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Changed injectors now car won't start

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Old 09-30-2003 | 10:12 AM
  #51  
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From: Fairview Heights Illinois
Car: 89 Irocz
Engine: 350TPI $6E
Transmission: 700R4
Thanks! I won't know for about a week if mine is going to run with these accels or not, but if not then yes I'm interested in the SVO injectors.
Old 09-30-2003 | 12:57 PM
  #52  
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Car: 84 SVO
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I am really begining to wonder if you have P/H injectors and not Sat injectors.. Have you by chance metered the "faulty" injectors?

thanks, Bob
Old 09-30-2003 | 03:23 PM
  #53  
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From: Fairview Heights Illinois
Car: 89 Irocz
Engine: 350TPI $6E
Transmission: 700R4
Originally posted by SATURN5
I am really begining to wonder if you have P/H injectors and not Sat injectors.. Have you by chance metered the "faulty" injectors?
thanks, Bob
Mine all read 14.6 ohms.
Old 10-02-2003 | 10:11 PM
  #54  
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From: Fairview Heights Illinois
Car: 89 Irocz
Engine: 350TPI $6E
Transmission: 700R4
This is new. I just pulled the heads off my engine tonight and there were 3 ground wires going to a bolt on the back of the driverside head. I went to remove this bolt and it wasn't even tight! So now I'm hoping that I just had a weak ground.
Whatever powers the fuel injectors, does it ground on the back of the head?

I'm planning to rewire the grounds and run them all to one spot that is sure to be a very good ground. Does anyone think this will cure the starting problem?

I probably won't have my car running again to test this for maybe another week since I'm waiting to get heads ready to go on, and I'm still porting on the intake a little at a time.
I can't wait to get it back together so I can see if the starting problem is fixed!

Last edited by TPIgirl; 10-02-2003 at 10:23 PM.
Old 10-02-2003 | 10:17 PM
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From: Boosted Land
Car: 92 Z28
Engine: Boosted LSX
A bad ground will deff do some weird things. I'd say its a good change that was the problem.
Old 10-02-2003 | 10:54 PM
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Car: 1987 Z28 Convertible
Engine: 305 TPI
Transmission: 5-speed
Whatever powers the fuel injectors, does it ground on the back of the head?

The ECM commands the fuel injectors. The ECM has a total of four grounds. These grounding wires run through a miriad of splices. Three of the four grounds are spliced together (with other grounding wires). This ground is on the back of the driver's side head. You should see three total wires at this head. The fourth ECM ground (again, through splices), grounds on the passenger side head with other grounding wires. You should also have a braided grounding strap on this grounding bolt.


Does anyone think this will cure the starting problem?

The loose grounding bolt is a potential problem, but based on my experience with the same injectors, I don't think this will solve the problem.

Did you try spraying starting fluid into the plastic intake "Y" before disassembly? I betcha that would have started the engine!

Willie
Old 10-02-2003 | 11:18 PM
  #57  
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From: Fairview Heights Illinois
Car: 89 Irocz
Engine: 350TPI $6E
Transmission: 700R4
No I was disgusted with it and started taking it all apart. I'm positive that starting fluid would've started it and then it would keep running. Like I said it would fire when I had an injector wire pulled and grounded through a test light. With the test light NOT hooked up it would not fire. Even though I was doing the test wrong since the ECM uses ground to fire the injectors, this sort of tells me it could've been a weak grounding problem. Maybe it's possible that the test light provided a better ground than the ECM did & maybe caused the other injectors to fire.
Whatever it was strange. I'd turn the engine over several times with all the injectors hooked up but it wouldn't fire once. Then I pull an injector wire and hook it to the test light and it fires on the first try. Plug the injector wire back on the injector and no fire again.
I hope the problem is gone once I get it back together, but if not I'll be doing more tests I suppose.
Old 10-03-2003 | 12:54 AM
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I've had some similar problems in the past. They were corrected with some creating tuning of cranking fuel tables in the prom. Starting fluid always worked, so I knew I had a fuel problem. As I read through this I've seen various things that I would have guessed could cause your problem, but you've caught them all. Good for you. Some problems help to fix more things than you know about yet.

