Fuel pressure
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Well I finally got around to changing the fuel pump. Now I get 38 pounds when the key is turned on and when started the pressure drops to about 29. Should it do that?
When running and the hose on the PR is taken off, pressure jumps up 10 pounds. Now what?
When running and the hose on the PR is taken off, pressure jumps up 10 pounds. Now what?
Racer
Joined: Jan 2005
Posts: 312
Likes: 0
From: Las Vegas / Scotland
Originally Posted by Joslinm
Well I finally got around to changing the fuel pump. Now I get 38 pounds when the key is turned on and when started the pressure drops to about 29. Should it do that?
When running and the hose on the PR is taken off, pressure jumps up 10 pounds. Now what?
When running and the hose on the PR is taken off, pressure jumps up 10 pounds. Now what?
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Originally Posted by stevec4
It sounds to me like you fixed it - pressure when running will be lower than just with ignition on as it is supplying fuel to the injectors.
Racer
Joined: Jan 2005
Posts: 312
Likes: 0
From: Las Vegas / Scotland
Can you use WOT to accelerate hard?
If so then the FP should be adequate and I'd start to look elsewhere such as the leaking injector theory. The L98 is a bank fire injection system and as such the leaking injector doesn't manifest itself in the same way as a true multi point sequentional fire system i.e the engine is rather more tolerant of the leaking injector than true MP.
Have you pulled the plugs to check? What state is the ignition system in (recent wires, cap, rotor etc?)
If so then the FP should be adequate and I'd start to look elsewhere such as the leaking injector theory. The L98 is a bank fire injection system and as such the leaking injector doesn't manifest itself in the same way as a true multi point sequentional fire system i.e the engine is rather more tolerant of the leaking injector than true MP.
Have you pulled the plugs to check? What state is the ignition system in (recent wires, cap, rotor etc?)
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Originally Posted by stevec4
Can you use WOT to accelerate hard?
If so then the FP should be adequate and I'd start to look elsewhere such as the leaking injector theory. The L98 is a bank fire injection system and as such the leaking injector doesn't manifest itself in the same way as a true multi point sequentional fire system i.e the engine is rather more tolerant of the leaking injector than true MP.
Have you pulled the plugs to check? What state is the ignition system in (recent wires, cap, rotor etc?)
If so then the FP should be adequate and I'd start to look elsewhere such as the leaking injector theory. The L98 is a bank fire injection system and as such the leaking injector doesn't manifest itself in the same way as a true multi point sequentional fire system i.e the engine is rather more tolerant of the leaking injector than true MP.
Have you pulled the plugs to check? What state is the ignition system in (recent wires, cap, rotor etc?)
Racer
Joined: Jan 2005
Posts: 312
Likes: 0
From: Las Vegas / Scotland
Maybe #1 injector is the culprit - pull the injector plug off and see if it still misses - it'll only run on 7 of course unless it's leaking in which case it may idle ok but then miss on that cylinder when you give it some gas.
Does the engine smoke? If it's a valve guide it should smoke like a bad un on the overrun.
Does the engine smoke? If it's a valve guide it should smoke like a bad un on the overrun.
Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Originally Posted by stevec4
Maybe #1 injector is the culprit - pull the injector plug off and see if it still misses - it'll only run on 7 of course unless it's leaking in which case it may idle ok but then miss on that cylinder when you give it some gas.
Does the engine smoke? If it's a valve guide it should smoke like a bad un on the overrun.
Does the engine smoke? If it's a valve guide it should smoke like a bad un on the overrun.
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Thread Starter
Le Mans Master
Joined: Jul 2004
Posts: 6,228
Likes: 698
From: Clifton Park, NY ............Clearwater, FL ... 85 Original Owner
Ok got the wire off. There was a decrease in engine speed. Didn't sound like a bad miss though. Probably wouldn't be a bad idea to throw some new injectors in anyway. 77K and 20 years old. Sits in an unheated garage all winter to as much as -30 degrees.
Last edited by Cruisinfanatic; May 9, 2005 at 05:56 PM.