[Coastie]

Need help dialing in my truck. I would like to hear from people that have the same or similar setup. I have a fresh 351w bored .040, crane computer friendly cam, performer heads and EFI truck intake, headers, full exhaust, all my emmisons, and stock fuel system.

Truck ran great untill I put the new intake on. Now I have a rough Idle at start and after a couple of seconds the "Check" light comes on and the idle smooths out and holds at a grand.

I can drive the truck and it has a lack of power when I accel hard. RPMS will hunt after i let off the gas. I have pulled codes and it continues to say TPS volts, but I have tested it and tests good. I replace it and it tests the same. I've got good vacume and I believe the timeing is good. I have also tried cleaning the Idle valuve. fuel psi is a little low.

Is my fuel system not able to keep up? why is it running better after the check light comes on? am i pushing the limits of SD? Does anybody else have the same intake and how do they idle?

 

[bigo93bronco]

You know the TPS has to be adjusted right? I forget what the acceptable range is, but turn it around until the voltage is within specs and tighten it down. I would also check all the gaskets for a vaccum leak and clean the IAC if not allready done. Never use anything other than throttle body cleaner or intake cleaner up there. The stop screw on the throttle body needs to be adjusted so that the engine starts and BARELY runs with the IAC unplugged. If set any higher your base idle will be too high.

 

[thin blue line]

interesting, is there a a tech article on the tbs setting?????? why is it different now??? i searched and nothing came up, can you post it up if you now of one

 

[inteva6184]

Have you made sure theres not a intake leak somewhere by using carb cleaner?

 

[BIGBLACK95]

From JKossarides yesterday in a post titled "high idle...


X2 with SnowTom, I use a Ford Code Reader with diagnostic book which now costes $29.99 at O'Reillys and worth every penny, just make sure the batteries are fresh or it won't trigger the computer properly giving either a test faliure or inaccurate reading.

All the above here and vaccum leaks are very common contributors with high idle but sounds like TPS may need replacing ....?

There is a Ford Racing Performance Parts "idle setting procedure" Instruction Sheet (Techline (800) FORD788) steps 1-9 on How To adjust idle by disconnecting the IAC using the throttle body idle stop screw, drilling out the mounting screw holes on a newer "plug & play" TPS so you can adjust it for voltage setting.

In the past the ideal setting was thought to be .93-.97 volts or just under 1 volt but recently posted information regarding this appears the setting should be between .55v-.75 volts.

Posted by FSB member Jermil01 recently:

Wanted to update this thread based on some TPS adjustment information I got from one of my tuning sites. This goes against the conventional wisdom of setting the TPS closer to .95 range. Thoughts??

Regarding any ECU controlled function (and idling conditions in particular), before any strategy based adjustment can be made by a computer controlled system, it must first run somewhat normally in a default and OL mode.

To do this with a FORD you must first follow a few rules.

You must keep the TPS input above the deadband area and below the "tip in" area. On a FORD this equates to below approximately 0.9V and above 0.45. Anything above 0.90V the ECU thinks the throttle is starting to open. This brings into affect possible dashpot and fuel cut strategies which can turn one grey real fast. Below approx 0.40-0.45V the system suspects an incorrect input and substitutes a default figure.

So first off, the TPS should be set to around 0.55-0.75V. You can also disconnect the IAC then disconnect the battery for 15-20 minutes, reconnect and the computer should default back to factory settings.

Good Luck ~

 

[jermil01]

So what TPS code are you getting, is it saying TPS voltage is too low? Are you getting any other codes? Out of the box any TPS should be in the acceptable voltage range, I doubt that is your problem.

You said it started running crappy after putting the intake on..the lack of power and hunting idle would lead me to believe you probably have a vacuum leak somewhere. Your set up could probably benefit from some tuning, but I don't think you're at the limits of the SD with what you've got.

 

[Coastie]

where do you recomend in jax I get a tune, hp said that they havent messed with sd in years, Checked tps again .84 closed 4.5 open whitch is with in specs. running a little better today (cold), It is still rough at start but then idles steady at 800 after check light. how long will it take the computer to relearn air/fuel? Changed the IAC as well but haven't ran it yet, grandma needed help washing her new caddy. I have tried the starter fluid and ******.

 

[Coastie]

Put in new/used IAC runs same, idle is a little lower but still rough untill the check light comes on. Soon as the check light come on it smooths rightout. I think the lack of power mybe due to it being in limp home mode. when ever I give it a quick rev it dies after the rpms come back down. I'll pull codes again. Anyone got a good site for codes? Fordfuelinjection.com has been shut down i think.

 

[/==0=\]

Which Crane cam are you using? Sounds like low vacuum at idle to me...

