ok I just flipped the tps and it didn't solve the start-up porblem but it seems like the truck idles down better when i let off the gas

 

One down, more to do. So, what about those components that you installed, did you flash the PCM to account for those different operating parameters? EDIT< just saw your previous post noting that you did not.

That's part of your issue. Hypertech makes a tune to accommodate that lower operational temp and, you really need to reflash your PCM with a Hypertech tune that's specifically addresses that component change or, you can use another tuner but, some don't account for that and, you have to get someone to program it into a new tune.

I am going through this now with my SCT tuner and my 180 T-stat as the SCT tunes are not accounting for that and it needs to be reprogrammed to lower that temp limit in the program. The problem is that the PCM thinks it is in warm up mode due to the lower temp and runs rich as hell for one and, second, the O2 sensors are not feeding back any data to the PCM to help control the A/F mixture because it's stuck in open loop mode vs. running in closed loop mode when the engine warms up to operating temp. The PCM is waiting for it to reach 200 per OEM specs and, since it never reaches 200, it never goes into closed loop mode.

Basically, if and when you change your T-stat- an adjustment to the PCM program needs to be made otherwise, the A/F mixture is going to be off and, the entire EFI system is not going to be working as was designed. It will be running in open loop mode which is like choke mode. This kills your CAT, fouls the plugs and plugs the O2 sensors if driven like this for a while. It also runs the heads hotter due to more fuel.

In fact, we are looking into the performance gains of lowering the coolant temp vs. running the engine hotter. All the engine guys I am talking to now about this issue all say the same thing and, that is to rip out that T-stat and run it hotter and run it leaner.

These guys swear the engine runs better when it's hotter for one, and, you actually want it to run as lean as possible and as hot as possible. This provides more HP and much better for the engine overall vs. pouring more fuel, running the heads hotter (more wear) and killing your CAT, fouling out the plugs, the O2 sensors etc.

The trick is to find the balance of keeping the air as cold as possible at the intake stage while running the motor as hot as possible (within safe operating temps of course) and running as lean as possible.

How long have you been running with that 180 T-stat installed? You may want to check your CAT and O2 sensors if you've been racking up a lot of miles with that setup.

 

about 2 months lol I never knew you had to change the tuning for a t-stat and this would explain why it runs like it does, would this also cause the starting issue?

 

What's your symptoms again? I forgot what they were to begin with. How's it starting now and, what's it doing when it is running? Hard starts? Slow idle starts? List it out and we'll have a look.

 

I'm suffering from the same cold idle issue. Starts and runs ok for 30 seconds or so, then goes into a lumpy rough idle. It drives out ok and idles ok after a couple miles. It diden't start this until I put the 14x3 air cleaner on it. Dr Donut I noticed your running a CAI set up that pulls from the engine bay just like my open element would. Any possibility it could be tied in somehow. It may just be coincidence in my case.

 

doesn't seem to start hard just until it runs for a few minutes the idle moves around a few hundred rpms usually not above 8 or 9 hundred, sounds like it has a big cam in it and if you try and drive it wants to stall out. Once it gets warmer it will ping up to 1200 then back down 5 and run fine. Once its running its a little rich but I think I can blame the 180 T-stat for that.

 

Ok, just got in from the garage here. I had the same problem when replacing my CKPS with one that wasn't working properly. The damn idle was all over the map and, in my case, it was not drivable as it was so bad.

Remove it, check it, clean it, apply a light film of mineral oil to the three sides of the sensor (not the face) and the rubber seal in the bell housing. Be extremely cautious when removing and installing this component. Reason is: that seal can pull out as well as be pushed into the bell housing. That's a pain. It happened to me so, trust me, watch and feel what is going on when you remove it and install it.

It should glide right in. IF it's not going in- STOP. Gently remove it, apply more mineral oil to both the sensor and seal and try again.

You will find it's very easy to get to if you can sit / squat down inside the engine bay on the passenger side fender. From there, reach around the back of the head and aim towards the tranny fill tube with your left hand. With a 1/2 socket setup, extension and a universal, meet your left hand to your right and feel for the 1/2 inch bolts. It is angled towards the passenger side so, you will need that universal.

Loosen the two bolts and set the drive aside. Remove them by hand the rest of the way. Grab the sensor with both hands- one on each side and gently walk it out slowly. Feel for the rubber seal to ensure that you are not pulling it out while your removing the sensor. If there's lots of friction and, it's pulling the seal- STOP. Apply mineral oil and try again.

Once it's out, wipe all ferrite particles off the face and clean all sides. Apply mineral oil to sensor and seal and install. Tighten those two bolts good. Make sure they are tight. If they are loose, it will bobble around and throw the timing out of whack. Replace the connector and start the vehicle.

IF it's good- your all set. If not, the sensor may not be putting out the correct voltage and may be out of the upper and lower voltage limits. But, sometimes, it is very hard to diagnose this condition as it needs to be installed and checked while the truck is running. It may be intermittent at cold startups only and the PCM compensates to bring the idle down to check by ramping it up to the upper limit and then down to the lower limit and landing it in the normal range.

IN order to check it while running, you will have to be careful here but, you would be tapping into the sensor hot line and ground with a DMM in order to see what the output of the sensor is doing voltage wise over time. I believe that for my truck, this is 5 VDC on / off pulses. For yours, you would have to check the spec for I am not sure about your year and make of sensor.

Try that.

 

That is a common issue with that size air hat. I couldn't get mine to work either. What has happened is there has been a change in the air flow rate. This flow rate has to have some resistance and balance with your output of your engine, when it's off from OEM specs, the engine doesn't run right.

Some say that the PCM will re-learn the new air flow over time and adjust accordingly while some recommend to clear out the PCM and starting over thus causing it to create a new baseline and not use data from the old setup.

How long have you been running that size air hat?

 

The air cleaner has been on since april or may of this year. The truck gets driven on average about 6 to 10 miles a day. I live very close to work. I'll search the procedure for resetting the pcm and see if that helps. The air cleaner looks and sounds cool, but when its cold here I would like to have a truck that will run long enough to blow hot air when i get in it.

 

cm when you were doing this did you happen to leave the truck running for a few minutes and if so did the idle smooth out finally?