choinga

I've got an email into John - hopefully he sees it tonight or tomorrow...but thought I'd post here and see if anyone had any ideas...

I installed the Vitesse MAF today (no new turbo...just the MAF). Everything seems to look OK. Car starts right up, I show good fuel pressure (~43PSI) on the rail with no leaks but it immediately dies. I can start it back up again, again…and it won’t even run long enough to let me get my foot on the gas and get a rev.

Any idea what that might be? I’ve double checked everything – I’ve got the positive lead on MAF control unit going to the test plug +12v, the new injectors are all plugged in to the harness with excellent fit. I’ve got the injector resistors on the grey/grey black wires on the DME. All the MAF connections should be good because I didn't have solder any wires from to the engine harness - John supplied a harness that allowed me to plug directly into the stock AFM connector and then into his MAF. So, unless there's a fault in the wire or the control unit, that should be fine.

New injectors are plug and play, correct? I just took the plastic protective caps off and plugged them right into where the old ones were...lubed up the o-ring on the engine side with finger dab of ATM fluid and torqued the rail back on at 6ft/lb on all bolts. So, good fuel pressure on the rail means that the fuel is getting to the injectors?

I installed new hard pipes, but everything is connected well – my BOV is on solid and I’ve got every vacuum connection back on. I’m at a loss. I started it about 20 times now. It definitely seems like something is cutting the fuel off...about 3-4 of the times it chugged a little...never really caught, but then sputtered out. The engine turns right over and catches every time - but then just immediately dies. I'm at a loss on this one - not even sure where to start.

MM951

Classic MAF power problem. Make sure your 12v source has 12v. My diagnostic plug did not have 12V at it and I had to find an alternate source.

David Floyd

Double check your 12v source

choinga

That's the point I'm using. I went and bought this nice Fluke 117 to make troubleshooting electical stuff easier for a electron idiot like myself...and it's not really helping much. I stick it on V, stick the red lead in the + spot on the test spot and the black to a ground point and it reads .0012V in DC-V mode. I'm guessing that's 12V DC? I stripped my +12v wire from the MAF down and just crimped and taped together just to make sure I didn't have a bad connection in my solder/crimp and tried starting the car again - it will now run for about 10-20 seconds (horribly) and then dies. So, at this point I'm pretty sure that's not the problem unless my test point is actually getting .0012V instead of 12V, which could be a problem, of course. I considered tapping it to the battery just to see - but decided against doing that until ran it by the folks here - there's obviously no fuse there and don't want to blow anything up.

Is there anywhere else over in that part of the engine you can get 12V from?

I'm at a loss on this one. Seems pretty straightforward with my setup. I even pulled the injector resistors off and crimped the wires direct again just to make sure that wasn't having any effect.

It definitely 'feels' like a fuel problem. When it starts now and is chugging if I even tap the gas it dies (sooner than if I just let it die on it's own...)

Does strong fuel pressure to the rail = injectors are getting fuel? I keep a consistent 43-45PSI on the rail and there's definitely no leaks anywhere up there. The rail went back on fine and the bolts are torqued exactly to 6ft/lbs.

No clue...

MM951

Apparently some cars (maybe just red 87 951s ) just don't have 12v at the diganostic plug. No idea why, thats just what I read here.

I currently have my 12V coming from the fuel sender fuse..I have been meaning investigate the diagnostic plug and find out if I can get 12v there just to have a cleaner install, but it works.

I wouldn't put the 12v wire to the battery, it probably wouldn't kill the MAF but better safe than sorry

choinga

OK - Edit...

So, just for testing purposes (I literally got my Fluke a week ago...first time to use it...) I hit a 9V battery and saw 9.0V come up. So, seeing .0012V on the test point doesn't check out. It's getting some power (and weird that it's at a 12v increment) but apparently not the full 12v required. So, maybe that is the problem. I'm done with it for tonight so I'll investigate further tomorrow.

Is testing with the key turned all way but the car isn't on/running a valid test for that point? Just curious if the voltage changes if the car is actually running...assume not, but you never know...

As for the fuel sender fuse - did you just run a wire up through the box into the fuse spot and then mash the fuse down on top of it?

Techno Duck

Connect 12v lead for MAF directly to the battery and see if it starts up. Then you can verify or rule out if its the test port.

MM951

Pretty much I did it for testing purposes and the car has run perfectly...I really need to figure out a permanent fix, but I'm not quite sure where is the best place to get power if I can't get it at the diagnostic plug. I'd be interested to hear what John suggests...

choinga

I pointed John to this thread in my email to him earlier tonight so hopefully he has other suggestions. I plan on taking a crack at this first thing in the AM. It has to be the problem...

I'm going to try a wire directly to the battery since I know that's a solid 12V source and go from there. I that works, I'll wire it into the sender fuse just to get the car running and sit back and see if anyone else has any 1) suggestions on how to get the test port working the way it's supposed to and/or 2) an alternate 12V source that's a little cleaner than running a wire up into the fuse box.

fast951

Ken, What are you doing working on the car on Friday at midnight?? Sorry you had to wait till Saturday morning to get a reply

As others mentioned. Make sure your power source is solid. I emailed you list of things to try, I'll post here so others can benefit as well.. I will not be checking the list, the forum is not for support so email is your friend.

A few things to check:

- Chip/board inserted properly and inserted fully into the socket. (Verify visually, do not break it).
- For test purposes, use a different source for your +12Vdc power source (like the battery positive terminal). Use a fuse on the line!!!
- Make sure the direction of the MAF is correct (flow wise). Conector must be toward engine.
- Verify the voltage at the MAF itself. Verify you are getting +12V at the MAF connector.

- Now check your spark plugs, make sure they are not soaked with fuel.

If the problem remains, you need to check the continuity between the MAF white wire and DME pin #7. If the signal is not making it to the DME or if the DME is getting a degraded signal it will not run (or will be rough).

Email me directly with your results and for further support if needed.

DarylJ

That is your problem. Hook it to the battery directly (to test) and I'm pretty sure you'll be fine.

choinga

I'm OCD once I start working on something. I had this thing so damn close that I was trying to figure it out or at least get some starting points so I could get it done this AM.

And....THANKS GUYS!!! It was the test plug - nada on the 12v there. I wired it up to the battery and it started right up. So, right now I'm using MM's 'wire it to the sender fuse' method which I'm not a fan of, but it's working.

So, anyone have any alternate 12v sources NOT in the fuse box or battery that I can re-wire this thing to?

I haven't driven it yet - but it idles good. When I was troubleshooting I stripped off the injector resistors so I need to go back to Lowe's to buy a new set of ends (of course, I have 3 left and need 4). Once I get that done I'll give it a test drive and I'll start a new post on my experience w/ pics.

BTW John - you rock. If I make to Hotlanta any time soon, is on me!

fast951

Great news, easy solution. You just have to love the Rennlist for the quick response!

You can get +12V switched power source from the back of the 14-pin plug by the fuse box area. Check which wire is switched +12V and splice into it. It's best to use a in-line 7.5-8 amp fuse!!!

choinga

Thanks - for those following this thread, I posted a full write-up over here:

https://rennlist.com/forums/924-931-...ml#post6609447