Hybrid still not running right:(

[Syn]

so i start it today and it stays at a good 2krpms idk why i adjusted the idle screw but i don't think it would cause that because before it'd idle at 1k. i unplugged the tps and iac and it went back to normal then i plugged them back in and shut it off. tried to start it but now it won't stay running without me giving it gas.

i can't get freescan to work at all either i am running out of ideas and patience. its been a month and it still won't run right

i case noone knows of my setup

3.1/3400 hybrid
crane 272 cam
in my 93 Z

[Darin]

Have you checked for vaccum leaks? Just a thought.

[Syn]

yeah i actually have too many times lol, i will look again.

i had a leaky fuel rail and had to take the plenum off atleast 10 times so i figured i was good in that department

just thought i'd throw these out, i don't have my evap canister hooked up to engine vaccum, my egr is un plugged and blocked off.

thats all i can think of that would possibly matter

also i hooked my boost gauge up and i am readin 12hg of vaccum very steady

[IsaacHayes]

I dont know how hot that cam is but shouldn't it be higher than 12? like 15 or so?

Check for vacuum leaks again. Do you have a chip tuned to raise the idle? What's stock idle on a 3.1? My 3100 idles very low, like 700-800 maybe even 600 rpm.


Have you tried leaving the idle screw alone (as it's really just a stop for the TB blade, not an idle adjustment, that's what the IAC is for.), and then keeping it idling with your gas pedal, then after a while see if the computer can pick it up. I'm not sure the idle relearn process is on the old motors or how to do it with a clutch...

Sounds like you really need someone to just burn you a chip with the idle set at 1k or so so you don't have to mess with this. Have you talked to Ben? Or marsman?

[Syn]

stock 3.1 chip, was talking to a guy who had a chip tuned for his 3.1 with this cam, but his idle is low and he has no problems. ben was gonna copy it for me. i am prolly just gonna do that and see if it solves the problem

mars is only for boost

thanks for the reply

[IsaacHayes]

Hey no problem. If you could scan some how and see what your IAC numbers are that might tell you if you have a vacuum leak. Not sure what you can read on an ODBI car thought. Was the other guy you talked to with the low idle running the same cam as you? Perhaps having the better breathing gen3 top end is enough to throw that comparision out the window...

Maybe it's not marsman, but someone else I thought was making a chip for 3400 swapped cars which you'd also run 3400 injectors (some injector harness connectors changes needed IIRC). Perhaps since you are basically running a 3100 now, but with a cam, that might help get the fueling a little closer to where it could idle on it's own.

[Syn]

freescan will tell me everything but it just won't work ever when i try, so i can't get any datalogs or codes. if this would work i would have this thing on the road.

i am a hybrid not a 3100. but Burn at v6z24.com does chips for the 3400 swapped cars for the mul 2 injectors. he doesn't do any other things but that,

the guy yes had the 272 in his 3.1, but again i have the gen 3 top end so idk how well thats gonna work. main reason i am in need of a datalog

[IsaacHayes]

Right, but a 3.1 with a 3100/3400 top end is basically a 3100 that runs on mpfi. The bottom ends are the same between 3100 and 3.1 as far as flow is concerned. Your motor is a 3100 swapped in as far as performance goes, except you can run any cam you wish in the block.

[treeZ24]

syn i have .472" lift on my hybrid engine and she starts to have a slight lope at around 1000 rpm's with about 18-21" mercury on the vac guage. i dont think the 272 is that hot of a cam you should be having vac problems with it. i agree with whats stated above, the iac will adjust for any adjustments on the idle screw stop just because thats what it was designed to do. iirc your cam lift at .050 is something like 460in/480ex

with the sds computer i have there is no iac motor, so i do adjust my idle like that lol but that doesnt apply to you.

whats going on with the engine, can you get decent vac values at rpm incriments? sounded like its firing on all cylinders? making any weird sounds at all? could it be something like your crank sensor is cracked? i know that been a troublesome thing to find in the past..

[Joseph Upson]

Your vacuum at idle is too low, my 3100 pulls ~20 mm Hg at idle. The PCM is probably having a fit trying too match closed throttle values to MAP sensor values characteristic of open throttle. It should be running rich. If you have a voltmeter with the right literature you can start checking voltage and resistance at the key sensors to see if you are within spec, though we can pretty much assume you are already out on the MAP and or MAF sensor readings with such a low vacuum reading at idle.

I'm not aware of what all you've done, but I would also check readings at the harness plug where it plugs into the PCM. When you can confirm that the PCM is seeing the correct range of values and it still doesn't run reasonably, consider the chip and the PCM or ECM whichever you are using. I burned a chip once and some how things got turned around between the time it was removed from the burner and installed in the car, the timing table had some values in the wrong place somehow.

[FallenZ24]

Have you checked the IAC. Maybe it is stuck. Try replacing it and see if it helps you any.

[FastGT31]

"stock 3.1 chip, was talking to a guy who had a chip tuned for his 3.1 with this cam, but his idle is low and he has no problems. ben was gonna copy it for me. i am prolly just gonna do that and see if it solves the problem"

its my car he's refering too. im still running a 3.1 topend and it runs beautifully. it idles between 650-700. i had a problem once with my car not able to run, running extremely rich. scanning it revealed it "should" run good (everything was within spec on the scanner). i decided to replace the computer thinking it was my last resort and it worked. i was told the older gm computers may crap out and mine certainly did. but my car also ran fine on the stock chip for weeks. i told him to try another computer and see what happens, wont hurt anything

[IsaacHayes]

Hey it's a possibility! Things like that have happened before. Do a mod then something else goes bad at the same time and you think your problem is the mod you just did!

[Syn]

issac yeah lol i know what ur saying lol mybad i was just saying

tree- i got 12 steady for some reason but it i rev it and let off i can pull 20hg lol

i put the idle screw back to stock and its still running like poop

your right about my lift but with 1.6 rockers the lift is intake .480 or something like that and exhaust is .5xx

i held it at 3k today and the hg would increase a few more in i will get an exact reading tomorrow i forgot, i'll get them at 1k,1.5,2,2.5,3

crank sensor is good i took that out and put it back in when i did my crank

good idea tho, freescan is gay and won't work i am gonna find another program hopefully



-joseph- yeah i figured vac was too low it was bouncing up and down today from 1k-1250 like a vaccum leak but i can;'t find a leak. but i did hear a like whineing noise com,eing from the front of the plenum like its a injector, maybe the plenum is slightly leaking idk

it is running rich thats for sure but it has crisp instant throttle response tho

i have a DMM handy its very nice i thought about usinge it actually

[Syn]

i have 3 iac;s lol i've switched em all around how exactly do i tell if its good or bad? how much i can push it in?

Fast if you still got that spare ecu let me know how much....

this project is maken me go broke ahh