rli7275

I would certainly look at them at the same time but the BLM and Integrator is the report card of what the management system is doing. A lot of adjustment the ECU makes are a result chasing the desired (look up) values. If truly out of range problems exist those values may not be achievable.

aklim

I have a very sneaky suspicion that the chip was reprogrammed and/or the IAC is not set up right. That he can screw it in all the way without changing anything makes me wonder what is going on.

On an 85, don't they have an adjustable TPS? Could the ECM be seeing it as the voltage indicating that it isn't at idle?

Cajaw Jordan

voltage is set at .54vdc

MrWillys

I would set the TPS at .60 to get a slightly increased pump shot, but I don't really want to get off topic.

I thought the OP mentioned a cam? I would assume that someone who took the time to put a siamesed runner setup on was making more mods than just the intake???? The OP should really get a cable, and or scanner and gives us more input. Everyone is right here about BLM, IAC counts (between 40 and 80 at warm idle), and any information to make a better judgment call. Where does the OP live? Maybe one of us could actually help?

Cajaw Jordan

I have found another vette shop in the area who will scan the car and really take look at it.......he has been working on vettes since he was 3! Didn't necessarily like it but sis running his fathers business.....claims to have seen every vette hack job ever invented...but is especially wary of early c4s.......he stated that the idle should be around 1000rpm +/=.......he thinks the car has a major vacuum leak....I can't help but concur...says he must see, hear, listen to car...doesn't agree that a custom set up was done.....but......says there will be no charge to look....changing the fuel injectorsut is on hold...I will put plenum back together and see what he thinks....I appreciate all the opinions i get but i do not have equiptment or workspace to do this car justice...I will keep you posted as I believe it has a combination of problems that need to addressed by someone who has the knowledge and the right equipment to do the job. He says vacuum leak which has been suspected all along....I will check it myself tuesday or wednesday and see for myself!

Cajaw Jordan

when i get a scanner printout i will be sure to let you all know what was found!
Thanks Again.
chris jordan

aklim

I have a bigger cam so I am not sure but my desired idle is about 800. Not sure about stock. Don't think it is 1000 but someone tell me.

MrWillys

Stock with an auto fully warm is around 600, add 50 for MAF, and 100 for MAP in park. Manuals are at 700 to 725 fully warmed depending on year. I add idle speed dependent on the cam when programming.

Dave 127

Just rebuilt C5 motor sounds great, problem car will not idle, to keep engine running I have to keep feathering the gas.any ideas

thedesertvette

Just thought I would mention that there is a TSB on the idle for the 85. The ECU is programmed incorrectly and will 'relearn' the idle speed. This problem is most noticeable for me in stop and go traffic where the idle will drop to 425-475. The TSB 'fix' was to raise the minimum idle speed, I think it was 500.

Cajaw Jordan

Decided to change the injectors as I found a leak near the distributor, can't determine if it was and injector leak or the little line that goes to the 9th(injector?). These rails were a pain to get at....Still can't figure how to loosen the runner bolt closest to the dist. cap. Any suggestions on how to get at this final bolt...to give me some extra wiggle room? Star 40s are large...perhaps they make a thinner "t" type that I can't find. Any suggestions? Also...on the drivers side of the rail is a small fuel line...this turns freely....the leak is undoubtedly there.

MrWillys

Pull the TB, plenum, and passenger side runner.

Cajaw Jordan

I have the complete rail out. Passenger side runner removed. I must remove the d/s runner as i have I have to replace the valve cover gaskets. What is this extra fuel line that comes off the d/s of the rail and wraps around the outside of the runners and goes back to the middle of the engine right below the rail. It does have and injector type electrical connector. I was surprised at this because I have/had not seen or had it mentioned in anything I read about rail removal.

Cliff Harris

That's the fuel line for the cold start injector.

When you take it off the rail check the large O-ring carefully. What I found on my car was that the O-ring got sliced by the sharp edges on the hole in the rail, which allowed it to leak. I went through 2 or 3 sets of O-rings (at $21 each set) before I figured out what was happening. I chamfered the hole and polished it so the O-ring would slip in without getting damaged.

Cajaw Jordan

thank you for the info on the cold start injector. do you have any suggestions for that last runner bolt? also the fuel line that runs from the cold start injector is "turns freely at the connection into the rail".....i would say that this is a bad o-ring or something failed inside the connection......i would guess this is the leak i observed...but taking anything for granted on this cars is a mistake i am working on correcting. on the first try..i could not get this nut to break...17mm if i am correct...i do not want to tear it up with perhaps...after all else has failed....a pipe wrench!.........lol..you can see my dilemma,....
cj

Cliff Harris

I find the best way to break stubborn bolts/nuts is to use a rubber mallet and bang on the wrench. I first pre-load the wrench so it is tight on the bolt/nut and then hit it with a 2 pound rubber mallet (a cool find -- 77 cents on the bargain table at Pep Boys). I have been doing this for years and then I saw a mechanic hitting a wrench with a lead hammer, so obviously others have discovered this solution.

You could try bolting the fuel rail back on the intake manifold so it will hold it and give you something solid to work against.

Cajaw Jordan

Finally got back to the people who serviced my 85 for the idle problem.......I actually got a copy of the mechanics notes...I do not have them here but was stunned that I was told by the mechanic when I paid the bill I had and aftermarket plenum........too much air so they could not adjust idle..BS! I call shenanigans! The note states 2 times that it is not the OEM Throttle body! I have it off the car right now while I am replacing injectors......How can you tell if the Throttle body is correct??? What part #? What should I look for....In the final sentence of the note...Correct Idle cannot be set because of modified TB......I find this hard to believe.....I will give chevrolet a call and get a part #....but that is longshot. Any suggestions? Bore size, butterfuly plates....also the the hot water has been disconnected. Any questions that might be relevent to idle I now have answers.....except...i see no number for Vacuum....I dont know if i will have replaced injectors for naught....but the old ones were 28 years old........i guess it was worth will be worth it.
cj

mtwoolford

Maybe not BS. "Too much air" ; "modified throttle body" could be nothing more than a old throttle body with worn butterflies, worn throttle bore, worn throttle blade bushings; all could = too much air;

if your throttle body is cast, and has a hot water circuit, it probably began it's life as a stock throttle body.

Drum roll please, 1985 throttle body, AC-Delco #40-718; GM # 10105379.

aklim

Will the throttle body blades close? Not sure how you have too much air if it closes. I thought it should just about close and shut off all the air so it is forced to run with the IAC plus whatever can seep past the small gap between the butterfly plates and the throttle body based on adjustment?

Cajaw Jordan

"Clean Throttle body;(was) Modified w/larger throttle blades and honed bore.......double check base-timing set at 8 degrees...Reset base idle. Note: Throttle body is modified. making it difficult to get stable idle." My question is........well.....what does this mean and how can it be corrected? will a stock throttle body solve this problem...it appears to be the original throttle body...if so...who and how and why this type of modification? it seems like a lot of trouble for a minimal increase in power...but maybe it would give you some kick....i don't understand this.

cj