Stumbling Idle

[SVOhNo]

Hey guys, what do yall think?
Fire the car up and it goes to 2k rpm and slowly comes down to about 900rpm where it stumbles up and down almost dying. After a little of that, it goes up to 2k rpm and drops down to about 1100 and stumbles from there. We thought it was a vac leak, no dice, now were wonderin if its electrical or what. Motor is newly rebuilt by previous owner and plugs were real clean. Guys have any thoughts? Were doin what we can to figure it out. DID figure out the fuel problem tho, put a vac line on the FPR and MAN does this car move...way to much fun for legal limits, lol
Matt

[NavySVO]

I put this under the other the other thread you had, explaining the first thing to do........I guess you missed it.

Try cleaning the IAC (Idle Air Control) valve that is bolted to the firewall-side of the throttle body. This is what will lets the proper amount of airflow to go around the throttle body during idle and decelleration periods.
Take it off and clean the internals with Throttle body cleaner. I even filled up the cavity and let it soak overnight. In addition, ensure the electrical connectors (male and female ends) are not corroded, and put dielectric grease on the pins.
Make sure that you use a new gasket too. This is still available from Ford.
Next, set base idle and TPS. Here is a thread on that:

http://www.svoca.com/forum/showthre...amp;threadid=11

[Alex L]

look like it ate the link, try this

[SVOhNo]

I read your post a couple minutes after putting this up there, thanks for both responses tho!!! We checked EVERYTHING thinkin it was vac, but the last thing we thought about before I had to leave for work was the Idle control... Ill call my mechanic and tell him to roll with that thought. The car runs amazingly once you get it rollin, cant wait to get all the bugs out and start REALLY enjoying this car. Ill let you know what happens
Matt

[SVOhNo]

Ok, mechanic said nothin worked, replaced the TPS and nothin. He said that it might be that the previous owner didnt get it tuned for the 35# injectors and T3/04B turbo. Would this do it? Im goin to get the car back tomorrow mornin and I will go over the suggested stuff about the IAC and TPS stuff one more time to make sure. If Im runnin the stock 84 comp, how would I tell, where is it, and what comp would yall replace it with. I know I asked this in another thread, but not sure if it got an answer yet...Ill check to be sure
Matt

[NavySVO]

Originally posted by SVOhNo
If Im runnin the stock 84 comp, how would I tell, where is it, and what comp would yall replace it with.

I can't remember offhand what the designation for the '84 is, but if you take off the passenger side kickpanel (panel between door opening and the fiewall) the computer should be residing in there. There should be a paper sticker on it that has the designation (PJ, PE, LA3, etc) in bigger letters in the uper right hand corner, and it should also have the ford part number on it as well.
Eyelawdoc (as well as others...no tomatoes please) has all the numbers for all the years for the SVO.......and probably every other Ford for that matter!! :0

[Pat_in_L.A.]

Original ECU is probably a PJ for an 84-85. I'll save the tomatoes for my salad.

[under pressure]

Pat in the rear pages of the manuels I gave you are a lot of code numbers for different computers and other info. I believe it's in the engine manuel.

[SVOhNo]

Im off to pick up the car from its power steering debacle, Ill check it out when I get it and post my findings, lol. Would be cool if it was actually upgraded, PO did his homework on other stuff, but then again, left out some others so who knows
Matt

[SVOhNo]

Picked up the car, runs like total dog crap!! Mechanic said he disconnected the battery and that the computer needs to "re-learn" everything and THATS why its runnin like junk. Found the computer, pulled it down...says LA3 on it...apparently the PO DID do his homework, but my mechanic says that with all the codes he pulled it must be the computer is bad. Right now, its idles alot better, but when your driving, it hiccups, like youll be goin from a stop and its jerky, then it will drive ok, then it will be cruisin and it will randomly hiccup. This is gettin old, and I need to figure out what the heck is goin on. Didnt take the list of codes he pulled, but there were a BUNCH of them! Could this be a bad comp, like he thinks, or does it really need to "re-learn" itself. I appreciate it guys, oh, Im gonna try and take a pic of the comp to verify that it truely is an LA3. Anyone got any words of wisdom?
Matt

[NavySVO]

I don't know if it could be classified as wisdom, but....

