I have a major problem!!!!!!!!!!!!!!!!!!
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Instructor
Joined: Feb 2008
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From: The Ham AL
I have a major problem!!!!!!!!!!!!!!!!!!
Did an injector swap. Bolted it all back together. Turned the key and the car takes forever to turn over. When it does, it ramps up to 3k rpms and then straight back to the bottom. If I don't touch the gas pedal the car dies. If I barely touch the gas pedal it ramps up to 3k rpms again and back down. The car is undrivable like it is. It won't even idle.
First thing we thought about is the throttle position sensor. It looks lined up (we marked it with a pen when we set it a while back).
The other thing is I noticed that when I shut the car off I could hear a hissing sound from the rubber hose that goes from the Plenum to the brake booster. When I grab the hose the hissing goes away, and when I let go it comes back for a few seconds. I guess this indicates a vacuum leak. I clamped this off with vice grips and when I started the car it turned over faster, but only with the same result otherwise.
Another thing is when my fellow vette forum member was standing over the car for the first start after bolting back together, he mentioned a popping sound coming from around the distributor cap. We just put a new cap on a few months ago!
Any thoughts?
First thing we thought about is the throttle position sensor. It looks lined up (we marked it with a pen when we set it a while back).
The other thing is I noticed that when I shut the car off I could hear a hissing sound from the rubber hose that goes from the Plenum to the brake booster. When I grab the hose the hissing goes away, and when I let go it comes back for a few seconds. I guess this indicates a vacuum leak. I clamped this off with vice grips and when I started the car it turned over faster, but only with the same result otherwise.
Another thing is when my fellow vette forum member was standing over the car for the first start after bolting back together, he mentioned a popping sound coming from around the distributor cap. We just put a new cap on a few months ago!
Any thoughts?
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
Sounds like a runner gasket might have gotten busted or removed during the injector swap. Check for leaks....or extra parts left over laying on the garage floor/workbench. Make sure you put all the runner bolts back in.
Le Mans Master
Joined: Oct 2003
Posts: 6,130
Likes: 2
From: seattle WA
And hook up a fuel pressure guage, see what it reads and when you shut the key off, how long does the pressure hold? Where did you get your injectors and what brand? Regarding the TPS, you need to check the voltage and it should increase smoothly from closed throttle to WOT. Als, it helps everyone if you state the year!
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Instructor
Joined: Feb 2008
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From: The Ham AL
All of the runner bolts are installed at 15 foot-lbs. The FSM suggested 18 foot-lbs, but we thought that 15 would be enough.
I don't think (yet) that I have a vacuum leak around the runners b/c in one of my tests I had the rubber hose at the brake booster clamped off and it held pressure for a minute or so until I took off the clamp after shutting the car down. I could hear the hissing for several seconds after releasing the clamp.
Oh yeah, I have an 89.
Instructor
Joined: Mar 2007
Posts: 162
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From: Mentor Ohio
Does the 89 have a cold start injector? I had a very similar problem on my 87 and the flange on the cold start injector was bent just a touch. Someone in the forum suggested I look at it and when I removed it, it was just barely bent. Put it in a vise and straighten it out, new o-ring and tightened up and it made a 100% difference.
While it was bent it run just as you said only mine would start quick ramp to 2400 RPM and then if I didn't feather the gas peddle it would die immediately.
Just a thought.
While it was bent it run just as you said only mine would start quick ramp to 2400 RPM and then if I didn't feather the gas peddle it would die immediately.
Just a thought.
Melting Slicks
Joined: Apr 2004
Posts: 2,773
Likes: 138
From: cyberspace NY
Pull the distributor cap, and take a look. the rotor may be hitting the underside of the cap, and slowly grinding away the plastic. ask me how I know
why would you upset the TPS for an injector swap?? you just pull the TB as a whole unit.
I assume you disconnected the battery for the swap. this means you MUST drive the car for the computer to re-lean everything. Otherwise it may not idle, it will run like trash. Get in the car and drive it, and it may straighten out.
and make sure you reconnect the vacuum booster
why would you upset the TPS for an injector swap?? you just pull the TB as a whole unit.
I assume you disconnected the battery for the swap. this means you MUST drive the car for the computer to re-lean everything. Otherwise it may not idle, it will run like trash. Get in the car and drive it, and it may straighten out.
and make sure you reconnect the vacuum booster
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Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
Did an injector swap. Bolted it all back together. Turned the key and the car takes forever to turn over. When it does, it ramps up to 3k rpms and then straight back to the bottom. If I don't touch the gas pedal the car dies. If I barely touch the gas pedal it ramps up to 3k rpms again and back down. The car is undrivable like it is. It won't even idle.
First thing we thought about is the throttle position sensor. It looks lined up (we marked it with a pen when we set it a while back).
The other thing is I noticed that when I shut the car off I could hear a hissing sound from the rubber hose that goes from the Plenum to the brake booster. When I grab the hose the hissing goes away, and when I let go it comes back for a few seconds. I guess this indicates a vacuum leak. I clamped this off with vice grips and when I started the car it turned over faster, but only with the same result otherwise.
Another thing is when my fellow vette forum member was standing over the car for the first start after bolting back together, he mentioned a popping sound coming from around the distributor cap. We just put a new cap on a few months ago!
Any thoughts?
First thing we thought about is the throttle position sensor. It looks lined up (we marked it with a pen when we set it a while back).
The other thing is I noticed that when I shut the car off I could hear a hissing sound from the rubber hose that goes from the Plenum to the brake booster. When I grab the hose the hissing goes away, and when I let go it comes back for a few seconds. I guess this indicates a vacuum leak. I clamped this off with vice grips and when I started the car it turned over faster, but only with the same result otherwise.
