If it's not one thing, it's another... (LT1 update)
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
If it's not one thing, it's another... (LT1 update)
OK, so I've got the LT1 intake on there... 
I even got it to run for a couple minutes.... then it died.
Can't get it to restart. Double checked the timing. It's fine.
I pulled a plug when doing this from #1 cylinder. It was wet with fuel.
When I was having a problem with leakdown, I had pulled the injectors to check that they weren't leaking...maybe now they are?
Enough to flood the motor?
I pulled an intake/fuel rail from a "baby LT1" caprice motor - supposed to have 19lb injectors. I will try those out.
I also found out that since the car hadn't been used in about a month my battery has all but died. When I took it for a test/charge it came back as 'marginal'.
I had it sitting in it's place disconnected all that time... Oh, well. I was using my other car to jump start the '91 so I was getting a good crank when trying to start it.
Frustrating to say the least...
I even got it to run for a couple minutes.... then it died.
Can't get it to restart. Double checked the timing. It's fine.
I pulled a plug when doing this from #1 cylinder. It was wet with fuel.
When I was having a problem with leakdown, I had pulled the injectors to check that they weren't leaking...maybe now they are?
Enough to flood the motor?I pulled an intake/fuel rail from a "baby LT1" caprice motor - supposed to have 19lb injectors. I will try those out.
I also found out that since the car hadn't been used in about a month my battery has all but died. When I took it for a test/charge it came back as 'marginal'.
I had it sitting in it's place disconnected all that time... Oh, well. I was using my other car to jump start the '91 so I was getting a good crank when trying to start it.Frustrating to say the least...
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Just prime the pump and pull the fuel rail with injectors out of the intake. If the injectors are leaking, you'll see it. Would it start after sitting? Have a strong spark? Don't be surprised if it's an ignition problem. Things tend to die at the least opportune time.
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
Originally posted by rezinn
Just prime the pump and pull the fuel rail with injectors out of the intake. If the injectors are leaking, you'll see it.
Just prime the pump and pull the fuel rail with injectors out of the intake. If the injectors are leaking, you'll see it.
Would it start after sitting?
Have a strong spark?
Don't be surprised if it's an ignition problem. Things tend to die at the least opportune time.
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From: Savannah, GA
Car: 1997 Jeep Wrangler
Engine: 4.0L
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Your injectors might not even be firing. To test do this-get a can of starting fluid, open the throttle blades and spray a couple seconds worth into the intake. Now try and start the car.
Let us know what happens, the troubleshooting path will split depending on what happens.
Let us know what happens, the troubleshooting path will split depending on what happens.
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
Originally posted by John Millican
Your injectors might not even be firing. To test do this-get a can of starting fluid, open the throttle blades and spray a couple seconds worth into the intake. Now try and start the car.
Your injectors might not even be firing. To test do this-get a can of starting fluid, open the throttle blades and spray a couple seconds worth into the intake. Now try and start the car.
I'm certain that the answer lies in the fuel delivery system...I just don't know what it is yet.
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From: Savannah, GA
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Have someone else check the timing. Sounds like you don't have a fuel issue.
Also try moving the distributor both ways while someone else tries to start the car.
Also try moving the distributor both ways while someone else tries to start the car.
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You're gonna need some help. Get someone to crank it while you ground a spark plug somewhere. You want a white spark. Starting fluid can actually overcome a rich condition and allow the car to start sometimes--it's more volatile than gasoline.
If starting fluid doesn't do it, it's gotta be timing or ignition. I'd suspect a faulty ignition module or possibly coil. If you've got an extra one of either try swapping it out. If the car was running real hot, you can be sure the module isn't gonna live long-the distributor gets very hot, and the old grease will harden and let the module fry.
If you've got the timing close, it should run. Try retarding it if you think it's too advanced to start well. The fuel is there, but it doesn't sound like it's getting strong enough spark. Maybe too much fuel, too weak spark. Does the computer know what size injectors it's running?
If starting fluid doesn't do it, it's gotta be timing or ignition. I'd suspect a faulty ignition module or possibly coil. If you've got an extra one of either try swapping it out. If the car was running real hot, you can be sure the module isn't gonna live long-the distributor gets very hot, and the old grease will harden and let the module fry.
If you've got the timing close, it should run. Try retarding it if you think it's too advanced to start well. The fuel is there, but it doesn't sound like it's getting strong enough spark. Maybe too much fuel, too weak spark. Does the computer know what size injectors it's running?
