Termanalor117

I just did a 350 swap into my 5-speed 305 '91 firebird. The motor is completely rebuilt but I started it up and did the break in and now after putting in 5w-30 oil I am working out the kinks.

First off the idle wont go down 1000rpm, it also goes up and down continuously. It was worse and was putting out a code 42. I read somewhere that after setting the timing you need to disconnect the battery to let the car learn the new timing. I did that and the code went away and it idles a bit better but still at 1000 and up and down. The car also shakes a good bit, it does have a mild cam but I don't think it should be shaking the car.

I know I've seen idle high on 350 manual swaps but I got a chip from custom chips inc on here and he took into account the manual transmission.

Any ideas or where too look?

Also my oil pressure gage is maxed out, it goes strait to 60 right when I turn the key before the car is even started. The switch is new so any ideas other than replacing it?

Thanks!

aliceempire

iTrader: (14)

the computer doesn't need to "learn" the new timing. Just disconnect to EST(brown with a black tracer wire on the p/s of the engine bay) and set your timing to around the 6-8 degree mark. Then reconnect the wire so that the computer can advance the timing again. You idle problem my be related to bad timing but check for vacuum leaks. They will do the exact same thing. if your code 42 reappears use this http://www.chevythunder.com/est_code_42.htm

Termanalor117

I checked all the vacuum lines and all good. Timing is set to advanced 6 which I did with that brown wire bypass deal detached. I tried following the chevythunder guide you posted when the code was up but I wasnt sure if I was checking the harness resistances or the ecm ports. Im at a bit of a loss, wont go below 1100 still.

mmadden55

Unplug the TPS sensor and see if it gets better or worse.

Termanalor117

Ok so this is stupid but the code 43 was because I was disconnecting the bypass wire for setting the timing while it was running setting the code. So there are no codes which is good.

I disconnected the TPS sensor and the rpm got higher, is that a good thing?

I also tried disconnecting the knock sensor, saw it in another forum, and it changed nothing. Also the alternator and ignition coil are new so I don't think it has anything to do with that.

One odd thing was it dropped down back to about 800rpm when i disconnected the tan bypass wire and stayed there, ran smooth too but then I reconnected it and it went bad. Any idea what that means? THANKS!

aliceempire

iTrader: (14)

Disconnecting the est stop the spark from advancing. The drop in idle just means the spark is at base timing. I still think you have a vacuum leak. Don't just check lines. Check gaskets, loose bolts, wrong side gaskets on runners etc.

Termanalor117

Well I checked the timin and it was a bit off so it sits at around 700 rpm, but it still jumps around about 100 rpm or so.
I checked and I dont see any vacuum leaks. I pulled the brake booster vacuum line while it was running and the rpms jumped, does that mean the vacumm is good?

Odd thing is when I touched the gas, the rpms would stop going down at 1000 and sit there rather than go back to 700ish.

Pulled the iac an tps sensors but it didnt make a difference in how it ran.

racerx520

iTrader: (1)

When I first got mine running the rpms were through the roof and I found a vacuum leak which was coming from the cold start injector being a little off when it was in. Check the plenum for any leaks. Best and easiest way to do this, when the car is running spray some starting fluid onto the plenum wherever there are potential gaps, if the rpm goes up there is a leak there

aliceempire

iTrader: (14)

No, that just meant pulling the booster line caused a bigger vacuum leak.

Termanalor117

So I found some leaks using a fog machine, at a phelum, the tps sesnro, the throttle body spring, a hose, and at the dipstick.

So, my question is what in the world can I do about leaking at the dipstick, the tps sensor, and the throttle body spring, is there even gaskets for any of those?

aliceempire

iTrader: (14)

I'm not exactly sure how you used the fog machine so I don't know how the dipstick is leaking. Your leaks at the plenum are probably the problem. The throttle body leaks are from worn bushings. Either get it rebushed by a pro or replace with a new one.

Termanalor117

I just connected it to the brake booster hose, It just seems odd but probably not much of a concern.

85Special

Unplug your MAF while it's running, if it smooths out get a can of MAF cleaner. Throttle body and carb cleaner will destroy the MAF. If it still surges after you get your leaks.

Termanalor117

Its a MAP car. Do the same thing? I tried that and the rpms shot up and it wouldn't go back down when i plugged it back in.

Termanalor117

So I double checked the valve lash today just to make sure it was good before driving the car, turns out the intake valve on the 5th cylinder wasn't even moving, somehow I had missed the bolt on the first valve lash. That explains the shaking, missing a hole cylinder...