1991 Z07 Troubleshooting
03-08-2011, 07:14 PM
#1
Safety Car
Thread Starter
1991 Z07 Troubleshooting
I've not been driving my car for the last few years much. I had it outside for ~ 6 months while working on the shop. Got in to start the car and it ran fine for about 30 seconds, then really went downhill and finally stopped (flagging about 8 codes in the process).
I left it alone (inside) and waited WAYYY to long to troubleshoot this nightmare. I picked this past weekend to give it a shot.
1) Checked out computer by swapping with my spare one - no dice.
2) Replaced battery due to dead cell
3) Checked spark with an inductive timing light...checked good.
4) Checked fuel pressure @ the rail = 42 lbs, checks good.
NOW comes the fun!
Took the fuel pressure gauge off and the fuel didn't feel (or smell) right. Took pressure gauge off end of hose, screwed it back onto the rail and turned the key on and pumped some fluid into a glass jar. NOT gas...mostly H2O. Crap!
5) Rolled it outside and siphoned the tank as much as possible. Had the hose in the sump well in the tank and got most out.
6) Disconnected the fuel line and return from the tank. Used compressed air to blow down the return line and clear the water from them...
7) Connected the siphon hose to the fuel supply on the tank, cycled the key until nothing else came out of the tank.
8) Connected lines back up, poured 5 gallons of 93 octane in and cranked again....no dice. A single cylinder was trying to fire, but that was it.
Figured from here it had to be the injectors being bad...having water sitting in them for almost a year CAN'T be good for them. Called the injection shop Monday morning...$35/ea to clean and bench them, or $280 + tax for the set. Made some calls and found Bosch Gen3's for $330 a set matched. Ding! Winner, winner, chicken dinner!
So, now I'm waiting for those to return. While the TPI upper section is off I called the powder coater's to ask why my plenum was flaking and looked generally like crap. They aren't sure, but I sent IT out today to get it stripped and redone.
Lesson learned: NEVER put off troubleshooting a major engine problem. IF I would have checked it that weekend, I might have found the water in the lines and gotten it blown out before the Ford 24# injectors were toast.
Another 10 days or so...I should have it back running. I forgot how fun working on this car is.
Back was KILLING me from leaning over all day Saturday and 3 hours on Sunday yanking the plenum, runners and fuel rail.
Turns out some little leaves blocked the drain in the filler area, and I got about 3 or 4 gallons into the tank through the gas cap. What fun!
Can't wait to hear it rumble again...
I left it alone (inside) and waited WAYYY to long to troubleshoot this nightmare. I picked this past weekend to give it a shot.
1) Checked out computer by swapping with my spare one - no dice.
2) Replaced battery due to dead cell
3) Checked spark with an inductive timing light...checked good.
4) Checked fuel pressure @ the rail = 42 lbs, checks good.
NOW comes the fun!
Took the fuel pressure gauge off and the fuel didn't feel (or smell) right. Took pressure gauge off end of hose, screwed it back onto the rail and turned the key on and pumped some fluid into a glass jar. NOT gas...mostly H2O. Crap!
5) Rolled it outside and siphoned the tank as much as possible. Had the hose in the sump well in the tank and got most out.
6) Disconnected the fuel line and return from the tank. Used compressed air to blow down the return line and clear the water from them...
7) Connected the siphon hose to the fuel supply on the tank, cycled the key until nothing else came out of the tank.
8) Connected lines back up, poured 5 gallons of 93 octane in and cranked again....no dice. A single cylinder was trying to fire, but that was it.
Figured from here it had to be the injectors being bad...having water sitting in them for almost a year CAN'T be good for them. Called the injection shop Monday morning...$35/ea to clean and bench them, or $280 + tax for the set. Made some calls and found Bosch Gen3's for $330 a set matched. Ding! Winner, winner, chicken dinner!
So, now I'm waiting for those to return. While the TPI upper section is off I called the powder coater's to ask why my plenum was flaking and looked generally like crap. They aren't sure, but I sent IT out today to get it stripped and redone.
Lesson learned: NEVER put off troubleshooting a major engine problem. IF I would have checked it that weekend, I might have found the water in the lines and gotten it blown out before the Ford 24# injectors were toast.
Another 10 days or so...I should have it back running. I forgot how fun working on this car is.
Back was KILLING me from leaning over all day Saturday and 3 hours on Sunday yanking the plenum, runners and fuel rail.
Turns out some little leaves blocked the drain in the filler area, and I got about 3 or 4 gallons into the tank through the gas cap. What fun!
Can't wait to hear it rumble again...
Last edited by 1991Z07; 03-08-2011 at 09:29 PM.
03-08-2011, 09:07 PM
#2
Race Director
this lesson is especially important for any 4 cycle engine that blows a head gasket. if you put it off a year there's a good chance you'll rust the cylinder bores and have ring seal issues when you get around to fixing it
04-08-2011, 03:27 PM
#3
Safety Car
Thread Starter
After some fits getting the plenum redone, I finally got it back together on Wednesday. Thought I had all the water out of the tank, and when I tried firing it up there was still water in there (even after I blew the lines out with compressed air).
I pulled the lines off the tank, blew them out again. Took the sending unit out of the tank (after applying 12VDC to the gray & black wires and pumping it dry). Wiped out the bottom of the tank with a rag on long mechanical fingers and put it all back together. I added about 2 gallons back into the tank, and just for grins left the return line off and applied 12VDC again to the fuel pump. I got about 4 cups of water/gas mix out and ensured there was just clean gas coming out. Replaced the return line, and then cranked...and cranked...and cranked. I was getting a little worried...I already had checked there was pressure, new fuel and there was definitely spark. Almost stopped and figured I'd give it another shot before another round of troubleshooting and this is what happened:
I know...I know...my finger was in the way. Too excited...
She is running again, and has lost NONE of her kick. Now time to get it on the lift and fix the slight oil leak from the dipstick/block connection and a fresh round of Mobile1 15W/50...already has a full tank of Super and is feeling much better now
Already fixed the electrical gremlin too...loose grounds will wreak havoc on an electrical system.
I pulled the lines off the tank, blew them out again. Took the sending unit out of the tank (after applying 12VDC to the gray & black wires and pumping it dry). Wiped out the bottom of the tank with a rag on long mechanical fingers and put it all back together. I added about 2 gallons back into the tank, and just for grins left the return line off and applied 12VDC again to the fuel pump. I got about 4 cups of water/gas mix out and ensured there was just clean gas coming out. Replaced the return line, and then cranked...and cranked...and cranked. I was getting a little worried...I already had checked there was pressure, new fuel and there was definitely spark. Almost stopped and figured I'd give it another shot before another round of troubleshooting and this is what happened:
I know...I know...my finger was in the way. Too excited...
She is running again, and has lost NONE of her kick. Now time to get it on the lift and fix the slight oil leak from the dipstick/block connection and a fresh round of Mobile1 15W/50...already has a full tank of Super and is feeling much better now
Already fixed the electrical gremlin too...loose grounds will wreak havoc on an electrical system.