The computer will have to "relearn" after the KAM is bled off. Look on ebay. there are several computers on there to reference the label orientation for your knowledge.
If you type in 2.3L for a search, there is even an LA3.
You can go to AZ or other places to get a code scanner for around $29.00. Read the codes and get back to us. The book that comes with it has the chart to break down the codes.
Did he do a KOEO scan, or engine running scan?
If it is running, and pulling codes, the computer can't be doing too bad. I may be wrong there....it depends on the codes.
Check the EEC ground. It is the strap attached to the turbo compressor housing. Make sure it is good to go.

You also said the mechanic replaced the TPS, did he set it correctly?

[Pat_in_L.A.]

Since the mechanic may have entered VIN# info for an 84 SVO in his scanner, he likely got many codes that only make sense for an 87-88 T-Bird. Weeding through the trouble codes would provide a starting point.

[SVOhNo]

Here are the codes he pulled, these may be for the stock comp, I dont know, all I know is that Im so pissed off right now you cant even imagine. I brought the car is runnin JUST fine other than the idle, now it drives like dog ****. It stumbles around, wont build boost, feels like Im drivin a hauler truck (really slow and heavy feeling and whistles alot from the turbo, lol). Mechanic says its the comp relearning, I drove around for an hour straight, put 30-40 miles on it and it didnt get any better. What is goin ON!!!!!!!!!!!!!!!!!!! he says all they did was mess with the idle air control and the TPS. Anyways, heres the codes it pulled, and what the mechanic decifered that they meant. This is an LA3 comp but I dont think he knew that

23-TP Sensor out range
54-Air Charge Temp open
24 Intake air temp out range
34 EGR closed valve high signal
42 (cant read his writing) EGO not switching rich?
75 Mass air flow too high

He said they pulled the codes then disconeccted the battery overnight then did it again, same codes every time they did it. Bad comp is what he thinks, but Im sick of thinkin, I wanna know for sure. This car ran well until now, you think disconnecting the battery would have THAT much of an effect?
Matt

[SVOhNo]

The power steering pump pitched its hose then burnt up, but thats fixed now. They replaced the TPS and it pulled the same codes, so they put the old one back on it, same outcome regaurdless. Thing is, if it was wired wrong, why would it run perfectly fine except at idle and not now, thats whats messin with my head. I DO need a nap, and I need the car to run right. Todays just not my day, first all that crap, then on the way to classes (30 minuted interstate jog) my jeep's top kept comin apart, had to stop 3 times to get it right then eventually just took it off, lol. I know a few people around here that could figure out the wiring and I have a lead on 2 LA3s local as well. Ill try and swap another LA3 in there and see if it cleans anything up. MAN this is come confsing stuff, runnin right one second, then like crap, and I dont mean a little off, I mean like CRAP, its rediculous!!! Im calmed down now tho, in the nice AC of my apt and im bout to go to classes, hope i can get this figured out, this car WAS fun up to this point, cant wait to get her back to that stage again, lol
Matt

[Pat_in_L.A.]

This is what the codes show:

23 Throttle sensor out of range or throttle set too high - TPS

54 Intake Air Temperature (IAT) or Vane Air Temperature (VAT) signal high - IAT VAT

24 Intake Air Temperature (IAT) or Vane Air Temperature (VAT) sensor out of range - IAT VAT

25 Knock sensor not tested (ignore if not pinging) - KS

34 EVP - (R) EGR did not respond properly during test - EVP
EVR - (O, R, M) EVP sensor is/was high - EVR
PFE - (O, R, M) PFE sensor is/was out of range - PFE

42 (R) System rich - Fuel control
(M) System was rich for 15 seconds or more (no HO2S switching) - Fuel control

75 Brake On Off (BOO) signal shorted to power - BOO

-------------------------------------

Something else got unplugged or moved around while the car was in the shop. O2 sensor and the VAF wiring harness connector are culprits. Code 75 is nothing, since that's a T-Bird item which is not on your car.

Copy this list and keep it handy:

http://www.thorssell.net/hbook/2digit.html