86 ltd v6 poor running??'s

[urrlord]

I talked with a guy that has the above car for sale. here is the text from his ad.

I bought this 2 years ago it had been sitting for a long time. I spent a lot on it but couldn't find the problem! It will run if he computer is unplugged for a while and if you pat the gas with the computer hooked up! I put a new throttle body on it and 2 rebuilt computers and it still does the same way
This was one of the first cars with computers I think. I thought about putting a carburetor and getting rid of the computer but I have too many
projects. The motor is the same as a v6 mustang


I called him for some clarification.He said that if you unplug the computer for a while then plug it back up the car will crank and run poorly(not drivable) as long as you keep the gas pedal depressed.if you release the gas pedal the car will die and not crank back up until you unplug the computer again and wait then plug it back in.


Any Ideas from the gurus here?

the guy seems pretty knowledgable on 60's and 70's vehicles just not on computer era vehicles.

[xctasy]

Would I buy an Essex V6 Throttle Body EFi?

Heck yeah, they are awesome, but you just gotta know that the wiring and sensors were borderline reliable in 1986, and what's what from the EVTM (Electrical and Vacuum Troubleshooting Manual ) and VECI (Vehicle Emission Control Information ) Label diagrams. And Technical Service Bulleten (TSB) relavent to the car is most important.

The two EECIV KOEO and KOER tests give you clues as to what to look for.

The other part is the EGR. EEC stands for Electronic Emission Control, all generations of it from EECI to EEC5 controls the operation of the big valved EGR system very carefully, and normally that gunges up real quickly with the aluminum heads famed ability to similarly gunge up. The Thermactor is 9 times out of 10 gunged up at the EGR plate.

WalkinTall, Mike, our most awesome Canuk Carb tuner, found similar issues.





Normally its making sure the EGR valve and the TPS give a clean signal. The later EECIV for Essex 90 V6's moved to internally regulated earth O2 sensors; they become earth points if people have dabled with the body earth and battery earth strap.

There is a specfic service replacement for the throttle body insulator. If the TSB work is done, it fixes a troublesome and common air leak. The propane test is they way to find this. The other part is the tin gasket which biases fuel flow under wide open throttle. People try to acess the EGR and TPS, and then decide to raised the 2-bbl throttle body, and then it leaks.

The physical EGR and TPS and fuel pressure fittings on the Essex V6 are distinctly strange, and very easy to break, drop parts and miss tune, so running codes with the EECIV fitted is the essential first step. A hydrocrabon test is then needed to varify that there isn't gasoline in the water supply, and that the whole thermostate and upper intake isn't chocked full of crud, the system has a chance of running okay. The HVAC heat exchager restrictor is the next step, another part that causes collatoral damage if a person isn't gentle.

Don't be affraid to rip off the EFi, and do a Walking Tall Bypass, but the EECIV era has a wealth of helpfull and experienced information out there.

The earthing out issues mask a range of other matters, its hard to be specific on what is Job One to getting Throttle Body EFi 3.8 to work.


Go Mikes car build, read up about what happens with 86 3.8's.

10 well writen pages,

here is page 3's goldne piece....

Update: Tested suspected MAP sensor...

VREF test: key off, disconnect MAP connector; measure voltage between VREF and SIG RTN at connector; KOEO - got 4.95v, good.

MAP/BP Sensor test: connect MAP connector; with digital multi-meter, back-probed MAP connector MAP wire with (+) and battery negative with (-) - got 2.50v, not good.

According to a table of MAP/BP voltage specs, this MAP sensor thinks it's a couple thousand feet below sea level. Maybe what the car needs is a periscope?

The frequency testing went as follows: 160Hz with no vacuum - perfect; 110Hz with full vacuum - supposed to be ~93Hz.

NOW, AFTER the above testing, is the FIRST TIME EVER getting a K.O.E.O. code 22 (MAP/BP out of self-test range), and it's been guzzling gas but not really showing signs of it besides the fuel gauge needle, and acts sluggish and hesitant upon acceleration with taking it for one spin around the block so far. I swear this car is possessed, with somewhat of a sense of humor, and likes to play games with me. Anyway, I need to find another MAP sensor... a used one that works, because new ones appear to be hovering around the the ridiculous amount of 90 bucks around here.

Checked fuel pressure today: with key just in the Run position, gauge read 38psi... it lost some pressure, because I had set it to 40psi a month or two ago...; with the engine running, the gauge said 40psi. I adjusted it up to 44psi while running.
Checked TPS idle voltage: 0.84 volts... again, a decrease. I set to 1.00 volt a month or two ago. Adjusted back up to 0.98 volts.
Doing these two things eliminated the low speed, light/normal acceleration hesitation it's been having.

Nothing else really to update. It's to be taken on an approximate 18 hour journey this weekend.
I've got all tools and will have some spare stuff on board. Wish me luck, lol

Page 4...

The next hiccup (I feel like trademarking/copyrighting/coining/whatever that phrase), in the never-ending saga of hiccups that is EEC-IV:



These sensors are supposed to have, through their range of movement to sensing and relaying the EGR valve's diaphragm's position, as a variable resistor, 5500Ω to 100Ω. Mine has exactly 4.85Ω of resistance no matter where it's stem is, lol. This has been causing the car to run like a can of smashed a$$holes. At first I presumed some bad gas (but 4 different loads (2 premium 91-octane) of ten bucks thrown in? I don't think so), and have retarded the ignition timing 2° twice to 6° BTDC, to no avail. It's also got a somewhat rough idle and off-idle, and pinging/detonation with from anywhere between 20-50% throttle application upon normal acceleration, but only at the lightest of loading, at the top of each gear just prior to shifting. Welcome to EEC land, where I'm suggesting, the ecm's response is to open the EGR when it should be nearly or always closed, and vice versa. That's bass-ackwards, and no, I'm not wasting one more dime on trying to get it to cooperate.

Thankfully, I have the cure for the hiccups. None of any kind of the above kind of inverted-universe BS will go on with carburetion and Duraspark. Soon.

EGR plate removal



Factory 1986 Restrictor plate below the CFi has to be pristine

[emerygt350]

Damn, and xctasy is the reason I click on random v6 posts.

[Walking-Tall]

The disconnecting and reconnecting of the computer could just be coincidence, and masking a rich condition (flooding) that dissipates enough over the amount of time passed between the disconnecting and reconnecting. The introduction of increased air with an opened throttle so that it runs is what leads me to think it, for a number of possible reasons with the system or it's components, could be flooding. This could be a faulty or leaking diaphragm fuel pressure regulator providing excessive fuel sucked straight in with intake manifold vacuum or excessive fuel pressure, dirty and sticking off their seats fuel injectors, clogged air filter, excessive TPS signal voltage, faulty ECT (engine coolant temperature) sensor or thermostat (overheating), vacuum leak or fault with the MAP sensor... and the list can go quite on and on... As mentioned above, besides experience and seat of the pants troubleshooting and testing every sensor and every connection and wire continuity between components and between components and the computer, there's really no better initial indicator of what might be going on with these things than checking it for trouble codes, for hopefully a direction or area to start looking and checking things...

[erratic50]

And here I thought I'd see another thread with mention of 351 to somewhere north of 469 CID of therapy. Some might suggest the car is simply saying I coulda had a V8.

Did I type that out loud?

All jokes aside I always wanted the setup Ford never built. V6 5 speed.

Doesnt the TBI injectors have pulse that can be checked with noid lights? Are they sticking open and flooding the ol gal out?

I hope you get it running right.

[urrlord]

I talked with the car's owner and gave him this web sites info so I imagine he'll be popping in here for some tech info.