theNMBR27

I swapped a 350 TPI from and 88 gta into my 91 Z28. The engine ran fine with no problems before I pulled it and now nothing. The car won't even crank but I have power to everything.

Can anyone identify the things I took pictures of? I also do not hear the fuel pump and when the key is turned the temp gauge pegs and the brake light goes on.

five7kid

iTrader: (14)

I'm not familiar enough with TPI to help you out with the connectors.

The no-start sounds like a VATS issue ('91 chassis has it, '88 ECM doesn't).

bradley23150

iTrader: (10)

The first pic looks like the plug and vacuum line for the cruise control unit.

theNMBR27

I figured vats. I used all speed density stuff for the swap (ecm, map sensor, harness) and I have both original keys which is why i'm at a loss.

Cruise control has been removed so that not an issue. Thanks

86White_T/A305

the second pic looks like a fuse holder(should be able to pop the top black cover off) and that other plug reminds me of the same plug going to my altenator which is on the passenger side on my car.

Its one thing that that car doesnt run..not cranking is a whole other issue,do you hear the starter solenoid click at all?

theNMBR27

It does click, but the security light goes on when i first put the key in. A relay under the hood release clicks.

86White_T/A305

hmm thats odd.sounds like a vats issue but it shouldnt matter since the 88 tpi doesnt use it.I would look into bypassing that relay and connecting the starter directly to the key switch.You dont need vats anymore and if you have it plugged into the ecm somehow still i dont think it uses the same pinout either and could be causing issues.

theNMBR27

I am only using the 88 block. all the electronics are originally from the camaro. that's why I can't figure out the problem

juanillox8

iTrader: (7)

was YOUR car running befor the swap? u said u reuse all sensors right? did u transfer the knock sensor also?

theNMBR27

just to clear things up

the engine and trans came out of an 88 gta that ran and drove no issues. I put it into a 91 z28 that I bought as a roller. The z was originally a 305 auto car. I'm using the 19lb injectors with the tpi because I'm using the 305 prom. Everything is speed density, the car is a factory ac delete and I don't have the correct vss in the trans.

juanillox8

iTrader: (7)

1st you are using a 350 block with a 305 prom, knock sensors from 305 and 350 are different, the second is the vss since thats a main sensor for the ecm to function correctly if you are not using it u need to bypass some wires

theNMBR27

alright. so the proper vss should clear things up then. have any clue what that sensor on the back of the motor is for, or is it just relevant to the MAF setup?

juanillox8

iTrader: (7)

where exactly in the back? you havent clarified if you are using the correct knock sensor...as of right now you have more than 1 problem..... vss injectors and prom i suggest you get the right sensors, prom and injectors and go from there otherwise you will be just guessing and you are not gonna get anywhere

86White_T/A305

regardless of using a 305 or 350 prom..or whether or not you have a knock sensor wont stop you from cranking the motor over at this point.My motor runs damn good for having a cut knock sensor wire..just gives me a check engine light.

my car was originally a 305 lg4 carb,and i swapped to 350 tpi.i knew sweet nothing about tpi and maybe only the size of my pinky about working on a carb lol. from reading lots on these forums i was able to build a stout car so the answer will be here i promise you that much.

the ecm wont stop the starter from cranking..BUT vats will.the 88 ecm doesnt use vats but the body of you car still has vats intact right? during the swap if i remember correctly..the only connections you need to do for the ecm inside the car would be main power,ground,ignition,park/neutral..maybe cruise control and a/c if you have them..vss.a handfull of things that it needs to see from the inside.the rest should be the big harness from the ecm going to the motor to plug into the sensors..distributor etc.

other than the ecm wires under the hood..you should still have the original main power wires for the rest of the car that used to go down to your starter..aswell as the thick purple starter wire.trace that purple wire all the way up to the relay where ever it is...if those wires trace back into the car to a module or a second relay it will most likely be from vats not working cutting off the starter circuit..hence hearing the relay click..but the starter solenoid doesnt click.double check it would be my guess.

all else fails..turn the key to ignition and leave it on..get under the car and jump a wire between the main power and the purple starter wire and she will crank..just be ready for it ..its loud

five7kid

iTrader: (14)

Check out the VATS articles in the Tech Articles linked from the thirdgen.org homepage.

https://www.thirdgen.org/vats_passkey_system

The ECM is part of the system. The '88 ECM won't have the VATS function. So, the VATS won't get a signal that it's okay to start.

