I have put a 1986 or 1989 tpi 350 from a corvette in my 72 chevelle and all is fine except one minor thing. The car start right up and goes dead immediately. Any suggestions. I am running a electric fuel pump and I have the entire wiring harness with computer and all seems fine. Please help ready to drive this beast.

Might try here......they've always been helpful to me.

http://www.thirdgen.org/techbb2/forumdisplay.php?s=898a497584a7b0de37e635ced00282f c&forumid=18

Where is Golden, Ms.?

Did you disable the VATS or put a VATS module into the harness?

Probably the easiest (cheapest) way is to use a stock GM VATS module and wire (plug) it into the harness. You have to find the correct resistor value to make it work. Look up VATS Camaro and resistor on the internet and you'll find a ton of info.

Peter

GM TPI will prime the fuel system at start up with the fuel pump relay which is controlled by the ECM. After the car starts, the relay drops out of the circuit, and an oil pressure switch mounted in the engine block closes to provide continuity to keep the pump running. It is designed that way to stop fuel flow if there is an oil pressure loss. If you don't have the pressure switch wired in, or if it's bad, you'll get that problem. There should be a plug in the harness that falls somewhere on the driver's side of the engine towards the rear.

P.S. If VATS is enabled, (89 or newer ecm)It can be turned off on the chip. Email me if you'd like to know what's involved if you decide to go that route. You can tell if your setup is an 86-88 setup by the 9th injector. 89 didn't have a 9th injector, and 90-92 uses a MAP sensor in place of the MAF sensor. Hope this helps.

Not trying to hijack your post, I have a line on a TPI from a 85-6 305 is it worth dropping on a 400?

The only difference between the 305 and 350 is the size of the injectors. The 85 ecm is not desireable, but it works. Stock TPI will make great torque on a 400, but it'll fall on its face after 4500 rpm. IMO, you'd make more power with a 650.

Originally posted by ZZ69chevelle:
GM TPI will prime the fuel system at start up with the fuel pump relay which is controlled by the ECM. After the car starts, the relay drops out of the circuit, and an oil pressure switch mounted in the engine block closes to provide continuity to keep the pump running.Sure about that? It doesn't work that way on the TBI cars. Any time I ask when this is posted I just get a "I think it does this but have never tried it myself" or "I read it does" answer. I have also read a number of sources that say the oil pressure switch is not needed and I have tried it on my TBI setup.

To summarize, check the pressure fuel and spark to make sure both are present when you try to start it.

To answer Dave's question, no I don't think so. The TPI intake is just too flow restricted for a 400. You'd be better off with a 2" bore TBI mounted on a RPM or similar manifold using an adapter plate. If you get it real cheap then try it but I personally wouldn't put a lot of money into it.

Peter

Yeah, you did mention that, and I did check it out on my 87 TPI setup, without the oil pressure switch, the car would only run for a few seconds on the prime, and then it shut off. I have the schematic for the O.P. switch at my shop, and can scan a copy for ya if you like.

EDIT: I did take the fuel pump relay out after starting the car, and before I unplugged the OP switch.

He wants $100 and has alot but not all parts for it. Missing sensors and wire harness.

Originally posted by ZZ69chevelle:
Yeah, you did mention that, and I did check it out on my 87 TPI setup, without the oil pressure switch, the car would only run for a few seconds on the prime, and then it shut off. I have the schematic for the O.P. switch at my shop, and can scan a copy for ya if you like.

EDIT: I did take the fuel pump relay out after starting the car, and before I unplugged the OP switch. Now I'm confused. Was a good working fuel pump relay in the ciruit when you disconnected the oil pressure switch?

I guess it's your call Dave. The TPI systems do look cool in the car and you could probably sell the intake for more than $100 if you decide not to use it. Just know that it won't rev like a good carb intake or something like a TPIS MiniRam would.

