EFI Gurus... need a little help.

[67EB_in_619]

Hey Guys... here is the deal...
Durring the KeyOnEngineOff test, I have been throwing a Constant Memory code 85 (Adaptive limit reached - lean). Since as far as I know the o2 sensors are the only thing that measure mixture, are my long tubes causing this? Something else? Maybe not even o2 related but the EEC trying to lean it out for other reasons?


It started running a bit doggy on the way back from Fab Fords yesterday... and it has been (since installed) idleing low and rough and surging (300RPM - 600RPM) with occasional stalling at lights... always starts right back up.

As far as running 'doggy' the only way I can explain it is that the power isnt all there like it was and the engine tone sounds lower than it used to.

Any suggestions are greatly appreciated!

(97 HO w/ 93 GT electronics & harness)

Thanks!
-Matt

 

[Unregistered]

Probably I would look into the fuel pumps, make sure that they are working properly and that the filter isn't clogged. If you have one available, use a fuel pressure gauge and hook it to the schraider valve tp see what kind of pressure you are running. If you are reading anywhere below 39 lbs, I bet that is what your problem is. Could be the pressure regulator is going bad. But I would say its a mechanical problam and not an electrical/computer problem. If it worked fine before, I can't see your long tube headers causing the problem. I have the long tubes on my '73 (with the O2 sensors right after the collector and flange) and it actually idles smooth, it just has that carbed sound, if you know what I mean.
-Eric

 

[Bronco Ben]

sounds like its going into a choke loop! Only thing I can think of is maybe your EGR is dirty or going bad, ...thats my guess!
Ben

 

[67EB_in_619]

THanks Ben.. but I dont have an EGR (at all.. no elbow.. nothing)... could this be the problem? I just hooked up a EGR sensor to the harness and will see if that makes any difference after a reset...

keep em coming guys!

 

[Bronco Ben]

back a few years ago, a buddy and myself owned a mustang performance shop, and when we eliminated the EGR we turned it off using an external EPROM "chip" so if yours isnt connected, and its acting up, I'd still say that would be my guess, but like a said its been a few years back since I've actually messed around with EFI stuff. Hope that helps!...if not I'll dig a little deeper back in the "old memory"
Bronco Ben

 

[bert]

Just answered a post that 66horse posted.
Try cleaning the MAF sensor. A dirty MAF will cause it to run to lean and the computer is unable to compensate. More air is entering the engine than is being measured by the MAF.

http://classicbroncos.com/forums/showthread.php?s=&threadid=44680

 

[66horse]

Just answered a post that 66horse posted.
Try cleaning the MAF sensor. A dirty MAF will cause it to run to lean and the computer is unable to compensate. More air is entering the engine than is being measured by the MAF.

http://classicbroncos.com/forums/showthread.php?s=&threadid=44680

Hey Bert, thanks for your answer on my thread. I was actually at 67ebin619's house today. It was like the blind leading the blind... no offense Matt!

 

[67EB_in_619]

none taken.. .
us blind guys got some stuff figured out.

 

[66horse]

none taken.. .
us blind guys got some stuff figured out.

God point yours should be good, and I think my problem is what you suggested. SHould have tested it at your place...

 

[67EB_in_619]

My problem turned out to be an out of whack TPS sensor (re-calibrated it now) and a shorting plug wire.... looks like the #6 plug on the GT40P heads with headers bit me... I ordered a shorter header plug from summit to igve me more clearance and a couple MSD wire kits so I can build a tight fit with the little 90* boots.. and some heat wrap for the boot and header.

 

[Bronco Ben]

kewl, glad you found the problem. Sometimes its something really hard and sometimes its the simple things, I prefer the simpler problems myself!
BRonco Ben

 

[Lttrbox]

Glad to see you got it. I was going to say check the TPS. Mine was that one as well.