kcaalarcon

Okay guys so I have an 88 bit and I swapped in an lt1. In trying to get it to run but it won't start. It tirns over good, Fuel pump is working and is getting fuel to and though the engine. I have spark. It will start right up for a second or two with starting fluid. Without it however it won't even try to do anything. Not even pop of in te slightest. It will just keep turning over. Please can some one give me some ideas or advice as to what it could be? Thank you

CALIROCZ28

iTrader: (3)

It would help if you told us what you did to make the swap? What did your '88 originally have in it? TPI, TBI 5.0, 5.7 etc. New computer, wire harness used etc.The year of the LT1 donor? I've done 3 TBI to TPI swaps and that problem is very common usually ends up being either a problem with the electrical upgrade or not having enough fuel pressure bad grounds and many other areas. Be more descriptive on what you had and what you've done and I'm sure many guy's can give you some great expertise on how to remedy your problem!

five7kid

iTrader: (14)

Depending upon how you did your wiring, you could have starter and fuel pump operate via the chassis systems, but if VATS wasn't programmed out of the PCM, no injector pulses. I'm not sure if it disables spark as well, though - if it does, then that's not it.

supr_fly03

iTrader: (2)

I agree, if you are rocking the factory PCM and it has not had the VATS disabled the engine will not run. I had mine programmed before I tried to start the first time and when I did it fired up on the first stroke of the key.

kcaalarcon

The car originally had an mpfi 2.8. The motor I swapped in there is a 96 lt1 out of an impala SS (96). I had a member build me my harness by combining the old v6 one and the impala harness. But I have not been able to contact him since and I honestly dont know if he evern did everything in the harness correct or not or if that is part of my issue. I sent my Ecm in to Bredan Patten at lt1swap.com and he was supposed to tune out vats but I have no varification that he did. hopefully im not forgetting anything. Thank you

kcaalarcon

I also have replaced my plugs and wires, opti cap and rotor and icm

Jeffs82TA

iTrader: (1)

if it cranks then vats isn't issue, check your injector fuses. I have a 4th and vats is supposed to stop cranking, fuel, and injectors. So your pump runs, cranks, but no injector pulse so check the 2 injector fuses.

supr_fly03

iTrader: (2)

If the harness was built by someone else you need to find out how they wired the fuses into the fuse box (which ones are for which PCM feeds). I made my own haness for my 96 LT1 swap and the system has a seperate fuse box I got from Napa that runs all of the LT1 PCM fused functions. Does your car have the chip in the key? I dont know if maybe you have a VATS issue with the car side. My camaro is an 83 so that was not an issue for me.

kcaalarcon

Yes the car turns over and the fuel pump is working, I have pressure and its is going through the fuel rail. I I've checked all my fuses and they're all good.The guy who built me the harness did wire in an under hood fuse block that came with the impala but i dont know what the fuses in it are for. My car does not have a chip in the key.

five7kid

iTrader: (14)

Jeff, that's the way the original 4th gen VATS works, but I would guess whoever did the harness melding used the original start and fuel circuits from the car.

The injection trigger signals have to come from the PCM, but the power for them doesn't. Check for power on one of the terminals of an injector plug with the key on. The PCM cycles the injector by providing the ground through the other terminal. If you don't have power, either he didn't get the injectors properly powered, or there is a fuse or relay problem with that circuit. That's the most likely reason for none of the injectors working, as every injector has its own trigger circuit (i.e., ground) to the PCM.

supr_fly03

iTrader: (2)

Well you have checked for spark and have it, you have a fuel pump working, I am assuming you have checked for fuel pressure at the fuel rail? If so check for power at the injectors, both side since I dont know how he wired it, I have a fuse for both injector banks in my harness. If you have power at the injectors did he wire in the check engine light? I went through the trouble to do that in my car. If not there may be a code for something so maybe the next step is to tap into the OBDII posrt and check for codes.

kcaalarcon

I checked most of my injectors on both sides and all of them have power when the key is on

kcaalarcon

I don't know if he wired in the check engine light or not because i have no dash in the car right now

