EFI bronco runs great, but idle is a little wacky?

NJB71 · Mar 14, 2010

I decidd after reading the SBF article on proper dizzy orientation, cause even after I found TDC, i didnt orient the stator/magnet correctly, ran great or I thought for a couple days, but the HEGO code, running lean -i came across how if the dizzy isnt correctly set base the engine will show lean on the o2 sensors, so I pulled coil, bumped engine, found compression stroke on #1, followed the SBF article step by step, oriented dizzy, started engine and set base timing, plug spout back in, 600-800 idle up/down, thought Ok drive her for a while and she will "learn"...when in D(auto) she drives awesome, perfect, matter fact when I stop at light, trans still in D no surging w/ Idle...couple of other tidbits, disconnected IAB and couldnt get her to start(tried to set base idle), also I have a 97'+ explorer TB and the TPS does NOT rotate....but the volts read 1.04, so i thoght close enough....the idle normal and work itself out, or am I screwed up on something, no vac leaks, no ground isuues, btw timing set to 12degrees BTDC

COBlu77 · Mar 14, 2010

This is from memory, but I think anything out of the .88-1.0 range keeps it in open loop which will give you 1200+- at idle. When the TPS is in the right range the ECU will take care of the idle and should put you at around 750. The IAB needs to be hooked up to have your idle controlled properly, also. Otherwise, you get the "limp" mode programming from the ECU.

The SBF site has good info on setting idle properly too.

NJB71 · Mar 14, 2010

COBlu77 said:
This is from memory, but I think anything out of the .88-1.0 range keeps it in open loop which will give you 1200+- at idle. When the TPS is in the right range the ECU will take care of the idle and should put you at around 750. The IAB needs to be hooked up to have your idle controlled properly, also. Otherwise, you get the "limp" mode programming from the ECU.

The SBF site has good info on setting idle properly too.

The SBF site is where I got the set Idle, and base timing etc...to set idle, it suggest unplugging IAB(after u have unplugged the neg terminal for 30 minutes), which i did, but when I went to start it w/o IAB hooked up, it wasnt getting air?, or just wouldnt catch....also does anyone have a later model explorer TB, i removed screws(loosened) to rotate TPS and measure the voltage, would NOR rotate, so like I said it read 1.04 and I left it that way, can someone described how they rotated thier explorer TPS??? Pls....

Viperwolf1 · Mar 14, 2010

I used a mustang TPS on my explorer TB.

If you can't get the engine to stay running with the IAB unhooked adjust the throttle stop screw in a little.

NJB71 · Mar 14, 2010

any thoughts on the strange idle.....TY VW for the suggestion and advice

Sabas · Mar 14, 2010

Trying cleaning the MAF, USE ONLY MAF Cleaner. Sometimes a dirty MAF sensor will make EFI run wierd.

Sabas

NJB71 · Mar 14, 2010

Viperwolf1 said:
I used a mustang TPS on my explorer TB.

If you can't get the engine to stay running with the IAB unhooked adjust the throttle stop screw in a little.

any ideas on buying a TPS? i know RJm has new one, but $50 bucks...pick and pull?

Viperwolf1 · Mar 14, 2010

You can get a handfull at a junkyard, cheap. Look for the ones with the slotted screw holes.

av bronco · Mar 14, 2010

I think its a pretty wide app. on the tps, I went to rock auto to see what else besides a mustang I could get a tps off of, turns out pretty much any V8 86 to 93.

6daze · Mar 14, 2010

You need to modify your TPS to work. Use a dremel or drill bit to elongate the holes. Then you can rotate it to get the right voltage.

More in the link in my sig.

ransil · Mar 15, 2010

Fan wash over the air filter will screw up idle.
Pin 30 not connected properly will too..

NJB71 · Mar 15, 2010

6daze said:
You need to modify your TPS to work. Use a dremel or drill bit to elongate the holes. Then you can rotate it to get the right voltage.

More in the link in my sig.

6daze nice thread....i ordered a new crown vic, 302 v8 fi tps $24 bucks, should be adjustable...ty for the suggestion

NJB71 · Mar 15, 2010

ransil said:
Fan wash over the air filter will screw up idle.
Pin 30 not connected properly will too..

fan wash, hmmmm yet another possible gremlin???-my large air filter runs between passenger fenderwall and engine block, and is about 6 " from fan, screw up sitting idle? I ask cause when I'm driving, everyhting fine, and like I said when in D and at a complete stop, she idles fine.....at least if I change TPS, and readjust base idle and still have problem, then maybe that muight be issue-

Bronco_69 · Mar 15, 2010

so do you have a high idle or surging idle?

NJB71 · Mar 15, 2010

surging, up/down, up down....500-1000, then as it runs gets tighter 600-800, still its not smooth at say 850, it was smooth before i unplugged the power for 1/2 hour, cause i got the o2 lean code, so i read an sbf article about setting base timing, which i didnt do(orient stator magnet), i reset timing 12degrees, but did not have anyone w/ me to pump gas and check full timing, which i have been told 32-34 degrees...i am going to try and reset base idle again, as per viperwolf and turn throttle adjust screw in a little, and i bought an adjustable TPS cause my volt reading was 1.04. like i said she runs great out on road, no stumbling or sputtering or backfiring, really fast and responsive while in D, even at a stop......not frustrated ...yet...,..

Bronco_69 · Mar 15, 2010

do a search on the corral for surge or surging. get ready to read for awhile.

some causes are: high timing, low fuel pressure, certain cams, vacuum leaks, ETC. rule them out one by one.

set the timing at 10* (if you have a chip this may be an issue) and set the fuel presure at 40 with the vacuum line off.

that will get you at a base set point. then tackle the TPS and read the codes. try raising the fuel pressure up to 45 or so as some gauges are off by that much or more.

after market mass air meters can also be a issue and need to be clocked or tuned.

i think at one point i mentioned going all stock and getting it running right, before adding the mods, this is why. if you get it running right stock then you can add one part at a time and you know what the issue is. if all else fails try the stock mass air and injectors with no chip, timed at 10*.

all in all it does sound liek you are running well.

what codes do you have now?

NJB71 · Mar 15, 2010

have not rerun test, will.....saturday, i had 3 codes, 2 ignore, egr, canister purge(rjm harness), the other code 41(o2 lean), whe i am using timing light and setting engine 12 degrees, spout disconnected, do i rev engine for fulltiming?- i say this cause i was getting 20-24 degrees when brother and i were sertting timing the 1st time, or do it when spout connected?

Bronco_69 · Mar 15, 2010

spout out. 10* while trouble shooting. put spout in and rev up to 3000 or so. you should have about 34-36* timing.

to much timing can cause the surge. put it where you wish.

NJB71 · Mar 15, 2010

Viperwolf1 said:
I used a mustang TPS on my explorer TB.

If you can't get the engine to stay running with the IAB unhooked adjust the throttle stop screw in a little.

hey viperwolf, I adjusted throttle screw in, and yes it did start, what am wondering is, as i set idle to about 1000-1050 rpm, she idle smooth, but i felt that was too high, and as i adjusted down to 850rpm, the engine did its surge again, is my cam to blame, e303? can i set rpm that high, seems to me the engine wants to run that high, any suggestions?, and when i did set idle screw my tps read 1.15, i did order mustang style adjustable tps, waiting on that-but honestly it seems the idle set 1000rpm works but i dont know if thats correct level???

NJB71 · Mar 15, 2010

when i was carbed, idle ran about 850rpm

EFI bronco runs great, but idle is a little wacky?

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