ok i just buttoned up my 91 3.1 motor that i just installed. I've been useing all of my 2.8 components intake manifold, exhaust, alternator, starter, ect. Well i go to crank it up for the first time with excitement and all i hear is the starter grinding. I lowered the dust shield and it looks like it's not shimed enough so I gradually shimmed it 1/4", 1/2", 3/4" (max for the starter bolts) and it never would turn the motor over. I looked up the part numbers for a 88 s10 2.8 starter and a 91 camaro 3.1 starter and they have different part numbers. I checked my battery, and it is at 12.08v. Do i need to use a 3.1 starter or am i missing something here?

thanks

 

I put an s10 2.8 starter on a 3.4 camaro motor with no issues.

I never could notice any excessive differences between the two starters.

 

Flywheel on backwards ???

The 2.8 and the 3.1 flywheel are not the same.........This should not make a difference with regard to the starter, but if you used the 2.8 on the 3.1 motor you will have a bad vibration due to incorrect flywheel balancing.

 

ya, im using the 2.8 flywheel. I was told the 3.1 is like a bored 2.8 and everything on the 2.8 would work fine.

 

Correction. The 3.1 is a stroked 2.8 and a 3.4 is a bored 3.1.

I didn't know that the flywheels are different...

 

ok i got under and looked at it and the starter is engaging and the teeth are meshing on the flywheel but it's just not turning the motor over. i think the gear is stripped or something because i can see parts spining and the gear engaging but the gear isn't turning. I'm going to get a new starter and try it.

 

The 88 s10 is the year where some where internal balanced, and some external. If you get it started and feel ANY vibration, instantly turn it off and put on the 3.1 fly.

Were you able to turn the motor over by hand?
Did the starter work before the swap?

 

yes i can turn it over by hand, yes the starter worked before the swap.

I just installed a new starter and it's turning the motor over now but no start yet. I looked in the throttle body and it's dry and smells clean without gas. So what should i check to try to get fuel.

 

Regardless of the starter issue - You need to pull the flywheel and put the right one on.


I installed a 3.1 RS engine in my 87 coupe last fall, I had to replace the original 2.8 that exploded under stress !!!!!


Since all the other accessories were the same; I too used the 2.8 flywheel. Seemed fine until I tried to drive the car. The higher the RPM,.... the worse the vibration. It was bad - so bad that I was afraid I might have caused damage by trying to drive the car. 8 I replaced the piolot bushing just in case - but caused no damage !

You will need the flywheel from another 3.1 or get one from a 3.4 out of a newer camaro. My car is a manual - but that really makes no difference. The difference is in the external vs. internal balancing of the 2.8 and 3.1 engine.

I've got the automatic flywheel from my 3.1 if you need it. The donor was an automatic and my car is a stick so the 3.1 auto flywheel wasn't used. $25 + shipping and it's yours.

Sorry dude,............ I've " been there and done that ! "



----------
P.S.

The 3.1 was made to use the VATS security system......

??? Did you use the 2.8 or the 3.1 ECM and Wiring harness ???

 

If you have actually "been there" and "done that", you should have done just a wee bit more research...

The difference is not a displacment change issue, the difference is a yearly change. MOST '88 2.8s were internal balance, all '89+ were internal.

If there was no additional weight attached to the backside (towards the engine when installed) of the flywheel, then you have nothing to worry about. If there was a weight there, it's part of the casting and looks like a squared addition on the flywheel.

Also the engine was not designed to use any sort of security system, the ECM was, so using the 2.8 ECM will retain all of the original electronics making that side of things easier.

 

My Car was clearly described as an 87 that got a 91 3.1 installed. Where did I go wrong ??? Was I wrong to remove the 2.8 flywheel the caused a vibration so bad that I didn't drive the car over 35MPH on it's test run ??

If there was a change to the Camaro's 88's internal Vs. External balancing, thanx for passing that along. He never said what year his car was and only mentioned a 88 2.8 starter from a Blazer.


To Be clearer,..... I also didn't say any thing about displacement. I said;


If the 3.1 ECM was used - didn't the ECM also control the fuel injectors on the 3.1 ? BY way of the "fuel enable input". ( terminal A2 of the pass key decoder to ECM Termimal B6 ) I asked what ECM and harness was used on the replacement motor 'cause if the 3.1 ECM harness was used - and if it does control the injectors - this might be why the car is not starting. He said something about no fuel. ( The Starter is getting power so I assume the 2.8 ECM harness was used OR the 3.1 ECM is getting tricked into sending a signal from the Starter Relay to the starter.. or the relay is bypassed altogether )

I didn't know what harness and ECM was used and that's why I asked.

 

I think i've got a bad fuel pump. When i turn the key to the on position, i dont hear the fuel pump prime.

 

on your oil pressure sesnor, on the 3.1 system atleast, if you have no oil pressure, you have no fuel pump. You may have simply knocked a wire loose in the swap, or even a bad relay, sensor, etc..

