 from EFI Live that I have tuned. Looking at passed logs, I noticed my MAP reading avg is higher at idle than before. Map readings used to be in the mid 40's, now the mid 60's, which is why it's adding too much fuel. At key on, engine off, my reading is 99, which is correct. Also, my IAT sensor seems to be correct. I don't know if this means my MAP is still good, and I have a vac leak somewhere?
The car has a mild h/c with about 50k miles. Where should I look for vac leaks? I checked the PCV, seems to be ok. What should I check or log before I pull the intake? Vac seems strong enough to open the vents and such in the car and on the brake booster.
Coming home from a car show last week, the car started to stumble and run rough. A week earlier, I had melted a plug wire on my B&B short tube headers, and thought I had fried another. I replaced all wires, as I was having a hard time finding the one. Well, that wasn't it, next I replaced the sparks that only had 2k miles on them, which were very black, meaning rich. But instead of just one of them, they all were. After replacing them, this issue still exists. My wideband is now showing a rich condition, (11:0 to 1 at idle) and the car smells as such. It stumbles and doesn't want to idle. This is a SD tune, the MAF is out of the loop. It is running a COS3 from EFI Live that I have tuned. Looking at passed logs, I noticed my MAP reading avg is higher at idle than before. Map readings used to be in the mid 40's, now the mid 60's, which is why it's adding too much fuel. At key on, engine off, my reading is 99, which is correct. Also, my IAT sensor seems to be correct. I don't know if this means my MAP is still good, and I have a vac leak somewhere?
The car has a mild h/c with about 50k miles. Where should I look for vac leaks? I checked the PCV, seems to be ok. What should I check or log before I pull the intake? Vac seems strong enough to open the vents and such in the car and on the brake booster.
Last edited by M396 #00-011; Jun 17, 2011 at 10:59 AM.
sounds like a broken valve spring - very common on h/c cars
Thread Starter
Burning Brakes
Joined: Oct 2001
Posts: 1,205
Likes: 0
From: Dallas City IL
I just noticed that the intake runner feeding cyl #2 is super hot compared to the others. Looks like I'll be taking that valve cover off first.
Update: Broken valve spring, exhaust cyl#2. Thanks for the help guys.
Update: Broken valve spring, exhaust cyl#2. Thanks for the help guys.
Last edited by M396 #00-011; Jun 17, 2011 at 10:55 PM.