Thirim

You need VATS de-tuned from the PCM.
and yes, the car will crank all day long and never start if it's a VATS issue.
You also want a few other things programmed out of the PCM too so you don't get check engine lights.. AC, SMOG, Auto trans if required.

kcaalarcon

I sent the computer in already to have all that tuned out and taken care of so supposedly it's done and taken care of

86gn

iTrader: (3)

Go to the local auto parts place and buy or rent a set of Noid lights and plug them into the harness and see if they light up while cranking. Its apperant that its a fuel issue since it fires on starting fluid, if the lights work then start to test the injector itself to make sure its spraying and not cloged. How long was the car down? It has good gas in it?

kcaalarcon

This is the first time running with the new motor. No idea how long the motor sat because I got it from somone. I could see a couple injectors being clogged or bad but not all 8 of them? But I don't really know. And yes it has good fuel. Any ideas on what it would be if the noid light doesn't light up

86gn

iTrader: (3)

if the noid light does not light up during crank and all the injectors have the 12volt constant hot , then you have a vats still enabled , bad pcm, or the harness that was made for ya is not right.

CALIROCZ28

iTrader: (3)

Are you running with the original fuel pump? If so this is most likely your problem. your original fuel pump can not provide the fuel pressure you need to run the LT1.

kcaalarcon

Yes it the original pump. And if its the same one as a tpi motor won't it work for the lt1? I'm pretty sure I've seen people do the Sam swap with oem pump. Even if not it should at least start and run bad right?

Jeffs82TA

iTrader: (1)

His pump will get a LT1 to run as long as it was a efi v-6 car. I did a 3.8 to lt1 conversion and while my v6 pump did ok and got the lt1 started the lt1 demands more volume so I eventually swapped it.

But like I said as long as he can get around 45psi on the fuel rails the lt1 should start.

Check all your grounds then. If you have 12 volts at the injectors the pcm grounds to open them not supplies power.

I know the 4th gen BCM does a lot more then vats stuff related to the PCM.

but if it starts with starting fluid and you hear the pump run it probably isn't vats related. But grounds can cause what you are experiencing.

kcaalarcon

I plan on putting a new pump in but for right not this one will hopefully work. The pump actually was not working unless I hooked power up to it directly which is what I'm doing now ( just for test runs ) but I'm not sure if it was getting power before because of vats or somthing or the harness doesn't have any wires powering it because I do t know what the guy who built it for me did.

kcaalarcon

This is probly really stupid to ask but it's not just the cars with the little chip in the key have vats right? Mine should have it?

Jeffs82TA

iTrader: (1)

GM uses 15 vats codes, not hard to get around vats. Just takes time because vats has a sleep time if wrong code is read like 4 minutes I believe.

So just go to radio shack and buy 15 resistors until one of them works.

sound like vats was never taken out of your pcm since you say you power the pump directly and that is when it runs.

so you do have all the signs that vats is active no injector pulse, no fuel pump running, why it cranks who knows but it shouldnt even do that. But your car if pre-vats will be able to crank. The crank enable relay is what stops vats cars from cranking so it basically splits the purple starter wire in two. On older pre-vats cars this purple wire went from ignition to starter direct.

kcaalarcon

I don't have that little resister chip in my key so that would mean the car is pre vats correct? I did buy a vats bypass for a 4th gen a while back and I still have it. But if my car is pre vats that would mean I do not have the wires running to my igniton switch so where would I wire in the vats bypass? Is there a wire I can splice is into off of the ECM or something?

CALIROCZ28

iTrader: (3)

The TPI and I believe the LT1 both require a minimum of 45psi of fuel pressure at the fuel rails to run properly, if your original pump is producing this amount of fuel pressure then you can scratch this off of your problems.

CALIROCZ28

iTrader: (3)

If your car did not have a VATS system originally then you will not have a VATS module, which means it does not matter what resister you try it won't be able to read it because you don't have the module. If it is programmed in your ecm then you have to have them remove it. I really don't think it's a VATS problem, check and recheck all your grounds! Very important part of the swap.

Do you have any trouble codes?

Does your Fuel relay click on when you turn your key on? It should activate the relay for about 5 seconds without cranking.

kcaalarcon

I have some new info to update everyone helping me out. Fuel pressure at the rail is around 45 psi so that should be okay right? Second, I hooked up a noid light, and it was flashing every time I cranked it over. I did it on a couple different cylinder. So does any of this mean anything or eliminate anything?

