Idle issues...

[1CrazySledder]

So, My sled has sat a couple years. Stage 1 Mpi blower, with bov and ulmer clutching.

When I first tried to fire her up, she wouldn't start. Pulled a plug and it was wet and black. Pulled the other 3, same. I changed them all and the sled would start but would only run with a little throttle. I ran it a little on the trail hoping she would clear up but that wasn't the case. My mpg was 7. Used a half tank of fuel in 35 miles. Whenever I would stop, she would die.

At the end of the day, when I started her to pull out of the trailer and drive into my shop, she idled high, as usual when cold and seemed to be normal, however once she warms up and the throttle lets down, she almost dies but not quite, then after a few minutes....dies. Then the only way to keep her running is to hold the throttle just a little.

Seems she isn;t getting enough air. My air/fuel is at 10-10.5 at idle and can't get her into the 12 area no matter my fuel box setting.

I've begun to tear her all apart to change all the fluids, grease, etc with hopes I find a lose hose somewhere or a clogged intake tube. I just don;t know.......

I could only reach 95mph with a 23t gear, which is slow for this sled.

 

[jd0270]

Any way a mouse could have made a home in there somewhere?

 

[kinger]

Sounds like the IAC is plugged up or stuck. I woudl removed it and spray it down with carb cleaner and make sure the plunger moves by carefully moving it with a screw driver back and forth.

If its moves free check to see if the coolant line getting to it is flowing good coolant, you may need to bleed that line as well by just taking it off the nipple while running and letting the air then the coolant come and slide it back on.

Dont adjust the air screws on this at all though just make sure its working and getting coolant.

You have a good problem in that its constantly rich so you know its not getting air. If it would be bouncing around rich lean then you would have a vacumn leak like I had and those are hard to track down.

Good luck vince report back what you find we can get it running clean again!

 

[FLYBYU]

Best way to check the plunger to see if it's moving is to pull those 2 screws on the end iac, They are tight ones, try not strip them. Once the screws are out BE VARY CAREFUL AS THERE IS A SMALL ROD IN THE END OF IT AND IT WILL FALL AND YOU WILL BE FUBARED. Place the end with the rod installed on a vice and slowly heat it and you will see the rod slowly move out telling you it's working correctly. THIS IS THE LAST THING TO TRY. Bleed those 2 lines first, air gets trapped there. Check your air filter. Try starting it with out it. give it alot of fresh air

 

[t_thall]

An unplugged or open circuit with the IAT sensor will do this, sled assumes it is -40C (or whatever the coldest temp the sensor reads down to, most cars are -40C) and will poor the fuel to it. This happened to me on my nytro, took 1/2 throttle to fire it up and 1/4 throttle to keep it running in the warm shop...

 

[FLYBYU]

-30C and it does make sense. Go in to diag mode and you can check it. If there is a problem with it'll default to it

 

[1CrazySledder]

An unplugged or open circuit with the IAT sensor will do this, sled assumes it is -40C (or whatever the coldest temp the sensor reads down to, most cars are -40C) and will poor the fuel to it. This happened to me on my nytro, took 1/2 throttle to fire it up and 1/4 throttle to keep it running in the warm shop...

Yeap, I checked this earlier before work. The plug was hanging out. I wasn't sure if I had pulled it out when I pulled the IC to have a better look or what but it was just hanging there. I took a better look and seen some other stuff was corroded so now I'm just cleaning everything.

Thanks for the help guys, I sure hope this was the problem. If not, I'll be back. lol

Vince

 

[1CrazySledder]

Yeap, this was it. Purrin like a tiger now. Just have the code 20 flashing, but I will take care of that next time I'm out in the shop. I think if I bypass the fuel box and then hook it back up that should clear it.

 

[shawnmcgr]

I'm having similar issues on my Stage I MPI Apex. It would not idle so I turned up the throttle stop and adjusted with the black knob on the IAC. I got it to idle but after sitting in a heated shop and thawing out I went to load it on my truck and it wanted to run on....wouldn't idle below 5000rpm. So I realized adjusting the throttle stop was the wrong thing to do. I set it back to stock and it idled and ran perfect for 20kms of high speed trail riding then back to the same thing. This intermittant issue is very frustrating. It wouldn't start unless I held the throttle open and would not idle unless I held it 1/4 throttle. It was warm out (around 0C).

I thought maybe my GEMS box was getting wet so unplugged it and plugged stock wiring back together and same issue. So I guess it's this IAC circuit, which I know little about.

So sounds like there is a temp sensor on this IAC. I'll check that it's plugged in. Is there a place in diagnostics to check it's reading? Is this where the coolant temp reading is coming from or is that measures seperately somewhere else? I'll check coolant flow and have a look at the plunger.

Thanks for posting up tips on solving this issue!

 

[kinger]

If you search my posts on idle issues mbarryracing gave a great explaination of the IAC, there are no electrical wires going to it.

My problem was a hole in the vacumn line going to the fuel presure regulator. It would be worth your time to pull the vacumn lines and inspect them. I waited till last to do it just because I had it in my head there is NO way there could be a hole it, how it got there I will never know. She has purred like a kitten since then.

 

[shawnmcgr]

Thanks Kinger, I haven't read them all yet but looks like I'm having the same issue! I'll check all the lines in and around the TB and this idle control module.

 

[kinger]

Pull them off and bend them around and look for any imperfections. If you find some I have some spare hose left over I could send you.

 

[kinger]

Also there is talk about bleeding the little coolant line going to the IAC, you pull it off ever so slightly while the sled is running and make sure you get a steady stream of coolant before putting it back on, I never had to do it but it wouldn't hurt to try that first assuming you can get it to idle while your doing it.


Mine would hunt from 700-1800 rpm rich lean rich lean rich lean yours sounds worse then mine which is a good thing because the problem should be easier to find.

 

[shawnmcgr]

Mine started off hunting and got progressively worse till it was hard stating and I had to hold throttle to keep it idling. Must be something related to this IAC, I'm just glad to have soemthing else to zero in on - I wasn't getting anywhere!

Thanks!

 

[kinger]

Yep mine got wirse too, used to be 1200-1500 then 1000-1700, till I couldn't take it anymore LOL

Good luck, the IAC is near bomb proof so I would lean towards to the vacumn lines. I never touched the IAC and was close to adjusting it and would have had it really screwed up then.