No way no how the VSS or knock sensor will keep the starter from turning over.

(BTW, the ECM doesn't care what size injectors you have. '88 is an MAF system, it'll adjust accordingly. In fact, in open loop, you'd probably be better off with 22 lb injectors, even with the 305 PROM.)

theNMBR27

I've done a few motor swaps already and never really had big problems like this. Tomorrow I will be bypassing the vats but as far as everything else is concerned the wiring is correct. After I check a few more things I'll update you guys . Thanks

juanillox8

iTrader: (7)

OK OK i was going the wrong way lol still he's ONLY using the block so it dsnt matter if the 88 didnt had vats that means what's wrong is on the wiring itself (on the vats circuit)

juanillox8

iTrader: (7)

here's a VATS circuit diagram hope it helps... let me know if you need more diagrams

five7kid

iTrader: (14)

Well, he did say SD stuff for the TPI, true. '88 wasn't SD, so I retract my earlier statement about the injectors. Basically, it isn't going to run right until the ECM is properly tuned.

But, that still doesn't get to the bottom of the no-crank (and I probably read through this thread too quickly - my apologies). Thinking about it more, if relays are clicking, that sounds like VATS is working.

Exactly what ECM did you use?

Before you go bypassing anything, you might want to check for voltage at the starter solenoid as the key is turned to start. Maybe what you've got is a bad starter, or a bad circuit to the starter. If you aren't getting voltage to the starter solenoid wire, start tracing it backwards until you find out why (may be a VATS problem). If you are getting voltage to the starter solenoid wire, then you've got a starter issue. Wouldn't be the first time a starter worked in one car then didn't work when installed in another.

86White_T/A305

this has happened a few times ive seen aswell.literally pulling a motor out of one car with the starter still bolted up to the block..dropped into the new car..and the starter just died for no reason.the famous line is.."its been working perfectly fine untill now". i realize now that some parts just dont need a reason to fail on you..regardless how new or old they are lol

how good is your battery and grounds in this car..ive seen some starters not crank or solenoid click with low voltage or a bad ground to the motor. she might just need a good boost

theNMBR27

five7: I'm using the stock 305 ecm that was in my car

86: The starter cranks when jumped so I believe it's still good. When I turn the key my temp gauge pegs and the brake light goes on if that means anything.

I'm leaning more towards vats, hopefully I can take care of that today

86White_T/A305

I still think you would be better off bypassing vats all together if you can.

Im assuming your talking about the lights on the dash..on my car the temp guage doesnt peg to all the way hot..id recheck the wire on the coolant sensor on the driver side head I believe is for the dash guage..or make sure that sensor works(could be dead and gives a false reading)

The brake light on the dash is the handbrake and it comes on and then turns off after the car has started if i remember correctly..or it was the seatbelt light.Not too sure as I have a transam..and im in the middle of a swap so i cant confirm right now :S

86White_T/A305

When you jumped the starter..was the key turned on?..did the car sound like it would run at all..I wouldve let it crank longer and see if it would atleast fire up for peace of mind.

theNMBR27

the car won't run, and I don't hear the fuel pump priming. but it is the vats, I measured my keys and they both read 1.105 and are severely worn down.

86White_T/A305

The car should still prime etc but wont crank if its a vats issue as far as I recall.You can test the fuel pump with the fuel pump relay.

theNMBR27

found out I was using the wrong type of harness to connect the battery and I don't have a vats issue.

can someone point out specific relays?

86White_T/A305

sorry im just unclear what ya mean by wrong type of harness to connect to the battery? does that mean you can crank the car now but it doesnt fire up?

my car doesnt have vats so i cant take any pics to help you :S

duckmanquacker

this sensor is for oil pressure