Started car, ( small tiny vacuum leak) but the idle is alright
hit the gas real quick, good responce seems ok.. so i hold down the pedal Kinda like simulating load on the engine and it boggs down then pops through the intake then revs up This indicates im running lean i think?

i checked codes and it threw a cts and o2 sensor im sure they could be the cause ill replace them later in the week, Could i get a pic of the cts? i dont
Know how it looks, i know its in the front of the intake But i wanna make sure i pull the right sensor

Also i did perform a quick drivers side injector test, pulled the plug of the first injector, but didnt really notice a big differance in engine tone, yet it ohmed out to 16.2 ohms Not sure what this means Any help in diagnosis would be appreciated

Stock 350 l98, Has a t-5(swapped in by last owner), no speed sensor hooked up but all the other sensors are except for maybe a knock sensor

Thanks guys ask for any more info you need

 

any ideas guys, BTW my idle screw the head stripped any ideas on the best way to get it out

 

That sounds typical of a timing problem. Your valve timing may be off, valves may be sticking/leaking, or ignition timing may be WAY off. Is idle vacuum strong and steady, or does the vacuum gauge bounce? Does it still occur if you bypass the EST?

Incidentally, that "idle screw" should almost never have to be adjusted if the IAC is working properly. It is only used to set throttle minimum air position once, then the ECM takes care of idle RPM.

 

Well the other day i did unplug the est and it seemed better but, i started it with it unplugged cold, same thing almost maybe a little bit better, well what i was doing when i adjusted the Idle screw was reseting the iac, the screw was a tough turn and of course my luck it stripped, Idle vacuum seems to be steady by ( dont laugh at me for *******ing it but... by the sound it seems steady i dont have a vacuum gauge"vacuum leak lol") What im trying to do is make it drivable so i can get it into my shop at my school, another thing i was considering was maybe it is way to rich? Theres no black smoke but with the 02 unplugged itll rev easy and barely/no popping, with it plugged in itll bog when i hit the gas so im gonna replace that today ill let you know if it changes anything, thanks again for the help Vader

 

It would have to be extremely rich to backfire, or very hot and lean, and then it would rarely happen except at WOT under load. If it's that rich, you should be smelling raw fuel in the exhaust. A new O² is never a bad idea anyway, but if it's that rich it probably should have set a code.

As for the throttle stop screw, soak both ends of it in penetrating oil. You may have to remove the TB to get it out, and try a new Torx bit or force an Allen wrench into it to straighten out the drive lobes. If that doesn't fly, you may be drilling it out with a left-hand twist drill bit.

 

well i gave the 02 a shot, but with my wrench i couldnt get to it, any advice/removal stuff because i even was underneath the k-member has barely any access and i only have 3/8 drive rachets and stuff
i hate not having a lift/being in shop

 

Intake backfire is almost always lean. The bad CTS is the cause (thinks engine is hot, but not). Timing would have to be seriously late (or very very very early) to pop in the intake, but it happens. The cold engines need a lot of extra enrichment to combat the cold ports and valves and cylinders. Lots of fuel falls out of suspension, and doesn't burn, so as long as the ECU knows it's cold, it can give extra fuel to compensate.

The CTS is in the front of the intake manifold. It's a 2 wire connector. The CTS itself is brass, and has a large hex head. Also, check the wires going to it for cracks or shorts.

 

intake popping, I would look at the intake valves, it sounds like one is adjusted to tight.

 

wow i was messing around and took of my plug wires, and i put them back and i messed up because, lol it backfired right through my intake Can anyone Show me the Distributor routing of the wires/ and the firing order for referance, thanks lol i almost S**** myself when i saw smoke coming from my intake

Redngold- Yeah it has thrown a code 15 before and it only pops when its cold so you may be right im gonna see if i can do that today After i fix my erm stupid/retard problem ( wires lol)

 

ok fixed the wires, Now my cold start injector i was toying around with it, i unplugged it to see how it would run it idles like a champ besides some surgin now all i gotta do is to see how it does when i hit the gas Didnt have time today, probly tomorow

 

when mine did that I bent 2 valves and 3 pushrods because of high rpm driving and a sudden let off to avoid a speed trap- on a pushrod motor high rpms then a had drop is very hard on the valve train,

late and GB
I hope you did not hurt the motor

rk

 

Yeah i hope i didnt as well, lol but all im trying to do is to get it into my shop, then i can tear the heads apart if i need 2

 

You bent valves from simply lifting quick at high rpm? - Either you don't have enough valve to piston clearance, or you don't have enough spring pressure for the cam/rpm.