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
Originally posted by rezinn
If starting fluid doesn't do it, it's gotta be timing or ignition. I'd suspect a faulty ignition module or possibly coil. If you've got an extra one of either try swapping it out. If the car was running real hot, you can be sure the module isn't gonna live long-the distributor gets very hot, and the old grease will harden and let the module fry.
If starting fluid doesn't do it, it's gotta be timing or ignition. I'd suspect a faulty ignition module or possibly coil. If you've got an extra one of either try swapping it out. If the car was running real hot, you can be sure the module isn't gonna live long-the distributor gets very hot, and the old grease will harden and let the module fry.
I've got a whole 'nother fuel rail from a caprice "baby" LT1 (has the 19lb injectors)...I'm going to swap that over.
If you've got the timing close, it should run. Try retarding it if you think it's too advanced to start well. The fuel is there, but it doesn't sound like it's getting strong enough spark. Maybe too much fuel, too weak spark. Does the computer know what size injectors it's running?
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
Originally posted by John Millican
Have someone else check the timing. Sounds like you don't have a fuel issue.
Also try moving the distributor both ways while someone else tries to start the car.
Have someone else check the timing. Sounds like you don't have a fuel issue.
Also try moving the distributor both ways while someone else tries to start the car.
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From: Evansville, IN USA
Car: '89 GMC Pickup
Engine: 383 SBC Stealth Ram
Transmission: 700R4/VIG 3200
Originally posted by 91-RED-WS6
I checked to make sure it's at TDC (it was). For the few minutes that I had the car running, it was rough. I manually retarded the timing a bit, and the car didn't like it - so I moved it back and it sounded better/stronger - then it died and wouldn't restart.
I checked to make sure it's at TDC (it was). For the few minutes that I had the car running, it was rough. I manually retarded the timing a bit, and the car didn't like it - so I moved it back and it sounded better/stronger - then it died and wouldn't restart.
Could be pouring raw fuel in the cylinders because it thinks that it's -46°.
Just a WAG. . .
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From: Dallas Tx
I had similar problems starting my 68 Camaro that I retrofitted with a tpi, the car sat for a few months and the fuel went bad. I had to drain the tank and refill with fresh gas. Used the electric fuel pump to purge lines. I was looking here to see about replacing the tpi intake with the Lt-1 intake. Hope you get the leak fixed
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Car: '99 HO Z28 / '03 Trailblazer
OK, hopefully someone will clarify some things for me. My IAC plug will not reach the IAC, so it is disconnected. I used some spare wire (good thick wire, though) to extend the connector to the map sensor (was also too short)..is this OK. I re-used the TPI map sensor, should I have used the LT1 sensor (LT1intake.com doesn't specify).
The coolant temp sensor which would plug into the front of the intake, was placed in the remote thermostat housing - but is not wired since the cable also needs to be lenghtened. I don't think this is causing a problem since when I first got the car the temp sensor connection was broken - all I ever got was running fans and a CE light.
There was also a sensor (temp?) for the bottom of the upper TPI plenum...there is no provision for this on the LT1 intake...no mention of this on LT1intake.com so I assumed there was no need to address it.
I was under the impression that without the computer connected, the car should still RUN...not well, but in open loop mode. Was I misled?
You know what they say about ASSuming anything, right?
The coolant temp sensor which would plug into the front of the intake, was placed in the remote thermostat housing - but is not wired since the cable also needs to be lenghtened. I don't think this is causing a problem since when I first got the car the temp sensor connection was broken - all I ever got was running fans and a CE light.
There was also a sensor (temp?) for the bottom of the upper TPI plenum...there is no provision for this on the LT1 intake...no mention of this on LT1intake.com so I assumed there was no need to address it.
I was under the impression that without the computer connected, the car should still RUN...not well, but in open loop mode. Was I misled?
You know what they say about ASSuming anything, right?
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Originally posted by 91-RED-WS6
OK, hopefully someone will clarify some things for me. My IAC plug will not reach the IAC, so it is disconnected. I used some spare wire (good thick wire, though) to extend the connector to the map sensor (was also too short)..is this OK. I re-used the TPI map sensor, should I have used the LT1 sensor (LT1intake.com doesn't specify).
Umm, do yourself a favor and reconnect the IAC. And yes extending wires is fine, just do a good job so you don't create a high resistance connection. Preferably solder it. And it doesn't matter which MAP you use. AFAIK all GM MAPs are the same except the rare 2bar apps.
