Yes I still have it lol. lets cut to the chase no 1 has a good answer for me so I just left my car alone for awhile just lost the fire to fix her. I can get her running and lay down rubber too . but the timing is not right the cam lobs are ok, it's not off a tooth, and I did all the timing stuff to set it. The timing is at 20* BTDC at idle, and if I turn it down it wont run. the the car sounds good at 2500 rpms and up, but sucks down low. It idles when warmed up but like at 1100-1500. I was told I was told i messed up the timing chain by rotating the engine the other way. for those that don't know it's a 305 with ZZ4 heads ported plenum, stock Vette base and runners, 1.52 roller rockes, headers, stock tune. The PCMforless tune made my car run worse, and stock is 10 times better. I do have a 355 short block but I want to try to get the 305 running right. But it looks like I will be carbing my 355 and selling it later to fund the LQ4 swap.

Things I tried
disconnecting that wire on the firewall.
jumping term A and B on the OBD1
disconnecting the 4 wire connector on the back of the dizzy
re dropping the dizzy in 1 tooth off both ways.
GM dealer master mechanics looked at it (did no good TPI is too old for them)
I ran into a guy with a 87 Vette and he had the same problem after swaping the cam.
The car is giving me every sign that the timing is to high, its also running rich from the lt1 injectors.

And i dont feel like swapping motors let that be the last thing, and also to swap I just need a L98 knock sensor and a retune on the piggy back tune.

 

What is the point of this thread to tell every one you messed up and rotated the engine counter clock wise with a worn chain and jumped a tooth ? the displacement would not warrant you to use a 350 knock sensor.

 

i could not reduce my idle timing below 20, replaced my coil, and it fixed it. I have NO idea why that worked but it did. food for thought

 

to tell everything I did, I heard that rotating it backwards could mess it up. I didn't know that and want to know if its true. The coil is new MSD street fire. But are you saying the timing chain is the problem. I don't want to do too much more to the 305 when I have a 355 sitting with no uses. Sorry if I offended you, I hoped u seen this you have been much help too me.

 

it's not difficult doing a compression check and if its way low you can trim the ear on the timing cover and remove it without dropping the pan.

 

A long time ago, my car wouldn't start unless the timing was 40* BTDC. After trying everything I finally figured out that my EGR valve was stuck open, letting exhaust gasses back in at cold idle and choking the engine. I have no idea if this is your problem, but it's something to check.

 

he has 113 heads no exhaust entry from the heads to the intake.

 

Sure the balancer is accurate? Find top dead center and use a degree wheel to compare marks.

 

It's OE that would happen if the key bends right. i just dont see something like that happening over night. If I have to do anything with that motor out its not going back in.

 

Sometimes those old harmonic balancers can start to seperate after many miles. this happened to mine at about 225,000 kms. maybe it has come apart slightly and slid out of position...

 

what I mean is it was running fine and when I rebuilt the top end and started it it did this.

 

did you replace the timing chain or reused the old one. reusing one with a cam swap is just a plain bad idea extra insurance is spend the few extra bucks and buy a new one so it would be acurrate. pull yout timing cover and see how much you may have advanced or retarded the timing.

question though, why would you build a 305 if you have a 355 and then want a lq4 when you could sell both and have a 6.0L they are cheap in michigan, in fact arent you the guy who wanted to buy ,y 383 and lowball offeed me 800 bucks for it and then wanted to do a payment plan? lol

hopefully you can get it running but sounds like a timing mistake while assembling. with the chip making it worse and the stock making it better than worse sounds like all mechanical. otherwise the running rich and all that just seems like mismatched/incorrect parts usage and assembly.

 

I would check the harmonic bal. to make sure it is right. I had a problem like your and found the harmonic bal. had spun and was no longer accurate. I replaced it and that fixed the problem. Hope this helps

 

I just built the top end, the cam was swapped when I bought it. All I did was swap the heads and rollor rockers. the cam was untouched so was the chain.

 

I got the 355 a few weeks ago. I will just put my heads on it but I will get a angle valve job first.

 

I had similar issues on my first build, and found that although I had been very careful, I had vacuum leaks around the plenum runners. Re-sealed them with new gaskets and a dab of sensor approved sealant, and it worked much better.

Also found that setting the TPS and IAC is very important, and an iterative process. Took about three times setting Timing, setting TPS and IAC, and then re-doing before it all settled in.

 

I checked the timing chain its ok. The EGR is not hooked up and is not going to because I have headers with out air tubes and all EGR stuff has been removed and blocked. I have new gasket for the tpi and the coil pack is new street fire.

 

How do I adjust the IAC it is new

 

Have you done a vac test?
Check vac at idle doe sit hold steady between 10-15, fluctuate 1-2psi or fluctuate and drop like 4-5 psi almost stall?

 

Start the car and the computer will do it.

 

The egr and the air tubes from the exhaust are 2 different emission components. If the EGR is still present under your plenum then you could have problems there. Not sure though as my knowledge on that side of things is limited.
The new gaskets could still be leaking, ask me how I know. Just because they are new doesnt mean something couldve went wrong on the install or at the factory where they were made. I installed the bottom ones on the wrong side and had a vac leak by my cold start injector that caused similar problems like you mention. It was hard to start, wouldnt run below like 2k, all around horrible running. Fixed the leak and it started right up and idled.