- anyhow, sounds to me like the proper firing order/timing and a new CTS is in order....

 

buddies LS1 up here bent 4 valves just missing a shift .

 

Yep i fixed the firing order yesterday, New cts will go in soon Now keep in mind it didnt even idle before i unplugged the Cold start injector, then it idled at 900 and surged a bit i will check the popping today, With and without the est If it seems good im just gonna leave it till i time it and give it a new dis cap

 

Well, had the CSI unplugged, didnt even idle just like before im starting to think the idle air control is bad when i gave it a little gas quickly it didnt pop, But Dunno im gonna see about replacing the cts tomorow, and see how i make out

 

...that would be because it over revved when he missed the gear.
Still caused by to little spring pressure for cam/rpm.

fire350tpi - have you pulled the TB, then pulled and cleaned the IAC/iac passage??? - checked timing????

 

Havent checked timing but, 3 or 4 months ago i cleaned out the tb and the IAC passageways, Not the iac itself though so possibly i need a new one as said before it barely ever idles u have to keep your foot on the gas

 

Just got it to idle at about 900, but it surged up about 100, then went down to 400 rpm so not sure whats wrong, This is with the cold start injector unplugged...i checked the front 2 plugs real quick and they were wet with gas so ... It was/or is def running rich but it seems its drivable enough to get it into my shop, and it threw a cts code again today so im gonna replace that asap, just didnt have time today also wasnt able to see if it was popping or not because It was a little late and my neighbors get pissed :/

 

put in the cts today, lol the old one wouldnt budge and since without the maf it runs fine When i start it ( cold start injector unplugged so without the maf it richens it up) runs fine idles ok so i took the csI switch out and put in the cts there, when i go into shop ill put it back in the correcnt way it runs ok, no popping so it should get into shop

 

Im considering switching out to a 89 ecm for no CSI, Can i just unplug/cut the wire as long as he csi itself is not leaking and leave the switch in, Also can anyone tell me the exact pieces i need to make a CAI for the 87 MAf Intake ducting ( Wont be able to reuse anything)

Thanks!

 

Yeah, if you buy a PROM/memcal from an 89 F-body, or burn the chip to 89 $6E, you can simply unplug the CSI. Some people even leave them plugged in without noticable problems. Just as long as it's not leaking, it shouldn't be a problem at all.

CAI - do you have the ugly older style? I think the 89 style is pretty good. Can just copy that in larger diameter, and throw an open element in the same corner, and open it up to some more air from the front, and maybe build an enclosure to keep engine bay air out.

There's a CAI on Ebay for about $60 shipped. eBay Motors: PONTIAC TRANS AM GTA 5.0 5.7 V8 TPI/FI AIR INTAKE 88-89 (item 8058585225 end time Apr-22-06 18:54:15 PDT)

I don't think it includes the elbow to connec MAF to TB.

 

wow thats a fairly nice piece, i think ill grab that asap and grab the other intake duct from the junkyard, Now the 89 doesnt have vats right?

ill have to talk to that seller to see if hed include that Throttle body duct piece

 

The guy from ebay Just responded that he has nothing for the 87, lol Didnt even answer my question, i asked in a diff way maybe hell respond again

 

What the hell?!?

Start fresh. Clear the codes, make sure your state of tune is good and see what happens and what codes you throw. Running around with stuff unplugged and half-assed is NOT the way to do it. You have confused all your issues now to the point that I don't even know where to begin.

The bent pushrods thing on LS1s is fairly common. I had a buddy of mine bend a slew of them from a missed shift as well. Probably intentionally designed that way by the factory.

 

Well this is just to get it into shop so i can do the correct repairs its only gonna be run like this for a half hour drive ( im in a tech school Bristol plymouth Perhaps you have heard of it just wanted to get it fairly reliable instead of backfiring etc its fine now probly running rich but fine for half hour drive

 

this is a confusing thread...

you replaced the cts and things started working?

 

problem is far been resolved now, Ended up drilling out the old cts, replacing the new one in the old cts thread/hole putting the csi switch back in then the popping was the timing bad it was of by 20 degrees, Idle was a vacuum leak.. Still isnt running good needs a new cap and rotor + wires, the wires to 6+8 are only getting 4k volt through them while the rest have coil voltage im going to replac e cap and rotor in about a week and a half and i hope it resolves everything for good

 

where is this csi switch?