Peter

Pete, here's what I did. I pulled the FP relay and of course, the pump wouldn't prime to start. I then replaced the relay, and started the car. Next I pulled the relay, and the car ran as usual. Finally, I pulled the pressure switch conector off, and the car shut off. Now the only thing I didn't do was to put the relay back in and then pull the OP switch out while the car was running. If it still runs then, I guess it is safe to assume they are both in parallel. I'll have to dig the prints out again and check it out. I'd try it on the car, but I have it apart again. The LT1 cam works well in a 305, but I need to put in some offset valve spring retainers so I can keep my stem seals in one piece for more than a week. :D

Sounds like the VATS to me.Painless makes a bypass module,and Summit sells it for $50.The oil pressure switch(as mentioned) ,if not wired properly,could also be the culprit.I have some printouts from my local Chevy dealer,and I believe all Corvettes from '86 or '87 had the VATS setup,therefore requiring the original ignition switch and under dash module,or the Painless bypass module.I've used the Painless module,and it works.I'll try to dig up more info from my diagrams in my garage,and you can email me through the link in my profile if you'd like. Steve

if it's the Vats then it shouldn't even turn over, and definately won't start....

I work on GM cars that we have in the postal service although none are tpi Camaro's.On our various GM vehicles the oil pressure switch is a back-up in case the fuel pump relay fails.At least you can get car started.You notice this right away if the relay has failed due to an extended crank time when oil pressure builds enough to turn pump on.We all thought at one time engine would die if it lost oil pressure but we have proved this to be not the case on our GM vehicles.Maybe GM made this a feature for the Camaro & Vette??

Originally posted by sschevyfan:
I work on GM cars that we have in the postal service although none are tpi Camaro's.On our various GM vehicles the oil pressure switch is a back-up in case the fuel pump relay fails.At least you can get car started.You notice this right away if the relay has failed due to an extended crank time when oil pressure builds enough to turn pump on.We all thought at one time engine would die if it lost oil pressure but we have proved this to be not the case on our GM vehicles.Maybe GM made this a feature for the Camaro & Vette?? Yep its redundancy...The relay will continue to work as long as there is an RPM signal. Thats why the pump runs briefly a quits, No RPM signal. As soon as you start cranking the engine you'll see the relay close again if you check it with a test light.

So they are wired in parallel then. That's good to know. I learn stuff all the time. smile.gif My next guess would be to check the injector plugs for a signal.

I have also heard that the pressure switch is only a backup for the relay. When I tested it that's how it worked. I can tell you with 100% certainty that the relay contact and oil pressure switch are in parallel.

I'm still thinking it's VATS. Without knowing what computer you have I can't tell for sure but I believe VATS started in 86 Corvettes so if you didn't do something about the VATS then the engine will not run.

Peter

I'm kinda with Peter..could be the vats....I'm not real familiar with the older vats but the newer gm antithefts work just like that..Starts then dies. I kinda thought the early VATS kill the crank circuit but I'm not sure about that. Shoot me an email if you need a wiring diagram..I can help out there...
Jack

Not VATS, GM uses the no-start theroy for anti-theft vs Chrysler which allowes the vehicle to start then shuts it down after 3-5 seconds if no valid key signal is detected. GM didn't have the technology at the time for this type of system. The Chrysler system operates at about 76K bps vs the old VATS system which operated at about 3-5K bps-too slow to be effective. Been a long time sisnce I played with GM FI, does the fuel pump relay get a secong signal once the RPM's come up. Most manufacters energize right away for pump prime and then cut out until a RPM signal is detected then another realy energizes the F/P relay. Chrysler kicks the fuel relay for a second or 2 at key on then once the engine fires the ASD relay turns the fuel relay back on again. I'm GM is virtually the same I just don't recall them using an ASD relay.

He has a painless vats module from summit, and said he gets the pulse at the injector plug using a noid light when it fires, but it stops when the engine dies. He also said one of the distributor wires gets real hot. If it is VATS, I would think it should throw the code for it like before. He also has 55# of fuel pressure. There's something keeping the injectors from firing, but it has spark. :confused:

Ha Ha
Right on Cue. Dennis likes argueing with me. ;) Actually he's mostly right on the Vats in that it does kill cranking but additionally even in 86
the VATS module also controls cranking fuel enable=(injector pulse)so theoretically it still could be Vats... Can he pull codes? Really need to know exactly what year setup and look at a diagram. What color wire gets hot on the distributor? Is it the bypass wire?