Make sure you check everything else before you tackle a pump. That is a job nobody on this board wants to do.

 

-- luckyou03 -- Did you use the 3.1 ECM and harness of the 2.8 ECM and harness ???

If you plugged the 3.1 ECM and harness into the 2.8 dash harness than you will need to "trick" the ECM to get the car to run.

The 3.1 ECM gets a signal from the security system ( Pass key moddule ) to activate the fuel pump relay - thereby activating the fuel pump. If there's no signal sent from the module to the ECM - the relay ( and the pump ) will not work.


<< Removed Pic >>

 

No, that would be correct for your application.

Actually he said "s10", also this is indicating that he is installing the 3.1 in his S10, so all components are '88 or newer.


Looks like you mentioned displacment to me, but maybe it's because english is my first language I missed something?
Wat you said implies that the difference is due to a displacment change and that all 2.8s are extermal balance and that all 3.1s are interanl balance. All 3.1s are internal balance, but 2.8s depandant on year can be internal or external.


If the 3.1 ECM was used - didn't the ECM also control the fuel injectors on the 3.1 ? BY way of the "fuel enable input". ( terminal A2 of the pass key decoder to ECM Termimal B6 ) I asked what ECM and harness was used on the replacement motor 'cause if the 3.1 ECM harness was used - and if it does control the injectors - this might be why the car is not starting. He said something about no fuel. ( The Starter is getting power so I assume the 2.8 ECM harness was used OR the 3.1 ECM is getting tricked into sending a signal from the Starter Relay to the starter.. or the relay is bypassed altogether )

 

John, that wiring diagram is for the wrong year. That shows "s" code, which IIRC is 4th gen, along with it callings vats "bypass2".

Most of all, we dont know if he is installing this into an 88s10 or 88 camaro. And what wire harness he used. I am going to assume he used the factory car wire harness... It wont have vats. If he used a 3.1 harness and ecm, it will have vats and not passkey2, which IIRC, kills the starter, not fuel pump.



So to the orginal poster....
1. What is this in..88s10 or 88camaro?
2. Which ecm/harness are you using?

 

Dale Nice catch,........ I had to correctly file that image as it was in ( and taken from ) the wrong place. I'm going to remove that image as not to confuse it with the 1991 3.1 version. Here are the ones from the 91 shop manual. ( Only usefull if the 3.1 ECM was used.....) You can see the Oil pump/fuel pressure switch in the diagrams that was mentioned earlier on this thread.


http://berlinetta.info/help/91V6PassKey1.jpg

http://berlinetta.info/help/91V6PassKey2.jpg

http://berlinetta.info/help/91V6PassKey3.jpg

http://berlinetta.info/help/PassKey-Injectors.jpg


Six_Shooter Your right; I have assumed to much - something I don't normally do. I assumed he was on a Camaro site swapping a Camaro 2.8 with a Camaro 3.1. I continued to guess what Harness was used as well as what ECM was plugged into it. Since the 2.8 starter and the 3.1 will interchange - I never gave the year of his starter a second thought. Since The Part numbers I got only specified the 3.1 and 3.4 flywheels when I needed a replacement (internal balance) for my 91 motor - and not one from an 80's S10 - I never gave that a second thought either.

I should have noticed the "S10 2.8" in the title of his posting to begin with.

luckyou03's got the starter working and can worry about a vibration ( if there is one. ) once he gets it running.

 

hey guys sorry I installed a 3.1 shortblock to replace my 2.8l. It's in a 88 s10 truck 2.8 computer, 2.8 wiring, 2.8 everything but the 3.1 shortblock. Yes the starter is cranking it over but i disconnected the fuel inlet line and nothing is coming out while cranking so it's definitely not getting fuel. I have a new fuel pump coming in today, I'll keep you guys updated after i install it. thanks everybody

 

Did you try using the fuel pump prime connector? I believe the S-10s had this, I'm not absolutly sure of the location, but they are usually near the driverside harness bulkhead feed through. Usually a red wire with what looks like a spade terminal connector on it, also sometimes taped to the harness.

If this works than, you need to look for a burnt fuse or possibly bad fuel pump relay.

 

alright, i pulled the gas tank and man this thing looks nasty. The fuel relay is about 1 month old and the fuse was good.

 

new sending unit ,new fuel pump, new fuel pump relay, new oil pressure sender, all fuses under the dash are good. I applied 12v directly to the pump and it turned on. I jumped the little test wire on the engine bay and it turned the pump on. When i turn the key to the on position, the pump doesn't prime, when i crank the pump doesnt turn on. whats up?

 

i applied direct 12v to the pump and turned it on but the engine didn't fire. I looked and smelled in the throttle body and it was dry. Even with the pump manually turned on the injectors didn't spray.

 

Sounds like the ECM is not getting power (constant or switched), or possibly bad ground(s).

You'll need to check that. If it is getting power than the ECM is most likely pooched.

 

I'll clean all my grounds, thanks

 

I dont remember if s10's had the oil pressure trigger setup or not. Might want to check that as well.