Now on to the IAC. Do this after you fix your timing issue. It really shouldnt need to be so high to run. So once you fix that then set the IAC and then set the TPS volts. There is a how to in the tech articles at the home page of the site.

 

did you ever get your knock sensor back in? that could give you lots of issues.

 

Alos I thought I read you used a 350 knock sensor in a 305? I think in 88 (maybe only year) They look identical but they are not the same resistance. Different Part# should confirm that will mess it up too

 

The knock sensor is for a 355 that I was going to drop in later the 305 has the 305 KS in. I will check for vac leaks on the intake 2day. if I can figure out this tpi thing I will drop in the 355 I don't want to carb it but if this stuff don't work it will be carb till I have timeto play with it this car has to be my DD now sence I lost my other car smh.

 

What is the timing at with the EST wire(single wire connector on passenger side firewall) disconnected? You said 20*, is that with that wire connected or disconnected?

 

Both its off the timing tape its str8 up when I have the timing light

 

With the wire disconnected, its off the timing tape? Which direction, before or after the 0* mark?

 

Btdc

 

With the wire disconnected and a stock prom, you only need 6* btdc. 20* is way too much, and that is why your car has too much timing.

 

Won't run on 6° btdc only high like 20+ I know that's wrong that why I have a timing problem but I thibk I fixed it I just have to put the pullys back on and run it.

 

If it wont run with a base timing of 6* with the EST wire disconnected you have other issues. You are only masking them by bumping the timing to 20*.

 

Yes you are right that I do know.

 

that is true also

 

sounds like your timing isnt even close to be right. 20 is far far far too high like everyone else said. id start over starting with your timing chain

 

had the same issue, the balancer was bad. mine was 30 degrees off.
new balancer , reset timing, and all was well.

 

I used the after market damper off the 355, look like it made me a tooth off on the dizz it started right up but I no longer have a timing light so I will play with 2morrow. I'm so happy I hope that is it I want to paint it so bad but I won't paint a car that won't run.

 

Nope didn't work its a raddle at lowwer rpms. And I don't see the spark control thing I need to swap when I do my 355 swap. I know they are on the cowl but its not on there. I have a 89 gta next to me and I don't see the wires for it coming out the harness. Any other location

 

its built into the ecm likely. unless your suppose to have it then youll have big problems

 

timing still off and i never seen it on the car even when i bought the car so it it maybe its in the ECU i will do a search

 

I had a 87 305 TBI and the ECU went bad on my truck while driving....Lots of popping, backfiring and I barley made it to the Chevy dealership. New ECU, engine ran like new.

The 85 Z that I own has a bastard ECU, so I stocked up with three of them. Painless wiring (65246) has a setup with a new ECU for around 1200. It's programmable and no MAF. You would use a MAP sensor instead. Good Luck!

 

Yep the 85's had a one year only failure of a ecm in most regards. But anyways for the price of that painless wiring setup you could just swap to the EBL Flash setup and not have to do as much wiring changes. It would still require a swap from MAF to MAP but it is easy. Oh and did I mention you would save like $800+

Now about the thing on the firewall you think your missing. I believe what your refering to is the ESC module. They have a decently large connecter and are flat looking. I can't remember what year but at some point they were deleted and that function was controlled by the ecm. BUT I am almost positive that was when they went to SD(MAP) systems in 89.

 

est module? electron spark control? my 88 truck had it and in my 93 i know its located in the memcal inside the computer or something, runs of the knock signals like the older external types.

 

Yep i got that name wrong its the ESC module as you stated*
If he doesnt have that then either his ecm has it and controls it, or he is missing it which could cause some problems. Not to mention a code 42?

 

dont know about the code for example 93 yukon missing knock senseor so the ecs(inside computer) couldnt read but i never had a check engine light, and yes it worked. ive read a couple places and told by a few gm mechanics now dont quote me or behead me over this but i was told the system goes into a loop around the issue not throwing a code at all. i just fixed this on my truck, new knock sensor, retuned it and shes running fine. the truck would idle fine, but hesitate severely and not pick itself back up when cold but when warm it was a rocket.

 

I have no idea if it is the full reason as to what is wrong. But i figured if he didnt have it then it definitely isnt helping the situation at all.

 

ESC is on my car just not on the cowl if it ran fine b4 and i do some mods that dont have to do with it. My boy has a 89 305 TBI car that has it on the cowl. I know how the look and what they do. I wont buy a Painless kit for 1200. I will be going to School of Automotive Machinists in a few weeks and I have to drive this car 1300 miles. I was thinking the PCM/ECM may be bad so I might do that but it dont matter I will be putting in the 355 and sending it to a local guy that is know for doing TPI, LT1, LSX EFI cars. And I need all the money I can get/save so some mods thats not need wont happen.

 

doesnt matter if its on the cowl, either its not tuned right, you didnt build it right, timing is off, or your parts conflict one another. if it ran before it should run now unless somethings been hacked up.

 

As stated by tyler, it had to be something you did when you did the top end work. It is beyond unlikely that something all of a sudden happened with the computer or other electronics. Unless you either shorted something, have something wired wrong, not wired at all, missing, etc. I still think it is a vac leak of some sort.

 

I told you what it was a long time ago Sojer.

 

i 4 got what it was i wanna take out the 305 anyway, tell me