L1tech, what do you think?

[Rick Shellenbarger]

I went to ford, they said without a DTC they wouldn't be able to find the problem without throwing parts at it... I didn't like that so I left. Here's the main issue:



When I start the truck my RPMs drop down to around 400 just after cranking/ignition, truck doesn't die, but its close. It sits at 400 for about 2-3 seconds, then climbs up to normal warm up idle. I also notice when I go from park to drive or reverse the RPMs dip about 50-100 below normal and then immediately rise back to around 680 where they are supposed to be in gear.



I cleaned the MAF, TPS is new (did the same thing with old TPS), and I've reset/relearned KAM. Interesting thing to note, for the first 20 or so miles after resetting KAM and relearning idle it is perfect. It's only after KAM is relearned that it starts acting up.



My throttle body is clean, and the plate isn't hanging up in either direction... However I'm still not sure the motor isn't binding.



Is a slightly off cam/crank position sensor capable of causing this? As far as throttle control goes, the only things I can think of is a bad throttle body or MAF at this point... Just don't want to blindly hurl money at this anymore.

 

[Richard L]

My suggestion is to take the vehicle to another Dealer, or an independent repair shop. Your problem can be diagnosed by a competent technician with the proper test equipment, but that's what your dealer seems to lack.



I'm sure there are diagnostic procedures that Ford uses to pinpoint the problem. Why your dealer is unwilling to do this makes me question their competency.



I'm sure that l1tech will have some suggestions, but then he does not have your vehicle in his shop where he can diagnose the problem, and I doubt that you can convince your dealer to follow l1tech's recommendations?



...Rich

 

[Gavin Allan]

Many of the mechanics around here are severely lacking in troubleshooting skills. Many are just plain lazy and do not want to try to find the problem, but rather would treat symptoms and change parts.



I see this as a serious problem for the industry. There needs to be a way to weed out the bad technicians and reward the good ones.



From what I have seen, technicians like L1Tech are pretty rare, at least around here. Most of them are BS'ers. I cringe when I have to take my vehicle in. Ford dealer techs here are slightly better than most. Some dealers here have techs and service writers who are totally worthless.

 

[Norm Reeves]

High miles, 100K+?.......plugs and wires....:grin:

 

[Mark Price 2]

...also may be

dirty air filter...

dirty fuel filter...

vacuum leak...

air/fuel/ignition - all systems need to be tested/troubleshot

no codes.(ie.misfires) so keep it simple

I whole heartily agree with Rich and Gavin.

Good job leaving that place. Although they probably have a tech there that is more than capable. You'll never know having a bad service writer.

 

[Mark k 4]

i had a similar problem. i seafoamed the engine and fuel system after a complete tune up, fuel filter , clean maf, clean IAC. So far it hasnt done it

 

[scott degroot]

This is difficult without having the vehicle as one really needs to be able to look at pcm data.



I know you said that you cleaned the throttle but this is usually the number one cause of this problem. Did you remove the throttle body when you cleaned it? If not I would recommend that you remove it and clean it again as it can be difficult to do a thourgh job with it installed.



After that I would be looking for vacuum leaks. The thing here though is that you really need to look at scan data to see what the fuel trims are doing as small vacuum leaks that aren't found the old fashioned way can be found by looking at scan data while testing for them. These may be small enough where they haven't tripped a lean code yet but are affecting your idle. Does your problem get better or go away when the vehicle reaches operating temperature? Does it do it after a hot restart? If yes to both of these then I would suspect a vacuum leak that seals up when the engine gets warm.



Have you tested the battery? A weak battery can mess with idle settings.



A wonky cam or crank sensor isn't going to cause your issues based on the symptons given.



How are you resetting the KAM? After you do how long do you let the vehicle run before you start driving it?



I don't like the whole part about if the check engine light isn't on then we can't diagnose it. Either they are flat out lazy or very incompetent or both. Unfortunately these days that's the way it goes when you go to a dealership. I have run into this before when I have had to take my BMW in for warranty work and they tell me that there aren't any codes stored in the computer which means nothing is wrong...really makes my blood boil being that I do what I do and then listen to the B.S. that they spew forth.

 

[Rick Shellenbarger]

I removed the throttle body, cleaned it. Removed the motor cover and made sure the gears were clean. I applied a light coat of lithium grease to the motor spline and gears. I checked the throttle plate in both directions to see if it was sticking, feels smooth.



I cleaned the MAF, changed the fuel filter, new TPS, new FPS, new FPCM, battery load tests fine and sits at 12.8 volts on open circuit, 12.6 with terminals hooked up.



I reset cam via my SCT X3. I let it warm up to operating temp with no accessories on, then allow it to idle for 5 min, then I turn on the AC and let it idle for another 5 min, then I set the E brake and let it idle in drive for 5 min. Then I figure its still learning for around 20 miles or so...



The problems occur after it is warm. On cold starts the idle doesn't dip and surge, only after a warm start.



The fuel trims are pretty consistent, long term usually stays around .98 to 1.02 on both banks at idle and cruising. Short term trims are lower but relatively consistent, usually around .89 to .94 depending on RPMs. Short term trims did vary between banks 1 and 2 sometimes, by around .04 difference (.89 vs .93) for short periods of time.



I'm starting to suspect its my throttle body motor though. It's really the only thing that controls idle, and sometimes on hot days it seems like the throttle wants to stick around 1000 to 1250 RPMs after a light tap of the gas pedal.

 

[scott degroot]

It is starting to sound more like a throttle body issue, sure wish I could look at the pcm data for you.

 

[Rick Shellenbarger]

I can email you an excell spreadsheet of my data log... Some of the data will be in a different format than you're used to since its an SCT program, but if you tell me what sensors to monitor I'll log it, extract it, and email it ya!

 

[scott degroot]

In some cases that just might work but I think this is one of those times that a person would actually have to be watching live data. What is the capture rate on the SCT

 

[Rick Shellenbarger]

when I'm watching it it's live, constant monitoring. In an excel spreadsheet I think you are right, it would chop it up in time stamps.



I went ahead and ordered a throttle body from Torrie at Fast Parts Network just to rule it out, im pretty sure the one on my truck isn't OEM anyway, not a single Ford or Motorcraft mark anywhere on it.



I also suspect a leaking injector, as I was going to pull my plugs to inspect them this weekend but couldn't find my 9/16 plug socket... However, the coil boot closest to the firewall on the drivers side smelled like gas and it looked like there was a small amount of fuel in the spark plug well (very small amount, maybe a few drops, just enough to see wetness around the bottom of the plug).



Im thinking about just ordering all new injectors as well, then getting a smoke test done somewhere to rule out any vacuum leaks that I didn't find via the propain method (because if my injector is leaking from anywhere, wouldn't that create a vaccum leak?)