throttle doesnt change rpm...help ASAP

[FaNtUm2113]

so i started my car finally after the rebuild, now the engine idles very rough and i move the throttle and it doesnt change the idle or rpm...i dont know what could cause this? would i be a vaccuum leak? or bad sensor? any ideas i need help ASAP

TPS is reading fine acording to DSMLINK

 

[95blackGsTurbo]

Does the car die out when you move the throttle at the throttle body or does it just remain steady. What was all changed in the rebuild. Did you check to make sure all your sensors are plugged in, firing order right, timing correct?

 

[hhuricane]

Check to make sure you hooked up the throttle cable.

 

[BigSorn]

check the iacv.

 

[FaNtUm2113]

throttle cable is hooked up, firing order is correct, sensors are all plugged in, im going to try to adjust the timing now but im pretty sure it has to be running properly to get the timing set correctly.

the motor was completely redone, bore .02 over, ross racing pistons eagle rods, SBR stage 4 head, BC 272 cams, DSM link added, magnus SMIM, fuel lab FPR, 950 cc FIC injectors, aromotive fuel rail, walbro 255 pump, 6an line from pump to rail, new clutch, manley valves and springs, arp main and head sutds, MLS head gasket, heat barrier intake gasket, NT throttle body. all this was done at once.

cant even drive it to do the break in cause throttle is not working.

when the throttle is hit by the throttle plate nothing really happens, it stays steady might bog out alittle. and its runs very rough, between 900 rpm-1500 rpm.

thanks for the help

another update...timing is at 5* now still the same problem

and i dont know if this helps anyone but if i unhook the hose from the BOV to the intake tube the idle evens out. until i hit the throttle then car died.

this is frustrating, i hope you guys can help

 

[DeadsEvolution1]

I had a similiar issue it turned out that my ECU was bad at one of the capacitors leaking. Take a look through your ECU and see if see any scorch marks or anything

 

[FaNtUm2113]

oh man i hope it isnt the ecu, its a new ecu to me. tom at dsmlink said he went threw it and checked it out before he shipped it. but i will check it out.

do you think if i throw a regular turbo ecu in that would work temporarily if it does happen to be the ecu?

 

[jrohner]

If you have stock size injectors that would be fine.

Check everywhere for vacuum leaks. If you can't find a cracked/off line, do a boost leak test to find it.

Are you running the stock tune or are you compensating for things such as injectors right now? What are you running for an airflow sensor? If it's a non-turbo one, that's the problem. Either way, unplug it once and see how it runs.

 

[FaNtUm2113]

i dont have stock injectors, they are 950cc

all the vaccum lines are brand new. but i will double check them. i have to find a boost leak tester somewhere, its not going so easy

im running whatever the tune is that came with the dsmlink for my set up.

i have just the stock maf, pretty sure it the turbo maf but i cant remember if i switched it or not.

 

[jrohner]

Well the plugin is different, so it shouldn't be too hard to tell if the MAS was switched to the correct one. Also, check that your BISS is not missing.

 

[DeadsEvolution1]

Does your car idle? When mine did what you are saying my car could idle just fine but if I stepped on the throttle no response. It would just idle surge when I stepped on it. So I checked the TPS, the throttle cable to make sure it's working, and I can't remember what else but I pulled my ECU and bam there was my problem.

 

[dallu22]

This happened to my 92 after i put my new engine in it, I ended up having to adjust the CAS and I got full throttle control back.

 

[DeadsEvolution1]

If he is at 5 Degree BDTC than his ignition timing is right

 

[FaNtUm2113]

so i checked the ecu, im not an expert but i didnt see any caps that looked like they were leaking or and scortch marks,

i have been playing with the CAS doesnt seem to really affect the problem much

the BISS is still there idk if it is adjusted right or not yet, im going to try to play with that a little bit and see what happens.

this is a 91 engine in a 92 would that affect anything? maybe the computer isnt matching correctly or something? just thinking out loud thanks again for all the suggestions guys...the more help the better =)

 

[DeadsEvolution1]

No the ECU's would work either way. Can you take a picture of the ECU and post up a picture?? Did you check the TPS yet? Use a multi meter to OHM it out and make sure it's working correctly?

 

[FaNtUm2113]

well the dsmlink shows that the TPS is working correctly, whats the process of ohming it out?

it wont let me upload pics of the ecu, just keeps saying that it fails. but like i said it looks to be in ok shape

new update...made my own make shift boost leak tester, and the bottom of the TB where it meets the SMIM seems to be leaking, would that be the reason for this problem? im going to take the TB off and check it out, any new ideas?

 

[DeadsEvolution1]

A bad leak would cause some serious issues, fix that asap and see if that helps. An air leak there is bad enough to hurt idle everything

 

[FaNtUm2113]

ok so i changed the throttle body gasket that fixed that big leak, i couldnt hear any other leaks so i started it up again and still same problem,

i tried that unplug the MAF idea and when i do the engine justs revs up like crazy the idle sky rockets.

im still stumped...

 

[jrohner]

That's probably because the fuel mixture is better that with it plugged in. If it's extremely rich (or lean) the RPM's will be much lower. Lower the idle down with the MAS unplugged and see what it's like.

 

[FaNtUm2113]

how do i lower the idle down? when i unplug the MAF the idle stays at 3000rpm steady?

the vacuum lines for the MAP sensor arent hooked up but it is plugged in. do you think that would affect anything? and if so where do all they go?

 

[jrohner]

The base idle set screw (BISS) is on top the throttlebody. It's supposed to have a black rubber cover over it but it's usually missing. Turn it in to lower the idle down.

What MAP sensor?

 

[FaNtUm2113]

ok so i unhooked the maf and moved the BISS and it didnt change anything still a high idle...and sill running rough with the maf hooked up and no throttle reponse.

just out of curiousity i also tried to put the old computer back in to see if it would fix anything...and the idle skyrocketed so i shut it down immediatly.

so i am wondering if thie ECU i have which was for a 91 is either bad or just not working with the sensors that i have maybe? the motor was out of a 90 and the harness is out of 92 turbo(i believe, not sure since i bought the shell with the harness installed)

or could this still be a vacuum leak that i just didnt find?

someone mentions that it could be a bad O2 sensor anychance that could affect this?