92 expl. no od. what ALL controls it?

[hdjour]

i have a 92 expl. i have no od or lockup. here is what i have checked
1) pulled vb changed sols and gaskets and confirmed power to them
2) changed vss on transfer case
3)ohmed out wiring between sol plug at trans and the computer
4) today i grounded both od and tcc at the computer while driving and it shifted and worked just fine.tranny is good.
the only other thing i can think of is tps. but i am tired of throwing parts at it. is there anything i am missing. i put a test light on computer while driving and it did not ground on those 2 circuits. so that tells me computer isnt telling trans to shift. so what else tells computer to shift trans?

 

[BrooklynBay]

Welcome to this forum! The TPS could be the culprit. Check it with an ohm meter. The TPS is considered a high wear part. Did you scan the PCM for trouble codes?

 

[hdjour]

no codes. i also thought if it was tps that it would give driveability probs?

 

[BrooklynBay]

The resistance could be out of spec or there could be dead spots causing glitches.

 

[hdjour]

to test this do i do an ohm test with it disconnected or do voltage with ign on eng off? aside from dead spots what readings should i get?

 

[Jack Flash]

when you "un" grounded the od at the computer while driving, did it downshift to 3rd ? possibly, the linkage is incorrect and keeping the tranny in 3rd/passing gear unless the computer tells it to shift.

also, you didn't mention any debris/shrapnel in the pan when you removed it, so I guessing every thing is ok in the od part of the tranny ?

I worried myself sick with my tranny having no od; turned out the band wasn't attached. I traced wires, then bought a new 3/4 solenoid just to find "pieces" of springs in my pan and filter.

...jjf

 

[cybergasm]

Not to hijack but...

The resistance could be out of spec or there could be dead spots causing glitches.

Could the TPS also cause wavering rpms before shifting? motor runs fine except when it get ready to shift then the RPM waver a bit before it finally shifts...almost like a surge but not really.....

 

[BrooklynBay]

It might be possible if the PCM lost the TPS for a brief second that it could cause a feeling of a flare up or a surge.

 

[BrooklynBay]

This link has some information on sensors: http://fordfuelinjection.com/?p=10

 

[MrShorty]

The most important inputs in the computer's decision to shift into 4th gear and to lock up the TCC are TPS and VSS. Others (like ECT, and MAF and others) figure in as well.

When you say "no codes" does that mean all pass (111) codes?

i put a test light on computer while driving and it did not ground on those 2 circuits.

Set up your test light like this again, and run it through the output state test (see my notes on pulling EEC-IV codes for how to enter output state test). This will indicate if the computer is able to command 3-4 shift and TCC lockup. Be sure to check the computer's grounds. PCM acts as a ground side switch, but that means that there has to be a good connection from the PCM to ground for the signal to get through.

 

[hdjour]

to respond: jack flash , while i grounded the coil wire for the tcc and the 3-4 shift it did as they are supposed to. i got up to hwy speed then after not getting my overdrive i overrode it by manually grounding coil. it shifted into 4th then i grounded lock up and rpms dropped down by 500. i did this a couple times just to make sure. and no debris was in pan just the usual little coating of clutch dust at the bottom. i also believe that the band is ok. i assume i was looking at it when i had vb off. i could see the adjustment point it wasnt loose. i also checked and adjusted band (thought if it was blown it wouldnt adjust properly it was only out 1/4 turn.

mrshorty, no codes by plugging in little box with blinking lights and it gave 11.where do i find your notes on doing a test that will check if pcm can controll them? i still have everything hooked up to use test light for confirming ground.

 

[BrooklynBay]

http://www.explorerforum.com/forums/showthread.php?t=147734

 

[hdjour]

if i had a tps with a dead spot or 2 in it, it may not show up right? i know a map would. thing i will buy one while i am in town tom. if i dont need it i will just take it back.
i will do output state test tom. and get back to you.thx for the help.

 

[hdjour]

ok i just tried test and computer gives me 1 1 1 then after test was done i depressed gas pedal as described in thread and solenoids grounded . so that tells me computer can control them and i know everything past computer works fine. so what other sensors tell computer to shift into od or lock up? i did buy a tps today but havent installed it yet, once i do i cant return it and get my 60 bucks back. so i would like to be sure(if thats possible)

any other suggestions/ tests? thx

 

[hdjour]

every time i think i have it. i dont. i waited as long as i could then i did it. i changed the tps. went for a road trip and the SAME THING! i can shift it by grounding my jumper wires which tee off the 3-4 and tcc solenoids. and test showed the computer will shift them in the koeo test.
what isnt telling computer to shift?
changed vss
changed tps

i dunno.

anyone?

 

[MrShorty]

I don't know the details of the computer's algorithm, but I wouldn't be surprised if most or all of them play some role in deciding to shift the transmission. If you want to guess at sensors, you could easily end up checking them all. Frustrating thing in your case is that the computer isn't reporting any DTC's, so it isn't helping to narrow it down.

Do you know anyone with a good scanner (not a code reader, a real scanner that can read PIDs)? I've never been able to confirm that a '92 can output PIDs to a scanner, but this sounds like a case where it could be real useful to "look inside" the computer's brain and see what inputs it is seeing and what it thinks the actuators' states are and see if you can see anything out of the ordinary.

In the absence of a scanner (or if a '92 is unable to output to a scanner), I might try putting a multimeter on each sensor (VSS, TPS, MAF, ECT, IAT, others) and see if anything looks out of the ordinary.

 

[hdjour]

i talked to the local ford dealer today to see if he could help. he asked if any lights were on dash. the rear abs light has been on since i bought it and od worked. could this be contributing to prob? i did change dif sensor and light still on.

 

[BrooklynBay]

You might find one of the links in # 58 in my list of useful threads interesting: http://www.explorerforum.com/forums/showthread.php?p=1762701#post1762701. It has the Ford part # of the updated speed sensor.

 

[hdjour]

tried to scan for rabs codes to no avail. i jumped wire under dash to ground and released and no flashing.this thing was supposed to be on the road last tues. any ideas ?

 

[wood1]

In my A4LD Reference manual (thank you E-Bay) in the Diagnostic Procedures section, page 10...

Electronic Ignition (EI) System, consists of a Crankshart (CKP) sensor, an EI Module, 2 four-tower Coil Packs and the PCM. The EI system operates by sending crankshaft position information from the CKP sensor to the EI Module. The module generates a PIP signal (engine RPM) and sends it to the PCM. Symptoms include no 3-4 shift, 4-3 shift, no torque converter clutch engagement.

AND

Throttle Position (TP) Sensor, is a potentiometer mounted on the throttle body, detects the position of the throttle plate and sends this information to the PCM as a varying voltage signal. It is used to determine the 3-4 and 4-3 shift scheduling and torque converter clutch engagement. Symptoms include abnormal shift schedule, torque converter clutch does not engage, torque converter clutch cycling.

AND

Programmable Speedometer Odometer Module (PSOM), receives input from the rear Anti-Lock Brake System (RABS) Speed Sensor, which is mounted on the rear axle differential housing. The PSOM processes this input signal information and relays it to the speed control module and the powertrain control module (PCM) this signal tells the PCM the vehicle speed. Symptoms include no 3-4 shift, no 4-3 shift, no touque converter clutch engagement.

I'd try the RABS sensor first as you have already mentioned the ABS light.

Regards,
Chris.