The coolant temp sensor which would plug into the front of the intake, was placed in the remote thermostat housing - but is not wired since the cable also needs to be lenghtened. I don't think this is causing a problem since when I first got the car the temp sensor connection was broken - all I ever got was running fans and a CE light.
Putting the temp sensor that far from the engine isn't a good idea unless you also put some bypass holes on the t-stat so it always gets flow. Otherwise the ECM isn't going to see consistent or 'real' values and be confused. It's not gonna trigger the 'CTS missing' code, but it could be bad enough to make it take way too long to get into closed loop, and also fluctuate from very hot downto operating temp with cycling of the stat, making the PE fueling inconsistent among other things.
There was also a sensor (temp?) for the bottom of the upper TPI plenum...there is no provision for this on the LT1 intake...no mention of this on LT1intake.com so I assumed there was no need to address it.
Ummm. The sensor on the bottom of the plenum is the IAT or MAT (intake/manifold temp sensor). I'm sure john didn't address it on his site because he probably assumed somebody who wanted to mod fuel injection knew what the MAT was and how you would take care of it. Ever hear of relocating the MAT mod? Just put it in the airbox. And really you should adjust the chip as well, and you should be burning chips anyway if you're going to a different intake.
I was under the impression that without the computer connected, the car should still RUN...not well, but in open loop mode. Was I misled?
Please tell me you are kidding? How would the injectors fire without the computer? This isn't MFI from a 60s vette.
You know what they say about ASSuming anything, right?
ROFLMAO...you said it. Sounds like you just have some basics to learn and check on and you'lll probably be in good shape.
OK, hopefully someone will clarify some things for me. My IAC plug will not reach the IAC, so it is disconnected. I used some spare wire (good thick wire, though) to extend the connector to the map sensor (was also too short)..is this OK. I re-used the TPI map sensor, should I have used the LT1 sensor (LT1intake.com doesn't specify).
Umm, do yourself a favor and reconnect the IAC. And yes extending wires is fine, just do a good job so you don't create a high resistance connection. Preferably solder it. And it doesn't matter which MAP you use. AFAIK all GM MAPs are the same except the rare 2bar apps.
The coolant temp sensor which would plug into the front of the intake, was placed in the remote thermostat housing - but is not wired since the cable also needs to be lenghtened. I don't think this is causing a problem since when I first got the car the temp sensor connection was broken - all I ever got was running fans and a CE light.
Putting the temp sensor that far from the engine isn't a good idea unless you also put some bypass holes on the t-stat so it always gets flow. Otherwise the ECM isn't going to see consistent or 'real' values and be confused. It's not gonna trigger the 'CTS missing' code, but it could be bad enough to make it take way too long to get into closed loop, and also fluctuate from very hot downto operating temp with cycling of the stat, making the PE fueling inconsistent among other things.
There was also a sensor (temp?) for the bottom of the upper TPI plenum...there is no provision for this on the LT1 intake...no mention of this on LT1intake.com so I assumed there was no need to address it.
Ummm. The sensor on the bottom of the plenum is the IAT or MAT (intake/manifold temp sensor). I'm sure john didn't address it on his site because he probably assumed somebody who wanted to mod fuel injection knew what the MAT was and how you would take care of it. Ever hear of relocating the MAT mod? Just put it in the airbox. And really you should adjust the chip as well, and you should be burning chips anyway if you're going to a different intake.
I was under the impression that without the computer connected, the car should still RUN...not well, but in open loop mode. Was I misled?
Please tell me you are kidding? How would the injectors fire without the computer? This isn't MFI from a 60s vette.
You know what they say about ASSuming anything, right?
ROFLMAO...you said it. Sounds like you just have some basics to learn and check on and you'lll probably be in good shape.
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Car: '99 HO Z28 / '03 Trailblazer
Originally posted by Ed Maher
Umm, do yourself a favor and reconnect the IAC. And yes extending wires is fine, just do a good job so you don't create a high resistance connection. Preferably solder it.
Umm, do yourself a favor and reconnect the IAC. And yes extending wires is fine, just do a good job so you don't create a high resistance connection. Preferably solder it.
Putting the temp sensor that far from the engine isn't a good idea unless you also put some bypass holes on the t-stat so it always gets flow. Otherwise the ECM isn't going to see consistent or 'real' values and be confused. It's not gonna trigger the 'CTS missing' code, but it could be bad enough to make it take way too long to get into closed loop, and also fluctuate from very hot downto operating temp with cycling of the stat, making the PE fueling inconsistent among other things.
