stegmo2

I have a 350 instead of the 305 with tpi out of a 85 iroc. The computer has had some parameters changed to allow headers and a small cam. My problem is it idles at 1400 and runs fine and it seems like when the electric fan kicks in it will try to idle the 600 it is suposed to idle at. I have tried to set iac valve but it when jumpering the a&B terminals the iac continues to click even after 30 seconds. Is the iac valve bad? I also may have a problem with the cold start injector. Is the cold start injector only for start up or does it continue to flow a small amount of fuel when idling ect.. Help on this would be appriciated very much.

TPI 85 Blazer

iTrader: (1)

Do you happen to have a low temperature thermostat?

The cold start injector is only supposed to run for a short time at start up. There is a switch that turns it off when the coolant is warm or it has been on for a certain amount of time.

stegmo2

I have a 190 thermostat in it.

On this system it does not have any wires going to the cold start valve. I am still wondering about the iac valve, what is it supposed to do when setting min air? Mine is just clicking. I have seen other sites that says it should click once. Or is there somthin with the temp switch that cycles the fan?

Sure would be nice to get rid of this headache!

BOSS 357

iTrader: (1)

Try setting you TPS, check for vac leaks (hoses, TB/runner gasket), verify timing set correctly (b/t 6-8 stock), throttle cable too short?, clean you TB if it has a bunch of carbon on it.

Eric

stegmo2

I have set the voltage on tps to I believe 5.4V. I need to check for vacuum leaks. What is the best way? A spray bottle with water. I have not cleaned throttle body neither. My timing is 6* btc. Throttle cable is ok. Any info on iac system?


Thanks

battman

iTrader: (2)

Pull out the IAC, jumper the ALDL connector, have someone turn the key forward and watch and see if the plunger fully extends or if it moves at all. also chech the IAC passage for carbon build up

BOSS 357

iTrader: (1)

The way I checked for vac leaks was to remove the air filter/hose leading up to the MAF, if your car shuts down almost immediately, no vac leaks. If there's a leak, you may be able to hear it, or you can check with the water bottle.

The Chilton manual sez your TPS voltage can be between .47 and .6 I hope you really didn't set yours to 5.4 If you have a scanner, try and check the voltage when the car is idling high. If it is high and it should be low (i.e. during closed loop), your TPS could be bad. That's not too bad of a fix, I was expecting to pay $75 or something rediculous, but my new sensor was $30 (although it was a Sorenson, not a Delco)

I'm not trying to be a critic, but are you using the correct procedure to set the IAC? More over, are you adjusting the idle stop screw as well as all the paperclip stuff? The instructions in the tech section are the correct way.

Eric

stegmo2

Thanks guys
I will pull the iac out and check plunger. Sorry BOSS I meant .54 my bad. By the way I have no maf sensor. I inherited this because my son wanted it. The guy before me had some work done on the computer from a shop who programs chips. There is a lot of things bypassed ie. egr since I have headers and who knows what else has been. Have you heard of no maf?

battman

iTrader: (2)

If it has no MAF, Its a speed density car.

BOSS 357

iTrader: (1)

Yes i have heard of no MAF, but that was 91 and up. Did he replace your engine w/ one of those years? If you have no MAF on your 85 and you have poor idle, then my suggestion is to find a mass airflow sensor or a good explination as to why it was removed.

If you have a trick setup, I'd love to hear about it 'cause I'm still learning about these things.

Eric

stegmo2

To make it a speed density car, is it a configuration change in the computer?


It use to idle well. I just think somethin went south. My block is actually a 1978 4 bolt main, regular 350 heads,and the plennum from I believe a 85 iroc. When I go to the part store sometimes I ask for 1990 iroc stuff or the 85 iroc stuff.

I may call KC Speed in merriam kansas, that is who programmed the chip, but that guy is expensive. I think he charged like 600 to do the custom chip for the cam.

mcwpns

Yeah----sounds a little wierd with no maf sensor. And the map systems did'nt have cold start injectors. Really should find out what all has been done so you can diag it. If it's a map system, idle problems are usaually a problem with the map sensor itself. Goodluck!