Jeffs82TA

iTrader: (1)

Then injectors are pulsing. But do they pulse when it does run a few seconds? Is there anything not connected? Is pcm/harness/engine of the same year?

kcaalarcon

No they do not do anything at all it runs off the starting fluid and that's it. Everything is hooked up. And I think the PCM is from the impala, I doubt the person I got it from for a different one

Jeffs82TA

iTrader: (1)

when I had my 97 pcm flashed they needed the VIN number to do it, I am not sure why but couldn't without it.

kcaalarcon

Well I told him what year and everything and what it was going into and what I'm getting rid of and keeping

Jeffs82TA

iTrader: (1)

so there were no leftover pigtails not attached to anything? Somewhere between 95 and 97 they incorporated a crankshaft position sensor but it was only used for missfire detection. What about the cam sensor it requires a signal to time the injectors since lt1 is sefi not batch fire.

kcaalarcon

I have a couple wires on the inside I need to wire up still label tcc pin a, b d and one other I can't remember. Also brake light switch and diag port. But those shouldn't be relevant to it starting. I don't have an other left over wires or plugs or anything. Everything had a place to go and was supposed to be there

Jeffs82TA

iTrader: (1)

Does it not give any codes as to why it wont start?

kcaalarcon

I don't have a dash in the car right now. God knows if any of the lights would work or are hooked up anyways

Jeffs82TA

iTrader: (1)

I would hook up everything so diagnostics work and then go fromt there. Until then it's a crap shoot whats really wrong.

kcaalarcon

Another update. I took off my rail and injectors and took it apart. Fuel is going the through the rail without a doubt. I did hook it back up With the injectors in the rail and pluged in but not in the manifold. I set everything on top of a clean whit towl so I could see if anything was happening. When I cranked it over, no fuel came out but like 6 of the injectors left a tiny little barly there rust colored brown spot on the towl. So I'm thinking clogged injectors? Anyone else agree?

Jeffs82TA

iTrader: (1)

find a junkyard injector that is known to be good and try it.

86gn

iTrader: (3)

Could be clogged injectors, but the 6 could also be seeping a little . I would still check with a noid light to make sure they are getting the signal from the pcm.

kcaalarcon

I have checked with a noid light and it lights up when I turn it over

Jeffs82TA

iTrader: (1)

if it has 12 volts it will light up. What you are looking for with a noid light it it flashing while cranking and running

kcaalarcon

Sorry I guess I should have said that. It didn't light up, it flashed when I turned it over so yes it is getting the signal it is supposed to

Jeffs82TA

iTrader: (1)

on all the injector pigtails?

86gn

iTrader: (3)

then I would say clogged injectors or ur FP is falling off as soon as it starts to crank but sounds like injectors

kcaalarcon

My fuel pump is working and I have pressure. And I didn't check all my wires but 2 on each side

five7kid

iTrader: (14)

It is possible the injectors are stuck closed after sitting inactive. When I started my LS1 for the first time, it wasn't running on all of the cylinders. I had heard here about stuck inactive injectors, and the advice was to tap on them to unstick them. And, for me, at least, it worked to get all 8 cylinders firing.

For all 8 to stick isn't outside of the realm of possibility. The noid light seems to confirm they are getting the commands, and the rust colored spots during your test would lead one to believe your injectors are not in good shape.

kcaalarcon

I've had the motor for about a year and its sat the whole time. I know the guy I got it from had it for at least several months and it just sat there and it came out of a wrecked car so god know how long it has sat. And they are kinda crappy looking so them being stuck closed seems like its highly possible

supr_fly03

iTrader: (2)

Have you pulled the plugs to see if any of them are wet?

I have access to an old OTC tool that fires the injectors individually to see spray pattern and see if they are working. I doubt you have access to one but you could always get some new injector o-rings and pull the rails and look at the bottoms of the injectors and see if anything is out of the ordinary.

kcaalarcon

My plugs are bone dry. And I did pull my rail and injectors and the injectors are all pretty crappy looking