Ummm. The sensor on the bottom of the plenum is the IAT or MAT (intake/manifold temp sensor). I'm sure john didn't address it on his site because he probably assumed somebody who wanted to mod fuel injection knew what the MAT was and how you would take care of it. Ever hear of relocating the MAT mod? Just put it in the airbox.
I was under the impression that without the computer connected, the car should still RUN...not well, but in open loop mode. Was I misled?
Please tell me you are kidding? How would the injectors fire without the computer? This isn't MFI from a 60s vette.
Please tell me you are kidding? How would the injectors fire without the computer? This isn't MFI from a 60s vette.
ROFLMAO...you said it. Sounds like you just have some basics to learn and check on and you'lll probably be in good shape.
[/QUOTE]
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Car: 1972 LT1 Corvette
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Originally posted by 91-RED-WS6
Nope, never heard of that mod. Guess I jumped to big mods and skipped over some of the smaller mods.
Nope, never heard of that mod. Guess I jumped to big mods and skipped over some of the smaller mods.
Ed's reference to "mod" is module not modification. You should have an unused 1/4" NPT hole on the passenger side of the intake. Screw the MAT module (sensor) in there. If you mean crimping as in the use of barrell connectors, that is sufficient. When you get all the bells and whistles reconnected, it should run OK.
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Car: 1997 Jeep Wrangler
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Originally posted by 91-RED-WS6
The coolant temp sensor which would plug into the front of the intake, was placed in the remote thermostat housing - but is not wired since the cable also needs to be lenghtened. I don't think this is causing a problem since when I first got the car the temp sensor connection was broken - all I ever got was running fans and a CE light.
The coolant temp sensor which would plug into the front of the intake, was placed in the remote thermostat housing - but is not wired since the cable also needs to be lenghtened. I don't think this is causing a problem since when I first got the car the temp sensor connection was broken - all I ever got was running fans and a CE light.
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Car: '99 HO Z28 / '03 Trailblazer
OK, here's the update.
I connected the IAC by extending the wires. I also took the 6 easy to reach plugs out for awhile and allowed the cylinders to evaporate.
I also connected a IAT sensor to the necessary plug...didn't insert it into the intake yet.
I had to jump the car, but it RUNS! It's ALIVE! It misses, but it's ALIVE!
I'll need to find out why it's missing...plus change the oil again and fix a couple minor things...but I'm definitely in a better mood than I was earlier this week. :lala:
Thanks for all the advice guys! I'll post on how things turn out.
I connected the IAC by extending the wires. I also took the 6 easy to reach plugs out for awhile and allowed the cylinders to evaporate.
I also connected a IAT sensor to the necessary plug...didn't insert it into the intake yet.
I had to jump the car, but it RUNS! It's ALIVE! It misses, but it's ALIVE!
I'll need to find out why it's missing...plus change the oil again and fix a couple minor things...but I'm definitely in a better mood than I was earlier this week. :lala:
Thanks for all the advice guys! I'll post on how things turn out.
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
Well, I think I figured out why it's missing. See when I swapped out the coil to the MSD one, I kept the same spark plug wires (el cheapo ones). The way I see it:
Too much voltage + crappy plug wires = a shocking experience when trying to adjust timing!
I changed the oil. I have a new set of plugs. I need to get some new wires...also a few other minor things... hopefully the car will be running strong after that.
Too much voltage + crappy plug wires = a shocking experience when trying to adjust timing!
I changed the oil. I have a new set of plugs. I need to get some new wires...also a few other minor things... hopefully the car will be running strong after that.
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From: San Antonio, TX
Car: '99 HO Z28 / '03 Trailblazer
Originally posted by Ed Maher
old, el cheapo plug wires. Right. And it wasn't even the first thing you checked.
old, el cheapo plug wires. Right. And it wasn't even the first thing you checked. Well because it was running with them before the LT1 intake, I figured they should be good enough for now. Although they are marginal - they aren't/weren't keeping it from running. And they aren't old - less than 6 mos in fact...just cheap autozone 7mm silicone wires. Also, they didn't zap me BEFORE the MSD coil, either. They are A problem, but not the main one that was preventing the car from running.
Thanks to the help I received from everyone, I'm certain it was the fact I had disconnected sensors that kept the car from running. With the MSD coil, the wires are not fine...with the stock coil (probably half-dead) they were ok.
I'll keep everyone posted of my progress.
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From: Manassas VA
Car: 04 GTO
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Transmission: M12 T56
Originally posted by 91-RED-WS6
What's that supposed to mean?????
What's that supposed to mean?????
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