1991 Pontiac Sunbird 2.0L TBI (injector?)

Tiny
AH_CID
  • MEMBER
  • 1991 PONTIAC SUNBIRD
Well here is the problem. Pump does not prime the system or come on at all when I turn the key on and while cranking the engine. Heres what I have tried. New distributer cap module rotor plug plug wires new engine computer. I know it is not the pump as I pulled a fuel line off the TBI and used the test lead to run the pump. There is fuel comming out of the line. I checked the relays as well tested the coils and the relays seem to work just fine (it clicks then there is continuity) there is a green wire that comes fro m the enginge computer under the dash to the relay and it does not seem to get any power. Also from this relay I can make the pump run. So here is what I think I narrowed it down to. The pump is fine. The relays are fine. The computer is fine. But what ever is telling the computer to prime the fuel system and run the pump is not.
Saturday, May 6th, 2006 AT 3:36 PM

6 Replies

Tiny
LOSONE
  • MECHANIC
  • 1,616 POSTS
Not a good way to check fuel pressure as you need 40 pounds. If the fuel shot over the fender than you have good pressure if not--then you need to find out why there is no/low pressure.
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Saturday, May 6th, 2006 AT 3:38 PM
Tiny
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Thnx man I will try that now. But even if I have low pressure shouldent the pump come on as soon as I turn on the key and run for 10-20 seconds?
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Saturday, May 6th, 2006 AT 3:43 PM
Tiny
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Ok tried that and I have lots of fuel pressure. As my shirt will testify
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Saturday, May 6th, 2006 AT 3:53 PM
Tiny
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Anyone else have any suggestions?
If I dont fix it today its going to the crusher
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Sunday, May 7th, 2006 AT 3:35 AM
Tiny
LOSONE
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Here we send old cars to become an oyster reef!

I did read in your original post if you check to see if the engine was in cam timng. I suggest you pull #1 plug and rotate the engine and see if you have compression (hold your finfger over the plug hole and se if it pops on TDC).

If you do then check for base engine timing by putting #1 cyl on TDC, check your distributer to see if the rotor points to #1 and that the timing mark is also on TDC.

You know many time when an engine is giving the start problems yours has, the cyls become dry and compression is lost to the point it won't start. Put a liitle engine oil in each cyl with plugs out, turn it over a few times, put in a little more (tablespoon) and try and start the engine. It is an old mechanics trick that goes way back before you were born--Good Luck
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Sunday, May 7th, 2006 AT 8:04 AM
Tiny
AH_CID
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The engine has no reason to be out of timing. If I por a little fuel down into the intake it fires no problem ansd will run. I think the problem is that the engine computer is not reciving the signal it needs to tell it to 1. Start the pump when ignition is turned on and 2. Inject the fuel into the system.
This car HAS spark and compression but is not getting fuel for some damn reason and I cannot get the injectors to inject.
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Sunday, May 7th, 2006 AT 11:53 AM

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