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I replaced all four wires from connector to connector. You want to use friction tape to rewrap the harness. It’s not fun but it is doable.
Your photos look like the nightmare I'd imagined it would be . I knew the wires ran behind the dash but I didn't think about getting to them from the blower motor area. Are you able to access all four with the blower motor out? What I ended up doing is I cut off the first 4 inches of each wire where the insulation was next to non existent then soldered new 12awg wires in. I would have preferred to cut back farther than I did but I didn't want to get into removing the dash at this point. All of my repair was done from the engine bay side and at least there's good wire now. So far, I haven't had the issue even using ac which kicks the fans on. But if I do I'll revive this post and keep working at it.
So the issue returned. I decided to block off the maf with cardboard to block the rad fans blowing into the area. This makes a significant difference. I've been driving like this for a few days with success. Today the weather was nothing but rain and wind and after driving home from work I noticed the air filter got just the slightest bit wet. Prior to, I've already been considering trying to find a better pipe (something metal) to hold the maf sensor as the one with the kit was plastic and bulky and the fit is very tight. I suspect putting some distance between the maf sensor and filter might reduce or eliminate some of the interference as well. So I've been trying to find a good solution now to plum the maf slightly differently while trying to keep the filter dry even on extra rainy days. Does anyone know what maf sensor the vitesse vmaf+ is so I can find different piping options for the sensor?
The only major plumbing options I've seen was to run the filter through the factory air box hole, or down through the bottom of the head light area, or a maf trap (shield) setup. The room is very limited .
none of these really offer rain protection though
Last edited by mahoney944; 05-29-2019 at 09:23 PM.
The fans are never an issue.. I run the same setup on my car without a problem.. 99% of the MAFs in the field run the std. Setup. I'm afraid there may be a problem somewhere else unrelated to the air from the fans.
It is best to keep the filter attached to the MAF. This is how the MAF is calibrated.
The fans are never an issue.. I run the same setup on my car without a problem.. 99% of the MAFs in the field run the std. Setup. I'm afraid there may be a problem somewhere else unrelated to the air from the fans.
It is best to keep the filter attached to the MAF. This is how the MAF is calibrated.
While the engine is running with the fans on high, I remove and install the cardboard shield.. the issue goes away and returns on point with adding and removing the shield. There's a pretty good gust of hot air going right into that area... At least on my car. Idk. Is there a metal maf sensor pipe instead of using the plastic one?
It'll be interesting to see a log file to capture the MAF signal while you remove/install the shield.
The fact that the issue disappeared when you fixed the wires for fan resistors, then it came back makes me wonder if there is something else.
The metal MAF is the same size as what you have. I do not stock it, but I can get it.
Originally Posted by mahoney944
While the engine is running with the fans on high, I remove and install the cardboard shield.. the issue goes away and returns on point with adding and removing the shield. There's a pretty good gust of hot air going right into that area... At least on my car. Idk. Is there a metal maf sensor pipe instead of using the plastic one?
It'll be interesting to see a log file to capture the MAF signal while you remove/install the shield.
The fact that the issue disappeared when you fixed the wires for fan resistors, then it came back makes me wonder if there is something else.
The metal MAF is the same size as what you have. I do not stock it, but I can get it.
The problem has been so intermittent that it's hard to say. The wiring was bad for sure but I'm not sure that fixing it did anything or not. It seemed to at first but the issue is only when the car idles to the point where the high fans stay on. Most times when just going here and there the car stays cool enough where the fans aren't running and the issue doesn't happen.
After you mentioned air turbulence before I tried just unplugging the fans to turn them off to test and the issue stopped. So I made a piece of cardboard to shield it and that definitely shows a difference. Since it's easily removable I was able to add and remove it while the fans ran. My afr immediately corrects itself and the idle smooths out. My shield isn't very good and it does well. I'm sure a properly made one would do even better.
The only time I have seen the fans creating problems was on a 944NA race car, where the owner put the MAF directly behind the fans. Never seen it on a 951 with the filter behind the headlight as you have it. Regardless a shield is always good to have..
A log file would help figure out what's going on.
As I remember, you are adding 10% fuel via the FQS. Another item that seems odd here.
You'll get it sorted out and you'll start driving and enjoying.
The only time I have seen the fans creating problems was on a 944NA race car, where the owner put the MAF directly behind the fans. Never seen it on a 951 with the filter behind the headlight as you have it. Regardless a shield is always good to have..
A log file would help figure out what's going on.
As I remember, you are adding 10% fuel via the FQS. Another item that seems odd here.
You'll get it sorted out and you'll start driving and enjoying.
Agreed, does the metal maf sensor pipe have the legs on it like the plastic one? I'm hoping not. How much?
Well I tried to move the maf away from the head light, more towards the coolant tank and still had it go lean when the high fans came on at idle. I made a better fitting shield to isolate the maf from under the hood hot air coming off the fans and the problem is gone the shield is just made out of a 1" foam pad and it blocks from the head light to the coolant tank fitting to the underside of the hood tightly.
The car is running great the only slight issue I've noticed is you can make the car stall if you get into mid to high range boost then immediately shift into neutral (can't remember if I had the clutch in or not ). The rpms just immediately drop to zero and stall. The car does not do this on reving the motor at idle or if you drop idle without boost or other similar situations like down shifting. From reading an old post on this it seems like the issue is caused by the the turbo still drawing air as the bypass valve shoots a gust near the maf creating a false input value. I have not logged this yet but other have in this old post explaining in more detail. https://rennlist.com/forums/944-turb...pm-drop-2.html
There is a solution in that post that seems decent but the issue is only occuring when you very quickly shift into neutral on boost, seems if you can catch the bypass valve whoosh right as your rpm drop quickly the stall is on point. If you let off boost and wait a second or so after the bypass whoosh then shift into neutral it idle drops perfectly. The gust on the drop seems to trick the maf just long enough for it to occur. Otherwise car is running perfectly
Glad to hear your car is running good. If you ever take a log of the boost then Neutral, please send me a copy. Try clocking the MAF a bit, it may make a difference.
When you lift, you get fuel cut, then kicks back in at lower RPM. And the ICV keeps it from dropping.
Still running +10% fuel? If so, I still wonder why... The extra 10% fuel is not helping the RPM drop issue.
Glad to hear your car is running good. If you ever take a log of the boost then Neutral, please send me a copy. Try clocking the MAF a bit, it may make a difference.
When you lift, you get fuel cut, then kicks back in at lower RPM. And the ICV keeps it from dropping.
Still running +10% fuel? If so, I still wonder why... The extra 10% fuel is not helping the RPM drop issue.
Yes still at 10%. Can't seem to figure out why but the car runs fine there. I'll log the hard idle drop and stall tomorrow.
05-26-2019, 05:42 PM
. I knew the wires ran behind the dash but I didn't think about getting to them from the blower motor area. Are you able to access all four with the blower motor out? What I ended up doing is I cut off the first 4 inches of each wire where the insulation was next to non existent then soldered new 12awg wires in. I would have preferred to cut back farther than I did but I didn't want to get into removing the dash at this point. All of my repair was done from the engine bay side and at least there's good wire now. So far, I haven't had the issue even using ac which kicks the fans on. But if I do I'll revive this post and keep working at it.
