CgMcKinney

I bought a 1991 3.1L Camaro about a month ago. It ran great after doing the usual tune up stuff (Fuel filter, fuel pump, oil, coolant, plugs, wires, cap, rotor, ignition coil). It survived the 5 hour trip back to my house afterward. I then took a 40 minute trip last Friday, and on the way back it started to lose power, then when I hit the gas, it made a knocking sound. Also when I hit the gas, it seemed like it would lose power and want to die, so I feathered the gas for a few more miles to try to make it home. I got about half a mile from campus (I'm in college) and it died between red lights. We pushed it back, and I got to work the next day.

Saturday I replaced the fuel injectors (I had already ordered them from SouthBay - the F1ZE swap) to no avail, and then the ignition coil (The one we had previously put in was used, but tested good). After we put the coil in, it seemed like it wanted to start, but just wouldn't stay running. Today I put new spark plugs in (They were all fouled out), and it still won't stay running.

Now I'm out of ideas...

CgMcKinney

Cool... I'll just figure it out...

micktroup2

You have gas and spark by the looks of it. Check the catalytic convertor. If that is toast, it can block up and the back pressure can kill the engine...

CgMcKinney

Is it possible that one of the o-rings on the injectors isn't sealing properly and causing a huge vacuum leak? I plan on pulling the fuel rail again soon to make sure I installed everything properly, and purchase another new set of o-rings.

copyfixr

iTrader: (3)

Not sure if an o-ring will cause a vacuum leak but it would cause a fuel leak. Any gas leaking under the hood? The knocking sound thing doesn't sound good. Did you have good oil pressure and it wasn't overheating?

Maverick H1L

iTrader: (8)

Um, fuel injectors have o-rings on BOTH ends... Only the fuel rail end will cause a fuel leak. The other end will cause a vac leak if the o-ring is damaged upon installation.

Did you pull any codes out of the ECM yet?

copyfixr

iTrader: (3)

You are correct Mav. MPFI is still new to me, I'm and old carb guy. The loss of power knocking thing is what worries me. I have ran plenty of demo derby cars and thats what they do before the go away. No mention of an SES light though.

Maverick H1L

iTrader: (8)

A lot of people don't even notice the light is on, or may assume it's normal if the engine isn't running anyways. Problem with that is there are several codes that pop up when a condition is incorrect to run the engine. Codes 12 and 46 come to mind for a 91, 12 meaning the ECM isn't seeing an RPM signal from the ignition, and 46 meaning that there is no valid VATS (antitheft) signal, which causes the ECM to not turn the fuel injectors on.

Also need to know if the car has an auto or manual trans... May make a difference.

copyfixr

iTrader: (3)

Or some putz that had the car before you took the light out so it didn't look bad when they were trying to sell it! I know this cause it happened to me once!

CgMcKinney

Yeah it had a SES light when I bought it, just haven't gotten around to seeing what the code was. I know, shame on me...

In other news... It's an automatic, I don't recall the oil pressure or temperature being high as I was trying to get it back, but I may be wrong.

Maverick H1L

iTrader: (8)

Well, find the ALDL next to the fuse panel and pull the codes by putting a wire or paper clip in the 2 top right hand holes in the connector...

Oil pressure will be rather high... The spring inside the oil pump is calibrated to 70 PSI. Temp may be another story, but something to worry about when the engine actually gets going again.

copyfixr

iTrader: (3)

No worries. It's new to you and you are trying to fix it up. When it starts crapping you you were just trying to get home, it's a bad feeling.

CgMcKinney

I'll pull the codes when I go out tomorrow. It's cold, raining, and dark outside right now. Definitely not optimal working conditions.

Maverick H1L

iTrader: (8)

... especially if you literally JUST left the auto parts store like I did the first time my 730 harness decided to be a PITA... And it leaves you in the middle of a busy intersection.

CgMcKinney

It left me and my girl on an interstate overpass... and no one stopped to help.

Then on top of that the next day the wheel falls off my girl's car as I'm driving in the fast lane. No warning or anything, just heard a knocking sound and then boom, no more wheel. And no, not the tire, the ENTIRE WHEEL. It was crazy, since we had already driven about 100 miles on the interstate, then that just randomly happens.

Oh, and another question. How do you get all of the air out of the fuel system after the injector swap? Do you hold the release valve while you crank it or just prime it then hit the valve?

Maverick H1L

iTrader: (8)

Air in the fuel system bleeds itself out via the fuel return line to the tank... You'll hear the fuel pump change in tone as it primes when the system is up to pressure.

CgMcKinney

So I should just repeatedly prime it until it changes pitch?

Also, thank both of you for all of you help so far...

CgMcKinney

So I put the old injectors back in with new o-rings and had no luck again. I'm running out of ideas. A few more questions though:

If some dirt/debris fell into the cylinder where the injectors go in, what would would happen? The lower intake underneath my fuel rail isn't very clean...

After I put the whole assembly back together I repeatedly primed the fuel pump, per Maverick's instructions, but when that didn't work I hit the purge valve again, and mostly air came out. What does that mean?

EDIT: Oh also, the knocking sound I heard when I was driving back... any ideas on what that could have been? I'm sure it was getting too much gas if the coil was going out, if that's any help. I'm just kinda brainstorming right now.

Maverick H1L

iTrader: (8)

That knocking sound was probably the engine running out of gas (knocks when it runs lean under load). You have a fuel delivery problem between the gas tank and the engine if you don't have anything but air in the fuel rail. Change the fuel filter again (and check to make sure it's going in the right direction as it has a 1-way only valve in it), but before you do, put a hose into a bucket on the end of the inlet line from the fuel tank and prime the pump to make sure it's pumping gas at least that far. You may have a clog somewhere.

And yes, you prime the pump until the note changes, may take a couple of minutes (ECM requires something like 30 seconds between key cycles before it will run the pump again) and a couple cycles.

:edit: And dirt and debris will run out of the cylinder just fine. Provided it's not a nut or bolt . Been there, done that (bolt in cylinder 6 helped kill my 2.8, swear I never saw that bolt before, either).

CgMcKinney

Well I fixed the problem...

The solution is actually quite embarrassing...

Anyways... Lol. Couple more questions.

There's a ribbed steel tube that goes into the passenger side of the upper intake. Does that go to the EGR? I'm having a lot of trouble getting the bolts to go all the way into the upper intake and it's causing a huge vacuum leak. Any tips on that?

I had another question but I forgot what it was... update later.

AmorgetRS

iTrader: (6)

What was the problem? The answer might help somebody in the future.

CgMcKinney

Just check your fuel level before you go diving into the engine... *facepalm

My previous questions still stand though..

Maverick H1L

iTrader: (8)

May either want to use a thread insert on the upper plenum for the EGR transfer tube or drill the holes in the tube larger and tap the holes in the plenum for larger bolts. If that tube isn't secure on the manifold, the engine won't run for more than a couple seconds due to the massive vacuum leak.