 

[Coastie]

I'm not ruleing out anything but if it was a vacume leak would't it still be having problems after the CEL comes on? would it throw TPS codes for a vacuum leak? I also have a Rich art idle code, I think. like I said fordFI.com is down codes are 63, 76, 37. I was also wondering if major fauling of the O2 sensor would cause this? I had a bad egr while trying to get it running and it caused a lot exhaust to cycle through the motor.

This is killing me, I could also use some word of encouragement as well. I'm starting to dout that I need the intake "upgrade"

 

[buckeye_fordman]

I have the Edelbrock intake and plenum set and a BBK throttle body on my completely stock '94 and it runs great. I got a pretty decent gain in torque over the stock setup and has great throttle response. Maybe you have an intake leak. I don't have a performance cam but I had to very little to mine when I installed the intake kit and throttle body other than adjust the new TPS and set the timing.

 

[jermil01]

I agree with buckeye, it doesn't have anything to do with the intake. Go back and double check all of your vacuum lines. make sure everything is connected. Did you put a new plenum gasket in when you installed the intake?

Also, the codes you're getting should be 3 digit not 2, how are you reading them?

 

[TravisITGuy]

take the upper intake off and install a new good quality gasket. make sure you start tightening the bolts down from the center out working in a cris cross pattern. I am also running this intake with no issues.

keep us posted.

double check your timing also

 

[Coastie]

Vacuum lines are on checked hundred times. I previously removed the upper and added rtv just to make sure I had a good seal. Also took my time to get a good tourque pattern again. I still have not tried the new O2 sensor.

Jermil, got code by KOEO waited for the inital flicker then counted CEL flashes, 6 flashes then pause then three flashes then a pause, then seven flashes then six and so on untill they repeted them self. I thought that ony the 96-up OBD-II had three digit codes. Is this correct?

 

[SnowTom]

I'm not ruleing out anything but if it was a vacume leak would't it still be having problems after the CEL comes on? would it throw TPS codes for a vacuum leak? I also have a Rich art idle code, I think. like I said fordFI.com is down codes are 63, 76, 37. I was also wondering if major fauling of the O2 sensor would cause this? I had a bad egr while trying to get it running and it caused a lot exhaust to cycle through the motor.

This is killing me, I could also use some word of encouragement as well. I'm starting to dout that I need the intake "upgrade"

The engine computer looks for voltages from each sensor. If the voltages come back out of the normally expected range, the computer isn't able to interpret what is happening. So, it defaults to a strategy that is preprogramed for such events. And, sometime the default settings of the preprogramed strategy make the engine run better that it was when it tried to use bad sensor readings.

According to my manual that came with my $24.99 scanner, your running rich and the TPS sensor is reporting below minimum voltage. Sounds like you need to check your TPS and clean your throttle body.

 

[rla2005]

Vacuum lines are on checked hundred times. I previously removed the upper and added rtv just to make sure I had a good seal. Also took my time to get a good tourque pattern again. I still have not tried the new O2 sensor.

Jermil, got code by KOEO waited for the inital flicker then counted CEL flashes, 6 flashes then pause then three flashes then a pause, then seven flashes then six and so on untill they repeted them self. I thought that ony the 96-up OBD-II had three digit codes. Is this correct?

Ford started to transition to 3 digit codes in 1991. OBD-II codes are a different story all together: http://www.obd-codes.com/trouble_codes/

 

[Coastie]

Pulled koer code. I do not have my MAP pluged in. I hang my head in shame. That is what I get for being to excited about a new upgrade. Now, I just need to find out where to plug it in to. Will the intake work? or does it need to tie into something else? All those that yelled vacuume problem, take a bow.

 

[jermil01]

Pulled koer code. I do not have my MAP pluged in. I hang my head in shame. That is what I get for being to excited about a new upgrade. Now, I just need to find out where to plug it in to. Will the intake work? or does it need to tie into something else? All those that yelled vacuume problem, take a bow.

Yes you can take and run a vacuum line off of the tree on the intake to the MAP sensor..man without the MAP plugged in I'm surprised the thing ran at all.

 

[Coastie]

I went stright to the maifold and rechecked the timing. It is amazing how smooth it is. I put it in gear to check idle. I could not tell much of a change so I taped the gas and man did she come alive. I left a foot of rubber in the driveway, not bad for 32" M/T. Now just need some help with the hood. I thank everyone for thier help. I love my truck again.

If the MAP sensor is on the firewall, what the hell is sensor in the top of the lower intake? It is in the center, just off to the drivers side.

 

[jermil01]

I went stright to the maifold and rechecked the timing. It is amazing how smooth it is. I put it in gear to check idle. I could not tell much of a change so I taped the gas and man did she come alive. I left a foot of rubber in the driveway, not bad for 32" M/T. Now just need some help with the hood. I thank everyone for thier help. I love my truck again.

If the MAP sensor is on the firewall, what the hell is sensor in the top of the lower intake? It is in the center, just off to the drivers side.

Glad to hear it...the sensor on the lower intake is probably the IAT (intake air temp)