Another thing is when my fellow vette forum member was standing over the car for the first start after bolting back together, he mentioned a popping sound coming from around the distributor cap. We just put a new cap on a few months ago!
Any thoughts?
Thread Starter
Instructor
Joined: Feb 2008
Posts: 201
Likes: 0
From: The Ham AL
Does the 89 have a cold start injector? I had a very similar problem on my 87 and the flange on the cold start injector was bent just a touch. Someone in the forum suggested I look at it and when I removed it, it was just barely bent. Put it in a vise and straighten it out, new o-ring and tightened up and it made a 100% difference.
While it was bent it run just as you said only mine would start quick ramp to 2400 RPM and then if I didn't feather the gas peddle it would die immediately.
Just a thought.
While it was bent it run just as you said only mine would start quick ramp to 2400 RPM and then if I didn't feather the gas peddle it would die immediately.
Just a thought.
Well....I have an 89 per the VIN #, but I have an earlier intake manifold which means I do have the cold start injector. Or should I say used to have it. I removed it and put in the billet set sold to block it off. both fittings had O-rings and best I could tell they are a good fit.
Jon, I will call if I get the chance tomorrow. My beef is not with the injectors, but you bring up an interesting theory. I know the bottom O-ring seats okay at least from a feel perspective. I left the middle O-rings on as you mentioned it didn't matter (I think).
Thanks for the posts guys.
Thread Starter
Instructor
Joined: Feb 2008
Posts: 201
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From: The Ham AL
Pull the distributor cap, and take a look. the rotor may be hitting the underside of the cap, and slowly grinding away the plastic. ask me how I know
why would you upset the TPS for an injector swap?? you just pull the TB as a whole unit.
I assume you disconnected the battery for the swap. this means you MUST drive the car for the computer to re-lean everything. Otherwise it may not idle, it will run like trash. Get in the car and drive it, and it may straighten out.
and make sure you reconnect the vacuum booster
why would you upset the TPS for an injector swap?? you just pull the TB as a whole unit.
I assume you disconnected the battery for the swap. this means you MUST drive the car for the computer to re-lean everything. Otherwise it may not idle, it will run like trash. Get in the car and drive it, and it may straighten out.
and make sure you reconnect the vacuum booster
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
before you remove anything. My son says he has a edlebrock like yours in the shop. We are open on sat. so I will test the fit to see if the injector does seat all the way. I also noticed the CSI and plumbing. So your rails are 88 down. As stewball said the cold start hole if not sealed properly will suck air big time. Its hard to find a vac leak at 2500 rpm so check everything you took apart. Did you remove the egr?
Thread Starter
Instructor
Joined: Feb 2008
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From: The Ham AL
Yes, I removed the EGR valve but replaced it with a custom TPI plate and gasket torqued per the FSM recommendation. My EGR pipe was already gone with plate and gasket. I did not touch it during the injector install.
Thread Starter
Instructor
Joined: Feb 2008
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From: The Ham AL
I still have the problem, but thanks to Jon to walking me through some things over the phone Saturday. Best we can tell at this point, I have a major vacuum leak. Looks like I will likely have to break to whole freakin thing down again and reassemble.
I really don't look forward to this. Those big runners are a pain in the rear end to work around. At this point, I would actually not recommend larger runners to someone asking.
I really don't look forward to this. Those big runners are a pain in the rear end to work around. At this point, I would actually not recommend larger runners to someone asking.
Le Mans Master
Joined: Jul 2007
Posts: 5,043
Likes: 8
From: Tampa Florida
I still have the problem, but thanks to Jon to walking me through some things over the phone Saturday. Best we can tell at this point, I have a major vacuum leak. Looks like I will likely have to break to whole freakin thing down again and reassemble.
I really don't look forward to this. Those big runners are a pain in the rear end to work around. At this point, I would actually not recommend larger runners to someone asking.
I really don't look forward to this. Those big runners are a pain in the rear end to work around. At this point, I would actually not recommend larger runners to someone asking.
Looks like the under side of fuel rails need to be ground down/away to make some room for the runners.
Last edited by engle1147; Sep 7, 2008 at 10:15 PM. Reason: +ed last sentence ....it's grinder time!
Pro
Joined: Oct 2007
Posts: 681
Likes: 0
From: Morris County, NJ
hope you find a fix for your problem-----
BTW I know who I'm going straight to if I ever need injectors-answering email from a borrowed laptop at a party on Friday night = priceless
This is the attitude and commitment America was built on-too bad it is not common practice today
Steve
BTW I know who I'm going straight to if I ever need injectors-answering email from a borrowed laptop at a party on Friday night = priceless
This is the attitude and commitment America was built on-too bad it is not common practice today
Steve
Supporting Vendor
Joined: Mar 2008
Posts: 1,762
Likes: 14
From: Cumming Ga
chad
just looked at the edlebrock set up like yours that i have here. there is a possibilaty that the lower runner gaskets are on the wrong runners. they both interchange as far as the bolt holes but if you use the wrong side on the other tube there is 1/4 inch gap in the cutout fot the egr port. That would definatly cause enough air to enter the engine and there is no way to stop it. I think you have to take it apart to find out since we plugged every vac line and the injectors are seated properly.
have fun!
just looked at the edlebrock set up like yours that i have here. there is a possibilaty that the lower runner gaskets are on the wrong runners. they both interchange as far as the bolt holes but if you use the wrong side on the other tube there is 1/4 inch gap in the cutout fot the egr port. That would definatly cause enough air to enter the engine and there is no way to stop it. I think you have to take it apart to find out since we plugged every vac line and the injectors are seated properly.
have fun!