New build won't idle

[Rideit636]

subject: New build won't idle. So I have been cranking 7 hours a day after work for the past few days to get this car together this week. Today was the time for first start. I half assed the stupid stuff to get it running, battery mount and such, but nothing that would have anything to do with the car running. For some reason I can't get the car to idle without a little help. And that's only sometimes. I swapped out the socketed ECU with link V3, the 850cc injectors, and to 2G MAF with stock parts to rule out my inexperience with ECMlink. I am running NGK BPR8ES plugs gapped at .28 (might switch to 7ES until I up the boost). I have grounded to proper connections to set the BISS screw because I did rebuild the throttle body (TPS is exactly where is was, ruled out). Unfortunately I can't adjust idle on a car that won't. The CAS is sitting on the footprints of where is was before, another thing that I can't adjust without the car running, but it should be in a good enough position to at least run. I installed a FIAV block off plate, theres no way you can screw that up though. I am thinking possible bad fuel. I know all vacuum lines are plugged in. Not 100% sure about boost leaks as I don't have a tester. But that shouldn't matter at this point. Any input from DSM gurus?

 

[Silent_White]

is your injector deadtime set correctly? Also, with the FIAV blockoff, your car will not idle correctly until it is warm, if it is cold, it will not stay running.

I'd also swap your plugs for either the bpr6es or 7es, and gap them more around 22 instead of 28.

If you can manage to do a BL test, do it. If you happen to have an air leak, it will cause problems at idle.

 

[Rideit636]

No need to set dead time as I have swapped my known good STOCK ECU in. I'm going to dig up the parts andd un-block the FIAV. If I can find some 6ES plugs I will grab them tonight. That was already a plan. .22 sounds tight to me, but its worth a shot. And I know, making a BLT when I get paid.

 

[dsmlover07]

Terry's Talon Troubleshooting Tips #3 - Fast Idle (aka. Idle Surge)


this should help out.

 

[Silent_White]

i run mine at 22 and it runs better IMO. I kept getting misfire due to spark blow out when i gapped it wider.

i'd swap plugs to see if it helps, then do a bl test if the issue persists.

 

[Rideit636]

I have read that. Helped me out back when I got the car when I made the stupid mistake of adjusting the BISS without jumping anything and screwed idle up good. Still, I re-read and no go. I'm bringing my DVOM home tonight to triple check the TPS is in the correct spot (0.63v I belive?).

 

[dsmlover07]

Whatever the specs says it should be, not sure.

 

[Rideit636]

It runs! I did a few things. First off, I shouldn't have guessed base timing. Way off. I had assumed it was set right because it ran nicely when I bought it, so I went off the shadows of the old washers. I installed some BPR6ES plugs for my low boost break in period. I put a fresh gallon in the tank and ran the fuel pump until tank went empty, did that with another fresh gallon, then put 3 gallons of fresh 93 in it. The old fuel looked like apple juice, 15 months is plenty for 10% ethanol 93 octane to go bad apparently. I also found the ECT wires frayed inside what I'm sure used to be flexible loom. I couldn't get it to idle as low as I was hoping with these cams. But I don't mind 850RPMs. Even after letting it get dead cold (30ish), it started without any help. I have a CEL too. I will look at that this weekend when I button the car up. Thanks for the help.

 

[Rideit636]

It's not running anymore! Not without some throttle... Anyways, I tried to drive the car to check air fuel ratios under light cruise. Its miss firing badly under load. Cruising pegs my LC1 at full lean. Light loads go to 13ish and the miss fires get real bad. Plugs from starting at 4 going to 1 get darker. 4 looks new, 3 has light burn, 2 is rich, and 1 is really rich. Air/fuel/spark/compression checks out MINT on all 4 cylinders, I'm using a known good ECU right now, O2 sensor was plugged in. I replaced it anyways, looked orignal! I don't get it... I'm starting to get really frustrated with this thing.

 

[1983gsp]

Change fuel filter, clean the fuel pump sock, clean injector screens ....little blast of Carb cleaner works great for that.