fast951

Read the voltage between battery negative terminal and Maf ground at the chassis. Do this with ignition off, on, running, running with ac on + blower fan at max.

fbgh2o

Thanks John. I am not going to email you until next week, when you get back from vacation. Go enjoy your vacation.

Will check tonight... Was 0 in all cases before...

choinga

I've been keeping a close eye on this thread as I've been having the exact same problem. I didn't have a rich problem at all (in fact I was running lean w/ 951MAX chips & LBE and blew a HG) until post-MAF and I just got my LC-1 installed and I'm running in the 12's at idle and about damn near anytime I put my foot on the gas I'm in the 11's...at WOT in the 10's. Not good. My gas mileage is horrible. I'm about on empty on this last full tank and barely have 200 miles on it.

I tested the ground voltage as well - got a small reading at around ~.002v with the car off and .012v with the car on and I'm tapped into the same spot as you are (I picked that spot based on your MAF install thread). I'm guessing that's OK don't know what an acceptable variance is there. From what I've read though, another test is resistance across the negative battery terminal to where the MAF is grounded and should be around .04 Ohms. I ran the MAF ground to the intake as well but that didn't make a difference either. I haven't checked voltage at the Piggyback or the MAF yet, but don't suspect that to be a problem (I'm running my +12v from the fuel pump fuse like you are as well since I wasn't able to get it off the DME port)

I bought an Armworx tool to test vacuum pressure but I don't think that is the problem. I recently redid all the lines with the Lindsey kit and I get ~15hg at cold idle and almost 20hg at warm idle. I've set and re-set the idle speed, cleaned out my ICV, put in a new Bosch O2 sensor, I've got a brand new Bosch TPS and DME Temp Sensor on order, and while I've got the TB off I'm going to re-seal it with the Armworx TB re-seal kit.

I'm also fighting a idle 'dive bomb' which is really frustrating. If I'm sitting at idle and rev it up, idle settles back down nicely. If I'm in gear and get up to 3-4k RPM and clutch and let off the gas, the idle dive bombs down to about 300-400RPM before catching.

I'm at a loss as well - can't figure this one out. Looks like we're in the same boat except I've had mine since the install...it didn't creep up on me. I've got the PB and at idle can tweak it so the AFR is around 14.7, but then the car starts to idle like crap and hunt around. The PB is good for fine-tuning, but when you are as far off as we are there's a bigger problem that needs to be fixed.

John said to check fuel pressure as well...I've got a new Bosch 3BAR in that looks good when idling but since I don't have a gauge in the car no way to tell what's happening at boost. I doubt that is the problem as well though otherwise at idle I'd be fine but only under certain loads would I run into a fuel delivery problem.

I'm also waiting for John to get back off vacation (although I'm out all next week traveling for work) but I'll be watching this thread closely to see what you find. I'll let you know if I find a fix as well...

fwb42

The ground to the intake manifold could be the problem. Do the intake gaskets insulate the manifold from the block ground?? Just for kicks try moving your grounds or even putting a "jumper"from the intake ground to another know good ground.
Good luck,
Fred

fbgh2o

Not grounded to the intake manifold - grounded to the turbo pump bracket as suggested by John.

StyleLab

have you tried grounding it to the frame? My girlfriend lives in Ottawa, I may be there tonight if you want to test my MAF. I have the full boat stage 2 kit.

-Nick

fbgh2o

Nick

Sent you a PM..

fbgh2o

I just want everyone to know that I am working directly with John on this issue and he has been very helpful as we systematically deal with it.

The intent of these posts is to provide a record for posterity's sake.

choinga

Just curious - but have you tried grounding the MAF directly to the battery? I'm considering running both my power and ground lines over there later tonight when I get out the garage and see if that changes anything. There can't be anywhere else better in the engine bay to get power/ground can there??

fbgh2o

Just wanted to provide a closing note.

I put over 300 highway miles on the car yesterday. Averaged 27 mpg (US gallon). It would appear the issue is resolved. While I cannot be certain that it was electrical grounds, it seems to be the most likely culprit at this point.

Thanks - I want to extend my deepest thanks to John for his above and beyond support in walking me through this very elaborate trouble shoot and fix. As well, I offer thanks to Tom M'Guinn and Techno Duck for their responses to my often dumb "how do I?" questions.

Apology - I also want to publicly apologize to John as I gather that this thread created all sorts of consternation for him as others have similar issues and innundated him with emails which he has supported. None of them related to his product. John, I am truly sorry for the work that I created for you.

I am closing the thread as it is now for posterity's sake only.

My advice to all with issues like this.

1. Clean your gounds first
2. Check for voltage drop between the battery negative and your grounding points to make sure your grounds are okay
3. Check to make sure the O2 sensor is operating correctly
4. Check the TPS (as per Clark's garage)
5. Check the temperature sensor at the DME (as per Clark's Garage)
6. Pressure test the intake for leaks