1984 S10 3.4 engine swap

[metalmulisha1268]

i have a 1984 s10 4X4 that had a 2.8 v6 that was a POS so i decided to swap in a 93 camaro 3.4 into it. Being that i live in CA it has to be smog legal, so i have to use the tuned port injection on it and the camaro everything. I got the motor rebuilt and swapped in, and got the motor to start, but it wont actually stay running. it starts idles for about 2 to 3 seconds and dies. It isnt losing spark or fuel pressure, and if you play with the throttle you can sometimes get it to stay running a little longer. I am completely lost and cant get it to stay running anyone have any ideas?

[jwvess00]

Hi there!

My first thought is that something like VATS is killing it but that would keep it from starting at all.

1) Vacuum leak. Check around the EGR valve, etc. to make sure you don't have a massive vacuum leak.

2) Check to make sure it's not cross-wired. Sounds dumb with coil packs, but check anyway. I've been guilty of just that. Also, use a spark tester to verify spark at *every*plug. Use a spark tester, too -- not a spare plug, screwdriver jammed in the plug wire, timing light, or anything else rigged up for this. I had a no-start on a Bravada that was due to a failed cap shorting out #4, so I check for spark on *every* cylinder now.

3) Dirty injectors. Are you *sure* all the injectors are firing and spraying right? If the engine was sitting for a while before you installed it, this could be the case.

4) What method did you use to go to the electric pump? On the S-10, the carb's in-tank pump assembly is different than the EFI in-tank assembly in that the return and canister lines are swapped. If you get this backwards, all sorts of goofy things can happen.

I'm sure there are other things it could be, but this is what comes to mind immediately.

[Weatheralls Auto]

A little more info on what you did during the swap will help.
You say you are not loosing fuel pressure, but did not say what the pressure is?

[metalmulisha1268]

when i did the swap i redid all the gaskets, and the seals, i put a newer s10 fuel pump assemble into the tank from a newer s10 with the camaro fuel pump. it is reading 45 to 50 when it isnt running and drops to 35 when u start but goes back up to 45 as it starts, if you pinch the return line you can get it up to 55lbs and it doesnt make a difference. i havent checked spark at each plug but i will now i didnt think about it after i found 2 of the plugs were sparking on oppisite coils, it has 3 coils each with 2 plugs per coil.

[Weatheralls Auto]

Thats a Waste(way) Spark system, coils 1/4 will fire at same time 6/3 will fire at same time 5/2 will fire at same time.
IS the Mil on with key on engine off?

[metalmulisha1268]

i havent gotten the engine light wired into the s10 harness yet but i could check why do you ask?

[Weatheralls Auto]

Its a good sign that the Ecm is awake and ready with KOEO, you may even have a DTC or two that will point you in proper direction.

I would finish then recheck all wires.

[metalmulisha1268]

would a vehicle speed sensor mess with it? i havent gotten that wired in because i had to use the s10 tranny and it is cable and i need an electronic one for the camaro?

[Weatheralls Auto]

VSS should not deter it from running, could be crank sensor and a variety of other wiring issues.

I would start by finishing the wiring, and then double check you have everything fed and hooked up correctly.

[cardana24]

would a vehicle speed sensor mess with it? i havent gotten that wired in because i had to use the s10 tranny and it is cable and i need an electronic one for the camaro?

It will run with out that VSS siginal, but it will cut out when you are decelerating out of gear. I bought an adaptor from Nevada speedometer to fix the problem.

Also did you say if you have your VATS system bypassed? If that is not bypasses then the vehicle will not stay running.

[metalmulisha1268]

how do you bypass the VATS? i have all of the hot wires hot when they are suppose to be hot as far as i know. all of the fuses are hot. and the ignition is hot. but is there a specific spot that i have to run hot to bypass it?

[BMC]

jwvess00 has a good list of things and I agree with him.

I have a 1982 S10 3.4L SFI and plenty of MGBs running the same driveline for 10+ years.

To not get myself in trouble, I will Not mention that we sell a VATs disable for the MGB conversions.

That said, the engine with a VATs needed usually only runs for a second but some people tell me they can get them to run for 3 seconds before the PCM shuts the injectors down.

-BMC.

[metalmulisha1268]

how does it hook into the harness? does it just wire into the harness at the PCM or what?

[BMC]

oh boy, its late so I am probably speaking wrong but C23 if memory serves at 3.35am for the signal and the other two wires are ignition power and ground. Can't recall at the moment if its a grey or blue wire. Easy. What am I still doing up?

-BMC.

[metalmulisha1268]

well thank you very much and i will hopefully be able to order that monday.