If the grounds don't fix your problem, but starting fluid allows you to start, and you've got access to prom burning equipment, you can check out the fuel tables with regard to cranking reference pulses from the distributor (I would have suggested ignition module, had you not just changed the injectors) and try adding more fuel earlier on. This is what we did with my car.
Old 10-03-2003 | 01:28 AM
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Car: '90 Trans Am-12.45@110.71
Engine: 355 w/AFR 195's Elem. 400/430 HP/TQ
Transmission: Tremec T-56
Axle/Gears: 12 Bolt 3.73
Sure glad you guys got off that kick about the welding.....as it has nothing to do with our cars it is only for magnetos.(about disconnecting the battery)
Old 10-04-2003 | 02:04 PM
  #60  
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From: Fairview Heights Illinois
Car: 89 Irocz
Engine: 350TPI $6E
Transmission: 700R4
I'm sure it's not the fuel table, the injector flow rate, or the welding because of the times that it fired right up and ran fine. I'm betting on the grounds being the problem. Let's hope that's it!
Old 10-04-2003 | 02:19 PM
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From: Tucson, Arizona USA
Car: 1987 Z28 Convertible
Engine: 305 TPI
Transmission: 5-speed
I'm betting the grounds are not the problem. If they were, the engine would not have run fine, once it started. That's the reason why I suggested using the starting fluid. Doing this would have eliminated ALL other possibilities. I did this and concluded the injectors were at fault. They were the culprit and because you're trying the exact same injectors I had and have experienced the exact same symptom, I have to conclude that they are the problem in your case.

A related question: Did you change the injector constant in the EPROM to accomodate the larger injectors? With your 350, going from 22#ers to 26#ers is a significant difference and if you have not changed the constant, you'll run extremely rich.

Willie
Old 10-07-2003 | 03:30 PM
  #62  
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From: Fairview Heights Illinois
Car: 89 Irocz
Engine: 350TPI $6E
Transmission: 700R4
Originally posted by Willie
I'm betting the grounds are not the problem. If they were, the engine would not have run fine, once it started. That's the reason why I suggested using the starting fluid. Doing this would have eliminated ALL other possibilities. I did this and concluded the injectors were at fault. They were the culprit and because you're trying the exact same injectors I had and have experienced the exact same symptom, I have to conclude that they are the problem in your case.

A related question: Did you change the injector constant in the EPROM to accomodate the larger injectors? With your 350, going from 22#ers to 26#ers is a significant difference and if you have not changed the constant, you'll run extremely rich.

Willie
What do you think could be wrong with the injectors?

I just kind a figured the power wasn't getting to them for some reason.
I just ordered a WB O2 so I can see if it's too rich but it didn't seem like it was getting too much fuel at the times that it did start and run. My spark plugs all looked fine and when I pulled the heads off the exhaust valves were all white.
Old 10-07-2003 | 03:32 PM
  #63  
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From: Oklahoma City, OK
Car: 92 Z28
Engine: 357 TPI (L98)
Transmission: 700R4
You ought to talk to Rich at Cruzin Performance. He's the resident injector expert as far as I know, so he may know something.
Old 10-07-2003 | 08:06 PM
  #64  
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From: Tucson, Arizona USA
Car: 1987 Z28 Convertible
Engine: 305 TPI
Transmission: 5-speed
What do you think could be wrong with the injectors?

I really never figured it out, hence the sale of mine. I'm speculating, but for some reason, the 26#ers may need more current during startup. They spit, but maybe not enough, causing a lean condition only while cranking. So lean that the engine won't fire. The starting fluid richens the mixture sufficiently that it starts. Then the injectors flow sufficiently to sustain the engine.


I just ordered a WB O2 so I can see if it's too rich but it didn't seem like it was getting too much fuel at the times that it did start and run.

Two points:
1) If it was too rich, starting fluid would only compound the richness (I believe), and
2) a WB won't tell you anything during cranking because the engine isn't running on its own.


My spark plugs all looked fine and when I pulled the heads off the exhaust valves were all white.

This means the engine was running fine, when it's running.


You ought to talk to Rich at Cruzin Performance. He's the resident injector expert as far as I know, so he may know something.

Rich doesn't know either. When I pulled my 26#ers, I sent them to Rich. All testing came back normal. That's when I decided NOT to use them and sold them.

Willie
Old 10-08-2003 | 08:55 AM
  #65  
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i'll bet you'll find at the same fuel pressure and ECM pulse width as stock injectors the aftermarkets have a different electrical design
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